Machsupport Forum

General CNC Chat => Show"N"Tell ( Your Machines) => Topic started by: Tweakie.CNC on August 26, 2009, 02:48:48 AM

Title: The Laser Project.
Post by: Tweakie.CNC on August 26, 2009, 02:48:48 AM
Now the shadows are starting to lengthen I am preparing for my next winter project - To add a CO2 laser head to my existing router. The output power of CO2 tubes is related to overall length and the size of my machine dictates that a 600mm length tube (which is rated at 30 Watts) is the largest that I can easily accommodate.
These tubes can be something of a ‘white elephant’ insofar as that I suspect more people buy them than ever get around to completing the project. When you start to investigate the additional parts that are necessary and the cost of those parts, I am not surprised.
However I have started so I will continue.
Initially I have had to add a mounting space to the machine and some more box section with a bit of welding has produced two brackets which have been bolted to the rear of the machine frame giving a position to fit the laser stage. I have also milled a pair of tube mountings and made bungee straps to secure the tube in place.

More to follow…….

I would appreciate your comments and advice on this project as the more info I can get the better.

Tweakie.
Title: Re: The Laser Project.
Post by: Jammerm on August 30, 2009, 09:15:22 PM
What are you going to cut? Titanium? :)

OK, I have forgotten what the power levels mean but, as a young teen, I was able to hang out at an Air Force Laser lab where my brother was stationed. They were playing with a CO2 laser, I think the tube was about 6' long. They were shooting pinholes through a cockroach and halfway through a piece of particle board using microsecond bursts. They also had an Argon laser and a Ruby laser, along with several He-Ne lasers. This was the late 60's.

I keep looking at your laser projects and may go that way once my CNC is complete. It has had to wait till winter, too much work and summertime stuff to be working in the basement.

Keep up the good work and keep us posted. 8)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 31, 2009, 02:52:06 PM
Think it should just about be able to cut a bit of acrylic - will be a pretty expensive mistake if it doesn't.  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2009, 01:57:09 AM
Mountings for the HeNe alignment laser made the same way as the main tube mountings.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2009, 03:19:16 AM
The psu has arrived from China. This unit consists basically of a TV line output transformer capable of producing some 18,000 Volts which is on/off switchable, with a short rise time, from a TTL signal and current adjustable from a 0 - 5 Volt analogue input.
I will need to construct a new enclosure for this unit so that it can be fitted safely to the framework of my machine and this is the progress so far.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on September 01, 2009, 07:51:29 PM
You'll be burnin' retinas before ya know it, super kitty!
Title: Re: The Laser Project.
Post by: budman68 on September 01, 2009, 08:16:54 PM
Heck, I just love the box you made for it!

Dave
Title: Re: The Laser Project.
Post by: Sam on September 02, 2009, 01:15:59 AM
He's certainly a better TIG welder than I will ever be.
Title: Re: The Laser Project.
Post by: Dan13 on September 02, 2009, 01:36:04 AM
It's going to be an interesting project, Tweakie.

Is the box made of aluminum? It looks very well made - did you use some kind of bending machine or fixture? How did you cut it?

BTW, thought a 30W laser would be enough to cut through a thin aluminum foil...?

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 02, 2009, 08:33:42 AM
Thanks Guys,

Afraid I can't take all the credit for the box. I cut the ally on a guillotine and used a band saw for the cutouts, cleaned the edges to the scribe marks with a sander, then bent it in a V block on a fly press (thanks to a local machine shop). The TIG work was done by a professional (I am OK on SS but you would not want to see any of my ally TIG work  :'( ).

Let you know about the thin foil Dan when the project is finished.

Right on Sam but did you know that CO2 lasers are, apparently, better at burning corneas than they are at retinas because eyeballs are quite opaque at the far infrared (not that it makes that much difference though).  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on September 02, 2009, 03:21:12 PM
Quote
did you know that CO2 lasers are, apparently, better at burning corneas than they are at retinas

I don't believe you. Now, I know your going to stick to your beliefs, and I'm set in stone on mine. So I guess were just going to have to settle it once and for all......We need an idiot brave volunteer.  >:D  >:D
Title: Re: The Laser Project.
Post by: Chaoticone on September 02, 2009, 04:32:05 PM
SAM SAM SAM.............................. your a mess.  :D

Tweakie, very interesting project your doing. But then again coming from you I expect no less. Looking great so far.

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 03, 2009, 03:39:38 AM
Already tested the theory Sam and Super Kitty can prove it.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 03, 2009, 10:34:12 AM
The new PSU enclosure is now, more or less, complete - just the protective earth terminal and ground strap for the lid and a small EM screen and thats it.
Title: Re: The Laser Project.
Post by: Sam on September 03, 2009, 05:12:14 PM
HAHAHA!!! Good one Tweak. I guess super kitty ain't to super, hugh.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 04, 2009, 11:23:39 AM
Warning label (engraved into traffolite) for the front of the PSU. First time I have tried this, it was 'raster' engraved rather than 'vector' and it took forever.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 09, 2009, 09:32:00 AM
The High Voltage PSU is now complete and it's time to start working out the best beam path from the tube to the Z axis.
I have made a frame of the same OD as the CO2 tube to hold a little HeNe which sits in the CO2 tube mounts and is ideal for this job. The mirrors I am using are OK for the 633nm and getting the beam path sorted but will need to be replaced with a type that works at 10600nm.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 10, 2009, 10:05:32 AM
A bit more progress on establishing the beam path. It has to get from the laser tube to be running parallel and plane with the X axis where it is again deflected (by a mirror on the X axis) to be parallel and plane with the Z axis. The focus lens will be mounted directly on the Z axis whereby the focal point can be adjusted for different thicknesses of work.
This is the wooden mock-up including adjustable mirror mounts made from MDF (yuk !). The little HeNe beam is quite square to the table in both planes which I think has resulted from a lot of luck.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on September 10, 2009, 10:09:54 AM
Quote
The little HeNe beam is quite square to the table in both planes which I think has resulted from a lot of luck.

Somehow I think with you working on this project, it's a bit more than luck...  ;)

Just fantastic, my friend  :)
Dave


EDIT: I think this should be your new avatar  ;D 

(http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=17257;image)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 10, 2009, 10:20:18 AM
 ;D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 12, 2009, 08:15:38 AM
The 'mock-up' mirror mountings.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 12, 2009, 08:24:40 AM
The final (Z axis) mock-up mirror mounting and tool made for inserting the springs.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 16, 2009, 08:26:18 AM
The Newport mirror mountings arrived from the USA today and beautifully made they are.
Well that's my very small contribution to the US economy until I have saved up some more penny's.

Tweakie
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 17, 2009, 12:56:54 PM
After a bit of machining the Z axis 'mock-up' mirror mounting has now been replaced by, what I hope will be the finished part.
Undecided if I should follow Sam's example and anodize the part and dye it black or leave it as it is.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on September 17, 2009, 01:22:50 PM
Ano it....It's an unwritten rule. Looking forward to seeing this thing work.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 27, 2009, 12:26:25 PM
Now that the geometry and dimensions have been established from the MDF 'mock-up' the beam steering fixture can now been constructed from aluminium box section. Not much to look at because the mirrors and Newport mountings are internal to the section.
Still a long way to go but I am getting there, slowly.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 05, 2009, 08:32:39 AM
A bit more progress - I have started on the focus lens mounting which will be fitted on the moving part of the Z Axis. The lens I will be using is 12mm diameter and made from Zinc Selenide with a focal distance of 40mm. I have still to make and fit the lens retainer sleeve, air inlet barb and output nozzle components etc.

Tweakie.
Title: Re: The Laser Project.
Post by: BarryB on October 05, 2009, 12:00:03 PM
very nice Tweakie.  I'd like to follow in your footsteps with this project;)

Barry
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 05, 2009, 12:46:46 PM
H Barry,

Thanks for the kind words. I can't say that I would recommend doing this yet, as a project it will certainly keep me busy for a few months and I am enjoying every minute but it is a lot more involved than it at first seems. I could write a book on what I have learned so far and I have only really scratched the surface. If the end results are successful then it will all have been worthwhile but at my rate of progress it will be some time before I know for sure.

Tweakie.
Title: Re: The Laser Project.
Post by: BarryB on October 05, 2009, 12:50:38 PM
Heh, no problems here.  I'm barely treading water just finishing my machine;)

Barry
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 05, 2009, 01:13:08 PM
 ;D

Tweakie.
Title: Re: The Laser Project.
Post by: XLR84x4 on October 06, 2009, 06:52:19 AM
Hey Tweakie,

Where are the updates, I'm hanging to see what you can cut up with your laser.

Jason
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 06, 2009, 08:31:26 AM
Have patience my friend.
I have a long way to go before the switch-on. ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 08, 2009, 11:29:31 AM
After a rainy day I have made a little more progress.
The EHT unit has been fitted to the frame and the enclosure for the CO2 tube has been constructed. The focus lens assembly has also been completed.
And a picture of my little helper.

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on October 08, 2009, 11:49:58 AM
Good looking work Tweak.....and good help is so hard to find. You are fortunate.
Russ
Title: Re: The Laser Project.
Post by: Dan13 on October 08, 2009, 01:01:34 PM
Thought you were adding a laser to your router, but it starts looking more like you're converting your router completely to a laser machine ;)

Looks like one got to have a lot of knowledge to do what you're doing. Where do you get all the info you need from? You make it seem like you're following a step by step cookbook ;)

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2009, 03:18:20 AM
Hi Dan,

No, the router will still be fully functional by removing the focus lens and fitting the spindle.  ;D I will, however, have to provide caps for the laser output aperture and Z axis mirror (although this component can easily be removed by releasing two bolts) to protect the optics from dust etc. but routing will not be affected by all the other parts. The additional weight of the complete machine is another matter.  :-\

I have researched the project before starting and I did gain a lot of practical experience from using the low power diode laser but my progress is all 'hand to mouth' and I am purchasing the parts as and when required. Wish I did have a cookbook to follow but the internet is a wonderful thing for gaining information once you have separated the facts from the speculation.

My next job is to establish if the CO2 tube I have has its anode/cathode electrodes in electrical contact with the water cooling as this will decide if I use a closed loop heat exchanger (non metallic) of if I can use a forced air radiator and in addition is ethylene glycol electrically conductive at 18,000 Volts ?.

Still a long way to go.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2009, 12:43:13 PM
The water circulating pump has just arrived from China.

This is actually a chemical pump with ceramic shaft and seals with no metallic parts in contact with the fluid flow. It has a continuously rated, 12 volt brush less motor with a life expectancy in excess of 40,000 hours (which should see me out if it is as good as it is claimed).  ;D

Tweakie.

Update:-

Now that I have had a chance to inspect and test the pump it does contain two stainless steel parts: a wear plate behind the impeller and a spire clip to retain the impeller, both parts are non-magnetic.
Title: Re: The Laser Project.
Post by: Sam on October 09, 2009, 06:02:29 PM
Got a link to the pump? Might be a good one for my acid containers.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 10, 2009, 03:49:24 AM
Sure have Sam.

http://shop.ebay.co.uk/sopis_c/m.html?_nkw=&_armrs=1&_from=&_ipg=

If you need it I have the address of the supplier which I can pm.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 10, 2009, 04:59:10 AM
These are my first thoughts on the control circuit for the laser tube.
May be changed a bit after I have thought it through but looks good for now.

Tweakie.



Update; Diagram updated.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 12, 2009, 03:02:06 AM
Pretty basic stuff but this is the proposed cooling circuit.

Tweakie.


Update; Diagram updated.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 14, 2009, 02:33:01 AM
Another piece in the grand jigsaw puzzle has arrived from the USA. This is the Gems Sensors flowswitch - it has 1/4 NPT threads and I have made hose connections from stainless and phonelic which can be attached with pipe fittings.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 17, 2009, 09:14:28 AM
Started getting the parts fitted to the machine. Radiator, circulating pump and flowswitch are in place. Still waiting for the header tank and fan guards but this will not hold up the wiring etc.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 19, 2009, 11:14:19 AM
Now that the beam steering fixture, mirror positions and adjustments have all been carried out using the HeNe laser it is now time to fit the CO2 tube onto it's mountings and connect the wiring and pipework. I have also fitted a small, digital milliamp meter (to the front of the laser enclosure) which will display laser current during use.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 21, 2009, 10:20:01 AM
Just engraved some of the obligatory labels that have to be fitted to the laser housing.

Tweakie.
Title: Re: The Laser Project.
Post by: SteinarN on October 21, 2009, 01:30:06 PM
Looking very good  :)

It's a hefty cooling system you have installed.
Title: Re: The Laser Project.
Post by: Chaoticone on October 21, 2009, 10:15:44 PM
Yup, that Tweakie is first class all the way.

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 22, 2009, 02:35:41 AM
Thanks Guys.

I keep wondering if the cooling system will be man enough for the job.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: SteinarN on October 22, 2009, 02:38:19 AM
Thanks Guys.

I keep wondering if the cooling system will be man enough for the job.  ;D

Tweakie.

Well, maybe one more fan to be sure it can handle the load ;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 22, 2009, 10:24:17 AM
 ;D  ;D  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: BarryB on October 23, 2009, 12:32:36 PM
nice, love the signs.  For some reason I was expecting some jokes about the danger on them, not real danger;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 24, 2009, 02:43:22 AM
I see my reputation precedes me Barry.  ;D

Tweakie.

Title: Re: The Laser Project.
Post by: BarryB on October 24, 2009, 12:11:13 PM
Now that's more like it!
Title: Re: The Laser Project.
Post by: Chaoticone on October 24, 2009, 12:42:57 PM
 ;D

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 02, 2009, 10:16:05 AM
A friend of mine has just had some stainless fabrication work done by a company that cuts the material with lasers. He mentioned that I was constructing my own laser cutting head so they cut me this bicycle from stainless and said that if I could make one like this then I have truly constructed a machine to be proud of. (It is 1mm thick and 5mm long).

Don’t think I will ever be able to do it but it is one hell of a challenge.

I wonder - can anyone else cut one like this on a home built machine?.

Tweakie.


Sorry for the bad photo but it is the best I can do without a close-up lens.
Title: Re: The Laser Project.
Post by: BarryB on November 02, 2009, 10:18:40 AM
yours will be the first tweakie!
Title: Re: The Laser Project.
Post by: Sam on November 02, 2009, 03:56:58 PM
Cut out some training wheels, attach them, and then send it back to them.
Title: Re: The Laser Project.
Post by: Garyv on November 02, 2009, 05:41:51 PM
Hey all just found this thread , just a stupid question ,. But what materials and thicknesses are you going to be able to cut with this laser?
Gary
Title: Re: The Laser Project.
Post by: Chaoticone on November 02, 2009, 05:51:26 PM
Good one Sam............ I say yes and a handel bar bell that rings.  ;D

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 03, 2009, 02:25:51 AM
Brilliant idea Sam. I just wish I was clever enough to do it.  :'(
I think the best I could achieve would be a blob which may look something like a bell Brett and as nobody has fingers small enough to ring it who knows if it works ?.

Certainly won't be able to cut stainless Gary but it should be OK for thin acrylic etc.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 04, 2009, 04:04:04 AM
I have now constructed the header/expansion tank (which has been fitted to the rear of the laser tube enclosure) and an inline filter (fitted at the circulating pump inlet). The cooling system has been filled with antifreeze and is being tested for leaks (none so far, but don't hold your breath  :)).
I was pleasantly surprised to find that the system cleared itself of the trapped air after the circulating pump had been running for approx. 15 minutes.

Now to make a start on the control electronics.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on November 04, 2009, 05:59:51 PM
Looks real good so far Tweakie.

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 09, 2009, 06:28:02 AM
Thanks Brett, so far so good.

Well made a start on the control electronics and cut the circuit board this morning. I am hooked on this 'isolation routing' method for making simple, one off, circuit boards - it is so simple and with no mess. Now to fit the components and bench test it.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 14, 2009, 07:33:28 AM
A couple more parts made for the grand jigsaw puzzle.

LED display panel, again isolation routed and the legend panel engraved in traffolite.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on November 14, 2009, 10:35:39 AM
That machine just keeps looking better all the time, Tweakie. I wouldn't want to use it for woodworking in fear of getting it dirty. You might just hafta build a dedicated router now.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 14, 2009, 11:31:04 AM
Thanks Sam.  ;D ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: BarryB on November 14, 2009, 01:53:46 PM
It seems like you are able to spend a LOT of time on this project making it look equal parts awesome across the board.  One of these days, that secret must be passed on how you can do that;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 16, 2009, 06:01:58 AM
I think it's an optical illusion Barry - you don't get to see the stuff that goes in the bin.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on November 16, 2009, 03:36:47 PM
 ;D Ain't that the darn truth. My scrap yard is much more populated than my 'show and tell' yard by far. Nice to know I'm not alone.
Title: Re: The Laser Project.
Post by: Chaoticone on November 16, 2009, 05:47:17 PM
No Sam, we are not alone.....................  :)

Looking very good Tweakie.............. top shelf.

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 19, 2009, 05:07:08 AM
The completed circuit board, well more of a terminal board really as just about everything connects here. The board contains 3 voltage regulators (12V, 9V & 5V) and the logic IC's to drive the indicator LED's.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 20, 2010, 01:01:06 PM
Well now the weather has warmed up enough I am back on the Laser Project, at last.
Connected up the final lot of wiring to the control panel, which looks a bit like a rat's nest but it will all be hidden from view by the cover, once I get it sprayed.

    (http://www.cooperman.talktalk.net/files/27_files/image581.jpg)

Checked all my work for silly mistakes and fired it up - Hey it works !!.

This is the first test piece, Wile.E.Coyote - thanks to Sam for the GCode.

   http://www.cooperman.talktalk.net/laser1a.wmv

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on April 20, 2010, 01:21:57 PM
That's one very tidy rat you've got there Tweakie.
Fine job .... VERY fine.
Thanks !
Title: Re: The Laser Project.
Post by: Sam on April 20, 2010, 03:23:59 PM
That's just awesome Tweakie. I think that's the fastest I've ever seen Wile be completed. You'll be cutting all sorts of things now, and hopefully sharing more vids, too! Thanks a ton for sharing.
Title: Re: The Laser Project.
Post by: Dan13 on April 20, 2010, 03:28:54 PM
Very nice job, Tweakie! Finally got to see it working :)

Now need to see how it cuts some hard stuff ;) which I assume it was primarily made for.

Daniel
Title: Re: The Laser Project.
Post by: budman68 on April 20, 2010, 07:18:58 PM
Amazing stuff right there, my friend, look forward to seeing how else you'll be using this piece of art....er um.... I mean machine  ;)


Thanks,
Dave
Title: Re: The Laser Project.
Post by: Jammerm on April 20, 2010, 09:39:52 PM
Very nice Tweakie, 8) Good tunes too.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 21, 2010, 02:30:52 AM
Thanks Guys, you are all too kind.

I really can't believe that it has been 7 Months since I started this project, still I have learned a lot in the process and goodness knows just how much extra weight has been added to my machine (I just keep bolting more stuff on) but it is very satisfying to know that I am well on the way to getting it all completed. I will post some more pics of the laser head as I get it all tided up.

                (http://www.cooperman.talktalk.net/files/27_files/image579.jpg)

Not everything went according to plan as I badly underestimated the size of the heatsink that was required for the 12 Volt regulator. The replacement here is a bit overkill but there was space on the machine to fit it !.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 21, 2010, 01:02:57 PM
Fitted a 10 turn potentiometer with graduated locking dial for the current control. Also the safety lockout key switch.

   (http://www.cooperman.talktalk.net/files/27_files/image587.jpg)

Finished and fitted the cover for the Rats Nest.

   (http://www.cooperman.talktalk.net/files/27_files/image577.jpg)

This is the display panel. The DRO indicates laser current when the laser is triggered and the LED's indicate the various parameters.

   (http://www.cooperman.talktalk.net/files/27_files/image589.jpg)

This is the front of the machine with all the extra stuff fitted.

   (http://www.cooperman.talktalk.net/files/27_files/image593.jpg)

Finally this is another test run with aluminum faced engraving laminate. The laser cuts through the ally skin with surprising ease.


Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 28, 2010, 06:52:41 AM
By way of an update on this project:-

The DRO struggled to display the tube current a low power settings and has been replaced by a retro moving coil panel meter straight out of the 1960's. A new scale was engraved with the laser and a suitable shunt fitted to calibrate the meter.

    (http://www.cooperman.talktalk.net/files/27_files/image607.jpg)

This is my first attempt with cutting acrylic. The red is 2mm and the clear is 6mm thick.

    (http://www.cooperman.talktalk.net/files/27_files/image612.jpg)

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 28, 2010, 07:03:41 AM
Very nice Tweakie!

6mm acrylic, now that's something! Could you take a better photo to show the cut edge? Just curious what kind of finish does it leave. Does it cut 90 degrees, or does it have a draft angle like with plasma?

Interesting photo, BTW, looks like a photo of a moving object with that blurred background.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 28, 2010, 08:10:17 AM
Hi Dan,

Yes it does have a draft angle because the beam converges from the lens to the exact focal point whereupon it diverges again. I am currently looking at ways to improve this situation either by using a lens with a greater useful focal length or multi-pass cutting at reduced power with Z movement resetting the focal distance on each pass.

The edge finish is not perfect with some vertical styrations similar to a bandsaw cut but at least it is polished and so looks acceptable - I need more practice and experience here !.

The picture was taken with flash and the acrylic is on a sheet of brushed alluminium - Quite a nice effect I thought !.

I will post some more pictures when the camera battery has been recharged.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 28, 2010, 08:33:56 AM
Hi Tweakie,

A friend recently bought a plasma table which was claimed to cut 30mm steel with no draft angle at all. Don't know how it's achieved there and haven't seen the machine yet.

You might be better using a lens with a longer focal length and further away from the workpiece, so that the beam travels more distance to the workpiece surface. May be that's what you meant...(?) But then you already have your design constraints. Also, can you play with the point where the beam is focused? Do you focus it on the surface of the material? Can you focus it in the middle of the material thickness?

The picture does have a nice effect indeed :)

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 28, 2010, 10:27:10 AM
Hi Dan,

Thanks for the suggestions / ideas - anything and everything is appreciated. I have just so much learning to do here.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on April 28, 2010, 04:37:25 PM
Wow wow wow! Nice looking stuff, my friend!

Love the old meter, nice touch  8)

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 30, 2010, 12:58:32 PM
I had boiled eggs for breakfast this morning and while I was dunkin my soldiers I thought " I wonder if..... ".
The answer is yes you can.  ;D ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on April 30, 2010, 01:04:56 PM
Cool Tweak.
How fitting.....is that a roadrunner egg ?
NEAT !
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 30, 2010, 01:14:15 PM
I think I ate the roadrunner bit, that just left Wile.  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on April 30, 2010, 02:12:18 PM
Hehe...that's funny. Your brain sure works in mysterious ways. I wonder if you burned around the circumference, would it crack perfectly. There's a million dollar invention for ya....perfect crackin' eggs.
Title: Re: The Laser Project.
Post by: Jammerm on April 30, 2010, 04:54:09 PM
Pretty cool, personalized eggs. :)

I saw a video of someone Laser etching a photo onto a piece of polished Granite. Do you think yours would do that?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 07, 2010, 05:12:46 AM
Hi Jammerm,

I think that Photo Etching is basically a 'raster process' and the purpose built raster laser machines have lightweight X and Y axis to allow high speeds and accelerations thus allowing the laser beam to possibly travel many miles and complete the job within a reasonable period of time.

Because my machine is basically a wood router and the mass of both the X & Y axis is quite high I think I will just have to content myself with vector use at present.  :'(

Having tried a few different materials now I can confirm that Granite, Glass and Slate all engrave well (although I am expecting the glass to shatter anytime soon as I must have put incredible internal stresses into the material).

Tweakie.
Title: Re: The Laser Project.
Post by: Jammerm on May 07, 2010, 05:31:53 PM
Maybe mount the Glass or ceramics on a hotbed to try to evenly heat the material.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 08, 2010, 03:39:46 AM
Good suggestion about the glass - thank you.

Tweakie.
Title: Re: The Laser Project.
Post by: Kipper on May 09, 2010, 05:53:16 PM
What a cracking read! :cheers:
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 12, 2010, 11:17:51 AM
Interesting but not quite what I had intended. This Calcium Carbonate is tough stuff and I was intending to go right through but despite two passes, no luck. Increasing the power setting was a total failure resulting in a burned mess.

Back to the drawing board with this one – I am sure it is feasible anyone have any ideas ?.

Thanks to Switcher for the DXF http://mydxf.blogspot.com/

Tweakie.

Title: Re: The Laser Project.
Post by: routercnc on May 12, 2010, 04:11:52 PM
Hi Tweakie

Really loving this post, great pioneering stuff.

Don't know anything about lasers, but the melting point of calcium carbonate is about 825 deg C.  How hot do you think the laser is at the focal point?

The other thing to think about is the chemistry angle.  I think vinegar will dissolve calcuim carbonate, so perhaps once you have engraved as much as you can, then soaking in this for a limited amount of time might dissolve the etched area and go right through before the main shell dissolved.  Hot vinegar would be quicker.

Or you could coat the whole shell with varnish, then etch away the image, then soak in hot vinegar.  This would be a bit like printed circuit board manufacture (sort of).

Good luck with it all  ;D

Thanks
Barry
Title: Re: The Laser Project.
Post by: Sam on May 12, 2010, 05:45:26 PM
I have no educated idea really, but I'll throw an uneducated one out there... Ink the first pass in with black, as white reflects a good deal of the laser light on the second pass. I think Barry had a good idea with etching. Never tried to eat away an eggshell with vinegar, but it does make sense, as that's how coloring eggs for Easter works, I'm assuming.
I think they'll slice your brain up for examination upon your demise, Tweakie. It sure works in mysterious ways.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 13, 2010, 01:29:32 AM
Thanks Guys, you have given me new ideas to try.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 14, 2010, 08:05:19 AM
Nobody would want my brain Sam. If they were to discover any joined-up thinking it would only confuse them.  ;D

Hey look -  Revolutionary Egg.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on May 14, 2010, 09:04:16 AM
Wow! That's nice! Looks like the image is projected onto the egg :)

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 17, 2010, 12:11:47 PM
Although my machine is not really fast enough for raster engraving I just had to give it a try.
This image of Jacko is engraved into glass, it is only monochrome so there is no PWM control of the laser at this stage – it is either on or off and controlled by the M11 and M10 commands.
However, when making the laser control circuit I incorporated a spare TTL gate in the trigger path which will allow me to logical AND two control signals – one being the existing on/off trigger (M11 & M10) and the other being a PWM signal derived from the spindle setup (S0 to S100). The PWM will vary the duty cycle of the applied laser pulses from approx 1% to 99% and provided I get the pulse repetition frequency correct should allow for true raster engraving with variable depth. Mach is not quite ready for this type of operation yet but I am sure that if enough people want it the necessary modifications will be made and Mach will become a full blown laser control software.

Tweakie.

Title: Re: The Laser Project.
Post by: budman68 on May 17, 2010, 01:05:34 PM
Wow, you're really moving right along, nice work -

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 24, 2010, 04:52:49 AM
I decided to make my 'home built' 4th Axis portable between machines so constructed a 'stand alone' controller which connects to the LPT3 port. Drilling a few more holes into the table of my router has enabled it to be fitted quite easily (fitting holes have also been drilled for the mating tail-stock but this is not required for eggs  :D ).
I made another Jacko egg and thought you might like to see the setup.

Tweakie.
Title: Re: The Laser Project.
Post by: SteinarN on May 24, 2010, 08:13:51 AM
Wow how you are playing  :D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 24, 2010, 08:20:48 AM
Right on !.  ;D

I do really hope that I never grow up, I just wana stay a kid - I love CNC there is just so much to learn and it is never ending.

Tweakie.
Title: Re: The Laser Project.
Post by: Jammerm on May 24, 2010, 09:05:58 PM
That is amazing, Tweakie. You continue to be a great inspiration. 8)
My wife really likes your Jacko things.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 27, 2010, 12:32:32 PM
Thanks Jammerm - the memory of Jacko sure lives on.

Hey Dan,
I forgot to post the close up picture of the striations in the acrylic. I think that there are techniques which produce better results than I have achieved here but then I will just have to keep practicing.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on May 27, 2010, 12:43:35 PM
Hi Tweakie,

Thanks for the photo. The striations are noticeable, but not as bad as I had thought. I am sure better results will come with experience.

Have you tried the laser at some metal foil yet?

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 27, 2010, 12:57:53 PM
Hi Dan,

I don't think CO2 lasers are too good with metal unless it is somehow surface treated (It's something to do with the wavelength of the beam that makes metals into damn good mirrors) anyway it would take a lot more power than I have available (probably kilowatts) especially for copper foil.
I think that YAG lasers are preferred for the metal stuff.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on May 27, 2010, 01:19:22 PM
Wow! Kilowatts huh... Thought it would be easier to cut thin foils. But no question about the reflecting qualities of metals at these wave lengths.

Have fun playing with this little toy ;) it's nice to follow this thread and see what else you come up with.

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 08, 2010, 06:41:33 AM
I seem to have got the hang of edge finish with acrylic - by reducing the power setting and reducing the feedrate the heat generated within the material is reduced and the finish much improved.

Something else that may be of interest is 3D decoupage - the multiple images are usually die cut but in this case are laser cut. The sooty edges are a problem which I think can be overcome once I discover how.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on June 08, 2010, 06:45:30 AM
This looks perfect, Tweakie! Glad you found the way... never doubted you would ;)

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 08, 2010, 07:01:40 AM
Thanks Dan I wish I had your confidence.  ;D

I am having real problems getting Mach to run fast enough to enable the PRF changes I need to adjust the output power by duty cycle (rather than the usual pulse width modulation) without slowing everything down too much. Bench testing with a Smooth Stepper and the Tempest TP is the next step to see if I can get an improvement.

I am starting to realize that this project will never be completely finished.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on June 08, 2010, 05:16:54 PM
Nice!  :)

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 12, 2010, 11:55:55 AM
Although mentioned before the mass of my X Axis is such that my machine is not really suitable for raster use with the laser. However, having just tried the 'Impact/Laser engraving' plugin http://www.machsupport.com/plugins.php I was surprised to find that it includes feed / power compensation (the slower you go the less the power and visa versa) . My results are not that stunning but with a bit of practice with 'setting up' I am sure that reasonable results can be achieved.
Initial setting up was done using paper and this is my first attempt with an off-cut piece of teak.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on June 12, 2010, 06:08:22 PM
That's pretty cool.
Title: Re: The Laser Project.
Post by: Jammerm on June 12, 2010, 07:04:13 PM
That's looks pretty good.

Why is he so mad. :)

Never mind, it's a cat. ;D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 19, 2010, 06:37:10 AM
This is my new (made in China) air pump. Air assist is essential for laser work, mainly to keep fumes and particles off the focus lens but it does also improve the cutting ability. It is rated to deliver 45 litres/minute (in free air) but is probably half that volume with the restriction of my air nozzle and tubing.
(Up to now I have been using one exhaust port from my vacuum table pump which has been a little overkill for the job).
Something else to bolt onto my machine.  ;D

          (http://www.cooperman.talktalk.net/files/27_files/image624.jpg)

Tweakie

Title: Re: The Laser Project.
Post by: Dan13 on June 19, 2010, 06:49:35 AM
Poor machine :D

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 19, 2010, 07:08:29 AM
Hi Dan,

Before and after, and this doesn't include all the latest stuff. Hope I don't ever have to shift it.   ;D ;D

(http://www.cooperman.talktalk.net/tweakie.jpg)

(http://www.cooperman.talktalk.net/tweakie1.jpg)


Tweakie.

Title: Re: The Laser Project.
Post by: budman68 on June 19, 2010, 08:50:35 AM
That is becoming one MEAN machine, my friend-

Dave
Title: Re: The Laser Project.
Post by: N4NV on June 19, 2010, 10:15:19 AM
Were did you get the air pump?

Vince
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 19, 2010, 10:27:55 AM
Hi Vince,

Bought the pump via eBay - there are lots of suppliers, this is just one of them  http://shop.ebay.co.uk/nihilist23/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340

Mine came in at GBP 23.50 inc postage from a UK source (cheaper direct from China but subject to import tax).

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on June 19, 2010, 11:48:36 AM
I like your creativity, Tweakie. Wonder what else you might bolt onto it next... ;)

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 22, 2010, 11:51:14 AM
Hey Guys,

More stuff - latest picture, taken this week.
Shows the new laser air assist pump and spindle VFD, stowage for spindle motor (when not in use) and change to laser current display - the rotary axis is only fitted occasionally and can't really be classed as 'bolted on'.

                (http://www.cooperman.talktalk.net/tweakie2.jpg)

You guys must be getting fed up with this thread by now - I must think of something new  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on June 22, 2010, 12:17:03 PM
Fed up, SHMED up !
One of, if not the best build threads here.
Keep em' coming Tweak !
THANKS !
Russ
Title: Re: The Laser Project.
Post by: budman68 on June 22, 2010, 03:34:39 PM
Fed up, SHMED up !
One of, if not the best build threads here.
Keep em' coming Tweak !
THANKS !
Russ


Couldn't have said it better myself.

Me-thinks Tweakies owner is really a machine  ;)

Awesome-
Dave
Title: Re: The Laser Project.
Post by: Overloaded on June 22, 2010, 04:24:51 PM
 
Quote
Me-thinks Tweakies owner is really a machine 

That might just be it Dave, as soon as it can do everything in the manufacturing realm it can then take over the world.....self replicate and all that stuff ! >:D
Spooky, Scary Tweakie.
Maybe he works for Dr. Evil ? ? ?    or should it be "Tweakie and the Brain" ?
 :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 23, 2010, 05:06:09 AM
Thank you guys, you are most kind.

This project still has a way to run so, with your permission, I will continue to bore you with pictures of my progress - The adventures of Tweakie.

The next part of the project is to add some form of temperature control / monitoring and provide for an automatic shut down in the event of tube over temperature. I am currently only running the laser for relatively short periods of time and at low power settings whilst monitoring the temp rise with a handheld surface contact probe. I perhaps should admit that the forced air radiator I am using is a bit overkill and so far I have not yet recorded a temp rise above ambient. However an automatic system will enable longer operational periods of the tube without causing any anxiety and it just has to be done.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on June 23, 2010, 05:15:36 AM
By all means, my friend, share away!  :)

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 24, 2010, 05:26:47 AM
OK Dave - I am sharing.

Still working on ways to improve the finished cut quality of acrylic parts. Having solved the problem with striations on the cut edge my next problem was with reflections from the table or work supports overheating or damaging the finish on the reverse of the work. These reflections were traveling about 50 - 80 mm beyond the work and although they were well out of focus still contained enough energy to cause damage. All metals reflect at 10600nm but glass doesn't so a simple solution was achieved by making a wooden containing box with glass base then filling the box with aluminum, concertina bent, venetian blind slats (on end) as the work support. This really does work so well and the money I have saved over buying ready made honeycomb cutting bed material can all be spent on Beer  ;) (Dave, Sam & Russ would approve of this, I thought).

(http://www.cooperman.talktalk.net/g373.jpg)

(http://www.cooperman.talktalk.net/g379.jpg)

Tweakie.




Title: Re: The Laser Project.
Post by: Overloaded on June 24, 2010, 10:56:42 AM
Gets my "Stamp" of approval for sure !  ;)
You are a "Master of Improvisation" Tweak.
Glad to see you're keeping the financial priorities in order.
Set em' up barkeep, this rounds on me.
 :)
Title: Re: The Laser Project.
Post by: budman68 on June 24, 2010, 11:02:52 AM
Indeed! Efficient, inventive, and the parts look "clean as a whistle".

Nice work, my friend-
Dave
Title: Re: The Laser Project.
Post by: Sam on June 24, 2010, 02:04:53 PM
If your buying, Russ, I'll take two. Looks like your really getting the hang of that laser, Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on June 25, 2010, 05:04:20 PM
OK Sam,
One more round and a six pack to go.
But first, you have to update this:
http://www.machsupport.com/forum/index.php/topic,13486.msg93224.html#msg93224
 
Russ
Title: Re: The Laser Project.
Post by: Sam on June 25, 2010, 05:16:00 PM
LOL...I look at it every day at work, and it's just begging me to get back started on it. Pitiful, I know!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 26, 2010, 01:11:38 AM
Yea - come on Sam you are lagging behind on this one.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on June 26, 2010, 02:38:05 PM
With all the cool stuff you come up with Tweak, I think to myself.."Ya know, why should I even bother"  ;D
Your inspirational, and demoralizing, all at the same time.  :D
As long as you can see that gray paint on your machine, there's room for more gizmos and gadgets. We sure do enjoy looking at all the stuff you come up with.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 27, 2010, 01:27:28 AM
Think I have done it this time fellas. The temperature controller arrived yesterday, it's bigger than I had originally thought and gray paint or not, I can't find anywhere to fit it.  :'(
I haven't found the right thermocouple yet so I may try my hand at making one (if I can find my spot welder which I don't think I have used in the last 10 years).

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 29, 2010, 05:26:09 AM
Well I couldn’t find a thermocouple of the right design (I want to monitor the temperature of the cooling fluid as it leaves the laser tube with perhaps a second sensor to monitor the coolant entering the tube) so I decided to make my own. On the offchance anyone is interested in thermocouples I have attached a few pictures…..

1.   Piece of 6mm bore stainless tube and length of ‘Type K’ thermocouple wire.
2.   This is the tricky bit, the wires are spot welded onto the tube one on top of the other.
3.   With a simple mold I have used some car body filler to support the wires and give some protection to the weld.
4.   Completed tubular thermocouple which, with a bit of insulation, should indicate the flowing water temperature.
5.   Tested and it works.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on June 29, 2010, 08:23:17 AM
You keep amazing me, Tweakie!

So is it the special wires that do the trick? Thought a thermocouple body was the one that was bi-metal, it didn't occur to me it was the wires...

Daniel
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 29, 2010, 08:44:28 AM
Hi Dan,

There are many different combination's of metals / alloys which exhibit potential differences which change with temperature variation, the most common being the Type K which is Nickel-Chrome / Nickel-Aluminum alloys. Fortunately, for me the different types are color coded so at least I know what type it is that I found in my stores. One thing is curious though the Ni-Cr is non-magnetic but the Ni-Al is magnetic ???.
This explains thermocouples better than I can. http://en.wikipedia.org/wiki/Thermocouple

Best regards,

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on June 29, 2010, 09:17:53 AM
Cool Tweak..........
Does your process meter have dual inputs ?
Are you just going to monitor the temps. or configure the meter to a Mach input ?

Looks like a nice meter with HI/LO , ALARM and configurable IO ?
Not familiar with that brand.

Very nice....will look real good mounted on your rig.
Be careful and watch the CG, it may topple over one day.

Thanks,
Russ
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 29, 2010, 11:34:30 AM
Hi Russ,

My plan for the temp controller was to keep it simple and hard wire the NC low output in series with my laser coolant flow sensor - if the temp rises above the preset then the switch goes open circuit and the eht unit shuts down power to the laser tube. It does only have one sensor input and I haven't yet figured out how to switch between two thermocouples, think I need inspiration here, any ideas ?.
The controller is made by IMO Precision Controls Ltd here in the UK and perhaps is not sold internationally.
You are certainly right about the C of G for my machine, bit worrying really, but I think it looks worse than it really is (fingers crossed).  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 01, 2010, 04:18:31 AM
I don't normally post pictures of my mistakes but this made me smile because it was just such a daft thing to do.

The spot welder applies a lot of pressure to the weld and the tube needs internal support to prevent distortion, the nearest thing to hand that fitted the tube nicely was this stainless bolt. After making the first weld it became obvious and yes you have guessed it, I have welded the bolt into the tube.  ;D ;D ;D

I turned a piece of brass to fit the tube for the next one, that didn't weld in.

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on July 01, 2010, 08:03:07 AM
By Golly...he is human. :)

Just curious Tweakie, could the attachment be made with a torch and a dab of silver solder ?

Thanks,
Russ
Title: Re: The Laser Project.
Post by: budman68 on July 01, 2010, 08:08:21 AM
By Golly...he is human. :)



 ;D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 01, 2010, 08:51:34 AM
Hi Russ,

Quote
Just curious Tweakie, could the attachment be made with a torch and a dab of silver solder ?

No reason why not, as long as the two wires are welded together first and the join is not contaminated with other metals, I think that would have been a better (if not easier) way to do it - why didn't I think of that.  ;D

Tweakie.

(I was just about to throw my mistake in the bin and I thought you guys would like a laugh as well).
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 02, 2010, 07:28:53 AM
As we all like pictures........
This bitmap image has been raster engraved, just lightly, into the surface of a piece of obechi using the Mach Impact/Laser Engraving plug-in.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on July 02, 2010, 07:39:04 AM
Wow, wow, WOW! That is a beautiful image and it came out beautifully.

How big is it and how long did it take?

That is just aces right there, my friend-
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 02, 2010, 08:44:34 AM
Than you Dave.

I was impressed with this mainly because it was made using the Mach plug-in which others before me had criticized. OK the plug-in doesn't work 'straight out of the box', so to speak, it has to be optimized and fiddled with a bit but it does work, at least for me.  :)

The image is approx 120mm x 120mm and it took about 40 minutes or so (the Mach elapsed time doesn't work when using this plug-in).  If my machine had less mass to the X axis it could have been a whole lot quicker. (when using a laser the slowest thing is the axis movement unless I make a galvo scanning laser  ;D ;D - Amir was thinking about it for printing Denim so it could be a maybe).

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on July 02, 2010, 08:51:16 AM
Interesting, thanks for sharing-  :)

Dave
Title: Re: The Laser Project.
Post by: Sam on July 02, 2010, 02:26:14 PM
Absolutely stunning! Your engravings of her are great also, Tweakie. :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 06, 2010, 04:01:44 AM
Thanks Sam.

(Don't forget we are awaiting more pics of your mill progress)  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on July 06, 2010, 02:22:26 PM
I can post some of the dust accumulation, if you would find that interesting.  ;D
It's only been 7 months. I'm still WELL inside my projected time frame.
The (badly needed) new clutch I purchased for my truck is over 3 years old, and it's still in the box.
The plaque of neptune on the wifes fountain, made a year ago, is still awaiting a frame.
I can go on, but you get the picture.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 08, 2010, 04:23:08 AM
I get the picture Sam - but I'm going to keep reminding you  ;D

Some people might ask if I have anything better to do with my time - answer NO, I am learning all the time and knowledge is everything.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on July 08, 2010, 05:09:36 AM
NICE!!! 

Dave
Title: Re: The Laser Project.
Post by: Sam on July 08, 2010, 06:57:03 PM
 ??? Where are the wheel spokes??  ;D
Title: Re: The Laser Project.
Post by: budman68 on July 08, 2010, 07:06:57 PM
These are the new "Dyson" wheels  ;D

(http://www.impactlab.com/wp-content/uploads/2009/10/dyson-fan-1234.jpg)

Dave
Title: Re: The Laser Project.
Post by: BR549 on July 08, 2010, 07:44:49 PM
WOWZER Tweakie, I don't often drool over organic art but I think I feel a new machine in the near future.  How fast does the Machine NEED to be to be effective with Laser cutting.

Got any Plans or info on the laser part. No problem on the machine build but that last thing I played with light wise was a flashlight.

Do you use mirrors or perhaps a fiberoptic system????  Spill the beans (;-)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 09, 2010, 07:28:38 AM
Hey Sam, our buddy Dave has already guessed it - I used the new Dyson wheels.  ;D

Terry, Its all done with mirrors  ;)  If your main aim was, for example, raster graphics then the faster the machine (and lower the mass of all moving parts) the better but for vector work, which is my requirement, then the machine can be just as slow as it turns out.

The first little bikes shown were cut too quickly at too much power and the acrylic overheated (boiled possibly) and they had a bad surface finish. Doing them again (lower power, slower feed) produced much better results (these ones are about 20mm long) and this was the original traffic sign artwork.

Tweakie.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 11, 2010, 11:22:28 AM
I came across this neat little program last week - It is just so simple I had to make some little boxes. My congratulations Rahul.

http://rahulbotics.com/personal-projects/boxmaker/

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 19, 2010, 06:26:44 AM
This little bike is very different from the others – It is edible, which means that I get to eat anything I make (after it has been photographed).  ;)

Inspired by the Candy Fab project http://candyfab.org/ this 15mm long bike has not been cut-out, it has been laser printed using sugar.
OK this is just my first attempt and it is perhaps not that brilliant, but it is early days yet and many obstacles have still to be overcome - not least, getting sufficient air pressure to keep the vaporized material off my focus lens without blowing everything else away. There are, of course, many other fusible materials with a much smaller grain structure than cane sugar which may well produce much better results so there is a lot of room for experimentation here. (I have just discovered how fine the particles of laser toner are, having just blown a teaspoon full all over my machine table).   :(

If I can get a grip on this and overcome the obstacles then 3D printing here we come (perhaps).  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on July 19, 2010, 08:45:16 AM
Awesome (again). Kinda reminds me of the makerbot  or fab at home stuff.
http://www.popularmechanics.com/technology/gadgets/news/4224759 (http://www.popularmechanics.com/technology/gadgets/news/4224759)
http://www.makerbot.com/ (http://www.makerbot.com/)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 19, 2010, 09:06:11 AM
Absolutely right Sam, just mine is not quite so good.  ;D
Thank you for the kind words.

Purely out of interest :- The technique I am using is slightly different from the makerbot and it is called "Selective Laser Sintering" and more details of the process can be found here  http://en.wikipedia.org/wiki/Selective_laser_sintering
The big boys have excellent results with this method but hey I have only just started out so I am excused from making anything too good.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: bwprice100 on July 20, 2010, 04:42:48 AM
Hi Tweakie

You do realsie that suger is a dust explosive :)
http://www.youtube.com/watch?v=LQZGWjVwN58

Have fun :P

Brian
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 20, 2010, 07:35:44 AM
You certainly know how to boost a guy's confidence Brian.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: bwprice100 on July 20, 2010, 08:08:00 AM
You certainly know how to boost a guy's confidence Brian.  ;D

Tweakie.
Your welcome

By the way great project
Title: Re: The Laser Project.
Post by: Sam on July 20, 2010, 08:40:20 AM
HAHAHAHA!! Lets hope that number remains a zero, Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 13, 2010, 02:57:28 AM
Hey Guys,

I wonder if you could help me out here.
I have just laser cut two 50mm diameter discs from 6mm acrylic - one has visible vertical striations one does not. The parameters (power, federate, air assist etc.etc.) are the same for both discs, the only difference is the GCode (disc 1 has been cut using a predetermined number of straight lines, whereas disc 2 has been cut using circular interpolation [GCode for each attached]).

Now this might sound like a daft question but “What causes the vertical striations to be made ?”.

Is it the fact that the cutting head stops and starts ?.
Is it the sudden change of direction ?.
Is it acceleration / deceleration of the cutting head ?.
Etc.???

With circular interpolation the step size (or length of each flat that emulates the circle) is, obviously, a lot smaller but just how small is it ?. The highest (theoretical) resolution I can achieve on my machine is 0.00625mm – are the circular interpolation steps smaller than this ?.

Grateful for any comments or info on this one, thanks,

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on August 13, 2010, 03:11:22 AM
Hi Tweakie,

Not sure about your question... I would get the same results if I milled the circles on my mill, once with circular interpolation and once with linear approximation. You just see the exact trajectory the machine was commanded to travel - if it's composed of small lines, then this is what you'd see.

Not sure this was the answer you were looking for, but then I may not be understanding the question ;)

Dan
Title: Re: The Laser Project.
Post by: gittt2000 on August 13, 2010, 06:27:05 AM
> “What causes the vertical striations to be made ?”.

You did :). If you tell the machine to cut lots of straight lines that is is exactly what it does.

Richard
UK
Title: Re: The Laser Project.
Post by: Sam on August 13, 2010, 08:50:22 AM
If I had to take a guess at it, I would say that it's because the first piece is not really that circular. If you zoom in on the circle, it looks like a drunk person on the road. It weaves left and right. At the cutting speeds that your using, I doubt that accell/decell, or anything-other than lack of resolution-would be the factor (that is, of course, with a sober circle).
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 13, 2010, 11:36:41 AM
Thanks Guys for your input, It is appreciated.

Dan and Richard,
You are, of course both quite right but...
The surface of the cut should appear to be a series of small flats (as you say a milling cutter path would produce) and there is really no reason why it should be striated - just a series of smooth flats. Unfortunately that's not quite what it looks like - for some reason.

Sam,
That's exactly what they look like - they weave left and right. They also get a whole lot worse if I increase the feedrate and subsequent laser power setting.

I did read, somewhere on the net, that they were caused by a reaction between the air-assist and the material vaporization but this doesn't hold true, otherwise both discs would look the same.

Tweakie.


Title: Re: The Laser Project.
Post by: budman68 on August 13, 2010, 11:39:42 AM
Could they indeed be straight lines but since you may have an overmelting factor (I'm grasping here  ;) ) maybe it actually creates the waviness?

Dave
Title: Re: The Laser Project.
Post by: Dan13 on August 13, 2010, 11:53:03 AM
OK, if it's not a sequence of straight lines to reflect the G-code and the striations are more pronounced than they should be if it were the G-code, then my guess is that the machine has some dwell between each line segment and the laser melts the material leaving those marks. Could you see if cutting in "Exact Stop" mode makes them more pronounced? I think that could prove the above point...

Also, may be playing with the Lookahead value will show some difference.

Dan
Title: Re: The Laser Project.
Post by: Sam on August 14, 2010, 12:55:43 AM
Hmmmm, maybe I'm missing the real question your asking. I interpreted it to be... "why does part 1 not look like part 2?"
Upon loading up the code for part 1, and zooming in, its clear that it is not a circle made up of equal length lines. When I think of a faceted circle, or arc, I think of an octagon or hexagon, or whatever. Equal length lines with a consistent angle between the lines. I think if the first circle had been faceted uniformly, and to a high enough resolution (or subdivision), it would have matched the second one in appearance. As it is now, the striations are there because, well...there programmed in.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2010, 08:19:33 AM
Thanks for the magnification of the cutting path Sam - that looks pretty much like the striations.

So Guys, correct me if I am wrong, but would it be right to say that the striations are being caused by the lack of resolution in the exported arc ?.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2010, 08:23:36 AM
Hey look, an acrylic footprint (much more eco-friendly than carbon)  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on August 14, 2010, 08:26:19 AM
So Guys, correct me if I am wrong, but would it be right to say that the striations are being caused by the lack of resolution in the exported arc ?.

Tweakie.

That was my guess right from the beginning, but I thought you were saying that the striations did not match the Gcode... ???

Dan
Title: Re: The Laser Project.
Post by: budman68 on August 14, 2010, 08:42:59 AM
Yes, I would have to say that's how it's coming through the GCode. Can you take the same file and actually machine it to see if it comes through with the same effect?

Side question for you, I'm seriously contemplating buying a laser engraver (been thinking about this for a long time actually), do your parts come though with the rounded egdes like that, or are you deburring them with a flame or buffing wheel?

Thanks,
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2010, 09:19:32 AM
Dave,

That's exactly the way the parts come off my machine - there is no refinishing or flame polishing. (I have had a lot of practice now and if you look back a few posts you will see that some of my earlier attempts with acrylic were rubbish).

In a way this is the reason for my question regarding these striations.
Many (perhaps all, for all I know) of the commercial laser machines are operated via a 'machine manufacturers Printer Driver' with acts as the post processor from the design software, typically 'Corel Draw'. Now there is some doubts about the way in which these printer drivers handle arcs and the maximum resolution they will allow to pass through because, it seems, that those I am in contact with who have a GCC laser are unable to produce a curved surface in acrylic without the striations. I have carried out a lot of research on this now and it is perhaps obvious from what I have made that a dedicated cutting software, such as Mach, way out performs these Printer Drivers - at least as far as cutting acrylic is concerned.
I know how to cut stuff with the striations and I know how to cut stuff without the striations - what I didn't know, until now, is what caused the striations.
You have all been most helpful here and as a result I think there is probably no solution for the GCC owners as long as they continue to use a printer driver and unfortunately their machines would not support Mach without some modification. There is one US business who is offering a Mach compatible addition but it is still doubtful if it will offer any improvement on the resolution of arcs issue.

Waffled on a bit but hope this is of interest.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on August 14, 2010, 09:21:38 AM
It may not be lack of resolution, rather lack of being a good circle. It could be both, but you wont know until you can get a proper circle. I tried to make one similar to the one you posted. Circle center is 0,0.  You can try it and see what happens if you like. If its still bad, I can bump up the resolution (and file length, of course) to test. Make sure you look at the code and make any changes you need before running.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2010, 09:54:04 AM
Absolutely brilliant Sam.  :) :) :)  just brilliant.

You have my full attention on this one - I have to know exactly how you did this - It is just about the best circle I have seen.

Don't suppose you could perform your magic on this foot or is that too much to ask ?.  :-\

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on August 14, 2010, 01:13:12 PM
You can use Gmax with CNC toolkit to achieve this.
http://www.cnc-toolkit.com/
All of it is free, but I'm sure Rab Gordon would enjoy a thanks.
Quote
Don't suppose you could perform your magic on this foot or is that too much to ask ?
I'll do ya one better. I'll make you one using arcs instead of the jagged lines.  ;D You might have to scale it to fit your needs.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2010, 01:53:07 PM
Sam,

I don't know what to say - you are just awesome.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 15, 2010, 04:06:18 AM
Ooops, forgot to say thank you.

Thank you Sam. Your help and support is much appreciated.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on August 15, 2010, 09:05:49 AM
No problem Tweakie. If we didn't enjoy helping out when we can, we wouldn't be here.
Out of curiosity, what software are you using that outputs everything in segments? Arcs sure do make for a cleaner file, cleaner cut, and a happier machine.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 15, 2010, 12:48:13 PM
Hi Sam,

I think the foot was done with Adobe Illustrator.

I really wish I could do everything in arcs. I think I asked this question before but how do I do it in arcs please ?

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on August 15, 2010, 10:42:20 PM
With Illustrator, I have no idea. I have never made anything with Illustrator. Maybe someone else can chime in on that one. Pretty much any cad/cam package will do the trick. I've never used lazycam, but it would probably do just fine.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2010, 07:16:30 AM
This little fella has been laser etched into some 6mm acrylic using the Mach Impact/Laser Engraver plugin. Glass would also work just as well but getting the power level /feedrate just right has to be done by trial and error (get it wrong and the glass may crack).
As with all clear acrylic this type of etching displays best against a dark background but good results can also be achieved by edge lighting, perhaps with LED's ?.

Just thought you might like to see the picture.  :)

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on August 19, 2010, 07:46:11 AM
A good looking one, Tweakie.

How does this etching work? How does it produce the required shade? Doesn't it just melt the acrylic?

Think you can do 3D shapes in a glass cube like those sold in souvenir shops? That would be lovely. But then you need to focus the laser at different heights -  can you do this?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2010, 08:13:18 AM
Hi Dan,

Quote
How does this etching work? How does it produce the required shade? Doesn't it just melt the acrylic?

The laser doesn't actually melt the acrylic, the focal point is far too hot for that, it vaporizes it. There is no residue or melted stuff, and the vapor just gets sucked out by my extraction system.
The image itself is generated from a raster scan with the laser being switched on and off as necessary (bit like an inkjet printer I suppose but just one line at a time). This is bit of a painstaking process for my machine because the mass of the combined X and Z axis is such that my maximum, reliable G1 feedrate is only 4000 mm / min. and with a line increment of 0.015 mm it took some time to complete.

Quote
Think you can do 3D shapes in a glass cube like those sold in souvenir shops? That would be lovely. But then you need to focus the laser at different heights -  can you do this?

No can't do this. The wavelength of my laser is 10.6 microns and that treats almost all stuff that we see as being transparent as opaque and dumps its energy on the surface. (Different wavelength lasers each see materials differently).

Hope this answers your questions,

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2010, 08:53:44 AM
Hi Dan,

When I re-read my previous posting I had missed out something which may be of interest.

Not all materials will change from a solid to a gas without going through the liquid state it is called 'sublimation' some things do it at room temperature (dry-ice and mothballs both miss out the liquid state) but acrylic needs a laser  ;D .

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on August 19, 2010, 10:05:59 AM
Tweakie,

Thanks for taking the time to explain it.

Dan
Title: Re: The Laser Project.
Post by: Sam on August 19, 2010, 11:59:28 AM
How long did it take for that one? I wonder what the effect would be if the side light was a blacklight. Might be interesting.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2010, 12:27:30 PM
Hi Sam,

I don't know just how long it took because I was busy doing something else and when I returned it had finished. Probably 1 to 1.5 hours.
Incidentally I made a mistake in the previous posting the vertical increment was 0.15 mm (if it was 0.015 it would still be running  ;D ).

I can't try any lighting effects with this one as it has now been fitted as a replacement for a cat flap.  ;D
I will make another similar and try different lighting effects and post the results.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2010, 02:40:22 AM
I am still awaiting the delivery of the power supply, so I can try it out, but this baby could spell the makings of a whole new machine.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 01, 2010, 03:10:03 AM
What's the power of this one?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2010, 03:44:23 AM
It's only a baby Dan, weighing in at 25 Watts.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 01, 2010, 03:48:46 AM
Ah... Looks like a monster on the photo  ;)...

Dan
Title: Re: The Laser Project.
Post by: manmeran on September 01, 2010, 03:54:22 AM
Tweakie
is it possible tell price?

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2010, 04:24:02 AM
Amir,

Second user they go at about $500.

http://cgi.ebay.com/Synrad-25W-CO2-Laser-Model-F48-2-285W-Great-Condition-/300456367802?pt=LH_DefaultDomain_0&hash=item45f49856ba

(all I need now is the galvo head  ;D ;D )

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 01, 2010, 04:36:51 AM
i agree for GALVO head  ;D ;D

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 03, 2010, 01:06:17 PM
I have not yet decided just how I will be controlling the Synrad RF laser but whatever system I use i am going to need a 'tickle pulse' generator so at least this is one part I can start making already. The required circuit is extremely simple and I like simple.

The 'tickle pulse' generator has to supply a stream of 1uS pulses repeated every 200uS  (5kHz) and this keeps the gas on the point of lasing and in readiness for the trigger or firing pulse which will in turn be a pwm stream ranging from 10% to 100% mark space ratio.

The finished controller will be modular in construction and this little pcb will just be incorporated into the main pcb (at least I think that's the way it's going to go).

This little pcb has been isolation routed, now to solder on a few components and test it out.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 05, 2010, 05:06:35 AM
Components added to the pcb. Fired it up and as luck would have it, worked first time.  :D

This circuit takes advantage of the hysteresis in the switching characteristics of the 74HC14 inverter IC.
One gate is used to create a 5kHz square wave oscillator with the output charging a capacitor which is in turn discharged by a resistor the time constant of which creates the 1uS pulse through a second gate which is finally inverted through a third gate. Simple.

The upper trace shows the 5kHz oscillator output.
The lower trace shows the 1us pulses repeated every 200uS which is exactly the requirements for the Synrad 'tickle pulse'.

I am still undecided about the controller design but this circuit will at least allow me to test the laser to check that it does indeed work.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on September 05, 2010, 10:00:09 AM
Neat stuff you get yourself into, Tweakie. I wish I had some of your electronic know-how. How is this laser better than the one you currently have?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 05, 2010, 11:12:01 AM
Hi Sam,

I don't really think it is any better although in industry the RF energized type are preferred over the DC energized type (not sure why).
It is just different to what I have already - and it was a bargain I just couldn't resist.  :D

It operates at 30 Volts rather than 16,000 Volts and is probably a lot easier to control by PWM and CW without electrocuting myself.
The output is polarized which could be an advantage with some applications but may be a disadvantage with others.

Amir was talking some time back about galvo, raster scanning lasers and this could be the starting point for me to build one - anyone know where I can obtain a 70mm ZnSe F-Theta Ronar lens real cheap ?.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 05, 2010, 11:48:05 AM
Quote
cheap
i am sorry   :D :D :D
Title: Re: The Laser Project.
Post by: manmeran on September 05, 2010, 11:55:52 AM
http://www.raylase.com/en/product_subhome.php?n1=2&n2=1 (http://www.raylase.com/en/product_subhome.php?n1=2&n2=1)

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 06, 2010, 04:35:35 AM
Just for fun and big enough to engrave a telephone number.

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 07, 2010, 02:09:25 AM
what news about galvo head ? :D

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 07, 2010, 02:11:55 AM
Hey Amir,

Stop spending my money  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 07, 2010, 02:13:52 AM
Inquiry about the price ?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 07, 2010, 03:36:50 AM
Best price for a (second user) scanning head I have seen so far (with ZnSe lens) is $2,800 + import duty, tax etc. and even then the focal distance is far too short to be of much use.

Patience is a virtue when it comes to getting bargains  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 07, 2010, 06:39:31 AM
In some ways the waste can be more interesting than the part.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 11, 2010, 02:00:21 PM
Another circuit board isolation routed, this part of the jigsaw is a TTL switch. It will allow the selection of one from two inputs. Its purpose is to insert the 1uS 'tickle pulse' in-between the pauses in the PWM signal controlling laser output power.

Incidentally, for those who might be wondering, it only takes me a few seconds to remove my focus lens assembly and fit the 3 phase router spindle thus converting the machine from a laser to a router (not forgetting to fit the covers to prevent the dust getting onto my mirrors) so making these (simple) isolation routed PCB's is really quick and easy.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 13, 2010, 03:31:32 AM
This is the completed TTL switch PCB and the basic diagram of my controller so far.
There is more work to be done on this but at least it will allow me to experiment with different PWM control circuits and methods.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 14, 2010, 04:56:42 AM
Hi Guys,

An Aztec calendar, laser cut into Traffolite (engraving laminate) using the Mach3 impact engraving plugin. CO2 Lasers seem to like hard stuff and it makes quite a noise when it chews into this Formica like surface. The image is 90mm diameter and I used a stepover of 0.1mm and feedrate of 4500mm/min (took around 10 minutes to complete).

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 14, 2010, 05:04:51 AM
coooooool ;)
Quote
4500mm/min
Do you build another machine ?


Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 14, 2010, 05:24:27 AM
Hi Amir,

No I haven't built another machine (yet  ;D ).
Because I do not have any cutter torque requirements, when using the laser, I can drive my X Axis right up to my G0 rapids feedrate and still get 100% reliability.

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 14, 2010, 05:29:05 AM
hi Tweake,

is it possible tell about ballscrew use in X axis ?
pitch?
4500mm/min is very good .

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 14, 2010, 05:56:18 AM
Both X and Y are 16mm dia. x 5mm pitch pre-loaded (twin ball circuits) not certain but I believe they are from NSK (Japan) same as linear rails.

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 14, 2010, 10:39:37 AM
That is awesome, cool tool!!!
Title: Re: The Laser Project.
Post by: Sam on September 14, 2010, 03:57:26 PM
That looks awesome Tweakie. It would be neat to see that being made. (hint hint, nudge nudge)
Title: Re: The Laser Project.
Post by: alfaalfa on September 14, 2010, 06:59:23 PM
Hello Laser Tweaker's!

I've been out from this site for a long time and just happened to check what all is happening in laser path  ;)

There was a question why RF exited units are more liked in industry?
1. They are very reliable. Can last N * 10 000 h without any problems. After this Synrad lasers can be serviced only at manufacturers service but if you send back the old unit in good shape - you'll get a another unit with reasonable price (less than a new unit thou).
2. Size is much smaller than with NF DC laser
3. RF unit is much more rigid and solid. Glass is a bit risky.
4. High voltage DC is a bit jumpy! Can cause heart beats  :o
5. Life of a glass tube NF CO2 is short. 500 - 1000 h often realistic.

About the CO2- scanner lenses.
Normally singlet lenses are used. A compromise between F-theta quality vs. price. You can try
http://www.ulooptics.com/ulo_optics/products/scannerlenses.asp

or used ones from:
http://www.europalaserboerse.com/eng_product_catalog.php

but they won't be very cheap there. If you find a cheap one - it's very probably ruined in some cleaning operation and full of scratches. ZnSe is actually a type of salt ie. quite soft. Rough cleaning will destroy it.

BTW. The Synrad laser can be tested just by steering it with 5V DC signal which will put it in ON state with full power.

BR.
Arto
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 15, 2010, 02:01:04 AM
Hi Sam,

There is quite a lot of smoke and debris with raster scan and I don't think a video would be too interesting but I will give it a go. In the meantime here it is half done  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on September 15, 2010, 02:19:12 AM
Quote
or used ones from:
http://www.europalaserboerse.com/eng_product_catalog.php
in this site there are many secondhand machine for laser.

Many times, has been looking to build a laser machine for marketing marking textile(jeans , cotton ...)
i share my information with Tweakie But my information is not enough. :)

Amir


EDIT: For Spelling by Budman68 at the request from Amir (manmeran ).
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 15, 2010, 04:54:47 AM
Quote
That looks awesome Tweakie. It would be neat to see that being made. (hint hint, nudge nudge)

Here you go Sam - It's a bit like watching paint dry  ;D  (ignore the intro spelling mistake) . http://www.cooperman.talktalk.net/Aztec2.wmv (http://www.cooperman.talktalk.net/Aztec2.wmv)

Music is good though.  ;)


Tweakie.

Title: Re: The Laser Project.
Post by: manmeran on September 15, 2010, 05:07:30 AM
very interesting.

Amir
Title: Re: The Laser Project.
Post by: Dan13 on September 15, 2010, 05:32:55 AM
Thanks for the video, Tweakie. Is it the true speed, or did you sped the video up? Is it possible to do the same on wood?

A lot of smoke... hope you have good ventilation there.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 15, 2010, 06:19:34 AM
Hi Dan,

Glad you liked the video. Sadly I can never do high quality because my web host doesn't like me posting large files and I haven't yet mastered YouTube  :-\

That's true speed but the video is compressed down to 3Mb so there are probably a lot of frames missing and it perhaps looks faster than it really is. The X Axis feedrate is 4500mm/min but because of the combined mass of my X and Z the acceleration/deceleration is set low so the axis only just reaches around 4000 at the centre of it's travel on this 90mm diameter piece.
The one in the video is wood, it's Obechi and yes I have a good extractor system, this is one big essential for laser work.  ;D  (the near neighbors haven't complained yet but if they do then I will have to fit the HEPA filters etc uggg).

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on September 15, 2010, 10:59:11 AM
Very nice, my friend, just out of curiousity, how "deep" is the image below the surface, or is more of a "burnt" surface in this case?

Thanks,
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 15, 2010, 11:20:41 AM
Dave,

Depth is difficult to tell with the Traffolite probably 0.2mm but it has gone between 1mm and 1.5mm into the Obechi.
Under normal circumstances the depth can be controlled by altering the power setting or changing the feedrate but this was done with the Engraving / Laser plugin and that links power/feedrate beyond my control so depth is whatever Mach decides it is.
I keep thinking I will break out my old C++ books and give the Engraving/Laser plugin a good talking too but you know what it is like - where does the time go ?.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on September 15, 2010, 11:32:00 AM
Quote
- where does the time go ?.

Boy, how true is that!

Thanks,
Dave
Title: Re: The Laser Project.
Post by: Sam on September 15, 2010, 02:58:36 PM
Thanks for the video, Tweakie. Yep, the older I get, the faster the days seem to pass.
Title: Re: The Laser Project.
Post by: Jammerm on September 15, 2010, 05:04:09 PM
The video was great Tweakie.

Why did you do that calendar, It ends in a couple years. ;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 22, 2010, 12:40:19 PM
Hi Guys,

I was issued with bit of a challenge recently to produce the Mayan Calendar to set dimensions on Oak together with their company name at as good a quality as their commercial controller and software can achieve. I think this full-size version is at least equal to their published example (the half-size was done just for a joke).
As with the others, this was produced with the Mach3 Engraving plugin – OK it’s a bit quirky but it gets the job done.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on September 22, 2010, 05:54:41 PM
Looks great. (as usual)
Title: Re: The Laser Project.
Post by: dar303 on October 07, 2010, 04:25:22 PM
Hi,

Great project, very inspiring!
I have a machine in the making that is surprisingly similar to your machine!

I have a Synrad 48-1 (16W) that I am going to fit on it and regarding the tickle electronics I solved that by asking a friend to program an 8 pin PIC microcontroller to take mach step + dir (or step + laser on), generating the tickle and adding that to the step-pulses. There is also a manual mode where a button sets laser on and a pot or voltage 0-5V sets the laser power for testing or other applications.
It worked right away but might need som tweaking and input from other users to be perfect. My friend also made a pcb for it but I have it on protoboard for now. Drop me a PM if you are interested in testing it, I have much work ahead until it's laser time!

I have been building my machine very slowly for a few years but life, work and kids seem to get in the way all the time... :)
I'll make a thread about it when I get a little further off the ground so to speak!

This is a pic from february 2008 and not much progress has been made since! :(
(http://i135.photobucket.com/albums/q136/Thomases/1cnc.jpg)

This is my laser with improvised cutting nozzle with 12diameter, 50mm focus lens. The lens is far to close to the laser for optimal cutting cuality but its ok for experimentation.
(http://forumbilder.se/images/c5122009113133804.jpg)

(sorry for the threadjack, I just saw some (infrared) light in the end of my tunnel!) :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 08, 2010, 01:52:52 AM
Hi Dar303,

As you say amazingly similar machine construction. Machining the ways and screw mounting pads prior to fitting the rails etc solves the welding distortion problems and is a lot more professional than my approach of using shims - keep up the good work.  :D

I look forward to seeing more pictures of your progress and completion of the project. Your PIC controller sounds very interesting and could be just what I need for my Synrad.

Thanks for sharing your information.

Tweakie.
Title: Re: The Laser Project.
Post by: dar303 on October 08, 2010, 10:51:32 AM
They are not only machined, the whole thing was put in a giant oven at Rolls Royce/Kamewa plant in Sweden, I have a friend that worked there building tools and fixtures for water jet propulsion eh... stuff! Lucked out on that one, they put it in with some giant machine parts for free!
I am not a machinist och mechanical engineer (my field is electronics) but I am learning with the help of forums like this and very patient friends... :)

I got some new energy now! Do you have a link to mor details about your machine, motors, drivers etc? This forum is big!
Title: Re: The Laser Project.
Post by: ostie01 on October 08, 2010, 01:12:35 PM
You could have a look at Tweakie website at this address.

http://www.cooperman.talktalk.net/


Nice stuff there

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 08, 2010, 01:50:08 PM
Dar303,

Nice to hear you say that this forum has given you new energy. This is a great place to learn and before you know it that project of yours will be completed and you will have little bits of stuff you have made all around the workshop and cluttering up the house etc just like everyone else.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: dar303 on October 08, 2010, 06:05:32 PM
wow, that was a good read, your site ate my friday evening! :)
I am especially impressed by the 4:th axle with the homemade worm gear!!!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 22, 2010, 12:39:48 PM
A few people have asked me if my laser could be used to make printed circuit boards and my answer has always been no. The problem is that copper is such a good reflector at the CO2 wavelength of 10600nm that possibly a kilowatt or more of power (certainly more than I have) would be necessary to vaporize the copper and then it would almost certainly vaporize the glass board underneath as well.
Like all things there is always more than one way of doing everything so as an alternative approach, and being a slack day, I tried this;

The copper clad glass board was sprayed with a rattle can car spray paint then, when dry, the required pattern was laser etched (paint removed) using the Mach3 Impact/Laser plugin. I didn’t quite get this one aligned correctly horizontally but it proves the point that as a system it will work. The car spray paint is resistant to the ferric chloride pcb etchant so all I need to do now is chemically etch away the unwanted copper, drill the holes and clean off the remaining paint. It only took a few minutes to produce this, certainly less time than it will take to etch.

I think this system would be more suited to surface mount rather than through hole because there is no X – Y GCode a drilling file cannot be easily produced and drilling by hand is a real pain when you have a CNC machine sitting idle.

I doubt that this application had been envisaged when the Mach3 Impact/Laser plugin was written.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: dar303 on October 22, 2010, 03:26:02 PM
Wow, nice! You are always on the cutting edge!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 24, 2010, 11:50:31 AM
Thanks, but I think I am a few years behind  :'(

I wondered if the color of the paint used would make any difference to the way the laser performed - answer no.
Surface mount is definitely preferable for this process - now where did I put that etching tank ?.

Tweakie.
Title: Re: The Laser Project.
Post by: ostie01 on October 24, 2010, 05:45:13 PM

now where did I put that etching tank ?.

Tweakie.

Look at the fish tank ::) ::) :D

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 25, 2010, 07:29:47 AM
Thanks Jeff, good call.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 27, 2010, 05:40:29 AM
Something lasers are pretty good at is ablating inks and dyes which is why they are often used for tattoo removals. They are also pretty good at removing the dye layer from anodized alluminium and here is an example.
It's only a scrap piece of material which I had kept to be used on another project but I thought I would give this a try and as it happens it turned out reasonably well, I think.

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on October 27, 2010, 07:01:02 AM
COOL Tweak !
What size is it ? Stepover ? Time to run ?
Thanks,
Russ
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 27, 2010, 07:16:32 AM
Hi Russ,

Total time probably about 20 minutes, the image is just 90mm x 60mm and the vertical step size was 0.06mm.

As soon as I lay my hands on a decent gloss finish piece of black anodized I will try and make a better job of this, larger image and smaller step size perhaps.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on October 27, 2010, 12:10:21 PM
Neat stuff Tweakie. I had often wondered how your laser would work on anodizing. That could prove to be very useful with my own projects. I had thought about just simple vector patterns, but seeing the image you done, completely opened up new ideas. Thanks a bunch for posting your work!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 29, 2010, 12:41:51 PM
Thanks Sam.

I never seem to be able to take the best photographs of a lot of stuff so I had another crack at this one, this time without the flash.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on October 29, 2010, 12:43:38 PM
Nice!  ;)
Title: Re: The Laser Project.
Post by: ostie01 on October 29, 2010, 01:16:23 PM
Is it your girlfriend  ::)

 ::)

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 30, 2010, 04:41:52 AM
Quote
Is it your girlfriend

In my dreams, along with 10 million other guys.  ;D ;D

A BIG problem
I have an issue with, what is commonly termed, ‘banding’. It can just be seen on this image but is perhaps better seen on this one http://www.cooperman.talktalk.net/files/27_files/image762.jpg .
This is not the same thing as encountered with some colour printers etc where there is insufficient colour depth for the image it is a distinct band of some 10 – 50 lines having a different contrast or brightness. I have run 5 identical images, one at a time, with the same settings, side by side, on the same material and the banding is different on each – it appears to be quite random in nature.
I have been doing a lot of reading and various forums searching to try and find an answer but it just seems to be a mystery.
Some have suggested that it is a mismatch between stepover and vertical pixel count, plausible but this should then produce a repeating pattern.
Different laser machine manufacturers disagree about the cause and almost all say their machines don’t exhibit banding but their competitors machines do.
Glass tube (DC excited) lasers seem to be more prone to this problem than RF excited lasers.
There is undoubtedly more than one type of ‘banding’ therefore there is obviously more than one cause and cure.

If any of you Guys have any suggestions for things I can try to eliminate this problem I would be more than grateful – I really must get to the bottom of this one.

Thanks,

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on October 30, 2010, 07:15:08 AM
I'm sure you've already come up with this, but can you raster at different angles to "cover" up the banding and smooth everything out? Or doesn't it work that way?

I know some CNC woodworking fellas do this to smooth everything over when using ballnose cutters and thought maybe this would be the same effect?

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 30, 2010, 07:49:16 AM
That's a thought Dave - thank you - I think that may work.

De- focusing a little may also have the same result of smoothing things out a little I suppose but it has become a real challenge now and I have just got to find the actual cause of this phenomenon.
It is so strange that, in the laser world, everybody seems to know about it, nobody admits to it and the cause has just not been defined. If this was the plot for a book it could be a best seller.  ;D

So far, I have checked my Y axis for backlash / slack and also for unequal step size (looking at the line scan spacing under magnification shows no problem). I have measured the time taken to complete each line (feedrate) from the X axis direction signal and they are as equal as I can measure on a chart recorder. I have recorded the incoming mains voltage and there is some fluctuation, but not much, certainly not in steps like the images show however I have a UPS voltage conditioner coming for a trial. And finally, for the test sample, I have matched the vertical image size and stepover exactly to the number of vertical pixels.

The saga continues.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on October 30, 2010, 07:52:49 AM
Can't say you're not "trying" !  :D

Good luck, my friend-
Dave
Title: Re: The Laser Project.
Post by: SteinarN on October 31, 2010, 04:38:57 AM
Does the banding consist of only one line or is it several lines next to each other? Wonder if the result would be the same if you applied some force to your x and y axes like a spring or a wire running over a wheel and a weight in the end of the wire so that a force is applied to the axes. Then any backlash would be ruled out completely.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 31, 2010, 11:33:03 AM
The banding I am referring to consists of many lines and can probably be seen best in this image http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=22163;image which consists of just two shades (black & white).

Not sure if I should show this because it may confuse the issue but the image below is a good example of color depth banding (similar but not the problem I am referring to) where the background consists of more shades than the eight which the Mach plugin can handle. As a result the background is stepped into bands that best match the true shade. The dithered image itself is unaffected by this procedure.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 10, 2010, 03:17:22 AM
I think that the ‘Banding’ issue is going to have to go on the back burner for a while – it is not going to be easy to find the answer to this. After much checking and testing I am now convinced that it is not a mechanical thing which leaves software and electrical still to be investigated. I have had bit of a setback on the UPS voltage conditioner which, due to some regulation or another, has had to be shipped without it’s batteries so this is turning into bit of a drama.
I will find the solution to this banding issue - just not today.

Meanwhile, I have been fortunate to have some help from Dar303 who has shared the design for his RF laser controller.
From his layout, schematic and PIC hex dump I have made the PCB, programmed the PIC and tried it out with my Synrad J48. Excellent work Daniel you have done a really good job there.

I still have some more testing to do with regard to ‘pulse width’ and ‘pulse repetition frequency’ which both seem to affect power density in a similar way but each have a different effect on the work piece. Once this is complete I will have a better understanding of exactly what is required to get the best results from the RF tube under Mach control.

Tweakie.
Title: Re: The Laser Project.
Post by: robotmar on November 11, 2010, 05:12:59 AM
Hi Tweakie

Have you see the new Laser/impact Engraving plugin that Art insert on this message?
 http://www.machsupport.com/forum/index.php/topic,16446.msg111335.html#msg111335

You had realized that there was an error in the old DLL?

You saw the description I made for the construction of the solenoid?
What do you think, very simple is not?

You remember that some time ago I have asked about this?

Andrea
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 11, 2010, 06:09:20 AM
Thank you for the update Andrea.
I have not seen or heard about the latest DLL, I am still using various 'workarounds' with the old version.
I have downloaded and will try the new one.

I will look at you solenoid next.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 24, 2010, 07:30:22 AM
Another little circuit board - this one is for the development of the PIC microprocessor program and circuit for the 'Pulse Repetition Frequency' and 'Pulse Width Modulation' part of the RF laser control unit.

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on November 24, 2010, 07:50:58 AM
Sweet, I have a couple of boards I need made, any chance your for hire? ;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 24, 2010, 08:10:11 AM
I will do your boards if you do my tree trunks.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on November 24, 2010, 08:32:16 AM
If you can handle the shipping cost I'm all yours (these things do get heavy). Always can make something for ya out of HDF. ;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 26, 2010, 07:19:33 AM
Got some bits soldered on to the prototype board, which now looks like a rats nest, but at least it works.
Now to get started on the PIC micro processor program.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on November 26, 2010, 07:48:08 AM
Nifty!  :)

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2010, 03:30:42 AM
Hi Guys,

At the risk of being totally boring, thought you may be interested in these little rotary encoders. They are low cost pulse generators which could be considered as the poor man’s MPG (light duty only) and their main field of usage is for the volume control / on off switch for vehicle and domestic audio systems. They output a 2 bit gray code which by comparing the current pulse with the previous pulse enables the direction of rotation to be established (for clockwise rotation the low order bit of the previous value always equals the high order bit of the new value whereas for anticlockwise rotation it never does).
The ones I am using output 20 pulses per revolution and are just ideal to set my PWM to any value between 0% and 100% in just 5 turns. The original concept was to use a multiturn potentiometer feeding an analog to digital converter but this little chap is all digital and simplifies things considerably. (pics show 10% and 90% PWM).
I was originally intending to have the PRF switchable between just 5kHz and 10kHz but I may just use another of these encoders to allow any setting between say 1kHz and 20kHz and limit the PWM accordingly (have to check the Synrad specification to see if this is allowable).

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on November 28, 2010, 03:50:21 AM
Thanks Tweakie. This one seems useful. Will remember to check them when I will be doing a control panel. Got a link?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2010, 04:34:47 AM
Hi Dan,

ebay turns up a few http://shop.ebay.co.uk/i.html?_nkw=rotary+encoder&_sacat=0&_dmpt=UK_BOI_Industrial_Automation_Control_ET&_odkw=&_osacat=42899&_trksid=p3286.c0.m270.l1313

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on November 28, 2010, 05:04:20 AM
Thanks Tweakie.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 03, 2010, 07:21:24 AM
The record amount of snow here in the south east UK has prevented me getting to work so I am working from home.  ;D  Fortunately the license has just arrived for Gearotic Motion so I had to try it out and these are my first, non linear, laser cut gears created with the program.

If you don't already know about Gearotic then check out their website and forum http://gearotic.com/ (this is where Art has been spending all his time lately and brilliant job he is doing with the program).

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on December 03, 2010, 04:33:21 PM
Hook up a motor and lets see them fly. ;)
Title: Re: The Laser Project.
Post by: Overloaded on December 03, 2010, 04:53:13 PM
..... or 1 step further. Could you make up an internal ring gear to go with this ?  :)
Make it like a full planetary arrangement ?
Would probably give one vertigo and a headache to see it running.  :P
Cool Tweakie.
I tried the forum over "there" ... couldn't gain access.
Do you know if it's up and running ?
Thanks,
Russ
 :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 04, 2010, 03:19:21 AM
Hi Guys,

Unfortunately the existing software does not support ring gears which are not round so making one would be a lot of work but it would be possible. Perhaps Art will add this feature at a later date.

The forum is up and running and you should be able to access - there are quite a lot of videos there http://www.youtube.com/watch?v=T8gnNkMUje0 and pics of excellent gear trains made by Greg.
Of course Gearotic Motion has a much more serious side – making the GCode for spur gears / helical gears which can be conventionally cut on a rotary axis but using a parallel end mill. This arrangement circumvents the patent which was taken out a couple of years ago for this method but using an involute ground endmill. Some of the examples of gears shown on the forum are just awesome.

Now to find a copy of the December Nuts & Volts.  :D

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on December 06, 2010, 05:23:51 AM
HELLO GUYS,
i AM NEW IN THE FORUM..I AM LOOKING DESPERATELY FOR SOME HELP ABOUT A 150WATT  2000MM X 1500MM LASER MACHINE I OWN. I ORDERED THE MACHINE OF A LOCAL MANUFACTURER IN GREECE!! I WANT TO USE IT TO CUT AND ENGRAVE ACRYLIC,WOOD ,LEATHER ETC. THE GUY UNFORTUNATELY WAS A SCAM(HOW YOU RIGHT IT?) AFTER A 5 MONTH DELAY HE STARTED TO BLAKMAIL ME TO GIVE HIM THE REST OF THE MONEY OTERWISE THE MACHINE WOULDN'T WORK.tHE DEAL WAS TO GIVE HIM THE REST 30% OF THE  MONEY WHEN THE MACHINE WAS WORKING(I HAD GIVEN 60% WHEN I ORDER IT)!!! FORTUNATELY I HAD THE MACHINE IN MY PLACE... HE LEFT THE MACHINE UNFINISHED(AFTER 5 MONTHS DELAY!!!!!!!
SO NOW I AM FINISHING THE MACHINE MYSELF! iI AM TRYING TO USE MACH3 .. AND I NEED SOME HELP..CAN ANYBODY HELP??
I WANT TO USE THE SPINDLE CONTROL TO MODIFY MY LASER POWER.CAN I DO THAT?AND HOW?
I WOULD BE GRATEFUL !
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 06, 2010, 05:46:43 AM
Ntlaser,

Mach3 will output a PWM signal which is linked to the spindle speed setting and I have found it is easiest to configure it so that S100=10% power and S1000=100% power then just add the appropriate S commands to your program as required. Your laser will have to automatically insert the 'tickle' pulses as necessary because these are not sent out by Mach3. You will also have to incorporate a method of switching the laser on/off and various methods are available.
Personally I prefer manual control of the power setting but I intend to incorporate auto/manual into the controller I am currently working on and keep all my options open.

What is the make and model of your machine ?

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on December 06, 2010, 10:03:22 AM
TEACKIE THANK FOR YOUR REPLY
THE "MANUFACTURER" TOOK PARTS AND ASSEBLIED THEM!! I HAVE 3 AC MOTORS 1000W EACH  WITH THEIR DRIVERS "MAXSINE". THE MOTORS ARE OVER THE TOP AND TO TELL YOU THE TRUGH THEY ARE NOT NECESSARY TO BE SO POWERFUL!!! I AM FACING THE SAME PROBLEM LIKE YOU WITH THE WEIGHT OF MY BRIGHE X AXLE.~ 50 KG!!!!
STILL I DONT UNDERSTAND HOW I CAN MODIFY THE LASER OUTPUT :-\..MY LASER SUPPLY CAN MODIFY THE LASER OUTPUT BY PWM PULSE OR BY CHANGE OF VOLTAGE BETWEEN 0-5V..I READ IN THE MANUAL MACH3 THAT SUCH AN OUTPUT IS POSSIBLE FROM MACH3.
ANOTHER THING IS HOW ACCURATE IS THE MODIFICATION OF A DXF IN G CODE USING LASYCAM!!AND HOW CAN I STOP LASER BETWEEN THE CUT, FROM ONE PART TO THE OTHER.SHOULD I USE PLASMA MODE?
I WANT TO POST SOME PHOTOS!HOW CAN I DO IT? I AM TRYING FOR 3 MONTHS TO SET THIS MACHINE IN ACTION..

Title: Re: The Laser Project.
Post by: dar303 on December 06, 2010, 10:40:39 AM
Hi,

It seams that you found a very bad seller and I hope that you get it fixed!
Please start a separate thread in the forum and I'm shure that Tweakie and the rest of us will help you get your machine working. And please take it easy with the caps, my eyes hurt! :)
Title: Re: The Laser Project.
Post by: ntlaser on December 06, 2010, 11:05:31 AM
Hi dar 303
How can I set a thread? Thanks for the encouragement!
Title: Re: The Laser Project.
Post by: dar303 on December 06, 2010, 11:12:08 AM
Klick the text "Show"N"Tell ( Your Machines)" in the upper right corner, above this thread.
Then you will get a list of all the threads in this cathegory.
Then klick the "New Thread"-button in the lower right corner.

Some tips to get good answers is to write a good description like "Help with unfinshed laser cutter" or something like that and posting good pictures, we love pictures and it makes everything easier!

Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 14, 2010, 05:52:03 AM
Hi Guys,

I am having so much fun with Art's Gearotic Motion that i just had to post another picture of some more laser cut gears.

Tweakie.
Title: Re: The Laser Project.
Post by: RICH on December 14, 2010, 06:17:33 AM
Tweakie,
Yes Gearotic is slick but just don't have the time to play with it much.
I like the mounted gears as they intrigue even the casual user and make for a neat display.
RICH
Title: Re: The Laser Project.
Post by: manmeran on December 14, 2010, 08:47:38 AM
fantastic
Title: Re: The Laser Project.
Post by: Sam on December 14, 2010, 04:45:34 PM
Pretty neat Tweak.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 16, 2010, 05:04:45 AM
A revisit to the Aztec calendar, as I had some mirror tile left over from another job.

This is laser engraved on the back of the tile and before anybody tells me - yes I know that I forgot to flip the image horizontally so the calendar is backwards  :D
This was a lot easier to make than it was to photograph - I took about 20 shots before I got one reasonable one. I have only just discovered how hard it is to photograph mirrors.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: dar303 on December 16, 2010, 05:06:59 AM
Very nice!
Title: Re: The Laser Project.
Post by: budman68 on December 16, 2010, 05:17:35 AM
Very nice!

What HE said!

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 16, 2010, 06:08:17 AM
Thanks Guys.

As a matter of interest, perhaps, the minimum achievable laser spot size is a function of the lens focal length and in my case the minimum spot size is about 0.1mm diameter. However, the photons (or whatever laser particles are called) are more concentrated across the center of this 0.1mm spot in the direction of it's travel (because the centre line of the spot is longer than a chord) and as the burn rate is time related, with a fast scan, a much finer line than 0.1mm can be drawn on an object. In some ways it is a bit like sharpening a pencil except that the faster the laser scan, the finer the burn line that can be achieved (within limits that I have yet to discover).
This is to a certain extent demonstrated in this Aztec calendar as finer detail than 0.1mm can be observed.


Tweakie.
Title: Re: The Laser Project.
Post by: Sam on December 16, 2010, 12:26:29 PM
Looks great Tweakie!
Title: Re: The Laser Project.
Post by: JHChoppers on December 17, 2010, 06:31:35 PM
Tweakie,

This entire thread is fantastic, the last project looks awesome.   Keep up the great work and thanks for sharing, I hope to do a laser project sometime, you have inspired me.  (and many others I am sure)

Thanks,
JH
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 18, 2010, 02:35:50 AM
Thanks Guys.

JH,
This thread has just somehow grown and grown, I was going to stop after about page 10 once the build was complete but with the ideas and suggestions from others I keep trying new things and learning new stuff. By sharing my experiences I hope others can build on them and in turn feedback their experiences etc.
The laser, as a tool, has certainly turned out to be more versatile than I had originally expected and thanks to the extra work Art has put into improvements to the Laser/Engraving plugin over the last month or so, things have just got better. Although my machine is not built for raster engraving, the Mach plugin has enabled me to obtain reasonably high standards of work (equal, I think to the low/mid price range professional machines).
It would be really nice to have someone else do a laser project / build log etc.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 21, 2010, 07:37:01 AM
I really should not do this because I have no permission to use this image which I came across on the internet but as it is just for my own testing and not for commercial or any other purpose I hope the artist will not mind too much.

This is a piece of 10mm acrylic, the reverse of which was sprayed black. The image was then laser etched into the paint/acrylic and then sprayed white. This is the result when viewed from the front. The next stage is, possibly, to laser engrave a foreground into the front of the acrylic - could have interesting results, perhaps.

Tweakie.
Title: Re: The Laser Project.
Post by: HighOctane on December 21, 2010, 09:16:22 AM
Tweakie,

I am setting up a machine with a synrad laser. I would like to do raster engraving. Are you aware of any manuals or how to guides on using the engraving plugin? Any suggestions on the best path to take?

Thanks,

Josh
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 21, 2010, 11:15:40 AM
Hi Josh,

As far as I know there are no manuals or guides but it is simple enough to use it is really just a matter of trial and error.

Output from the plugin is on the 'digital trigger' and this can be configured within Mach to any output pin# of your choice. The output power from the plugin is related to axis speed and it may take a while to get this just right but that's it really.

Good fortune with your project.

It would be really nice if you would start another thread with details and pictures of your project and the progress you make.

Tweakie.
Title: Re: The Laser Project.
Post by: HighOctane on December 21, 2010, 01:22:31 PM
Just so I understand, with the plugin you are doing raster engraving where the laser varies the power level based on the bit depth of each pixel in the image as it scans back and forth along the x axis?

What type of signal are you using to tell the laser how much power to put out? 0 to 5 volt analog signal or a PWM signal?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 22, 2010, 02:35:23 AM
Hi Josh,

The output from the plugin is a short duration pulse (40uS) it is the pulse repetition frequency that varies and this is in turn related to the feedrate. I am not sure this helps but the signal I am using to tell the laser how much power to put out is PRF.
I will be back on the project again in the new year but I am documenting the Synrad laser control here http://www.cooperman.talktalk.net/files/28.htm

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 30, 2010, 08:51:27 AM
A little bit more progress on the Synrad RF laser controller. After spending some time with the software trials I think I have now finalized the required layout for the circuit board. Nothing too fancy, just the basics.
This is the isolation routed PCB waiting for it's complement of components.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 31, 2010, 07:10:50 AM
Managed to get most of the components (the essential ones at least) soldered on to the new PCB.
Now to test it out.

The IC bottom right is type 74LS08 manufactured in Portugal by Texas Instruments and looking at this picture, I just noticed the date code which is May 1981 !!  Texas certainly make stuff that lasts  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 08, 2011, 01:19:33 PM
For anyone considering building their own RF Laser controller / interface for use with Mach3 I have now posted my draft constructional details which may be of interest - Circuit diagram, PCB track layout, PCB component layout, PCB isolation routing GCode and the PIC programing Hex code. These can be downloaded from here http://www.cooperman.talktalk.net/J48.zip  It is early days yet and there is bound to be more revisions to the firmware but this link should always point to the current version.

Tweakie.



Title: Re: The Laser Project.
Post by: Spruft on January 29, 2011, 11:23:29 AM
Hello Tweakie and others!

I've been following this thread for a while now with great interest.

I've recently got a Synrad J48-2 and tested it yesterday with the controller of your design. Thank you for sharing!  :D

Here is a picture from it.
(http://forumbilder.se/images/f29201150746Pccfe.jpg)

It says V16.1 when I turn it on.

I have some questions about the controller that is unclear to me.
1. Is there a tickle pulse even when I turn the encoder to ==OFF== mode?
2. From what I understand, the red LED on the J48-2 is supposed light dimly when it get the tickle pulse. Now it light up first at 1% PWM. And I've tried to get some light by changing the trimpot.
3. Do you change the frequency by pushing the encoder?

Best Regards
/Isak Nordell
Sweden
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 30, 2011, 03:36:31 AM
Hi Spruft,

Great work my friend that looks really good.

Obviously the controller is still under development and there will be some more changes to the firmware before I am finally happy with its operation. Version 16.1 is the current version.
I just don’t get enough time to work on this project so, like all my projects, progress is slow but sure.

1) In the OFF position there is no tickle pulse and the laser cannot be triggered (fired). The lasers red LED will be extinguished.
2) With the controller set to anything but OFF the laser’s red LED will glow dimly (after the lasers internal 5 second warm up delay) to indicate that a tickle pulse is present and that it is safe to fire the laser. Be careful adjusting the pulse width trim pot as tickle pulses wider than 1uS can cause the tube to start emitting a low level beam without actually having been triggered. (Currently the trim pot range is approx 0 to 2uS). With the controller switched to OFF the laser’s red LED will extinguish indicating that no tickle pulse is present.
3) Initially the frequency was changed by pushing the encoder, as you suspected, but I have a lot more work to do on this function because just changing the frequency without taking other factors into consideration enables the laser, in some circumstances, to be operated outside of it's comfort zone. So to be safe the frequency is currently fixed at 5kHz which is Synrad's recommended operating PFR.

Current work in progress:-
The development firmware now uses the encoder push function to switch between 5.0% steps and 0.5% steps so there are now190 possible settings between 0.5% and 95.0%.
Provision was made on the original PCB to add a pair of push switches (on a piggy back board) and these will be used to set other functions such as ‘last setting memory’, ‘store’ and PRF frequency settings etc. Full details of any updates will, of course, be posted.

Good fortune with your laser project and please keep us all posted with details of your progress and lots of pictures please (we all love pictures).

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on January 30, 2011, 07:34:47 AM
Thanks for the support Tweakie!

to switch between 5.0% steps and 0.5% steps
Haha I didn't notice it. Took a long time to get to 95% sometimes :D


A picture from the back. Currently working on the electronics.
(http://forumbilder.se/thumbs/920201113204Pd544.jpg) (http://forumbilder.se/show.aspx?iid=920201113204Pd544)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 30, 2011, 08:14:34 AM
Wow, that looks like a real good sturdy construction.

It may be helpful so I have attached the V16.2 firmware which includes the 5.0 and 0.5 step sizes (switched by clicking the encoder push). This version has not been fully tested yet but looks good so far.

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on January 30, 2011, 08:31:17 AM
Thank you I'll try that one out soon. There is some left before I can start playing around with mach 3.
1. Making a holder for the focus lens.
2. Air assist for protecting of the lens.
3. Setting up some kind of limit switches. Don't know what to use yet for this high speed application.
4. Some PWM regulation for the four PAPST fans to cool the laser (they are a bit overkill for shorter runs - 18Watt each - and make a lot of noise).
5. Knock a hole in the brick wall for poisonous gases to get out.
6. other stuff that will come up  ???
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 02, 2011, 07:35:35 AM
Managed a bit more progress on the RF laser controller.
This is a small 'piggy back' board that will be mounted over the top of the existing IC's and carries two 'push to make' switches. You have to be creative when building prototypes because the time when you can start over again soon disappears.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 04, 2011, 04:18:19 AM
Hi Guys,

This is the little sub-panel fitted in it's place on the controller board. I used a couple of spots of cyno to fix it's position on the IC's before making the through connections to the main board. The function of these two switches will be software programed to control such things as ‘last setting store and retrieve’, 'PRF frequency', 'menu selection' etc. What started out as a simple project just keeps growing  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on February 04, 2011, 09:20:40 AM
You are an inspiration Tweakie, beautiful work as always.
Thanks for the update,
Russ
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 24, 2011, 08:43:08 AM
'An Inspiration' ?, you are being far too kind Russ - I think if a vote was taken 'pain in the butt' would probably win.  ;D

Spring is on the way here and the laser was back in action today. I think I explained this before but Acrylic is one of the group of materials which will sublimate (turn from a solid to a gas without going through the liquid stage) consequently to avoid breathing the stuff (the laser vaporises acrylic almost instantly) I have a powerful fume extraction system. The extractor changes the workshop air in minutes so the temperature drops to outside ambient very quickly and during this cold winter, it takes it below the temperature at which I am happy to operate the laser, computer etc.

Ever since a sprog I have been interested in the work of M.C.Escher http://www.mcescher.com/ and the guys on the Phlatforum recently reminded me about Escher's Lizard, which is perhaps one of his most popular tessellation's. These have been cut from 3mm frosted acrylic.

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on February 24, 2011, 11:30:59 AM
Pretty cool Tweakie !
Did you burn them out as nested ? Or individually ?
What is the size .... roughly ?  (each)
I'll guess 25 x 25 mm ?
Thanks,
Russ
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 24, 2011, 11:46:23 AM
Hi Russ,

They are about 50mm toe to toe.
They were cut individually (my first attempt was nested but I was unable to separate the parts without damage).

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 28, 2011, 12:26:57 PM
I have received a couple of emails from others who have cut this lizard but said that the parts are too big to fit together properly and asked me how I did it.

Well…..

Eschers original drawing had just one line defining the boundary between each lizard and it’s mate and if you pick one image, convert it to dxf and then cut on the outside of the line the resulting pieces will not fit. Cutting on the centre of the line results in the clearance between one lizard and it’s mate being the diameter of the laser beam (0.05mm). Although it may well now fit (if it was drawn accurately enough in the first place) this clearance is still not enough to enable easy assembly and disassembly of the pattern so this is why I chose to cut on the inside of the line and why I cut the parts separately and not nested.

Hope this answers some questions.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 02, 2011, 06:25:41 AM
Something I have not really tried before is the inlay of wood into wood. Thanks to Switcher http://vectorink.com/ I downloaded one of his .dxf’s and using LazyCam created the wood cut outline GCode. This was then used to cut some parts from 2mm Obechi veneer. The .dxf outline was then filled black, using Photochop and saved as a .bmp which was subsequently then used with the Engraving / Laser plugin to cut the pocket into a leftover piece of Teak. Both the Obechi and Teak were covered in paper Transfer Tape (the stuff used for applying vinyl signs) before being attacked with the laser to protect the surface from smoke marking and discoloration. The part was then fitted in place using PVA and sanded flush when dry (the part was about 0.5mm proud of the surface).
It is not perfect but hey this is my first attempt, I have learnt a lot here and I am sure that I can make improvements. The edges of the cut have suffered from blackening and unfortunately, this is quite noticeable – perhaps using Nitrogen instead of Air as the assist gas would reduce this effect, something to try another day.

Tweakie.
Title: Re: The Laser Project.
Post by: Jennifer on March 02, 2011, 08:34:12 AM
Good Show tweakie!

that is my one remaining concern, that blackening around the edges, it is not an issue with woods like ebony or rosewood, so fretboard inlays are safe. However if i needed to inlay on a spruce top or someone who wanted a maple neck or head I could be in trouble. From what i am seeing it is mostly contained to the surface, so a little rigorous sanding could help. The nitrogen gas thing may help, or perhaps less heat by doing many light passes as opposed to one heavy pass with the laser, or maybe immersing the part in liquid nitrogen and cutting in a total vacuum :P

I am almost ready to "pull the trigger" on an epilog laser system. they have incredible accuracy for a small machine and their speed is blazing. while it would not replace a lot of what i am using CNC for it sure will improve my throughput with regard to cutting the inlay materials. cost is negligible about 15-20k for a mid range machine.

I also recently purchased a copy of V-Carve Pro. It is really nice stuff. generates nice tight G-code and has a lot of cool bells and whistles, the one i especially like is the 3-d images it renders, images of what the finished job looks like. you select the material, "run" the toolpath and voila you get a 3 axis rotatable image that you can export in a number of formats that i can send my customers. it is wonderful for getting them to "sign off" on a job before i ever have to cut a thing. comes in handy for thwarting the old "gee that's not what i thought i was getting" problem.

the only thing is the laser does not accept G-Code, and here i just spent the last six months immersing myself in that discipline. not to mention all the monies Ive put into that silly router and software. but the education i have received is priceless. Also i would not have met so many nice people into machinery if it was not for the Mach3 back end.

Speaking of the router, i have decided to change the X&Y axis from belt to a ball screw setup. Both axis already have pretty hi precision rails they slide on, it is just that little bit of play in the belts that gets frustrating, especially when there are a lot of quick direction changes. they sort of vibrate, which sometimes causes a couple of thou error in the parts.

Would it be worth exploring some kind of belt vibration dampening before i embark on changing it to ball screw?

Jen


Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 02, 2011, 10:06:52 AM
Hi Jen,

I have no experience of belt drive so cannot offer any advise here. (Incidentally the Zing will be belt drive and they work OK).

Not sure about cutting with many light passes, I will have to try this and see what happens. From past experience when cutting profiles a second pass had little effect unless you can get the carbon residue out of the bottom of the kerf. The true solution is probably more laser power so it can be vaporised before it has a chance to burn  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: OCNC on March 02, 2011, 10:10:48 AM

Speaking of the router, i have decided to change the X&Y axis from belt to a ball screw setup. Both axis already have pretty hi precision rails they slide on, it is just that little bit of play in the belts that gets frustrating, especially when there are a lot of quick direction changes. they sort of vibrate, which sometimes causes a couple of thou error in the parts.

Would it be worth exploring some kind of belt vibration dampening before i embark on changing it to ball screw?

 
Jen


Jen,

Slightly off topic here but I'm just wondering what size your drive belting is.  The reason I ask is that I've just built a router that uses 3/8" belts for the xy drives and I'm trying to determine what kind of accuracy I can expect from it.  Right now I see no issues with it but I'm not working to .001 inches.  I have the belts quite firmly tensioned.  I'll try to see if I can measure the stretch later today.

Chris
Title: Re: The Laser Project.
Post by: Jennifer on March 02, 2011, 10:52:08 AM
Thanks Chris,

sorry i posted this in the wrong place. not so much stretch, these are very large kevlar reinforced belts, it is more of a vibration issue. when the router head changes direction quickly, like working a tight corner with a 1/64th inch (.015") bit, yes they make them that small, it sets up a vibration you can see in the belt, especially with those nice machine generated G-Code files, the "wave" in the belt is what i think is the culprit. if i could figure a way of dampening this wave, i think it would improve accuracy.

with the laser it seems to work more like a printer making long sweeps with a single direction change at the end of each pass, so this condition may not occur. in fact i think a lighter (less mass) belt may be another consideration. Less mass less inertial force to set up vibration. gawd i sound like a freakin engineer, this is supposed to be art :)

i'll stay tuned,
Jen
 
Title: Re: The Laser Project.
Post by: OCNC on March 02, 2011, 02:14:20 PM
Hi Jen,

To test my repeat accuracy I ran the x axis 50 times back and forth over a 20" run and it came back after the 1000 inches less than .001 off of the zero position.  That doesn't really test the accuracy at the exact moment of an acceleration/deceleration and I'm not sure how I would do that.  With the motors locked I can stretch the belt about .005 in either direction before I hit a really solid resistance point.  My belts aren't kevlar so that may be an improvement I can make should I someday find the current accuracy insufficient.  My belts also have very little mass to them and I would never consider them to be contributing to a problem with inertial vibrations.  I imagine though that if this is the situation in your case you could put one or several idler pulleys along the backside of the belt to kill the harmonic tendency you're now seeing.  Also even though I'm new to this and can't speak with much authority I have noticed that some G-code files are more ridden with inertial changes than others.  There seems to be a bit of an art to generating files that are efficient at producing the highest quality part.  G-code generating programs are at best only working with a 'typical' geometric input in mind.  Another point I might mention is that I'm using a Smooth Stepper to generate the pulse stream (currently set at 64k) and this pulse stream is most definitely smoother than the default parallel port output.  Whether the quality of the pulse stream is contributing to your difficulties would be another item to consider.  If the laser unit doesn't run G-code then you won't be using Mach and I'm going to assume that it has it's own pulser which may be the source of the smoother result you're seeing in that machine.  You might want to find out what the spec is for the laser's pulsing engine just to be informed about it.

Thanks and I hope some of this is helpful.  By the way I can't imagine using a 1/64" bit. 

Chris
Title: Re: The Laser Project.
Post by: fer_mayrl on March 02, 2011, 02:21:12 PM
For anyone considering a Belt drive... I recommend looking into this thread at the zone:

http://www.cnczone.com/forums/linear_rotary_motion/59570-best_belt_drive_ever_if.html

There is a lot of information to digest in that thread but it is a very ingenious system which I believe would work very good,
It eliminates most of the belt stretch and the vibration in the belt which Jen mentioned.

Jen, by the sound of your comments, you are more of an engineer than a few engineers I know.

Take a look i think you'll like it
Title: Re: The Laser Project.
Post by: Jennifer on March 02, 2011, 02:35:01 PM
Thank you both for your comments,

i will check out the CNC zone thread and see what they have come up with. a simplified way to visualize this "wave effect" is to simply push in teh center of a belt with your finger. When you do the gantry will move a few thousandths, but spring right back. Now picture a wave running up and down teh belt from rapid repeated changes in direction, like when routing the apex of a triangle.

my machine will repeat with wonderful accuracy, even after a thousand traverses, thats not really an issue, it is this jiggling of the router head when i am attempting very fine sweeping inlays of abalomne or some other shell that drives me nuts. i have to go back and manually sand off this roughness. once i am involved in doingthat i have lost any time i may have gained by cutting the part with the darn machine in the first place.

i have a meeting, but will check the ink out in a bit... Thanks again, Jen
Title: Re: The Laser Project.
Post by: OCNC on March 02, 2011, 10:50:49 PM
Hi Jen,

I see what you're talking about.  If I pluck the backside of the belt like a guitar string I get the effect you're describing.  I wouldn't have thought that that light a load on the belt would show up as stretch (for me not much more than .001) but it does.  So this ultimately has to be belt stretch.   Have you tried adjusting the acceleration rate in Mach under Motor Tuning?  I found it necessary to play with this a bit as my initial tendency was to have the acceleration too high for the best cut.  

Good luck.

Chris
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 08, 2011, 08:21:50 AM
This inlay work has turned out to be incredibly easy to do but so so difficult to do well (perhaps that applies to everything) but I am now just starting to learn the key point like matching the aspect ratio of the whole image not just matching the height and width.

Thanks, once again, to Switcher for the DXF of the Rocking Horse.

Tweakie.
Title: Re: The Laser Project.
Post by: Jennifer on March 08, 2011, 08:59:31 AM
Hi Tweakie,

I use a software package called V-carve Pro ( http://www.vectric.com/WebSite/Vectric/vcp/vcp_index.htm ) for my inlay tool paths. it can create two different tool paths for each drawing i make. One for the piece and one for the pocket. It even tales into consideration the radius of the tool you use and corrects outside corners on the parts so you do not wind up with the old square peg in the round hole problem. You can also just specify your offset so the pocket will be a little larger than the piece thus allowing for glue space and finishes. it is really neat stuff.

They allow you to download the entire package for free, you can even save your drawings. it just will not generate the G-Code from them. But if you are nice to me i will let you send me a drawing or two and generate if for you.

they also have many hours of video tutorials on-line i think one of them is geared specifically for inlay basics.

inlay is big fun especially when you get into real intricate patterns, but it can also be maddening. It really is not the best candidate for a CNC solution unless you, like me, need to repeat the same design many times. it is a lot faster to cut your part with a saw and route out your pocket by hand, unless you are getting into a production scenario.

Jen
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 09, 2011, 09:13:45 AM
Hi Jen,

Thanks for the offer to generate the VCP files – I may just take you up on that one.

Most of the things I do, in a way, demonstrate that CNC can and in fact is replacing skill in the workplace. I doubt I have the ability to manually do inlay work, to make even a reasonable job would require many skills that I really just don’t have, artistic ability being one of them. This is where CNC comes into its own and the Turners Cube http://www.machsupport.com/forum/index.php/topic,9755.msg59684.html#msg59684 is a good example of something I can easily make with CNC but not with a lathe as it was originally intended.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 10, 2011, 10:40:48 AM
Not perfect but an interesting exercise nonetheless.
This may have been a little over ambitious, it certainly took a while fitting in all the little parts (which I carefully kept in order) but it did prove to me that the Mach Engraving/Laser plugin and LazyCam can, together, produce reasonably acceptable results.
I have no doubts that it would have been easier and perhaps quicker to use VCP and perhaps the results may have been a little better but I just had to try using the software which already comes with Mach3 at no additional cost.
I think I may have had my fill of inlays.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Jennifer on March 10, 2011, 12:09:46 PM
Tweakie,

I love Celtic Knots. You did a very nice job. now shrink the whole thing to about an inch and a half, use abalone shell for the part and you will have an idea of my challenges :P

Jen
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 10, 2011, 12:26:49 PM
As long as you make a better job of it than I have done it will be just fine I am sure.
When do you get your Zing, have you got a date yet ?

Tweakie.
Title: Re: The Laser Project.
Post by: Jennifer on March 10, 2011, 12:50:30 PM
Tweakie,

i went with the Mini 24 in a 60 watt confugiration. it has servo motors rather than steppers, 20w more power, high grade optics with a different lens more geared to vector cutting rather than engraving, a vccume table and air cooing. it cost me a couple bucks more but it will allow me to grow without outgrowing the machine.

delivery will be after i retun from Floriduh, in about three weeks.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 22, 2011, 12:05:24 PM
Fredzway has been kind enough to share his design for a Christmas decoration with me and to prove the toolpath I have removed the tool radius offset and laser cut the parts from 2mm Obechi. Fred tells me the halo is made from a part section of brass tube so allowance has been made for this to be fitted.

Nice one fred, good fortune profile cutting the parts.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 23, 2011, 12:47:06 PM
Another etching, made using the Mach Laser/Impact plugin.
The material is an aluminium surfaced engraving laminate which, fortunately, does not contain any PVC and lasers extremely well.
This is one of my musician buddies, just hope he likes it.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on March 23, 2011, 03:55:48 PM
Wow, that's pretty impressive, Tweakie. I like it.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 24, 2011, 03:15:40 AM
Thanks Sam.

I am going to experiment a bit more with this as the results are unusual or different to the norm.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 24, 2011, 09:45:51 AM
At last I think I have finally been able to produce a raster image without any horizontal banding. It is early days yet so I must not be too complacent but I have now made some 5 or 6 of these same images of young Lena (top part of photo only - this is a family forum  ;) ) all different sizes and without any banding at all. Like many problems it appears that there was more than one component to this problem.

Tweakie.
Title: Re: The Laser Project.
Post by: Matospeter on March 26, 2011, 12:59:06 PM
Forgive the ignorance here, but who is lena?   She shure is pretty.... You are doing some AMAZING work with your Luke Skywalker router there man. Very cool stuff... Keep up the good work and pics... peace

Pete

Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 26, 2011, 01:23:13 PM
Hi Pete,

She is Lena Soderberg and her picture featured in a Playboy mag of 1972 when she was in her early twenties. The pic itself went on to be used as a standard for digital image processing and the very first .jpg compression trials. The pic in it's entirety is truly beautiful and well worth doing a Google search to find.

Thanks for the encouragement, I just keep learning as I go.

Tweakie.
Title: Re: The Laser Project.
Post by: Matospeter on March 26, 2011, 06:22:02 PM
Tweekie,

    Yes she is stunning and I can see why the picture is so famous, beautiful girl....

    You may be just trying to learn but all the while you are teaching the rest of us what is possible with this interesting and challenging endeavor of CNC. Your pictures and details serve to help the rest of us to see what is possible and more importantly how to do it. Thanks for sharing your ideas and imagination. Peace

Pete
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 28, 2011, 07:55:21 AM
This is the laser cut 'proof of concept' face for my Aztec Clock.

It will have a quartz movement, keep perfect time and is guaranteed to run right up to Midday on the 21st December 2012.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: ostie01 on March 28, 2011, 09:08:46 AM
Does it come from an Aztec playboy magazine  ;D ;D ;D


Nice job, really appreciate your work. ;)


Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 28, 2011, 09:47:36 AM
Thanks Jeff  ;D ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on March 28, 2011, 04:00:52 PM
Have you a design made up for the clock arms? You realize you gotta make some fancy dancy frame for it, too, don't you?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 29, 2011, 03:55:39 AM
Have you a design made up for the clock arms? You realize you gotta make some fancy dancy frame for it, too, don't you?

Oh dear, I hadn't realised that Sam, thought I could get away with the standard quartz mechanism hands and a block of Teak.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on March 29, 2011, 05:19:16 PM
Well, I mean........if you wanna put the cheap grade gas in your Bugatti, I certainly wouldn't want to stand in your way.  :-* Super kitty wouldn't stand for it, for sure. Tell him what you just told me, and look him in the eyes when you do it. Don't send him a text message, don't send him an email, don't tell him over the phone. Look him in the eyes. I want you to witness the emotion he portrays to the fullest extent possible.
Title: Re: The Laser Project.
Post by: JungleStreetRecords on March 30, 2011, 12:44:20 AM
Everybody needs a laser! yeah. I was wondering if you knew, if you ran the laser beams through color filters, would that change its Nm size if you used them instead of optic lenses?

I messed around with fiber optic digital audio bouncing the light beam from cables off of cd at 45 degrees, recaptured the beam with another cable and still made it through even though I added and changed color filters in the beam's path.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 30, 2011, 03:38:21 AM
Hi Sam,

I took your advice and had a long talk with SK.
Glad I did really because he says that my whole idea is rubbish because the Aztecs never did subtract from 5 in the same way that the Romans did in their number system, he says that from the evidence available they only used addition.
This throws off my whole design and concept, so I think it’s back to the drawing board before I even get around to the hands. SK says he is going to help me to get the numerals right next time (he is still thinking about the hands).

Hi JungleStreetRecords,

My laser operates at 10600nm and at this wavelength color filters don't actually exist (this is well outside the spectrum of colored light). Even the focussing optics have to be made from special materials such as GaAs or ZnSe otherwise the transmission losses would be far too high and cooling of the optics would start to become a major problem. Fiber optics don't work well in this range although there are some made from Zinc Selenide but these are well beyond my price range. Shame really because if it wasn’t for the Chlorine gas I bet I could cut a mean track in a record blank.  ;D ;D


Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 30, 2011, 01:53:10 PM
Well this is SK's design which is a lot more subtle with the chapter ring around the outside. Now for some hands (or paws)  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 06, 2011, 07:27:53 AM
Another of the aluminium coated engraving laminate pictures produced with the Impact / Laser plugin.
(The aluminium coating is only microns thick here and the laser chews its way through this stuff far too easily - the trick is getting the power level low enough not to end up with a totally black image)  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 10, 2011, 07:21:47 AM
One more of these, just to bore those that I haven't already bored to death.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 11, 2011, 05:29:25 AM
I know that a Permanent Marker would have been just fine but it is these little things that earn me Brownie Points.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: ostie01 on April 11, 2011, 06:19:12 AM
Spinach brownies, will pass ;D ;D


Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 19, 2011, 08:08:00 AM
Over the winter months the Synrad RF Laser controller went through much testing and as luck would have it, performs better than I had even hoped - the inbuilt, hardware PWM of the PIC micro is just brilliant and so stable under all the test conditions.
Now on to the enclosure which is really just a front cover because the PCB will be mounted on the outside of the laser housing and this cover fitted over the top.

1) The enclosure cutout and window milled to size. This cover started it’s life as the lid from an IP65 enclosure.

2) The front panel (1.5mm engraving laminate) which has yet to be engraved. I prefer to draw my work on paper, others prefer to use CAD - whatever, the end result is still a toolpath for the CNC.

3) The knob - perhaps doesn't look like it but more work has gone into this knob than I care to admit. It was turned, CNC machined, sand blasted and then anodized. And, like most things, if I had a second go at it I could probably make a better job.
 
4) Still some way to go but this is how the parts made so far will fit together.


Tweakie.
Title: Re: The Laser Project.
Post by: Sam on April 19, 2011, 08:27:40 AM
Great job Tweakie. Looks great.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 19, 2011, 08:31:55 AM
Thanks Sam.
When I made the knob I could hear your words, saying "anno it"  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on April 19, 2011, 02:46:57 PM
Darn right! Hey, I dropped an anodized part on a concrete floor one time. The concrete chipped, the anodized part wasn't even dented. It really makes the durability of aluminum go up considerably. Looks purdy too.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 20, 2011, 07:22:44 AM
A bit more progress on the enclosure. The engraving is done and the buttons sand blasted and anodized to match the knob.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 21, 2011, 07:38:05 AM
A quick bench test, just check it all works OK now that it has been assembled up.
Here, the laser was fired for a 1 second burst (pressing the trigger then camera shutter almost simultaneously) at a setting of 20.5% PWM which, according to the Synrad power graph is approx. 25% of the lasers output power. It makes an instant and satisfying 'pop' as the cardboard ignites.
This is the beam straight out of the laser (approx. 6 mm diameter) without any lens, when it has been focussed to a point the size of a pin prick (0.04 mm) it should be quite awesome.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on April 21, 2011, 08:29:37 AM
Hello Tweakie. I need your help. My machine computer hard drive collapsed.I had in the hard drive the licenced mach3 programm.I dont know yet if i can retrieve it.Do you know in which file there is written the licence data? I dont remember under which name i had purchuased it!!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 21, 2011, 08:35:55 AM
Hi Buddy, it is called 'Mach1Lic.dat' and it is in the Mach3 folder. If you have really lost it then contact Scott and he will re-issue the license but you may have to specify the name or possible names you used when you purchased it.

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on April 21, 2011, 08:39:07 AM
Thanks very much
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 26, 2011, 05:24:40 AM
Just something I tried during the holiday - as opposed to 'inlay' this is 'onlay' or laser marquetry.

This example is rubbish really because it was produced by cutting two identical images from different veneers and then transposing the parts. It has no allowance for tool radius offset so I have filled the kerf just to see the end result.
By thickening the outline of the original .dxf I should be able to produce two toolpaths (one for cutting on the outside of the line and one for cutting on the inside of the line) then, if I get it right, the parts should fit exactly with no visible kerf.  :-\
A lot more experimenting before I get it right but it is an interesting technique and eminently suited to lasers.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 26, 2011, 08:52:38 AM
My Boss took an early lunch today and while the cat's away..........

It took two attempts to get the tool radius offset correct but once I got it right the parts do fit pretty well.

Tweakie.
Title: Re: The Laser Project.
Post by: Fastest1 on April 26, 2011, 12:31:32 PM
So is this laser cutting a negative and positive and you are switching the cutouts? I am not sure of what I am seeing and havent really followed the thread.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 26, 2011, 12:46:35 PM
That's about it.  ;)

( I haven't shown all the leftover parts that are thrown away).

Tweakie.
Title: Re: The Laser Project.
Post by: BR549 on April 26, 2011, 09:47:41 PM
WOWSER Tweakie that is great work. Good Job

PS You are going to have ART drooling all over the shop.

(;-) TP
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 27, 2011, 01:48:46 AM
Thanks Terry, who knows, I could be stalling out at the craft fairs later on in the year.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 06:54:39 AM
Very very nice control box you've got there! Mine is not as nice but I have much bigger problems right now  :'( :'( :'(

My Synrad made the worst kind of smoke. Looks like I could repair it but it would be nice to know why this happened in the first place.

Edit: A service manual would be good and schematics over the RF board. Synrad have not answered yet.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 03, 2011, 07:30:53 AM
Ohh dear.  :'(

With a bit of luck it is just the 1000pF silver mica which has expired.

Here is the RF board schematic (assuming you have the version with just one single RF output transistor).

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 07:51:38 AM
Yeah I sure hope so. Thanks for the schematic. What voltage do you have? I have 30VDC.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 03, 2011, 08:03:21 AM
The same here, regulated 30 Volt, 14 Amp (made in China).

Tweakie.

(Observe caution with the riser from the tube, this is in a gas seal and has to be treated with respect when un-soldering / re-soldering the cap. Also all the conductive carbon / metal deposit (from the arcing) has to be removed from all the insulated areas of the circuit board if repairing).
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 08:20:56 AM
Thanks for the advices.

I'll start with the caps. I've got two of them, one one each RF board.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 09:19:19 AM
OK ??? I have two different RF boards. One has the MRF150 transistor, the other one MRF151.. I wonder if they have different MICA caps then. The blown one is quite unreadable..
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 03, 2011, 10:44:38 AM
Do you have a problem with both RF boards ?

I am no expert here but I understand that it is quite common for one RF board to fail and the laser to continue to operate on reduced power. So far I have seen two Type 48's which have had just one RF board replaced at some time or another during their lifetime.
The MRF151 is a slightly higher gain than the MRF150 but they are essentially the same component. The mica caps will be the same value on both boards.
I am uncertain about the setting up / matching but if it is adjusted at the threshold then lasing will begin at a pulse width of 3uS +/- 0.5uS at 5kHz PRF.

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 10:54:07 AM
Thank you! Sorry for posting here in your thread without asking. Your name was the first to pop up in my head when the laser broke.
I'm on a mission to gather all the knowledge about repairing the synrads yourself >:D

Someone said that you could tune this boards with an oscilloscope. I'm just guessing but I think you want the boards to be in sync?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 03, 2011, 11:38:30 AM
No problem using this thread - this forum is all about sharing knowledge (it is slightly Mach related so I think we can get away with it  ;D )

As far as I can see, there are two issues regarding setting up.

1) Matching, where the power output of each board is the same and adjusted with R3 (see earlier posting).
2) Tuning, where the RF frequency of each board is the same and adjusted with C5.

An oscilloscope, preferably dual trace, would be ideal when adjusting the frequency to match both boards. I don't think Synrad specify the exact frequency although it is probably around 30Mhz so you will have to measure the good board and adjust the repaired board to match it.
Take care when making any adjustments (use non ferrous, insulated tools) as high power RF is dangerous stuff to mess with.

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 11:48:16 AM
Well the situation is that there is no lasing at all so I guess both boards are dead. Or There is something stopping the second one when the first one is dead. Hopefully I don't burn my Fluke.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 03, 2011, 11:58:24 AM
Just a thought but there should be two 7 Amp fuses (F1 & F2) on the main board - these relate to each RF board supply.

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 12:21:09 PM
Checked them now and they are still good. What good did they do anyway? haha
Title: Re: The Laser Project.
Post by: Spruft on May 03, 2011, 01:32:47 PM
Now I got in contact with Synrad. I'll keep you updated.
Title: Re: The Laser Project.
Post by: Spruft on May 06, 2011, 10:41:59 AM
YEEEEEEEEEESSSSSSS!!!! :D (could not find any crazy happy smiley)
New Caps made it work! No I'm going to tune this tube before it blows again.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 06, 2011, 10:47:10 AM
Good news indeed, glad you got it sorted.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 10, 2011, 07:29:59 AM
These are the prototypes of a solder paste mask for a small SMD circuit board. It was really just a test of Art's mathematics to see if the engraving plugin maintained it's scale and aspect ratio which, of course, it does. So easy to make that they are throw away items and don't really have to last for that many uses but we will see how they hold up. The cut-outs are the same size as the solder pads on the pcb which is perhaps a mistake as I now think that they could be made smaller and thus apply slightly less paste. As with everything new, you read-up on it first but practical experience always wins out in the end.

Tweakie.
Title: Re: The Laser Project.
Post by: Spruft on May 11, 2011, 02:56:44 PM
Good usage of laser!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 14, 2011, 09:09:56 AM
Thanks Spruft.
If that was a good use of the laser then this has got to be the daftest - my own personal Grain of Rice.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: ostie01 on May 14, 2011, 03:58:47 PM
Have you done the box or only one ;D ;D ;D


Jeff
Title: Re: The Laser Project.
Post by: Sam on May 14, 2011, 05:58:26 PM
He's only done the one. Tweakie is smart enough to only have to do the one, plant it, and the rest simply grow already monogrammed.
Title: Re: The Laser Project.
Post by: Dan13 on May 15, 2011, 03:37:11 AM
Amazing!

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 18, 2011, 05:02:47 AM
He's only done the one. Tweakie is smart enough to only have to do the one, plant it, and the rest simply grow already monogrammed.

Spot on Sam. This is the plan  :D

http://www.identity-links.com/environmentally-friendly/seeds/magic-bean-that-sprouts-a-leaf-with-your-logo

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 27, 2011, 02:25:07 AM
I have been using the Impact / Laser plugin quite a lot recently and one problem cropped up twice (one time too many in my book).
Depending on the image height and the vertical stepover the scan can sometimes finish at the top right of the image. If this final pixel turns the laser on then the work is automatically spoiled when the laser path is draw diagonally back across the work when the head returns to the X0,Y0 origin.

As Art generously made the code ‘open source’ it was time to take a look and I have now added code to always turn the laser off before returning to the origin at the end of the scan and (as belt and braces) altered the return path to X0 then Y0 rather than the diagonal. In addition, I took this opportunity to remove the redundant 40uS runtime check box  and make a couple of alterations to the appearance of the UI.

The modified DLL has been attached just in case anyone else using this plugin has encountered the same problem and needs a solution.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 28, 2011, 04:33:50 AM
Whilst still on the Impact / Laser plugin - I recently carried out some basic measurements of the trigger pulse duration and timings so I thought I would share this information together with some other basic stuff which I have put into a PDF document.
I hope this will be of interest to other users of the plugin and perhaps of assistance to new users when setting up their systems for the first time.
Although I expect to update it with additional information soon, the first issue is attached.

Tweakie.

Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 08:30:52 AM
Tweakie, thanks for offering your knowledge.Not a long time ago i had bothered you with the problem I had with the double image while trying to engrave!!I still have it .I noticed that as I put the speed up the distance between the two images tend to be bigger.As I told you before i use pwm pulse  from my circuit board to the laser power supply.I have put so much thouht in solving it but nothing. If it was the speed that the pulse or even the power supply reacts to given pulse , then i think that the the images wouldnt be simetrical.Any idea?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 02, 2011, 08:39:15 AM
ntlaser,

Do you have "Sherline 1/2 Pulse mode" checked in Ports and Pins ?

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 08:46:12 AM
no,everything is as you discribe to your pdf
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 08:49:42 AM
if i push the " sherline......." the the images are again two. If it was a problem with the laser supply and its reaction speed then I believe that the images should be 4.Very crazy!!!!!!!!!!!!!!!!!!!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 02, 2011, 08:58:14 AM
You could well be right here.
Increase your stepover so you can study each individual line of the images produced.
Because the plugin operates in duplex mode (bidirectional) then if each image is produced by alternate lines it would indicate too great a delay in firing the laser after receiving the Mach trigger pulse.
(Not sure I have explained this very well).

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 09:03:37 AM
yes, but if this was the issue why there are two images.If ther was a delay in firing then the one image should be dithered or something like that.The double image in a given space (examle.I have one rectagular 30x30,then in the width axis(x) there are 2 images in the space of 30mm).!
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 09:05:56 AM
doesnt make any sense.And why the double image is produced in the one axis(x) direction?I have to mention that my x axis has faster speed than the y axis!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 02, 2011, 09:07:08 AM
Certainly a mystery.
Could you possibly post a picture of the result and a copy of the test image you are using please ?

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 09:09:12 AM
I will make some samples and posted tommorrow,if this ok!Thanks you very much for your help.
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 09:15:05 AM
could you post a simple test image that you have already tested and your plugin screen(settings).To make a sample on this?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 02, 2011, 11:07:46 AM
Something like this would be good.

Say 30mm x 30mm, Stepover 0.5mm, Feedrate 20,000 (not inverted)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 02, 2011, 01:52:24 PM
This is the result I get from the above image settings.
The scan starts bottom left and it can be seen from alternate lines that there is a slight delay where the laser turns on and another slight delay where it turns off. This delay is so small that it makes no difference to the quality of photos or other images processed by the plugin.

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 02, 2011, 04:29:14 PM
I ll try it first thing tomorrow.
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 05:16:57 AM
Tweakie good morning.These are the results.
1 st photo  30x30 0,5  20000
2nd    only change the feedrate   7000
3rd   feed        4500

Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 05:20:35 AM
here are the photos
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 05:25:52 AM
As you see for 20000 the images are 2 and the power output is too strong(how I can modify the output?)
with 7000 the images come closer thats why you see totally burnt in the middle where the two imagew meet
4500 the same but here is more obvious.The black is where the two images meet..........
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 03, 2011, 06:47:43 AM
It is difficult to see exactly what is happening from those pictures but it could (as I said earlier) be related to a delay in turning the laser on and therefore vary the spacing of the two images with changes to federate. What I was hoping to see was if each of the two images was created by alternate line scans (one image created by the left to right scan and the other image created by the right to left scan).
Going back over earlier posts in this and the other related thread, I think it would be a good idea to investigate the PWM laser current control aspect. I never managed to succeed with the Mach PWM control and it’s a long shot but perhaps this is what is causing your problems.
As a test, would you consider the following?
As I understand it, you have a board which converts the Mach spindle PWM signal to an analogue voltage from 0 to 5 Volts which is in turn connected to the laser PSU (IN and GND terminals) to control the maximum laser current.
Try disconnecting this board and connecting a potentiometer, as attached diagram.
Set the potentiometer to mid travel (never set it to maximum unless you can monitor the tube current to ensure that the makers maximum recommended current is not exceeded).
Turn off the PWM function within Mach and then repeat the same test as you did before.
I don’t know for certain but Mach really has a lot of work to do running this plugin and it may just be too much to ask for it to generate the PWM as well.
Either way this will at least rule out one possibility.

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 06:52:54 AM
Thanks Tweakie.Actually my board sends the pwm signal of mach dirrectly to the Psu.The PSU works either with Pwm or Analog dc 0-5v. The problem with the external potentiometer is that I cannot control on/off the laser!!
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 06:54:31 AM
I tried to attach a video but was to big.In the video it shows that the to images are made as you said.The left from left to right and the right from right to left!!!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 03, 2011, 07:03:27 AM
Another question comes to mind - How exactly do you control turning the laser on / off ?
Where do you connect the Digital Trigger output ?

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 07:05:41 AM
I connect it to the board of mach where all Mach signals leave!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 03, 2011, 07:18:53 AM
As I see it the Digital Trigger should be set Active Low and the assigned output pin# should be connected to the laser PSU TTL(L) input and this is where the laser is turned on / off.
Are you switching the laser on / off a different way to this ?

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 07:25:24 AM
I do exactly this! I use the same pin (9) that i control the laser when cut.In cutting I  control it like controlling the spindle speed.This only when I cut.For engraving I have made a separate Mach (engrave) where I disable the spindle and I enable pin 9 for the digital trigger.Do you see a problem in that connection?
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 08:00:09 AM
I will do that
Thanks
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 03, 2011, 12:53:09 PM
ntlaser,

From what you have said and after looking again at all the possibilities I think it is definitely a delay issue, but perhaps not as I first thought.
Looking at your double image - if the laser was fired late then the left image would be created during the right to left movement of the axis. The only way in which the left image could be created during the left to right axis movement is if the stream of trigger pulses started early or in other words there is a delay in the start of the axis movement. This would also hold good for different feedrates altering the spacing between the two images and could also explain the non-linearity in your earlier Micky Mouse double image.

I have attached a revised diagram of how I think you should consider connecting your laser PSU and Mach. (Ignore PWM control of laser current and set it manually for both Engrave and Cut operations).

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 03, 2011, 02:59:11 PM
Tweakie thanks again I will try it and  tell you as soon as I test it.....
Title: Re: The Laser Project.
Post by: ntlaser on June 04, 2011, 03:18:58 AM
Tweakie good morning! I was thinking about two things. 1) how i will be able to achieve shades in the engraving mode if I will  change the laser output with analog way manually.I suppose I will set the potentiometer to a certain value and I will not be able to change it through the engraving.During cutting I will not have this problem because the laser output is the same and doesn't change.
2)If by connecting my pin 9 ,that gives a pwm pulse eguivelant to 0-5v, on the TTL(L) ,I will damage my PSU?
Thanks.
Title: Re: The Laser Project.
Post by: ntlaser on June 04, 2011, 03:21:14 AM
** Until now the laser output in the engraving mode was connected someway with the feedrate!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 04, 2011, 05:30:53 AM
ntlaser,

Within Mach disable PWM spindle control.
When I refer to your pin#9 I am referring to the pin#9 from the computer's LPT parallel port.
Configure your pin#9 to the Digital Trigger and set active low.
Ensure that pin#9 is not configured or enabled to any other function within Mach.
Connect pin#9 to the PSU’s “TTL(L)” terminal (see earlier diagram).
Set the potentiometer mid travel for testing and adjust as necessary but make sure you don't set it too high and exceed the tubes maximum current specification. If you don’t already have a milliamp meter (0 to 30mA) connected in series with the earthy end of your laser tube then you should obtain and fit one.
Make whatever safety interlock, water flow etc. connections to the “WP” terminal of the PSU.

Shades are achieved within the Engraving plugin by varying the Pulse Repetition Frequency (not PWM) on the digital trigger output. A PRF of 100% would be equivalent to maximum power and a PRF of 0% would be equivalent to minimum power. In practice the Engraving plugin never gets anywhere near to a 100% PRF (see my pdf document for values related to feedrate http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=26734 ) but manual control of the maximum tube current can, to a large extent, compensate for this.
The manual control of tube current can be adjusted at any time during operation to achieve the appropriate laser power for the job in hand. A multiturn potentiometer with calibrated dial is good because the adjustment is quite fine and the dial enables the correct settings to be recorded so that they can easily be used again at a future date for a similar job.
The Engraving plugin, as mentioned earlier, controls the laser’s output power by adjusting the PRF and this, in turn, is directionally proportional to federate and pixel value (high federate = high laser output power : low federate = low laser output power : no feed at all = laser off). It’s really just as simple as that.

I hope I have explained all your questions.

Tweakie.
Title: Re: The Laser Project.
Post by: ntlaser on June 04, 2011, 07:21:54 AM
I have already a miliamperometer!!I will try it!!!!! To see what will happen!!Fingers crossed:) ..Thanks
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 07, 2011, 07:17:26 AM
I finally got around to making another "Che" coaster and more or less got the cut-out dimensions right this time. The problem is that, for the same power settings and feedrates, different types or wood veneers laser cut with different kerf widths. Still, I am quite pleased with the result - just need to make a couple more, with different images for the set  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on June 07, 2011, 10:34:47 AM
Hi Tweakie,
  Hopefully, the set would include one of him with a bullet hole in his head .... and / or maybe hanging from a tree.  ;D

He is very pretty, but I'd think you could find a better subject given the atrocities he's responsible for.  :)

Beautiful work none the less.
Thanks
 :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 07, 2011, 11:07:42 AM
Thanks Russ, you are of course quite right, but he did finally meet a fitting end.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 13, 2011, 02:24:49 AM
Last week I urgently needed a couple of gaskets so, just for fun really, I used the same technique used a couple of years back to make the crankcase gasket for my OS61. Provided the casting or part requiring the gasket is small enough to lay on the platen of a flatbed scanner it is fairly easy to get an image then, after a bit of cleaning up, an outline DXF can be produced and converted to GCode.
My laser will not cut all types of gasket material and there are limits to the maximum thickness for the stuff it will cut but these fellas are 0.8mm thick and came out pretty well. I only needed one of each but made an extra while I was at it.  ;D
Gaskets made this way would be ideal for Steve, building his excellent V8, where neat and precise cutting is important but it takes time, mainly in the preparation and cleaning up of the artwork.
This took me just over the hour to make some parts which I probably could have cut with scissors in 10 minutes but it has made a very tidy job of something, with a bit of luck, I may never ever see again.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on June 13, 2011, 05:10:52 PM
Only sissies take the easy way out with scissors anyhow. Good job Tweakie. (as usual)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 14, 2011, 01:11:50 AM
Thanks Sam, I never really thought of it like that  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 20, 2011, 01:46:50 AM
Returning yet again to the Mach Impact / Laser plugin - I have now managed to add a little more information to the PDF document on it’s use.
If anyone has any suggestions, corrections or information they would like to see added please PM or e-mail me and I will add it to the document.

The revised PDF can be found here;  http://www.cooperman.talktalk.net/Engraving.pdf (http://www.cooperman.talktalk.net/Engraving.pdf)

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on June 20, 2011, 02:24:30 PM
Thanks Tweak! Your certainly an asset around here.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 22, 2011, 02:43:35 AM
Thanks for the kind words Sam.

Unfortunately there are only about 5 or 6 of us (that I am aware of) that currently use this plugin with a laser as those before me, who could not get it to work, have now taken other routes.
Our minority Mach group desperately needs new members.

Even Art has purchased a laser machine that uses the HPGL printer link rather than GCode and Mach so I doubt he will ever get to use his own plugin  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: naPS on June 22, 2011, 02:50:59 PM
Hey there Tweakie -

I've actually been using the plugin since completing my own laser a week or so ago - and I have to say, thank you very much for the changes that you made.  They work great.

In general, I've found the plugin to work great.  Took a couple of passes to figure it out, but it's simple, and does the trick. 

My only problem with it is more a problem with my own laser and it's design.  I'm using a pot to control the 0-5 volt signal to my laser power supply, and unfortunately I don't have a display showing me the current voltage that I'm sending, which makes repeating my past successes challenging.  When I get it right though, it's pretty amazing.

The only bummer is, I will also probably end up using a third party control card, such as the RetinaEngrave or something similar.  I would like to combine some vector and raster work into single pieces with varying power levels, and while I can get it working using a couple of different steps in Mach3, it's just not to the level of simplicity and replication that I need in a hobby laser.  Well, the combination of the two, at least.  The actual vector and raster operations individually are a snap.

I will continue to use this plugin for small runs that I have, it works great.  And I like that it doesn't require any other external software.  It's really pretty cool!

Thanks again for keeping this going!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 23, 2011, 02:16:20 AM
Hi naPS,

Thanks for the feedback (there is now 6 or 7 of us using the plugin  ;D ).

If you do decide to go for something like the FSE option please report back on your results (even though it will not be Mach driven).

Of all the laser stuff I have completed so far there has only been one job where I have combined two different power levels http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=25183;image so I have not really given a power changing option serious thought. Something more to add to my 'to do' list I think and thank you for the suggestions.

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on June 23, 2011, 03:41:26 AM
 hey tweakie  
  very impressive
 i have a friend who going to bye  a lazer cnc . he was tellling me about cutting plastic  and if  the gases get on the lens of the lazer .  8) 
 
    mikee
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 23, 2011, 04:40:48 AM
Hi Mikee,

My lens is made from Zinc Selenide and is AR coated on both sides - cleaning it is a delicate process which I really don't want to have to do very often so I use a 'co-axial, air assist' at all times and I have adjustable pressure / volume settings that I can select for different jobs. Because the lens assembly is always above ambient pressure during use it keeps the smoke out.  ;)
You can see the nozzle and just see the air supply line in this photo http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21034;image

Tweakie.
Title: Re: The Laser Project.
Post by: robotmar on June 23, 2011, 10:56:34 AM
Hi Tweakie

You think that your new modified pulgin is able to drive my systems?

Andrea
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 23, 2011, 11:59:37 AM
Hi Andrea,

Yes indeed it will Sir and it can be downloaded from here;  http://www.machsupport.com/forum/index.php/topic,12444.msg127947.html#msg127947

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on June 23, 2011, 01:58:30 PM
 hey tweakie
if it ok with you i was going to tell my friend about you. is going to buy a lazer cnc  his name is owen at one time he was a mill wright. i dont think he will be needing alot of help like me. i lack a formal education. and to make thing worst i was very sick and in a coma for 6 weeks last  OCT-NOV there is a lot of things i cannot remember . this is a struggle to me. and i have no hope of making anything . without ppl like you helping me .  i am most llikely, the least educated person in here.  i just like to say thank you. 
Ps my wife was educated in kent  ok back to work i go
mikee
not much land dam few cattle co
Title: Re: The Laser Project.
Post by: naPS on June 23, 2011, 03:31:45 PM
So one of the things I'm going to give a shot to help with making engraving using the plugin a little more consistent is adding a digital volt meter that reads the input signal to the laser.  That will at least let me know what's going on instead of just relying on the scribe mark on the knob of the pot.

I'm also looking at getting a multi-turn pot that will hopefully allow for finer adjustment of the voltage signal to the laser as well.  Right now the one that I have is fairly rough, and has quite a bit of 'backlash' if there is even such a thing in pots.

I should have all of it installed by next Friday, I'll let you know how it goes.

Also - that picture of the engraved egg is pretty amazing.  Ingenious!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 24, 2011, 02:17:36 AM
Hi Mikee,

All of us, yourself included, each have expertise in different areas or directions and it is when we all come together, on a forum such as this, that a tremendous amount of knowledge and experience becomes available (bit like the individual pieces of a jigsaw making the complete picture).
Others will help you and you will in turn help others - it doesn't matter how clever another person seems to be, there will always be things that you know that they don't - that is the way it is.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 24, 2011, 02:41:58 AM
Hi Todd,

I would be most interested to hear how the digital voltmeter performs.

I don't have any backlash problems with my multi-turn dial but obviously there are good ones and bad ones and perhaps I was lucky.

Tweakie.

Title: Re: The Laser Project.
Post by: mikee on June 24, 2011, 03:32:57 AM
  hey tweakie  
  thanks for your support .
   you might want make up check list  kinda like a pre flight  for safty reasons for your lazer. super kitty may not be lazer proof
well still working on my cnc router .  and reading  
 had a little set back but i am back at it  .
every once  in a while  i have to close mach 3  then open it up to get my motors to turn  
i emg stop status ( drive instalation complete ) if i right click reset emg stop button the motors will not turn .
pins port imput signal estop is enable i disable e stop apply ok main screen reset status (e stop needs to be reconfig).  motors turn  and off to work i go  
   be careful
    mikee
not much land dam few cattle co.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 24, 2011, 10:13:26 AM
Hi Mikee,

Good suggestion that checklist - it's on my 'to do' list.

Superkitty did have a minor incident a while back.  ;D

(http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=17257;image)

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on June 24, 2011, 02:17:56 PM
  hey tweakie
  just noticed eye patch  lol  
  are you trying to say  super kitty needs safty glasses
 bad part about this is we dont practice the best safty standards  in our own shops .  
 i am concerned about when my part or piece is cut out  somehow gets back into the cutting tool .
  be safe
mikee
not much land dam few cattle co
  
  
Title: Re: The Laser Project.
Post by: naPS on June 26, 2011, 11:37:22 PM
So I received my 10 turn pot, and installed the digital volt meter.

Man, what a difference.

I am now able to repeat just about anything using the volt meter.  So much better.  Plus, the 10 turn pot really allows some fine control over laser power.  My laser is now much more functional.

I'll post some pictures of some of the engraving I've been doing using your plugin modifications.

Thanks Tweakie!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 27, 2011, 01:48:19 AM
Hi naPS,

Thanks for the information, I am glad you have it all working OK.
I look forward to seeing some pictures.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 27, 2011, 06:40:30 AM
I have said this many times but Lasers and Acrylic were just meant for each other and the acrylic’s curious ability to sublimate (change from a solid to a gas without going through the liquid state) is the icing on the cake.
There is however, another curious thing about acrylic in so much as the material acts as a waveguide to the CO2 laser’s infrared beam. Bearing in mind that the laser’s focussed beam is hour glass shape with the waist at the exact focal point, this hole was made with the focal point at the top surface of the acrylic with the laser set on 75% power for a 3 second burst. Now this is the curious thing, apart from tapering a bit at the bottom, the hole (kerf) is more or less parallel which is not what is expected.
Useless bit of information perhaps but I thought it may be of interest to some as it could explain how a relatively low power laser, such as mine, can easily cut 10mm acrylic whilst still maintaining relatively parallel sides.

Tweakie.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 03, 2011, 05:40:18 AM
Another small update to the Impact / Laser Engraving plugin. Not necessary really but I have added a routine to round the Size of the X and Y pixel in steps to just 4 decimal places to prevent the display overflow and I have also made a small change to the formulae so the steps are calculated exactly.
These changes have no effect on the operation of the plugin, they are just cosmetic and because I cannot update the previously posted version I have put the latest version here http://www.cooperman.talktalk.net/Engraving.dll (http://www.cooperman.talktalk.net/Engraving.dll)

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on July 04, 2011, 04:32:30 AM
hey tweakie
 looks like im up and running  cut 6 in circle  little flat on the sides i had some play i got most of it out  we shall see tomorrow
 how is lazer comming along
 mikee
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 04, 2011, 04:56:06 AM
Glad everything is coming together for you Mikee.

I am looking forward to seeing some pictures of the stuff you make (If the river keeps rising a boat could be good  ;D )

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on July 04, 2011, 02:18:05 PM
  thanks tweakie
  and yes i have a boat  and i have sailed 7 seas 
  i have always want to make a pirates ship hmmm
  well back to work.
 I'm trying to understand, i guess it will be (offsets)   when i air cut my first circle i did not know where it was going to cut it out on the table.  
 the good part i have feed rate control.
 i really need to know  how to operate this machine safely
you have great day   
don't hurt yourself with your bug zapper 
mikee
not much land dam few cattle co.   
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 12, 2011, 06:23:19 AM
Again using the impact/laser engraving plugin some quite stunning results can be had with ceramic tiles. The laser produces micro-fractures in the surface of the glaze which are subsequently filled with a dye. This was one of my first attempts, using some left over’s from a tiling job, it’s not bad but I still have a long way to go before achieving results that I am fully satisfied with. Tiles marked this way are much more durable than I had first thought, they may fade with time but washing and cleaning have no effect on the dye once it has penetrated the surface.

In a way this serves to illustrate the stupidity of our patent system. Using a laser to mark the surface of ceramic tiles has been patented and technically I am not allowed to make or experiment with making such things as this (my comments will be written on the piece of paper which will be passed to the clerk of the court). And as you would expect it is not just limited to tiles – marking house bricks with a laser and marking Denim jeans with a laser have also been patented although half of Asia seems to be marking Denim with dis-regard to any patents. The list just goes on and on to the extent that I am surprised that a patent has not already been granted for just switching a laser on at the wall outlet.
I know that drug companies have been accused of patenting compounds and formulae they have no intention of using just to prevent a competitors research.

How, I wonder, would we all get on if a patent had been granted for machining a piece of material with a CNC machine ?
Not that much different in principle from marking a ceramic tile using a laser is it ?

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on July 12, 2011, 08:33:41 AM
Can you give us some background on what wavelength safety glasses you are using and how you are protecting yourself and visitors while the unit is running? I am looking at adding a Co2 tube to one of my Routers. Engraved signs are good idea, but my health and all safety factors are more important. I purchased a 40watt cheap unit from www.lightobject.com including the DSP. Everything works pretty well, for less than $2500, My intent was to learn so I could add a larger unit for one of my gantry routers. The Unit I purchased needed quite a bit of engineering upgrades but nothing that can't be overcome.
Thanks
Keep up the great thread
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 12, 2011, 09:10:10 AM
Good question Sir.

My machine is Class 4 radiation at a  wavelength of 10600nm and it only operates behind closed doors (there are no visitors). The workshop door is actually one of the interlocks which has to remain shut during use. I have a relatively high power, roof mounted, extraction system to remove toxic fumes and poison Bambi outdoors. I also have Halon (sales now banned in the UK, except for aircraft) fire extinguishers, just in case and my eye protection are goggles (intended for YAG) which are rated with a reduced OD of 7 at 10600nm but are adequate.

You can't take safety too seriously as it only takes one mistake. I have a number of friends in the woodworking industry and it seems to be a badge of office to have at least part of one finger missing - well I intend keeping all my fingers and eyes and etc.

In general CO2 lasers are a lot safer than lower powered diode lasers as far as eyes are concerned. A laser beam with a wavelength of 633nm when entering eyes will get focussed on to the retina and if any damage is caused it is permanent. A CO2 laser with a wavelength of 10600 will have to burn through the cornea first and this may be repairable damage but I would not want to put it to the test.

As a general statement to everybody and this applies to everything - If you have any doubts that you can keep yourself and others safe then don't do it.

Tweakie.

Title: Re: The Laser Project.
Post by: Sam on July 12, 2011, 09:16:56 AM
That's just crazy about the patent, Tweak. Sounds more like an infringement on personal rights to me. I could see it, if it were applicable to a specific method that was unique. Anyhow, that looks very interesting! So, you could ink the pattern however you liked, I suppose, eh? Say if you were to make a grape vine, you could color the leaves green and the vine brown, and grapes blue or whatever. If you made hundreds, then you could just silkscreen them I suppose. How does a cleaner such as bleach affect it? Looks great as usual, Tweakie!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 12, 2011, 11:34:53 AM
Hi Sam,

I will try it but I am guessing that neat Bleach will destroy the dye in no time but there may be other alternatives.

Acrylic paint has been used successfully to fill the pores in laser'd glass so may work OK with glaze and if it does may resist a Bleach attack.
In a commercial process, low temperature glaze is applied over the top of screen printed ceramics and fired for a few hours this should work just as well with dye filled laser'd stuff.

There are also a few other things I need to try, just need more spare time.  :D

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on July 12, 2011, 12:43:46 PM
 hey guys
from what i understand supper glue is  a forum of acrylic
mikee  
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 14, 2011, 02:25:09 AM
Thanks Mikee I didn't know that.

My main problem with this as a process seems that it is extremely difficult to get enough dye to penetrate through the micro-fractures and into the substrate. The final image is just not bold enough (compared to screen printing).
Perhaps I should Autoclave a couple of tiles to make them "thirsty" prior to applying the dye  ;D

Anybody have any ideas on this please.

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on July 14, 2011, 03:24:20 PM
    tweakie 
on most of my finished wood products
painted with super glue, polishing to a glass finish it looks like a over lay of glass. i can do a glass finish on wood that has been treated with oil. 
Super glue's and most epoxies breaks down at about 220 degrees  Fahrenheit.
if this will work on a Laser lens i have no idea.
 Worked on trucks that carried lime. lime pitted the windshields. cleaned glass with sulfuric acid.
polished glass with meguiar's polishing car compounds 
 possible option ..... treat lens before pitting happens
 good luck
 
 river still coming up!
mikee

 
 
   
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 15, 2011, 02:03:14 AM
Hi Mikee,

I think we are at crossed purposes here. It is the ceramic tile which needs sealing (to keep Sam's bleach out  ;D ) not the laser lens.  ;)

Does the waterfront property come expensive ?

Tweakie.
Title: Re: The Laser Project.
Post by: mikee on July 15, 2011, 02:19:24 AM
 nothing new me getting things backwards
 you guys should be getting used to me by now
 in this cost it may cost me everything

mike
Title: Re: The Laser Project.
Post by: mikee on July 15, 2011, 01:03:24 PM
 
hey tweakie
the river is about as high as it can get
 any higher and im going to have to leave
 river front land for sale great fishing.
mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 16, 2011, 11:05:26 AM
Another update for the Impact / Laser Engraver plugin (v1.2a).

Image aspect ratio;
I have re-instated the ‘maintain aspect ratio’ function (somehow lost along the way) which is now operated in a slightly different way to which it was originally. There is a new screen button “Calculate Parameters AR” and this automatically sets the vertical (Y Axis) height based on the, user input, horizontal (X Axis) width information and the original image aspect ratio. This new function works alongside the original “Calculate Parameters” function and provides a choice of either locked or free aspect ratio.

Changing the Mach mode of motion;
If the original image detail extends to the vertical sides of the canvas it has been found best to process the engraving in the Exact Stop mode whereas if the image detail stops short of the edges there is a small but significant gain in process speed if Constant Velocity mode is used.
By default the plugin now operates in Exact Stop mode and I have added a new check box “CV mode” so that Constant Velocity can easily be used, as and when required. (Without having to open the Mach General Config page to change the settings there). On exit the plugin returns Mach to CV mode.

I have also updated the PDF file to reflect these changes.

Engraving.dll   http://www.cooperman.talktalk.net/Engraving.dll

Engraving.pdf   http://www.cooperman.talktalk.net/Engraving.pdf

Tweakie.
Title: Re: The Laser Project.
Post by: naPS on August 02, 2011, 06:12:49 PM
Testing the new version of the plugin now Tweakie.   I rebuilt my laser this weekend, added a few things, tweaked things, etc. etc. etc.  I'll shoot up some pictures of my results when I'm done.

Thanks for doing this!  I love this plugin!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 04, 2011, 02:37:26 AM
Hi naPS,

That's great news that you have it all running OK so where are these pictures then ??  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2011, 05:46:28 AM
Relating to the Mach Impact / Laser Engraving plugin, Andrea (Robotmar) has very kindly provided me with a couple of his magnets in order to evaluate the plugin's impact engraving performance. It is a lot slower than the laser but the results are so similar that I thought you may like to see a side by side comparison with the same image produced by each method.
The first picture has been produced with the magnet and the second with the laser.
(This thread relates http://www.machsupport.com/forum/index.php/topic,16446.0.html).

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on August 14, 2011, 07:37:04 AM
Very interesting, Tweaks, what is the material you're using to get the contrast like that?

Thanks for sharing-
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2011, 07:59:22 AM
Hi Dave,

It's a non-PVC engraving laminate I purchased in France with brushed aluminium look alike on the surface and black plastic beneath. (If using the impact magnet on aluminium sheet the indentations could be colour filled to obtain the same effect).

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on August 14, 2011, 08:02:53 AM
Ah, ok, thanks for that tweaks.

Any idea of the range of how deep/shallow the magent is actually pushing?

What type of tip is it? Is it blunt or?

Thanks again-
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2011, 08:23:30 AM
Hi Dave,

Andrea pioneered the magnet design which is driven from the Mach digital trigger by one phase of a bipolar stepper motor driver. The impact tip is, I think, tungsten carbide and it is ground to a very sharp point but what is perhaps most interesting is that it impacts the work on the return stroke so it is the spring pressure x travel distance (Z height) that determines the impact force and therefore the depth.

This Impact engraving is not something that will necessarily work 'straight out of the box' because my first attempts were just terrible but with the right setup the results are, I think, quite stunning.

Tweakie.


(http://www.machsupport.com/forum/index.php?action=dlattach;topic=16446.0;attach=27497;image)
Title: Re: The Laser Project.
Post by: budman68 on August 14, 2011, 08:26:46 AM

This Impact engraving is not something that will necessarily work 'straight out of the box' because my first attempts were just terrible but with the right setup the results are, I think, quite stunning.

Tweakie.



Thank you, and I wholeheartedly agree  :)
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 14, 2011, 08:30:44 AM
Have you tried it yet ??

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on August 14, 2011, 08:32:29 AM
Have you tried it yet ??

Tweakie.

No sir, I meant the work that I've seen you folks doing with the impact engraver is stunning -
Dave
Title: Re: The Laser Project.
Post by: manmeran on August 14, 2011, 10:50:36 AM
hi Tweakie
Very interesting.
is it possible tell about time for last photo(dog) with mangnet Method ?
and pls dimension ?

thx
Amir
Title: Re: The Laser Project.
Post by: manmeran on August 14, 2011, 01:00:44 PM
i have a idea for build Magnet
by Air Valve Solenoid, magnet segment.

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 15, 2011, 02:49:45 AM
Thanks Dave.  ;)

Hi Amir,

The image size is 90mm x 90mm with 0.15mm stepover. I don't remember the exact times but the laser took minutes (at 4500mm/min) and the magnet took hours (at 300mm/min).

I certainly like the idea of an air operated solenoid, particularly if it could be operated faster than a magnet.
Because the moment of impact lags behind the trigger event and the plugin operates in bidirectional mode, currently, any increase in feedrate beyond 300mm/min results in noticeably staggered verticals.
It's a challenge, but even a small increase in impact speed could reduce process time considerably.

Tweakie.
Title: Re: The Laser Project.
Post by: manmeran on August 15, 2011, 03:55:28 AM
Thanks Tweakie
about your cnc : ball screw driver or belt driver ?
in laser mode : how much max feedrate if we use belt driver for motion ?

Amir
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 15, 2011, 04:19:20 AM
Hi Amir,

I use 5mm pitch ballscrews and my maximum, 100% reliable, G0 and laser feedrate is 4,500mm/min.

I doubt belt drive would improve my machine speed because of the mass of my combined X and Z axis but a purpose built machine could perhaps exceed 20,000mm/min without too much effort.

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on August 15, 2011, 10:53:18 AM
Tweakie,
I am having trouble with my small laser setup using the Digit Trigger (?).  When set active low, the laser stays on full time (even when no axis movement) - when active low the laser is off.  I am using a 1 watt laser diode - homemade TTL driver.  It works fine when using the Z axis direction signal, and I get excellent wood burns with sharp line starting and ending points.  I am using pin #9 output for both modes, and just change pin assignments in Config>Ports and Pins to test - no wiring changes.  I suspect that I may have not set something correctly in Mach3, but cannot find it.  I have tried both yours and Art's version of the Laser/Impact plug-in with same results.  The plug-in seems to work OK when I load an image and start Mach3 - just no laser pulsing response.

All advice greatly appreciated.
Best Regards,
John Champlain
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 15, 2011, 12:01:10 PM
Hi John,

Sounds as though you have the 'Ports and Pins' set up correctly and that the problem may be feedrate related.

The plugin's output on the digital trigger is dependant on the Kernel speed, the image pixel value and the axis feedrate - currently, the Kernel speed should be 25000Hz  and the axis feedrate set in motor tuning somewhere between 4,000 and 20,000 mm/min with the plugin feedrate set somewhere above 300 mm/min.
If your laser diode has good response then you are in with a chance but it is pretty much 'trial and error' here.

As an example, my true X Axis feedrate is 4,500 mm/min and I set the plugin feedrate to 15,000 mm/min and this just squeaks in at the bottom end of the requirements for a CO2 tube which has really poor response at the lower end of the power scale.

Experiment with the feedrates and let me know if this resolves the problem.

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on August 15, 2011, 02:16:57 PM
Tweakie,

Thank you.  I have (had) two problems.  First, I discovered a minor wiring mistake on my driver board.  Corrected it and the Digit Trigger signal is now controlling my laser diode.  I'm not sure why it was working with the Z axis direction signal and not the Digit Trigger before - just luck I guess.  Secondly, as I'm sure you already know, because of the low power laser diode, I have to run at too low of a feed rate (7 to 10 inch/min.) for the current Laser/Impact software to work.  I will have to stay with my present 'full on-full-off' method of diode operation for now.   Later, I may dive into the source code to see if I can adapt it more to my circumstances.

My Best to You,
John Champlain
Title: Finally going to drop some pictures....
Post by: naPS on August 15, 2011, 04:24:50 PM
Tweakie - I know I've been saying I'm going to post things, and it's taken me forever.  I'm usually farting around on my laser trying to figure out the best feeds / speeds for everything instead of taking pictures of stuff... :)  Sorry about that.

Anyhow - here's two small things I've done.  the picture of my boy running actually looks a lot better in person than it does in the picture.  Also, balsa seems to be a horrible wood to engrave in - it's so grainy.  It produces some pretty nice contrast though.  It was done at 375 in/min (10,000 mm/min) at about 22% power, which was probably set a little too high.

(http://www.angryamerica.com/buildlog/nate_running_cropped_small.jpg)

The second image was some text I engraved into some scrap acrylic I had lying around.  Same settings, basically, but bumped laser power up to about 50%.  Came out good.  I did start finding out that I really need to turn off my air assist when I'm engraving, it condenses the acrylic vapors and leaves a fine powder all over the rest of the engraving, which ends up leaving a ghosting effect around the letters, all in the same direction, since the air is blowing out of the nozzle.  Once I turned the air assist off, the problem went away.  I also noticed that when I'm engraving in beechwood that I was having the same issue.  Although, not leaving the air assist on led to the dust collecting all over the print and staining the really light areas when I brushed it off.  I might actually make a two-way air assist for my laser, one that blows out, and one that vacuums.

(http://www.angryamerica.com/buildlog/pandemerity_small.jpg)
Title: Re: The Laser Project.
Post by: naPS on August 16, 2011, 12:03:31 AM
something's weird - it's not letting me post again for some reason.  Going to give it one more shot.

Anyhow - fired up the rotational engraving attachment this afternoon, and put a Newcastle logo on a glass.  The logo is about 3" tall.  It's much more detailed in person than it is in this picture, the skyline in the star and the borders on the letters all stand out.  Pretty cool stuff.  Used the engraving plugin to do it.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 16, 2011, 01:26:23 AM
Hey naPS,

That's brilliant, looks like you are really getting the hang of it. Thanks for posting the pictures (we all love pictures).

(with deep engraving of wood / plastic I use paper transfer tape [used for vinyl sign application] - this prevents the surface smoke discolouration and is easily removed after the work is completed  ;) ).

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 18, 2011, 07:42:13 AM
This was the prototype, laid out using Microsoft Powerpoint, saved as a .jpg then run through the Impact / Laser plugin.
It has poor resolution but this could be improved by using a larger canvas size in Powerpoint then scaling down the final work.

Should cause a smile  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on August 18, 2011, 08:34:20 AM
  :) ;D :)
 ..... hip boots recommended, chest waders preferred.
 :)
Title: Re: The Laser Project.
Post by: budman68 on August 18, 2011, 11:57:57 AM
  :) ;D :)
 ..... hip boots recommended, chest waders preferred.
 :)


 ;D
Title: Re: The Laser Project.
Post by: Picengraver on August 18, 2011, 01:07:48 PM
Tweakie,
What version of C++ are you using to modify the Art's plug-in?  I tried MS C++ 2008, but get an error on one file after C++ 2008 converts the source code from an earlier version.   I am not familiar with C++, so learning as I go.

Thanks,
John Champlain
Title: Re: The Laser Project.
Post by: obal on August 18, 2011, 04:33:57 PM
hallo.
Look video working machine magnet.

http://www.youtube.com/watch?v=ylsMUTGTx1Q
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2011, 02:09:16 AM
Hi John,

You need the MDE 2003 v7 with .NET framework.
I don't think this is a current product anymore but it appears on ebay, quite cheaply, every now and again.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 19, 2011, 02:19:09 AM
Hi Russ,

Thinking back on some of my fishing trips, I may have told the odd one or two hip boots but never told any chest waders.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Overloaded on August 19, 2011, 07:49:23 AM
 :) ;D :D ;D :)
Title: Re: The Laser Project.
Post by: Picengraver on August 19, 2011, 07:41:07 PM
Thanks Tweakie.
I'll look for a copy.
Regards,
John Champlain
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 30, 2011, 07:05:12 AM
When using the Impact / Laser Engraving plugin, I have found that the initial preparation of the image or photo is key to success. A free program which has just come to my attention is FotoSketcher by David Thoiron. http://www.fotosketcher.com/download.htm
(When installing use the advanced options unless you want to install the unwanted toolbars etc or else download the portable version).
This program is capable of producing some quite stunning results and in some ways can be better than the Photochop plugin I have been using to date.

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on August 30, 2011, 08:22:34 AM
Did you see the new beta version?... under the:

http://www.fotosketcher.com/blog.htm

Thanks for the heads up on fotosketcher, always nice to have new tools.
Title: Re: The Laser Project.
Post by: naPS on August 30, 2011, 11:57:33 PM
Are you using the Gold Method photoshop plugin?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 31, 2011, 02:03:10 AM
Quote
Are you using the Gold Method photoshop plugin?

Yes sir.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 31, 2011, 01:07:41 PM
Quote
Thanks for the heads up on fotosketcher, always nice to have new tools.

Especially FREE tools   ;)

There are many different types of art and I am not sure if this qualifies or not. It is a computer generated "etch-a sketch" saved as a .dxf then as GCode. I must admit that I have seen better laser engravings but as I am in no way "artistic" this is perhaps a start.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 01, 2011, 12:44:17 PM
These little insects were laser cut in wood from the .dxf files posted in Dave’s thread where he cut the excellent aluminium butterfly. http://www.machsupport.com/forum/index.php/topic,15111.0.html

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 01, 2011, 01:13:06 PM
Nice, Tweakie. What's the size?

Dan
Title: Re: The Laser Project.
Post by: Sam on September 01, 2011, 01:27:10 PM
That's just beyond cool. Nice job to both Dave and yourself.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 02, 2011, 02:17:35 AM
Thanks guys.

They may be smaller than you think Dan  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 02, 2011, 02:35:24 AM
Actually no Tweakie - I figured it was about that small, judging by the zoom level (background is quite blurred ;) ).

The reason for my question in the first place was you saying it was cut from wood. It looks not more than 0.5mm thickness... didn't you mean to say "paper"? :D

By the way, the size adds very much to its charm.

Dan

Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 02, 2011, 06:52:09 AM
I thought you were from across the pond? Now I see a US Quarter and not a 20 pence piece, LOL (Good thing you did cause I would have no idea the sizes of your coins.)
 
Dan has to be close to being correct on thickness. But I don't consider paper as wood. Where do you get wood that thin, Looks more like a thin veneer or laminate.

Questions:
How do you prep your pieces before burning, like staining?
Do you do anything after you burn them, sand them?
Do you use any glue to hold them together?
How do you manage not to break the fragile pieces, my fat fingers would make them toothpicks?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 02, 2011, 08:16:16 AM
I found an old Nickel (and a Dime) just for the photographs and most of the regular forum members.  ;D ;D

The wood veneer is 0.6mm thickness (no idea what type of wood it is though), there is no pre-preparation or after sanding, no glue is used as I have scaled the parts so the slot width is approx equal to the material thickness and final adjustment is made by cutting on the inside or outside of the lines, as appropriate, using tool radius compensation.
(usually I would use a higher level of air assist, which blows the smoke through the kerf and prevents surface discolouration but in this instance low level air just to prevent lens contamination was all that I could do so there was some discolouration).
As for assembly, I used tweezers and an illuminated magnifying glass viewer.  :D  (and patience).

I have found a problem with making these 3D puzzles - everybody who sees one wants one and I have so many requests now for horses,  a bear, the Eiffel tower etc etc.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on September 02, 2011, 07:28:13 PM
Most excellent, my friend!!

Dave
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 02, 2011, 08:56:50 PM

I have found a problem with making these 3D puzzles - everybody who sees one wants one and I have so many requests now for horses,  a bear, the Eiffel tower etc etc.

Tweakie.

So your saying your making more than a US quarter making these puzzles? And we all should benefit and ride the cash cow. LOL ;-)
For the most part everyone thinks I should be giving my things away. After all its just wood.

And ya wonder why they are out of work and can't find a job.

"Ya-Nvr-No" Even thou the name looks its a city in China my Uncle "Sam" wants his cut too.  (not to leave out the power company, mortgage lady, Insurance man)
If I could get everyone to give me their good and services. I guess then we would all be true Democrats.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 03, 2011, 09:14:08 AM
Thanks Dave.

Ya-Nvr-No,

I didn't say they were worth as much as a quarter, I just used the coin for size comparison.  ;D ;D

Quote
For the most part everyone thinks I should be giving my things away. After all its just wood.

Just not true, my friend - your things are the envy of most.  ;D

Quote
And ya wonder why they are out of work and can't find a job.

Don't talk about jobs - unemployment is rising here in the UK and the influx of eastern European (cheap) labour is helping to keep overall wage levels down - many employers are starting to see a considerable rise in their profits.

I, for one, just don't know who to vote for any more - it appears they are all ..... (rhymes with Bankers).

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 03, 2011, 10:54:13 AM
Thank You for the kind words.

Wait till you see my new Gantry Router I am building, I just got it moving this last week X=2700mm Y=1700mm Z=600mm Has a belly pan cut out that will handle a 600mm diameter log 2500mm long. (not as shiny as Dave's) It will take me the rest of the winter to finalize it.
So far the Top speed about 6500mm per minute using rolled ball screws and linear 16mm dia rails. I designed and built it because I need to create a railing on my front porch. Thought Id do some wildlife artwork for effect, after all it is a log cabin. Now that I got it moving It got me to Insulate and panel my new shop (and I had to picked a hot week to do that) and get it ready for my new home away from home.

If nothing else I sure learn a lot from every one that shares their knowledge and experiences.
Fun to enjoy what you do.
Keep up the great thread.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 03, 2011, 11:50:14 AM
Thank you Ya-Nvr-No,

Don't forget that we want to see pictures of your new build (shiny or not).  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 07, 2011, 05:30:49 AM
Something I perhaps didn’t cover very well earlier in this thread is “Air Assist”. This plays quite a key role when using the laser in two main areas and is, in my opinion, essential.

1) By directing the smoke / particles away from the focus lens this prevents contamination and the need for constant cleaning of this rather delicate component. (The lenses used at 10,6um are usually made from Zinc Selenide and AV coated – they scratch easily and are extremely brittle so the less they are handled the better).

2) When cutting anything that carbonises the air assist is used to remove the deposit from the bottom of the kerf and thereby increase the cutting / engraving efficiency.

I have chosen to use a co-axial air assist, for the most part, and have a 3mm diameter exit nozzle for both the beam and the air. This essentially pressurises the focus lens cavity and prevents the ingress of smoke and small particles. I use 3 different air supplies, the first is a low level, double acting, aquarium aerator which is always on whenever the laser is powered up, the second which is Tee’d into the same air line is a larger koi pond pump and the third is the exhaust side of a twin cylinder “Roc-r” pump (which is also used to power my vacuum table). All three of these pumps are oil-less and between them provide various air volumes for most applications.
Additionally I have a separate nozzle (not co-axial), which can be fitted when required, and can be used to direct a relatively high pressure “shop air” directly into the kerf. This is only used occasionally (when cutting plywood) and has the disadvantage that the high pressure / volume enables the fumes to escape the existing air extraction system (bad smell of burnt wood in the workshop).

When the little insects, shown in the earlier post, were cut I was using just the aquarium aerator, any greater volume of air would have scattered the individual pieces everywhere as no tabs were used.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 07, 2011, 11:41:28 AM
Now I really don’t want my wife to find out about this but, after a lot of research, I have discovered that once these tasty little morsels have been laser cut they can be cooked to perfection using GHD “Pink Orchid” hair straightners (although the “Gold Classic” work OK the “Pink Orchid” are best).  ;D ;D

Tweakie.

(I should perhaps mention that nothing was wasted here as my faithful little helper rapidly disposed of all the offcuts).
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 07, 2011, 01:44:47 PM
What is it? Must be a UK thing!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 08, 2011, 05:52:11 AM
I must admit that I hadn’t really thought about it but yes I suppose it is a UK thing.  :)
The clue is in the shape – Its Ham (or called bacon when it’s fried).

There is enough serious stuff going on in life so I find that doing something completely daft, perhaps to bring a smile, every now and again makes a break.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 08, 2011, 06:45:06 AM
hell I thought it was chocolate or a thin brownie. Never crossed my mind it was Ham, even though I could see it was a porker. Cute idea. What is it again that you drink? LOL
Title: Re: The Laser Project.
Post by: Sam on September 10, 2011, 04:41:04 PM
Lol. Bacon scented hair. You might have stumbled upon something, Tweak.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 16, 2011, 09:53:22 AM
Hi Sam,

Thanks for the heads-up, in retrospect I don’t think the ‘bacon scented hair’ is going to go down too well so I am thinking that washing off the GHD’s thoroughly in WD40 after use may be the way forward.  ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 16, 2011, 10:02:46 AM
Something that has become more popular during the last couple of years is personalised paper / card cut wedding and party invitations / cards etc http://paperorchidstationery.com/ . Traditionally these items were ‘die cut’ and we had to choose from just those variants available but lasers have removed the ‘tooling costs and limitations’ and are just so brilliant at cutting paper and card that individual and personalised greetings are now so easily created and of course, affordable.

The following example, obviously not for weddings, is an old and perhaps weird Mexican paper cut which I found interesting and just had to reproduce http://www.craftsmanspace.com/free-patterns/miscellaneous-illustrations.html . Using a federate of 700mm/min this took me just over 14 minutes to cut and indicates why the galvo scanning type of laser heads are usually used for this type of work http://www.synrad.com/Products/marking.htm . They would, for example, cut something like this in just a few seconds so the end product would be economic to make in quantity and should yield a respectable profit on time and investment for the maker.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 16, 2011, 10:29:31 AM
Very interesting Tweakie. Thanks for showing.

Was it at the laser's max power or were you limited by the top feedrate of the machine? And how is it that the laser doesn't leave burnt edges?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 16, 2011, 11:21:57 AM
Hi Dan,

The laser power was set at 5mA (20mA is the maximum I ever use) and a feed of 700 is what I  normally set for cutting thin stuff (in practice I doubt that either axis ever got anywhere near to this speed because of the small movements involved and my acceleration settings.
Regarding the edges, some paper / card cuts with less burn than others (perhaps due to the chalk content) and this stuff just happens to be good. The co-axial air assist combined with an air extraction system also reduces any surface smoke stains.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 18, 2011, 04:02:43 AM
Another  ‘Papel Picado’.  http://www.internationalfolkart.org/eventsedu/education/muertos/papelpicado.html

Presumably relating to the different festivals, these paper cuts usually incorporate Skeletons, Birds and Flowers and although the Mexican tradition is century’s older it is in a strange way similar to the UK folk art of ‘canal boat decorative painting’ which almost always incorporates Roses and Castles.

Tweakie.

Title: Braille Signage and a Pitfall for the Unwary ??.
Post by: Tweakie.CNC on October 04, 2011, 06:53:11 AM
It all started out as a laser project but…….

This is one of the first (proof of concept) of a number of different signs which are to be placed adjacent to the related plants at a special garden event in 2012. The intention is that partially sighted / blind people who can read Grade 2 Braille can, at their own pace, associate a smell / aroma with the relevant type of plant / flower.

The material I have finally used is a PVC based engraving laminate, I have not yet been told the actual colours that are be used but this piece of white / red was handy.
The Braille characters have been formed using the well established process of drilling a series of holes, just over half the depth of the diameter, then pressing in (interference fit) spherical balls, in this case they are 440c stainless.
Try as I may with the laserable (acrylic) laminate I have just not been able to get the hole depth consistent between the different colour samples – it seems that the pigment of the colour affects the laser penetration so each colour sample has a different setting and obviously the depth has to be maintained quite accurately - also, with the laser, it is a raster process and not a vector one as I would prefer.
The advantage of spindle drilling the holes (vector process) is that the same GCode toolpath can be used, with offset, when automatically inserting the balls. The disadvantage is that the engraving process is a lot slower with a spindle than it is with a laser. Anyway I decided it was “swings and roundabouts”, I would use the PVC laminate and it would be an all spindle process with two tool changes. Engraving point first, endmill second and ball insertion device third.
 
As you can probably guess by now, the process of placing balls in holes to form Braille characters has been patented (there are many related patents in fact) and I have just had a teeny little bit of disagreement with the main patent holders, who would have me (and others wishing to produce ADA compliant signage) believe that the extent of their patents are far greater than they really are. Also they are asking $2000 USD for a license (which I have severe doubts has any validity) to use their process, tools and consumables.
However, thanks to some international co-operation and an opinion by the UK Intellectual Property Office, I am now confident that this ‘$2000 licence’ is totally unnecessary and is little more than just a ‘pitfall for the unwary’. If I am wrong – well, we will just have to wait and see.

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on October 04, 2011, 09:26:31 AM
Good for you, I too heard about the restrictions on ADA signage and found it hard to believe they had exclusive rights they seem to bloat about. It seemed like such a simple process, I remember having that conversation with him about it and told him, they was out of line. Hope you can get this matter resolved and make this monopoly an open market.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 05, 2011, 08:06:16 AM
Thanks Ya-Nvr-No.

I have to admit to a slight Faux Pas here because I obviously checked the wrong box in the online interpreter I used and this sign turned out to be Grade 1 Braille.
Grade 2 (as I had been asked to do) would have had the ‘ing’ replaced by a single ‘contracted’ character.

I just learn as I go.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on October 05, 2011, 08:50:49 AM
So you will remake it? I watched their process and was amazed as to how fast and simple it was.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2011, 06:04:01 AM
So you will remake it? I watched their process and was amazed as to how fast and simple it was.

That one did the trick. They like the border shape but the signs will be stuck in place (so no screw holes). Looks like I have got the job, which will be free of charge.  :)
(I have learnt quite a few Braille characters now but there is considerably more skill to reading the dots with a finger than I had ever imagined).

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on October 09, 2011, 06:45:37 AM
Remember Winston Churchill
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2011, 07:00:52 AM
 ;D ;D ;D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 10, 2011, 03:20:02 AM
Another one of the little 3D Puzzle Insects, laser cut, just for a bit of fun.

These miniature 3D puzzles have, in a way, turned out to be a little bit like the "Turners Cube" - once friends see them, they want one for themselves so I have now had to make a few extra  ;)

Tweakie.

Title: Re: The Laser Project.
Post by: balsa burner on October 13, 2011, 03:53:33 PM
Couldn't resist.  ::)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 14, 2011, 02:44:54 AM
Nice work BB.

Did you use Dave's dxf for this ??

Tweakie.
Title: Re: The Laser Project.
Post by: balsa burner on October 14, 2011, 05:04:11 AM
yeah, scaled the slots for 1/8 birch ply and cut.

came out at about 12" in height

will probably cut a dragonfly but will take the time to tab it properly first.
That's when i can find the time to do it.

BB
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 11, 2011, 09:07:33 AM
Hope this is not considered as advertising but there is a new UK based forum just starting up which is aimed exclusively at owners of the Chinese imported laser machines. These machines use print drivers (probably HPGL based) and dedicated controllers but the system is nowhere near as versatile as GCode so I suspect there will be some refits where Mach3 and the Impact / Laser plugin will come into their own.
It is still early days yet (with a membership of just 13, myself included) but it will grow and may be of interest to those who are starting out in the world of lasers. http://oplaser.co.uk/opsupport/ (http://oplaser.co.uk/opsupport/)

Tweakie.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 22, 2011, 05:27:51 AM
I just had to laser cut this beautiful flame eagle (downloaded from a free scroll saw patten website http://fssp-arpop.blogspot.com/ ), perhaps as an example that CNC enables non-craftsman, like me, to make stuff that traditionally required a great deal of skill. This is cut from wood veneer but I will scale up the pattern to around 350mm and cut the same image from sign vinyl, as a sticker (using a vinyl cutter knife rather than the laser).

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2011, 07:11:03 AM
I expect we all do it, I have many times - arrived at the supermarket and found I have no coin for the trolley.  :-[

I have just cut out a few of these from frosted acrylic, as incidental gifts for friends at Christmas, not sure what to engrave on them yet but hey - tomorrow is another day and something will come to mind.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: bwprice100 on November 28, 2011, 07:22:01 AM
How about

"FOR SALE £1.50"

 :)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2011, 07:23:23 AM
 ;D ;D ;D ;D

Nice one Brian.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on November 28, 2011, 07:27:46 AM
What are they?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2011, 07:43:20 AM
Come on Dave, keep up  ;D

They fit in place of the coin but have been specially designed (for our sort of trolleys) so that they can be weaselled out and this lets you become a real vandal and set free all the trolleys that have been imprisoned in the trolley park.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on November 28, 2011, 07:45:07 AM
Actually I knew that (used to try this as a kid), but never in a million years thought the pure and honest heart of Tweakie would ever do this.  ;)

We also used to regrind blanks from electrical boxes to use as well  ;D

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 28, 2011, 08:47:29 AM
Sorry Dave - perhaps I am not quite as white as white.  ;D

Incidentally, my CNC programmed car park cards were a real hit last month.  ;D

Tweakie.

(http://www.machsupport.com/forum/index.php?action=dlattach;topic=13389.0;attach=28302;image)
Title: Re: The Laser Project.
Post by: budman68 on November 28, 2011, 09:39:13 AM
I've now lost all respect for you, my friend -  ;)

Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 01, 2011, 07:58:38 AM
I've now lost all respect for you, my friend -  ;)

Dave

Hi Dave,

I have been having sleepless nights about this - Could I possibly redeem my position if I sent you some free samples of the 'infinite trolley token' and the 'car park entry card' ??

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 15, 2011, 08:27:52 AM
Those of you that have been following this (never ending) thread will know that between Andrea in Italy and myself in the UK we have spent quite a lot of time putting the Mach Impact / Laser engraving plugin through it’s paces. Although there are still some improvements that could be made to the plugin and it still has a lot of mileage left in it, the legacy issue of it’s requirement for a parallel port are starting to show and it is perhaps time to start looking at alternatives.

In the Eastern European countries, for many years, it has been common practice for black marble monuments and remembrance plaques to display an engraved ‘photographic style’ of image and this has inevitably prompted the development of CNC software to complete the task. One such software is “DotG” a Hungarian program which has just had an English translation version released. It is completely ‘free of charge’ and can be downloaded from here http://dotg.weebly.com/download.html

DotG works in an entirely different way to the Mach plugin insofar as it creates GCode from a pre-processed 1 Bit image and although I haven’t quite got my postprocessor completely sorted everything looks extremely promising so far.
It is early days yet but I will keep you posted of my experience with this software as I learn more.

This example image of Audry Hepburn with the glamour of the 1950/1960’s was laser cut into some scrap MDF whilst I was testing various settings and it would, I think, look quite stunning cut into some mirror tile (project awaiting).

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on December 15, 2011, 09:18:32 AM
Hi Tweakie,

This sounds interesting. Can you please explain how it works or post a Gcode snippet? How is the modulation done in the Gcode?

Thanks,
Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 15, 2011, 10:58:37 AM
Hi Dan,

The image has to be pre-processed until it is essentially a 1 bit halftone which is really just a collection of dots. DotG then scans this image in raster fashion and creates the GCode as a series of ON or OFF instructions for the laser or impact magnet.
For some time now I have used the B Axis as my laser control with B1 to turn the laser on and B0 to turn the laser off  and for me, this has two major advantages. Firstly the on or off commands can be synchronised with the start or finish of axis movement and secondly the G01 federate can be used to control the laser burn time.
I have attached the GCode used for the previously posted image which you will see is pretty basic stuff with just two lines per dot (or dash). I haven’t quite got my post-processor right yet so the code is still a bit messy but this can only improve  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on December 15, 2011, 11:43:52 AM
Hi Tweakie,

Thanks for the description. So it isn't as smooth as it is with the plugin. The axis has to stop and then the laser comes on and off and then it proceeds to the next point. Seems to be slower also.

It is the direction line of the B axis that you're using, right?

Is there any meaning for this in this Gcode:

T1
S8000 M3 f1500

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 15, 2011, 12:13:10 PM
Hi Dan,

Yes I think it is slower than the plugin but the jury’s still out on this one for the moment because it does not make any unnecessary line scans or unnecessary increased length of scan lines. More comparative testing is necessary before I know for sure.
As far as magnet impact is concerned it should be a lot faster but I think Andrea will have more information on this.

Yes I am using the B Axis direction signal and only the F1500 is being used from those other commands.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on December 15, 2011, 12:17:33 PM
Thanks, Tweakie. Will be waiting to hear more results from you guys.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 27, 2011, 12:02:34 PM
This image is 106mm x 130mm and comprises entirely of laser dots on some scrap MDF. It took 80 minutes to complete but the interesting thing is that the same GCode could (theoretically) be used with an impact magnet and again it would take 80 minutes to complete. Higher resolution and larger images would, of course, take longer but I still have a bit of reserve as far as the speed settings are concerned. It is all a matter of putting theory into practice  :D :D

Tweakie.

EDIT. I have attached the .jpg / .bmp and GCode if anybody would like to try it.
Title: Re: The Laser Project.
Post by: Dan13 on December 27, 2011, 02:19:39 PM
Nice, Tweakie. Is it with that new program? When you say impact magnet do you mean using it with Art's plugin? A comparison with Art's plugin would be interesting.

Your earlier works using the plugin had much finer detail. I wonder how this new software would compare if you increased resolution.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 28, 2011, 12:03:29 PM
Hi Dan,

Thanks for taking an interest in this and I am sorry if I don’t always manage to explain everything very well (there is a big difference between what is stored in my head and what actually manages to escape  ;D )

The Mach plugin and the DotG program really operate in entirely different ways and I think it would be ‘apples and oranges’ to try and make a direct comparison mainly because each would be good at what it does best.
My earlier examples with the plugin were at 0.1mm stepover whereas the previous cat is at 0.4mm stepover. This has been done deliberately so that the dots are visible and can be compared with a subsequent magnet produced image (using the same GCode). The attached, enlarged, pic shows the dots better.

It is perhaps interesting to note that, as far as the professionals are concerned, it is usual when creating laser produced images from halftone to de-focus the beam so that the individual dots blend and produce a smooth result.
There is a quite lot of useful info relating to halftone on the PhotoGrav site if you are interested http://www.photograv.com/index.htm

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on December 28, 2011, 12:21:06 PM
Hi Tweakie,

Thanks for the information.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 29, 2011, 07:35:49 AM
Initially there was failure.
I mapped my B Axis direction pin to Output #1 (which is my spindle relay) and used the relay to fire the magnet. Unfortunately my version of Mach doesn’t like any Output # being repeatedly turned on and off rapidly as it introduces extra delays while it, presumably, catches up. This has caused missed pulses and ‘patterning’ indicating the repetitive nature of the problem and shown in the first picture.

Then there was success.
To be fair, Mach had never intended for an Output # to be cycled in this manner so I constructed a separate magnet driver circuit which is driven directly from the B Axis direction pin and this performed perfectly. The image produced is ‘dot-perfect’ to the laser produced image and was made from exactly the same GCode in exactly the same time frame of 80 minutes.

Tweakie.
Title: Re: The Laser Project.
Post by: bwprice100 on December 29, 2011, 08:03:12 AM
.
Hi Tweakie

Brilliant as always.
this may sound like a dumb question but do you have any info on the workings of a impact magnet. I understand the gist of how they work but having searched for more detail on their workings found nothing. Do you have any detailed info?

Thanks Brian
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 29, 2011, 09:32:54 AM
Hi Brian,

My electromagnet was a gift from Andrea (Robotmar) http://www.robotfactory.it/Cnc_indexMain.htm (look under Micropunti) who had the first successful results using a magnet with the Mach Impact / Laser plugin. He shows the construction on his website or in this thread http://www.machsupport.com/forum/index.php/topic,16446.0.html but other than that I have no specific technical information relating to the field properties / iron saturation etc.

Hope this helps,

Tweakie.

Title: Re: The Laser Project.
Post by: bwprice100 on December 30, 2011, 03:14:39 AM
Hi Brian,

My electromagnet was a gift from Andrea (Robotmar) http://www.robotfactory.it/Cnc_indexMain.htm (look under Micropunti) who had the first successful results using a magnet with the Mach Impact / Laser plugin. He shows the construction on his website or in this thread http://www.machsupport.com/forum/index.php/topic,16446.0.html but other than that I have no specific technical information relating to the field properties / iron saturation etc.

Hope this helps,

Tweakie.



Cheers, I will read and digest:)

Brian
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 31, 2011, 09:05:29 AM
Perhaps going a bit off topic but this halftone image was produced with the electromagnet although it could equally have been done with the laser by using the same GCode and for anyone old enough to remember them, the process sounds exactly like the old ASR33 Teletype’s although just slightly faster.

The GCode was produced with ‘DotG’ (http://dotg.weebly.com/index.html) and the image pre-processed with ‘Infanview’ (http://www.irfanview.com/) and the ‘Ximagic Gray Dither plugin’ (http://www.ximagic.com/) – All of these being free to download and use programs.

Like all halftones you need to be some distance from the image to get the best effect and the end result, shown here, is far from being perfect. It does, however, look exactly like the image shown in Infanview so now I have to experiment with different settings and gain some practical experience to produce an image and a group of settings that I am satisfied with. The final object of this exercise being an acrylic, edge lit display which contains a photographic image as well as text.

So far so good.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 20, 2012, 05:43:54 AM
Good news for laser users - Artsoft, Brian and the Team have now restored the operation of the undocumented M10P1 / M11P1 commands to their former glory. These commands switch an Output pin (determined by the P#) coincident or blended with an axis movement starting and stopping. This now means there is no noticeable delay between the laser being switched on and off and an axis movement so there will no longer be any missing starts to lines or dots appended to lines. Perhaps the most important change here relates to safety in so far as that in returning to an Output (from an axis pin) the software polled EStop can, in an emergency, be used to switch the laser off.

This scale was used as a test piece and was engraved using the M10P1/M11P1 commands and Output #1 to switch the laser and, as far as I can tell, is equal in quality to a similar scale engraved using the B0/B1 commands and the B axis direction pin (as I have previously been using).

A big thanks to Brian and the Team.

Tweakie.

(http://www.machsupport.com/forum/index.php?action=dlattach;topic=20546.0;attach=29206;image)
Title: Re: The Laser Project.
Post by: Dan13 on January 20, 2012, 11:36:51 AM
Good news indeed, Tweakie! And this was a quick fix. I wonder though what advantage does it give you over your original B0/B1? The only advantage I see is a more "correct" Gcode.

What is scale engraved onto?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 20, 2012, 12:00:55 PM
Hi Dan,

That is just a piece of scrap MDF I used for testing.

There are quite a few problems associated with using an axis direction pin which crop up from time to time and eventually become a real pain.
As mentioned earlier the software polled EStop does not change the state of a direction pin but it can turn off an output thus using an output gives an added safety feature.
Feed hold, if it ever has to be used, creates another issue when motion stops with the laser still on - easier to handle an output than a direction pin here.
My B axis DRO can, in error, somehow get to a -1 step position then the B0 command that is supposed to turn the laser off actually turns it on - another B0 command does nothing to turn the laser off - only the separate commands B1 and B0 will turn the laser off.
At initial power up the state of an axis direction pin is not always guaranteed.
There are a few other issues as well so overall using an output for switching is far far preferable.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on January 20, 2012, 01:53:17 PM
Hi Tweakie,

Thanks for clearing it up. Looks like it has some significant improvement indeed.

The reason I asked about the material is that on the photo above it looks like there is some transparent layer between the numbers and the background.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 23, 2012, 03:20:28 AM
Quote
The reason I asked about the material is that on the photo above it looks like there is some transparent layer between the numbers and the background.

I think it's the lighting Dan. All the tests were done on the same piece of scrap but if the earlier pic was taken inside the workshop it may have been with flash.

Just for ref.    Top right is original M10/M11 : Top centre is B0/B1 : Top left is first revision of M10/M11 : Bottom left is final revision of M10/M11.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on January 30, 2012, 06:35:55 AM
Tweakie

I hope it is the right place to ask questions about the engraving plugin.  If not could you let me know where is the best place or thread.

I am just starting to try and figure out how to use the engraving plugin on a laser.  As far as I know, I have the latest plugin version and PDF documentation.

The PDF talks about CV, and the pictures of the plugin show a selection box for it.  However my plugin does not have that selection box.

Also it looks like the auto aspect ratio is gone.   Does this sound right?

I have some reading to do.   :)

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 30, 2012, 07:34:34 AM
Hi Greg,

As Art has made the plugin open source I have made a few modifications to it and the latest version can be downloaded from here http://www.cooperman.talktalk.net/Engraving.dll (http://www.cooperman.talktalk.net/Engraving.dll) (just copy paste the dll into the plugins folder).

We all look forward to seeing some pictures (please) of the work you produce with your laser and the plugin.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on January 30, 2012, 07:43:42 AM
Thanks Tweakie

Got the latest version now.  It even looks like the one in the PDF.  ;D

I am not quite at the stage of firing up the laser tube for the first time..........but getting real close. :o

Reading your guide, and trying to get my head around it all.  

Just finished writing a post processor for my Vectric CAM program, to do vector cutting.  Using M10P1 and M11P1

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 30, 2012, 08:05:39 AM
Hi Greg,

As I think I mentioned in the PDF, the plugin doesn't necessarily work 'straight out of the box', it takes a bit of practice but once you get the hang of it then I think you will find that the results are extremely hard to beat. I am hoping that one day Art will convert his laser machine to using Mach 3 then he will be able to use his plugin as well  ;D

I would be grateful of a copy of your Vectric PP if it is to be shared.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on January 30, 2012, 08:10:10 AM

I would be grateful of a copy of your Vectric PP if it is to be shared.

Yeah no problem.   But you better wait until I get a chance to test it.

And besides, I just realised I made a mistake and was fixing it when you posted.  :)

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 30, 2012, 08:48:09 AM
 ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on January 31, 2012, 04:08:37 AM
Tweakie

How do I set up for M10P1 / M11P1 and or E1P0 / E1P1?

"Output 1" or "Digital Trigger" or something else?

And is it different for vector cutting and the engraving plugin?

I have the laser firing manually and got the mirror alignment fairly good.  So I am dead keen to try it out.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 31, 2012, 05:30:31 AM
Hi Greg,

I use two different Mach profiles;
For Raster and the Mach plugin the Digital Trigger is mapped to the LPT parallel port pin that is used to fire the laser.
For Vector my GCode has M11P1 to turn the laser ON and M10P1 to turn the laser OFF then Output #1 is mapped to the LPT parallel port pin that is used to fire the laser (the P# relates to the Output Pin#).

You have probably seen this already but the schematic of my laser control is here http://www.cooperman.talktalk.net/circuit2aa.jpg  and the LPT parallel port pin (referred to above) connects to the TTL input. (The two, series TTL gates I am using are there just as a buffer and to ensure a proper 5 Volt logic switching, for the laser PSU, from the parallel port output which could possibly be 3.3 Volts).

Hope this helps.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on January 31, 2012, 06:17:35 AM
Tweakie

Just got in from the shed. (its getting late)   Been cutting and engraving.    Woo Hoo!!!  ;D ;D

I worked it out before seeing your post.  I am using Output1, not Digital Trigger, for both vector cutting and engraving (with the plugin).  Only one profile.  I hope this is right.  It works anyway.

Using M10P1 / M11P1 for vector cutting.  Had them around the wrong way at first.  Doh!   :o

The Vectric PP worked fine so far.

"............Output #1 is mapped to the LPT parallel port pin that is used to fire the laser (the P# relates to the Output Pin#)"

Output Pin# is confusing.  Don't you mean Output#, which can be mapped to any output pin on the LPT?


"............. buffer and to ensure a proper 5 Volt logic switching, for the laser PSU, from the parallel port output which could possibly be 3.3 Volts)."

I am using one of Peter Homman's BoBs which buffers the outputs, so no worries there.

Anyway I am very happy.   Engraving results are not great yet.  Lots to learn.  But at least it works.

Thanks for the help,

Greolt

Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 31, 2012, 07:46:59 AM
Hi Greg,

That's great news, I am really pleased you have it all working OK.

Don't forget to post some pictures.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 03, 2012, 12:49:05 AM
Tweakie

Cutting acrylic, it cuts great but I am getting lines on the cut.  I think you call them striations.

Can you suggest a strategy to eliminate them?

Tried a combination of power and speed settings, but to no avail.

Greg
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 03, 2012, 02:39:15 AM
Hi Greg,

I went through this a while back, tried various speed / power settings with no improvement.

Thanks to Sam, who looked closely at my toolpath, he found that my circles / curves were not smooth so the cut was not smooth and the results were rubbish.

This was typical of the problem - note how the true horizontals have been cut perfectly yet all other angles are poor.
(http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21730;image)

After cleaning up the dxf the results were much improved.
(http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21738;image)

Hope this helps,

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 03, 2012, 04:29:25 AM
Tweakie
I don't believe that is my problem.  I am cutting test circles using G2 and G3 commands.  So movement, in theory, should be as good as it gets.

I would love to have a go at those bicycles.  Do you have a DXF or similar?

I have tried to take a picture but it is poor.

Greolt

By the way I am not referring to the one large mark.  That is where the cut starts and stops.  I can use strategies to minimise that.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 03, 2012, 07:43:12 AM
Hi Greg,

The problem I have is knowing where to start because the cause could be so many things.

You need to be using true Acrylic (Plexiglas / Perspex) and not Polycarbonate. Cast acrylic is best.
Practice initially with rectangles (single axis movements rather than compound) this will eliminate the issue I mentioned earlier.
You need air assist to protect your focus lens from contamination but not so much air that the vaporised acrylic is blown back into the kerf.
The acrylic needs to be supported above a non-reflective surface (I use a home made grid with glass base).
Do not use too much power, just enough to cut through and no more.(Cutting acrylic is a bit like machining metal – there is an ideal speed and feed – put in too much energy and the results will be poor).
Remove any protective film before cutting (some protective film is OK and some is bad so at this stage it is best to remove it).
I achieve best results by setting my focal point about 1/3 of the thickness into the material.

Does this help at all ??

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 03, 2012, 05:05:12 PM
Thanks Tweakie

I will continue to play around with different power and speed settings.

And I will cut rectangles rather than circles.

I had read that plastic film should be removed before cutting and paper should be left on.

Do you have that bicycle file?

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 04, 2012, 02:29:09 AM
Hi Greg,

Those bicycles were made some time back and the dxf's are long gone. I did come across this GCode which may be OK for you (scale it to your own requirements).

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 04, 2012, 06:37:53 AM
Thanks Tweakie

Converted it to DXF.

I have been playing with the engraving plugin.   Slowly making progress.

Had a big leap forward when I resized the picture to the engraving size before brining it into the plugin.

Greolt
Title: Re: The Laser Project.
Post by: stirling on February 04, 2012, 06:59:01 AM
Beat me to it. Not sure what it is about bikes. A guy I know has loads stacked up that he did when evaluating various water-jets. Some of them were amazing - around 10mm high AND thick - done with water-jet!!! and they were perfect. Anyway here's one I did on plasma - it's about 150mm long. Don't laugh at the quality  :o - it was one of my first attempts with a crappy cutter and no thc a few years back (honest!).

Ian
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on February 04, 2012, 11:04:04 AM
Tweak: I don't see any G2 or G3 in your tap file. So I have to think that is your first attempt at your bike cutout. I was kind of looking forward to trying out my laser on your fine example of how a cut should look. Thanks for sharing, your a inspiration to all.
Title: Re: The Laser Project.
Post by: Greolt on February 05, 2012, 04:44:55 AM
Tweak: I don't see any G2 or G3 in your tap file. So I have to think that is your first attempt at your bike cutout.

If you download either of the DXFs in the above two posts, you will see the lines have been cleaned up.  They have arcs, so they should cut nicely.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 05, 2012, 05:11:46 AM
Tweak: I don't see any G2 or G3 in your tap file. So I have to think that is your first attempt at your bike cutout. I was kind of looking forward to trying out my laser on your fine example of how a cut should look. Thanks for sharing, your a inspiration to all.

Hi Buddy,

This bike was cut from the .tap file I posted earlier.
Incidentally there were no G02 / G03 moves in the code for the second picture in post #576 either.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 05, 2012, 08:31:49 PM
Tweakie

I assume that the engraving plugin will only operate with an active low output to fire the laser.

Is this something that can be changed?

It is MUCH safer for me to use active high.  This works fine with vector cutting but alas the engraving plugin does not turn the laser on.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 06, 2012, 02:56:36 AM
Hi Greg,

The Impact / Laser plugin uses the Digital Trigger as its output and this can be configured within Mach as Active Hi / Active Lo as necessary.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 03:25:59 AM
Tweakie

I had discovered since posting that the plugin will operate via Digital Trigger  active high.

Funny thing is, I had been using the plugin via Output1 active low.  This worked fine and I had been engraving the last couple of days that way.  As soon as I set it to active high it no longer worked.  Go figure.

Anyway I am now happily using Digital Trigger.  Engraving results are steadily improving as I try more variations.  Need some better material for testing.

Greolt
Title: Re: The Laser Project.
Post by: Dan13 on February 06, 2012, 03:32:01 AM

Funny thing is, I had been using the plugin via Output1 active low.

That's funny indeed, Greg ;D Looks like a serious bug though.

Dan
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 03:57:39 AM
Not sure I would call it a serious bug.

A bit of an anomaly, but does no harm that I can think of.

Greolt
Title: Re: The Laser Project.
Post by: Dan13 on February 06, 2012, 04:15:39 AM
If you had Input #1 controlling something else which you wouldn't expect to get triggered while using the plugin it could get not pleasant.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 06, 2012, 04:17:52 AM
Hi Greg,

Dan is on the right track.

You mentioned earlier having the Digital Trigger and an Output both configured to the same port and pin and both Enabled at the same time. Conflicts can cause problems such as you are describing and which I am sure you are aware of.

This is exactly why I suggested using two different profiles Raster / Vector.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 04:35:15 AM

You mentioned earlier having the Digital Trigger and an Output both configured to the same port and pin and both Enabled at the same time.

If I did, I didn't mean it.  Not a good idea to have to things assigned to one pin.

However with some poking around I discovered that M11P0 and M10P0 will activate and deactivate the Digital Trigger.

So there is no need for a separate profile for engraving and vector cutting.

Both vector cutting and engraving would both use Digital Trigger.

In fact if you edit the M10 and M11 macros then I suppose you could drop the P0 or P1 altogether.  Just use M11 and M10.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 06, 2012, 05:23:04 AM
Quote
Funny thing is, I had been using the plugin via Output1 active low.  This worked fine and I had been engraving the last couple of days that way.  As soon as I set it to active high it no longer worked.  Go figure.

Hi Greg,

So, is this problem resolved now ??

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 05:45:05 AM
Yes as I said said above M11P0 and M10P0 work fine with Digital Trigger, so resolved it is.   

At least for me.  Everything is working great. Thanks.

Funny that the engraving plugin would fire the laser with Output1 active low but not active high.  Maybe I overlooked something.  Wouldn't be the first time.  :D

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 06, 2012, 08:21:26 AM
Hi Greg,

I am pleased you have got it all working OK now.

Don't forget the pictures.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 08:21:14 PM
The internet is a wonderful thing and I have learned more from forums like this one that I ever did at school.

However one of the small frustrations is that there is always misinformation mixed in with the good.

It is my strong desire to not add misinformation, particularly to this most informative thread of Tweakie's.

So I need to clear up what I have said about outputs used by the engraving plugin.

What testing has told me is that the plugin uses Digital Trigger only.   The really odd thing is that it uses Digital Trigger even when it is disabled.

My previous belief that it could also use Output1 was because it worked when Digital Trigger was disabled and Output1 was enabled.

But it was not using the enabled Output1, it was in fact using the disabled Digital Trigger.

If you look at the pic of Ports and Pins, you will see that I had both outputs set to port1 pin9. 

Not a good idea, but I had it set thus, as I was swapping back and forth to try and see what was going on, in the mistaken belief that disabling one and enabling the other was sufficient to change the output.  WRONG.

Don't know what to think of that.  A bug or my lack of understanding as to how Mach works.

Now the important thing after all this, is that I was wrong.  It is NOT sufficient to just disable an output in this case.

As Tweakie said, Digital Trigger is the correct output to set up for the engraving plugin.

Sorry for my misleading posts and I hope this clears it up.

Greolt
Title: Re: The Laser Project.
Post by: Greolt on February 06, 2012, 08:33:53 PM
Now to hopefully get this back on track, here is an attempt at engraving.

The wood is Huon Pine.  Rather than blacken, it more sort of ate it.  As if I had cut it on the router.

I have an awful long way to go on this learning curve.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 07, 2012, 06:12:04 AM
HiGreg,

Nice leopard.

On your learning curve you will find that some woods will produce quite a black image whilst others just get 'eaten'  :D

Keep posting the pictures.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 07, 2012, 10:11:22 PM
Here is the same pic engraved on a bit of cheap generic 3mm ply.  350 x 240mm

This did blacken nicely.  Power 40%, speed 18000mm/min

I don't know where I found this artwork.  It has the name Seyit on it, so I can not acknowledge better than that.

Tweakie do you know where I could find the Aztec Princess?

Greolt
Title: Re: The Laser Project.
Post by: Greolt on February 07, 2012, 10:31:39 PM
Had a go at Tweakie's bicycle.

I have a long way to go to get the finish that Tweakie has demonstrated.

Greolt
Title: Re: The Laser Project.
Post by: Overloaded on February 07, 2012, 10:39:18 PM
Long way to go ? ? ?  I don't think so !
Looks like you are well on you way and nearly there.
That is one cool looking cat, nice job Greg.
Russ
Title: Re: The Laser Project.
Post by: Dan13 on February 08, 2012, 03:15:22 AM
This leopard looks so much more better than the first one. Nice, Greg!

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 08, 2012, 07:16:36 AM
Hi Greg,

The Aztec Princess is a test file somewhere on Ray Scott's excellent site http://www.rabbitlaserusa.com/ but finding it again is another story  :(

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 11, 2012, 04:24:24 AM
Hi Guys,

Just a heads-up to let you know that the English translation of the DotG Manual is now available on Béni’s website here http://dotg.weebly.com/download.html
Both Amatör and I are currently working on an English translation of the Post-Processor Manual and this will be available shortly.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on February 11, 2012, 12:12:32 PM
Wow Greg, looks like your gonna be giving advise with Tweakie, rather than receiving it, in a short time. I'm envious of you both.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 11, 2012, 12:34:09 PM
You are not wrong there Sam. It's about time this thread had a few more laser users.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 12, 2012, 07:47:24 PM
Tweakie

If you have discussed this in the thread already I have missed it and apologise for not reading thoroughly.

Regarding M10P1 not turning the laser off until there is a subsequent move commanded.

Found this old thread where Tim did some testing on what was the current version.

http://www.machsupport.com/forum/index.php/topic,12653.msg82436.html#msg82436

I might have assumed that this was fixed with the latest work done on the M11/M10 commands.

When I test it here (Version R3.043.057) it does not turn the laser off until another movement is commanded.

Now in most circumstances this would be no issue, as another move would almost always follow a M10.

However almost always is probably not good enough when it comes to something like a laser power.

Very interested to hear your take on this and if I am way off track or not.

Greg
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 13, 2012, 04:36:35 AM
Hi Greg,

No worries, you know me, I am always happy to post my thoughts and opinions.

I have carried out extensive testing of Artsoft's corrected / modified M10 P1 / M11 P1 command set and can honestly say that I have had no problems with the M10 P1 command and the way in which it operates with a laser. IMO it is just perfect.

Perhaps it is common for us to blame tools for not working in the way which we want them to work rather than learn how to use these tools to our best advantage. (I have read far too many posts, on this forum, mentioning a bug within Mach which subsequently turns out to be a bug within the user).
The most important thing here is to understand the way Mach behaves, once this is understood then code and post processors can be tailored to suit. We all have our own preferences but my post processors always end the code with an M10P1 prior to the home move.
If you are having problems you could, if you wish, set your spindle to Output #1 then use the M5 command or, as an end command configure Mach to turn off all outputs then use M30 followed by a CR or %, which most post processors use as a standard program ending anyway.

If you could post a code sample of just where you are having difficulties or detail the problem I would be happy to investigate and suggest a solution.

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 13, 2012, 05:59:02 AM
OK it sounds like you feel I am off track .  :D

If I use code as follows,

M11P1  'turn laser on
G1 X25 F1000
M10P1  'turn laser off
M30
%

After running this code the laser does not turn off, it remains on.

I guess knowing that should be sufficient. 

I must remember to place a movement command after the M10 so as the laser will turn off.  Such as,

M11P1 'turn laser on
G1 X25 F1000
M10P1  'turn laser off
X0
M30
%

If I am correct in this, and that is certainly not guaranteed, I might call it acceptable, but not perfect.

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 13, 2012, 08:46:00 AM
Hi Greg,

Try checking the 'Turn off all outputs' on the general config page.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Greolt on February 13, 2012, 07:04:40 PM
Thanks Tweakie

Two options then;

1.  Follow the M10P1 with a move command so that the laser turns off.

2.  Follow the M10P1 with an M30 so that the laser turns off. (if it is set in config to do so)

The second option is not so good, as there is a delay before the laser turns off.  So the first option may be the only one.

Thanks for clearing that up,

Greolt
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2012, 05:32:18 AM
Hi Greg,

Yes, I think that is about the size of it - always follow the commands with an axis movement (which would normally always be the case anyway).

There may be some occasions when it is necessary to ‘fire’ the laser for a short period when an axis is stationary, as would be the case when using DotG in ‘dot’ mode but as it’s post processor if fully configurable a ‘dummy’ axis movement can easily be included. This was tested yesterday for the attached image and it works well.

As mentioned in the earlier post we do need the ‘turn off all outputs’ checked for safety reasons this way the laser will be turned off with ‘feed hold’, ‘limit switches triggered’, ‘estop’, M30, etc.

Tweakie.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 20, 2012, 04:59:21 AM
The recent period of cold weather has rather slowed things up a bit but spring is now on the way.

Another forum member ‘PicEngraver’ has sent me an advance beta copy of his new program ‘PicDither’ which will convert a bmp, jpg, etc image to halftone. This is capable of applying a number of different industry standard algorithms which in their own way produce differing results but the overall effect is extremely similar to the, rather overpriced, commercial program ‘PhotoGrav’.

These are my first tests made from a standard .jpg image which was then laser engraved onto MDF  using the Mach3 Impact / Laser plugin. It is early days and I have not yet tried a photographic image but that is next on my list.

Further details of ‘PicDither’ can be obtained by contacting John through his website  http://picengrave.com/

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 20, 2012, 07:25:53 AM
Exactly the same technique as previously used but this time with a photographic image.

I really don't know if all CO2 lasers behave in the same way but, as mentioned in way back postings, when using the Mach plugin directly I am only able to achieve a maximum of 5 shades of grey which, I suspect, may be a function of my high voltage power supply operating in a digital rather than an analogue way. Converting an image to half-tone seems to overcome this limitation by introducing the visual effect of many more shades.

My congratulations on an excellent program John.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on February 20, 2012, 09:20:27 AM
Can you explain please, Tweakie? The power supply still operates in digital mode so how does the image conversion help?

In the image the program outputs, are all the dots equal in size?

Dan

Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 20, 2012, 11:14:18 AM
Hi Dan,

A very good question (you always ask good questions) – as far as I can tell, yes the dots are all the same size so this would indicate that the laser has been fired at exactly the same power level throughout the whole image. The thing that varies is the dot density and this is the clever part which gives the illusion of shade.
In some areas of the image the dots actually merge because the burn marks on the wood are larger in diameter than the laser spot that created them. So, in theory, if I could increase my axis speed and reduce the burn time of each dot they would be smaller in diameter and I could increase my resolution. But, as said before, everything is a compromise.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on February 20, 2012, 11:52:36 AM
Hi Tweakie,

So how does it vary from the Impact plugin which still fires the laser at the same power each time? Roughly speaking, if I understand correctly the way the plugin works, it does internally the same thing as that program does, but following a different algorithm.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 20, 2012, 12:22:00 PM
Hi Dan,

I think you have got me there, because I just don't know the answer.

On it's own, the plugin will not always smooth a gradient of tone without producing 'steps' as can be seen in the background of this image which is a smooth transition from light to dark. I have spoken with Art about this and he feels that the cause is mathematical in nature.

(http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=23043;image)

Once an image has been 'halftoned' this does not happen, the gradient is much smoother.

As for why ? hopefully I will eventually discover the reason but for the moment it illudes me.

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on February 20, 2012, 12:29:06 PM
Thanks Tweakie,
I am close to a release version of PicDither, but as you know some other personal things slowed me up for a while, but I'm getting back up to speed now.  As always, your work is first-class and your pioneering work is much appreciated.  Please keep the examples coming.  Maybe someday my little laser diode will grow up into a full blown CO2 laser  :)

Dan, I can not use Art's plug-in as it does not work well with my lower powered, slower firing, 1 watt laser diode.  But if I understand correctly, Art's plugin varies the on/off cycle time of a laser based upon the gray value of an image pixel.  This means as a pixel goes from black towards white, the laser will fire a series of shorter bursts for each pixel to simulate a gray value.  Converting (dithering) an image changes all pixels of an image to either white (laser off) to black (laser on) according to a matrix formula, of which there are several.  This allows the laser to fire full power for each pixel that is black in a dithered image.  This is similar to the process that newsprint photos are printed (look closely at a newspaper or magazine with a magnifying glass to see the "dots" that make up an image).

My program will apply any of several different dithering matrix algorithms to an image to produce a 2-bit image suitable for impact or laser engraving.  I have not tested impact yet, but hope to do so soon.  Tweakiie has posted some great examples of of his impact work here on site.

Regards All,
John Champlain
www.picengrave.com
picengrave@verizon.net  
Title: Re: The Laser Project.
Post by: Dan13 on February 20, 2012, 12:43:59 PM
On it's own, the plugin will not always smooth a gradient of tone without producing 'steps' as can be seen in the background of this image which is a smooth transition from light to dark.

Tweakie, just out of curiosity I would try engraving the same image rotated by 90°.

John, I think the plugin outputs equal length pulses for each pixel. As far as I understand it's the spacing which creates the toning.

Dan

EDIT: Found original Art's description:

http://groups.yahoo.com/group/mach1mach2cnc/message/74912

Title: Re: The Laser Project.
Post by: Picengraver on February 20, 2012, 12:47:00 PM
As examples, here are three pictures - original, grayscale, and Floyd-Steinberg dithered.  I hope this helps to clarify the process a little.

John Champlain
www.picengrave.com
picengrave@verizon.net
Title: Re: The Laser Project.
Post by: Picengraver on February 20, 2012, 12:49:28 PM
Something ate the other two pics - trying again.
Title: Re: The Laser Project.
Post by: Picengraver on February 20, 2012, 01:03:34 PM
OK, think now the original image will post  - got my fingers crossed  :)

Dan, I probably do misunderstand the way Art's plug-in works, but tried to base my explanation my personal trial and this:

"Shades are achieved within the Engraving plugin by varying the Pulse Repetition Frequency (not PWM) on the digital trigger output. A PRF of 100% would be equivalent to maximum power and a PRF of 0% would be equivalent to minimum power. In practice the Engraving plugin never gets anywhere near to a 100% PRF (see my pdf document for values related to feedrate http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=26734 ) but manual control of the maximum tube current can, to a large extent, compensate for this.
The manual control of tube current can be adjusted at any time during operation to achieve the appropriate laser power for the job in hand. A multiturn potentiometer with calibrated dial is good because the adjustment is quite fine and the dial enables the correct settings to be recorded so that they can easily be used again at a future date for a similar job.
The Engraving plugin, as mentioned earlier, controls the laser’s output power by adjusting the PRF and this, in turn, is directionally proportional to federate and pixel value (high federate = high laser output power : low federate = low laser output power : no feed at all = laser off). It’s really just as simple as that.

I hope I have explained all your questions.

Tweakie."


At any rate, it did not work for me, hence my search for another way.

Regards,
John Champlain
www.picengrave.com
picengrave@verizon.net

Title: Re: The Laser Project.
Post by: Dan13 on February 20, 2012, 01:09:39 PM
Well, I think the plugin doesn't control the laser power whatsoever. All it does is trigger it on and off.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 22, 2012, 04:29:43 AM
Well, I think the plugin doesn't control the laser power whatsoever. All it does is trigger it on and off.

Dan


Hi Dan,

In a way you are right – the plugin does indeed just switch the laser on and off but it does in a cunning way called modulation. As laser ‘burn’ is related to both laser power and exposure time when the plugin switches the laser on it does it in pulses or dots per pixel – a few pulses on top of one another produces a light mark and many pulses on top of one another produces a dark mark. You have seen from Art’s description that these pulses or dots are pretty quick and providing the step-over has been set correctly they will blend and this in turn produces the shades of grey. I have tried to describe the process in my PDF http://www.cooperman.talktalk.net/Engraving.pdf (http://www.cooperman.talktalk.net/Engraving.pdf) which I am sure you have probably read already.

Overall, the function is not dissimilar to a PWM spindle speed controller – it only turns the spindle on and off at full power but by varying the duty cycle it controls the speed. There are a few more refinements in a speed controller such as measuring the back EMF and adjusting the pulse width so that a constant speed can be maintained under varying tool loading but basically all it does is turn the spindle on and off.

Tweakie.

Title: Re: The Laser Project.
Post by: Dan13 on February 22, 2012, 04:45:54 AM
Hi Tweakie,

I agree with this. It's just that I think that using the word "power" to describe this process is misleading as the laser is being turned on to the same (predefined by some other means) power each time.

And to be more correct, I think that the laser never really does several pulses on top of one another (well if it's focused fine enough that is), as the axis is in a constant move. I think the correct way of thinking about it is the dots intensity. And the other thing to consider while at it is that the exposure time is determined by the axis feed rate.

Yes, I had read through your PDF and I must say you've done great job there!! Thanks for that!

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 22, 2012, 05:19:16 AM
Quote
And to be more correct, I think that the laser never really does several pulses on top of one another (well if it's focused fine enough that is), as the axis is in a constant move. I think the correct way of thinking about it is the dots intensity. And the other thing to consider while at it is that the exposure time is determined by the axis feed rate.

Hi Dan,

You can do the maths – when the laser is pulsing at twenty thousand dots per second with a line scan speed of just four hundred pixels per second, there can indeed be many dots on top of one another. If it was not for this fact, the plugin would not, I think, be able to produce any shades of grey.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on February 22, 2012, 05:55:26 AM
Hi Tweakie,

I agree again. I was just trying to say it was not theoretically correct a way of description. There will always be the slightest offset between the two dots. It might be small, but it's there. And without it you wouldn't again be able to produce shades of grey ;D

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 22, 2012, 06:08:47 AM
Hi Dan,

OK, I submitt. You know best  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on February 22, 2012, 08:00:05 AM
Sorry, Tweakie. Didn't mean to sound that way. Let's just consider the issue closed... till we know better anyway ;)

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 27, 2012, 07:25:31 AM
Another image of Brittany Snow produced in a slightly different way.

The initial image was resized to 100mm x 135mm, adjusted in brightness and contrast then processed with PicEngraver’s excellent program PicDither using the Sierra algorithm. It was then reduced to 2 bit with IrfanView, saved as a .bmp file and the GCode created with the new Hungarian program DotG, in dot mode, at 0.25mm step over.
The result comprises 77,800 laser produced dots and took approx 50 minutes to complete, using the recently fixed M10 / M11 command set. The material is a faux-aluminium faced plastic engraving laminate (a non-pvc, laser friendly material).

Tweakie.


Title: Re: The Laser Project.
Post by: Picengraver on February 27, 2012, 12:23:52 PM
Tweakie,
With each of your posts, I become more and more envious  ;)

Great work.  Thanks.

John Champlain
www.picengrave.com
Title: Laser Lenses.
Post by: Tweakie.CNC on March 04, 2012, 04:05:26 AM
Many of the focus lenses used with CO2 and other lasers are of the single element Plano-convex type. As there have been some discussions recently, in various forums, regarding the orientation of these lenses I would like to clarify the situation.

Whilst this type of lens will operate in either direction the focal point will not be as sharply defined unless the convex surface is placed towards the photon source and I have tried to illustrate this point in the following photos. (Please ignore the backscatter from the test lenses as they do not have the customary anti-reflection coatings).

Basically, the tighter the focal point the greater the concentration of photons the greater the power and thus the greater the efficiency.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 19, 2012, 08:20:42 AM
Hi Guys,

LazyCam is provided free with Mach3 and although this is essentially an unsupported beta product it is still very useful for working with HPGL and .dxf files ( for example - changing the scale / origin or editing the tool paths etc.) then to create the necessary GCode.

For laser profile cutting and engraving I have written a very basic Post Processor for use with LazyCam which utilises the undocumented M11P1 / M10P1 command set.
The laser trigger is connected to a suitable LPT output pin ( I use pin 16 ) then in Mach / Config /  Ports & Pins / Output Signals, Output #1 is mapped to pin 16 ( or whichever pin has been chosen ) and the active Hi / Lo set accordingly. These M commands will then turn the laser on and off coincident with axis movement ( M11P1 = laser ON and M10P1 = laser OFF ).

The feed-rate, in the post processor generated GCode ( currently set to F300 ), needs to be adjusted to suit the application / material and this can either be edited within Mach3 using Windows Notepad or adjusted with the FRO slider on the Mach screen.

For any that are interested the Post Processor can be downloaded from here; http://hobbymaro.puhasoft.hu/Tweakie/Laser.zip (http://hobbymaro.puhasoft.hu/Tweakie/Laser.zip). To use, unzip and copy the file ‘Laser.pst’ into the Mach3 folder then from within LazyCam  select Setup / Posting Options and select ‘Laser.pst’ from the ‘Set Post Processor’ options.

Tweakie.


Title: Re: The Laser Project.
Post by: PicengraverToo on March 20, 2012, 03:05:56 PM
Bob attached a link to here in the thread I started over on the Vectric forum. http://www.vectric.com/forum/viewtopic.php?f=16&t=13405 (http://www.vectric.com/forum/viewtopic.php?f=16&t=13405)

I converted my CNC router over to a 1W diode laser engraving machine running in Mach 3. Read in my thread on how I did it with the electronics totally Independent from Mach control and it just runs a standard g-code to pulse the laser.

I just finished lasering this photo.

Jeff

Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 21, 2012, 02:50:01 AM
Hi Jeff,

Excellent solution for laser control and excellent results you are achieving  8)

I must admit that I have never tried  PhotoVCarve - perhaps I should.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on March 21, 2012, 11:58:32 AM
Thanks Tweakie,

I know there are other programs out there more reasonable in price that will do Lithophanes and imaging software to process the image first that may be used to laser engrave, but Corel PhotoPaint and PhotoVcarve is what I had already and wanted to see if it was possible using the combination of the two. I'm sure you know, allot of trial and error was involved with the process. ::)

Jeff
Title: Re: The Laser Project.
Post by: obal on April 10, 2012, 03:47:30 PM
Hallo Tweakie. Please paste postprocesor for DOT-G  Laser.dgp.    Thank you.

Those of you that have been following this (never ending) thread will know that between Andrea in Italy and myself in the UK we have spent quite a lot of time putting the Mach Impact / Laser engraving plugin through it’s paces. Although there are still some improvements that could be made to the plugin and it still has a lot of mileage left in it, the legacy issue of it’s requirement for a parallel port are starting to show and it is perhaps time to start looking at alternatives.

In the Eastern European countries, for many years, it has been common practice for black marble monuments and remembrance plaques to display an engraved ‘photographic style’ of image and this has inevitably prompted the development of CNC software to complete the task. One such software is “DotG” a Hungarian program which has just had an English translation version released. It is completely ‘free of charge’ and can be downloaded from here http://dotg.weebly.com/download.html

DotG works in an entirely different way to the Mach plugin insofar as it creates GCode from a pre-processed 1 Bit image and although I haven’t quite got my postprocessor completely sorted everything looks extremely promising so far.
It is early days yet but I will keep you posted of my experience with this software as I learn more.

This example image of Audry Hepburn with the glamour of the 1950/1960’s was laser cut into some scrap MDF whilst I was testing various settings and it would, I think, look quite stunning cut into some mirror tile (project awaiting).

Tweakie.

Those of you that have been following this (never ending) thread will know that between Andrea in Italy and myself in the UK we have spent quite a lot of time putting the Mach Impact / Laser engraving plugin through it’s paces. Although there are still some improvements that could be made to the plugin and it still has a lot of mileage left in it, the legacy issue of it’s requirement for a parallel port are starting to show and it is perhaps time to start looking at alternatives.

In the Eastern European countries, for many years, it has been common practice for black marble monuments and remembrance plaques to display an engraved ‘photographic style’ of image and this has inevitably prompted the development of CNC software to complete the task. One such software is “DotG” a Hungarian program which has just had an English translation version released. It is completely ‘free of charge’ and can be downloaded from here http://dotg.weebly.com/download.html

DotG works in an entirely different way to the Mach plugin insofar as it creates GCode from a pre-processed 1 Bit image and although I haven’t quite got my postprocessor completely sorted everything looks extremely promising so far.
It is early days yet but I will keep you posted of my experience with this software as I learn more.

This example image of Audry Hepburn with the glamour of the 1950/1960’s was laser cut into some scrap MDF whilst I was testing various settings and it would, I think, look quite stunning cut into some mirror tile (project awaiting).

Tweakie.

Title: Re: The Laser Project.
Post by: Joshua on April 10, 2012, 10:33:22 PM
Mahalo Tweakie,
I was just wanting to know how the cooling system worked out with the CO2 Laser. Does it keep the laser cool during long run times or duty cycle work? I live in Hawaii where the ambient temperature is over 80 deg Fahrenheit. I'm thinking that I may have cooling problems with my new machine, what do you think? Should I build/buy some sort of refrigeration/water cooling system Kinda like what a saltwater fish tank would use? ???
Thanks Josh
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 11, 2012, 03:06:28 AM
Hi Obal,

My current DotG post processor is attached. This is for ‘dot mode’ operation of both laser and impact magnet and will produce three lines of GCode for each ‘dot’ (the laser / magnet is only fired when the X axis is stationary).

If it is of interest, there is some more information (in English) relating to the use of DotG here http://hobbycncart.com/forum/61-146-1 (http://hobbycncart.com/forum/61-146-1)

Tweakie.


Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 11, 2012, 03:16:50 AM
Hi Josh,

As you have seen I am using a ‘closed loop’ water cooling system with a forced air radiator as the heat exchange element. This type of system will only cool the tube to ambient air temperature but, for me, works just fine within the UK where our (ambient air) temperature rarely exceeds 25 deg.C.
From tests carried out (with a glass tube CO2 laser) the maximum efficiency is achieved with a tube temperature of  around 7 to 8 deg.C so in some circumstances it may be an advantage to consider active cooling with a refrigerated device such as a ‘beer chiller’ or purpose built cooling unit. The down side to this is that relative humidity has to be taken into account because condensation forming on the output coupler lens can cause premature failure just as condensation on the outside of the glass tube could compromise the electrical insulation of the high voltage electrode connection (as an example - the condensation that forms on the outside of glass of a cold beer).

In reality, it should never be necessary to drive a CO2 laser at it’s absolute maximum power output but I think you should be aiming to maintain a nominal water temperature between 10 to 20 deg.C during operation.

Hope this helps.

Tweakie.
Title: Re: The Laser Project.
Post by: Joshua on April 11, 2012, 06:10:13 AM
Tweakie,
Thanks you brought up a good point that I didn't think about, condensation. I was so focused on cooling the fluid below 25 Deg.C. I didn't take that into account. Especially here in Hawaii where the humidity is high during the summer months. I think you are on to something with the "beer cooler" ;) looks like I will be insulating the Laser tube housing, pumping chilled air as well as chilled fluid.
I could see it now "Laser by Day, Beer Cooler by Night" :)

Thanks

Joshua
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 11, 2012, 06:20:34 AM
 ;D ;D ;D

Most of the beer coolers I have seen have multiple circuits so it could be 'laser by day' and 'cold beer by day' (sort of multi-tasking).

Tweakie.
Title: Re: The Laser Project.
Post by: fer_mayrl on May 22, 2012, 05:34:02 PM
Hey Tweakie,
quick question, do you know if a sealed Co2 laser 200w can cut metal?
Do you know which metals and what thicknesses?

Thanks
Fernando
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 23, 2012, 01:08:21 AM
Hi Fernando,

With the right lens yes it will cut metal but only very thin stuff and not all types / compositions (the shorter wavelength YAG lasers are usually used for metals).

Sorry but this is not an area in which I have practical experience so cannot give any more detailed information.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on May 23, 2012, 04:28:28 AM
Tweakie,

I seem to remember I saw some manufacturer of small CNC CO2 laser machines which claimed they cut metal (SS if I recall) up to 1mm with something like 80W. They had a video as well. I'll see if I can find the link.

Dan
Title: Re: The Laser Project.
Post by: Dan13 on May 23, 2012, 04:35:28 AM
Can't find this now, but here is a similar one:

http://www.youtube.com/watch?v=e9BvPeAmuvc

May be I was wrong about the 80W, but it's still way lower than we thought.

Dan
Title: Re: The Laser Project.
Post by: fer_mayrl on May 23, 2012, 10:37:33 AM
Thanks guys
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 23, 2012, 11:42:13 AM
Just a note, for others that follow….

The bench top type of CO2 laser machines imported from China will not cut metals without some major modifications. It is basically a reaction between the combination of the laser beam heat, the assist gas and the carbon content of the material which allows metals to be cut (with stainless steel being the preference).
A group of us, here in the UK, investigated metal cutting but as quite large volumes of Oxygen were required as the assist gas it was concluded to be an extremely dangerous venture for a home shop environment and it was suspended.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on May 23, 2012, 01:51:11 PM
Ah... so I guess it explains the video then.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 30, 2012, 08:44:17 AM
A picture of a very good friend, laser etched using GCode produced with the free software DotG.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 31, 2012, 06:49:06 AM
Appologies to John (Picengraver) I forgot to mention, in the previous post, that the original drawing was converted to a dithered image using his fine software PicDither – then the GCode was created with DotG.

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on May 31, 2012, 06:25:55 PM
Thanks Tweakie - much appreciated.  I'm glad PicDither is useful.

BTW, as we discussed, PicDither is now posted on eBay.

My Best Regards, Friend,
John Champlain
www.picengrave.com
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 17, 2012, 04:15:24 AM
Something I have perhaps only briefly mentioned in earlier posts is the advantage, even the necessity, of Air assist.

When laser cutting wood, for example, carbon is produced and if this occupies the bottom of the kerf it will reduce penetration considerably. Air assist, if correctly orientated, will remove these carbon particles from the kerf as they are produced and cutting efficiency is much improved as a result. Although wood is perhaps the best example, many other materials will exhibit similar properties and the end product will almost certainly benefit from the use of air assist.

If the air is applied co-axial to the laser beam, for example – the air is fed into the side of the lens assembly and then exits through the same (small diameter) nozzle as the beam, this has the added advantage of preventing vapours or particles from the work piece being deposited onto the surface of the focus lens thus extending the life of the lens and reducing the necessity of frequent cleaning of this component. The disadvantage is that a clean, dry and oil-less air supply is required. The Koi pond aerator type pumps are pretty well suited to this task, they are available in various sizes and air flow rates and are not expensive to buy. These are relatively quiet in operation and are probably the most commonly used type for small laser machines. Shop air could also be used, providing the necessary traps / filters (similar to those used for vehicle spray work) are included in the line together with suitable pressure regulation but with a compressor there is always the potential risk of oil contamination of the lens if the filters are not changed regularly.

For cutting thin materials (veneers, gaskets and the like) a relatively low air pressure / flow rate is all that is necessary – too high a pressure can result in the cut parts or waste material being blown around on the cutting bed and causing problems. For this type of work I use a small Koi pond pump and also have an air-bleed valve in the line so that I can reduce pressure / flow rate if necessary. For the thicker materials I use an old twin cylinder Gast Roc-R pump and between these two different pumps manage to cover most eventualities.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 09, 2012, 07:52:02 AM
I have been asked by Picengraver to test a beta version of his latest software ‘PicLaser’ and as I have no commercial interest in this product think it would be OK to post a few details here.

PicLaser takes a bitmap image and enables it to be converted to a dithered halftone (using one of a number of different, industry standard algorithms) then generates the necessary GCode to reproduce the image. It uses a unique method to create a laser ‘on time’ dwell which makes it just as suitable for high as well as low power lasers. I have not yet tried it using an impact magnet (my next task) but I have every confidence.

This was my first test piece with the laser, it is faux aluminium faced engraving laminate, with the image just slightly larger than life size and took around 20 minutes to complete. I have deliberately scaled the image up a bit and kept the focus tight so the individual dots are clearly visible but for portrait work it is generally considered best to de-focus slightly, producing a somewhat larger dot size which blends in a smoother manner.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 20, 2012, 04:06:44 AM
By way of an update - I have now tested PicLaser generated GCode with an impact magnet (using exactly the same code I would use with the laser) and the results have been posted in this thread -  http://www.machsupport.com/forum/index.php/topic,20490.msg154622.html#msg154622

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 24, 2012, 07:30:04 AM
Eventually my laser has started to show some erratic behaviour by failing to trigger properly at low current settings and it is now evident that it is time to replace the tube.
The original has done some sterling service over the last few years (imported from the USA in March 2007) but they don’t last forever and must always be regarded as expendable components.

Also as always, nothing is ever simple and I have not been able to easily obtain a ‘size for size’ replacement so some modifications are going to be required to accommodate a longer length of tube.

The standard 30/40 Watt Chinese laser tube is approx. 700mm overall length and offering one up to the existing enclosure shows that I will need to construct bit of an extension to enclose the high voltage end.

Something I learnt a few years back – no CNC project is ever finished it always remains an ongoing adventure.  ;D

Tweakie.

Title: Re: The Laser Project.
Post by: Jammerm on August 24, 2012, 09:57:23 AM
What would cause this? Do you think the CO2 is breaking down or the mirrors are clouding up? I would think the power supply would quit before the tube.

I just looked, it's been 3 years, almost to the day, since you started this thread.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 25, 2012, 02:11:21 AM
Hi Jammerm,

In creating the photons (laser beam) atoms in the gas mixture get consumed - bit like a battery, it has to run out one day.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 26, 2012, 06:46:56 AM
My family had great plans for the holiday weekend but, fortunately, the poor weather forecast came to my rescue and I was able to take a day out to construct the extension to my laser tube enclosure. This did not exactly go down too well with them but they now have my full attention for the next couple of days.  ;D

The new tube will sit on the two existing mountings, held in position by the elastic bungee cords and the laser beam will exit through the small hole in the far end of the enclosure. Although the mountings are adjustable, from underneath, I am hopeful that the alignment will not be too much of a drama.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on August 30, 2012, 11:16:30 AM
Tweakie,

Have you ever tried to vary the power of any of your lasers with analog modulation to engrave a picture with g-code in Mach3 to get shades instead of pulsing your laser to get the allusion of shades? I have perfected a process to do it using PhotoVcarve software and an absolute shaft encoder with analog 0-5V output.

Read this thread and it will explain how I was able to do it. 

http://www.vectric.com/forum/viewtopic.php?f=16&t=13405&start=60

and here

http://www.vectric.com/forum/viewtopic.php?f=16&t=15161

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 30, 2012, 11:41:01 AM
Hi Jeff,

I have been following your progress on the Vectric forum with great interest - Very nice work you are producing.

Art's Mach3 Impact / Laser plugin does just as you describe, producing the shades of gray by a PWM method of varying the laser on time. This is OK for certain materials (such as wood) but many other materials just do not accept shade.
After many trials and comparisons I prefer the half-tone method but, as you have shown, each method has it's own merits.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on August 31, 2012, 07:48:25 AM
Thanks for the compliment Tweakie.

I do have to say though, technically by using PWM in Art's plugin is still pulsing the laser on and off to get shades. It's not really varying the power like I am with the MA3 analog absolute encoder and the PhotoVcarve software. My laser never turns off until the engraving is finished.

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 31, 2012, 08:11:57 AM
Hi Jeff,

How does your laser vary it's output power when you input the analog 0 - 5 Volt input ??

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on August 31, 2012, 09:20:34 AM
Hi Tweakie.

I have one of these driving the 445nm laser diode. http://hacylon.case.edu/ebay/laser_diode/FlexModP3.php. It has analog and TTL modulation I'm using the USB port to power one of these. http://usdigital.com/products/encoders/absolute/rotary/shaft/MA3 I purchased the analog output version instead of the PWM output one and it's attached to the Z axis stepper motor by a timing belt and pulley setup with a 6-1 ratio. With these ratios, when my Z axis motor moves from Z0.00 to Z-.016" the encoder outputs 0-5V. With a 2-1 ratio to my Z axis screw the laser only moves .008" and it's not enough to go out of focus. I'm not using any special code, but just like the PhotoVcarve software outputs for a Lithophane or rotary bit engraving with the X Y & Z g-code moves. Darker areas with a deeper depths of cut, it throttles up the power of the laser and lighter areas it throttles back so it is truly variable and proportional with all shades in between. This could be done with a more powerful CO2 laser if there was a way to vary the output power of it. I was planning on down the road to build my larger CNC router into one, when my finances with allow. I guess the tube would have to be mounted vertically to make it work properly. That way it could still move up and down based on material thickness so the beam would still stay in focus.

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 31, 2012, 12:53:08 PM
Hi Jeff,

Thanks for the information, most interesting.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 19, 2012, 11:34:53 AM
Based on the excellent results Jeff (JJWMACHINECO) has achieved with burning ‘shades of grey’ into wood…

There are those that have converted imported CO2 laser machines to operate with Mach3 who do not actually have a motorized Z Axis and others who perhaps do not wish to add an encoder to their existing Z Axis. For this scenario I submit the following design idea which is primarily aimed at CO2 lasers with 40 Watts (or more) available output power.

Because the Mach3 internal PWM generator cannot easily be controlled ‘on the fly’ with the S*** commands blended with X Axis movement, or at least not fast enough to be useful, another approach has been considered.

It is perfectly feasible to construct a ‘stand alone - step / direction’ controlled PWM generator the output of which is easily converted to a voltage with a simple DAC (digital to analogue converter). Then by using 2 voltage dividers, one to set the lower voltage at which the wood is just marked and the other to set the higher voltage at which the maximum burn is achieved the laser output power can be fully controlled (via its PSU), with 8 bit resolution, from a lithophane type GCode tool-path.

I threw out the initial idea of connecting an encoder to a stepper motor and then using a standard stepper motor driver in favour of an all electronic solution which will enable ‘on the fly’ adjustment of the minimum and maximum thresholds whilst still maintaining an 8 bit resolution of  voltage over a typical 2mm depth of tool-path.

My design may well be a bit theoretical at this stage but so far I have established that a PIC microprocessor, clocked at 20MHz, can be configured within Mach3 as an Axis which can then be driven at a typical feed-rate of 1000mm/min with 127.5 steps/mm and produce a continuously updated PWM output between 0 and 100%.
Referring to my very basic schematic, this PWM is then opto-isolated, to remove the GND constraint and place the 255 step output potential between the maximum and minimum voltage settings of the two potential dividers. A simple DAC is then used to drive the emitter-follower output voltage to the laser PSU.

For the initial testing and for convenience, I am using a partially populated pcb from my RF Laser controller design (mentioned many posts back) purely because the display is useful, at the software design stage, to be able to observe the various settings and values. The final design will be a lot less complicated.

As always, early days yet but it all looks promising.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on September 20, 2012, 06:06:43 AM
That's cool Tweakie.

Can't wait to see some pictures with shades you engrave using that setup. I'm getting allot better and consistent results with John's PicEngrave Pro software then before using PVC. Here is one I did the other day and the detail is amazing.   8)

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 20, 2012, 06:24:46 AM
As always Jeff, excellent results.

I am pleased you are now using PicEngrave - John has put a lot of work into writing his software and results like this, I am sure, will make it all worthwhile.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on September 20, 2012, 07:22:03 AM
Tweakie,

At first I was concerned that it did not have as many settings as PVC does, but what I found is all those extra settings was really driving me bonkers to get each picture to come out right. With PVC I had big problems with allot of reds and blues in photos and was trying to compensate in Photo Paint to correct it. Reds would engrave to dark and blues would engrave to light. John's software does allot better job interpreting those colors to grey-scale when creating the tool-paths. The tool-path preview in PVC was harder to tell how the engraving would come out also. I really like the grey-scale preview in PicEngrave because it shows how the engraving will actually be engraved and I'm not scrapping as much wood.  ;D

The G-code files are allot smaller too because there are no retracts at the end of each pass which it only needs the feed-rate put one time at the beginning of the file. It eliminates all those G00 and G01 changes in the file which cuts down on engraving time by instantly reversing the machine axis direction. I can tell he put allot of thought and work into his software and how it generates the g-code efficiently to do lithophanes, engravings and now laser engraved shaded photos. 8) 8)

Jeff
Title: Re: The Laser Project.
Post by: Picengraver on September 20, 2012, 05:12:33 PM
Thanks Jeff and Tweakie,
But I'm just a guy making some of the tools that you true artisans use.  Your work and laser pioneering deserve all the credit.

My Best,
John Champlain
www.picengrave.com
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 21, 2012, 10:32:16 AM
My new tube has just arrived from China, been plumbed in and the water circulation system run for some 2 hours (to remove all the air bubbles) now to test it out.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 26, 2012, 12:02:36 PM
The new tube works a treat.

I have to give full credit to the suppliers who made such an excellent job of the packaging that even our Royal Mail Parcelforce, at this end, did not manage to break the delicate glass tube inside.  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 04, 2012, 03:45:31 AM
This classic image of Ashley Olsen has been laser cut into Obechi.

This was produced using the Mach3 Impact / Laser plugin with a step-over of 0.2mm and a feed-rate of 3000mm/min. The laser beam was slightly de-focussed to cause a small increase in the spot size to create a better blending of the horizontal scan lines.

The dark areas essentially consist of carbon soot so images produced in this manner need to be sealed (perhaps using a lacquer spray) to make them more durable, if they are to be preserved.

Tweakie.

Title: Re: The Laser Project.
Post by: TOTALLYRC on October 04, 2012, 07:12:32 AM
Nice work, Tweakie.

I just need to add a laser to the list of things to do.

Mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 05, 2012, 12:02:44 PM
During recent work, using the Mach3 Impact / Laser Engraving plugin when engraving photographic images into wood (similar to the one shown in the previous post) it became apparent that in order to re-produce the lighter shades the required laser output power was burning too deeply into the darker portions and loosing some of the detail present in those areas.

To offset this problem I have made a small change to the plugin’s .dll to incorporate a user selectable Greyscale Compression feature the function of which is shown in the following picture. This function essentially alters the ratio of output pulses in relation to pixel value so that a different balance is achieved over the total range of values with the density of the low value pixels increased thus allowing laser output power to be reduced and create improved detail within the high value pixel areas of the work.

I hope this change may be useful to others using the plugin and the latest version of the .dll and it’s associated .pdf document can be downloaded from here;


Engraving.dll   http://www.cooperman.talktalk.net/Engraving.dll

Engraving.pdf   http://www.cooperman.talktalk.net/Engraving.pdf

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on October 05, 2012, 01:38:54 PM
Thanks Tweakie!  That's awful nice of you.  :)

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 06, 2012, 07:43:59 AM
Thanks Brett.  :)

As always, learning as I go but different types of wood produce such entirely different contrast ratio's that it is very difficult to obtain a datum upon which to base comparative tests.

I am no expert when it comes to wood so I don't know exactly what type this is but the results were not what I was expecting. So far Obechi seems to give me the best contrast ratio so perhaps I should stay with that.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on October 06, 2012, 08:00:40 AM
Tweakie, have you done any test or comparisons with the different woods and their surface finish, density and moisture content?  I'm just thinking if those 3 variables were monitored maybe a formula could be created to give consistant results. 

You do some of the neatest stuff Tweakie!

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 06, 2012, 08:10:41 AM
Hi Brett,

I had not even thought about measuring moisture content (I do have the equipment to measure that) but surface finish certainly does play a big part in determining the result.

Any thoughts or suggestions on the easiest way I can determine density ??

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on October 06, 2012, 09:07:48 AM
I have used this before.

http://www.engineeringtoolbox.com/wood-density-d_40.html

I don't know how accurate that will be really because of growing variables but it should get you with in a reasonable range.  You could also just measure and weigh and account for moisture content or its probably overkill but you could do a displacement vs weight test.  Maybe vaccum seal the wood in a known size bag and sink it in a pan of water and measure the amount of water that gets displaced.  I wouldn't think you would need that at all unless you were trying to measure odd shaped pieces.

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2012, 07:00:10 AM
Thanks for the info Brett, it is most helpful.

Overall the Obechi seems to give me the best results with, contrast ratio, so far but I still have a few more different woods here to try.

Tweakie.



Title: Re: The Laser Project.
Post by: Dan13 on October 09, 2012, 07:17:45 AM
Hi Tweakie,

Why are there vertical lines on the last one?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2012, 07:32:58 AM
It's the grain of the wood Dan.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on October 09, 2012, 07:40:59 AM
Ah... They are so evenly spaced and bright (I would have expected the grain be darker than rest) that it didn't occur to me it was the grain ;)

Dan
Title: Re: The Laser Project.
Post by: Chaoticone on October 09, 2012, 08:02:10 AM
Tweakie, what are the physical dimensions of the piece in the last picture you posted?

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 09, 2012, 08:24:38 AM
Hi Brett,

It's 150mm x 95mm.

Tweakie.
Title: Re: The Laser Project.
Post by: patter on October 13, 2012, 03:50:57 AM
WOW  Tweakie.... the contrast is perfect....excellent
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 15, 2012, 03:09:51 AM
Here in the UK Winter is coming and if anyone, like me, has their glass-tube laser located in an outside workshop and lives in a similar seasonal location, it is always wise to take precautions to prevent a cooling system freeze-up.

I have a 5 deg.C ‘frost-stat’ workshop heater but that could fail so my laser tube cooling system comprises Distilled water with 30% vehicle antifreeze added. The system is closed-loop and fully contained but precautions must always be taken to ensure that children or pets cannot possibly gain access to the coolant.

WARNING – If you use antifreeze please be aware that it is a particularly dangerous substance and can, even in extremely small quantities, be deadly to cats as well as extremely toxic to young children.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on October 15, 2012, 02:02:31 PM
Good point Tweakie.  Do you guys have the "safe anti-freeze"?

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 16, 2012, 04:52:58 AM
Hi Brett,

The 'pet-safe' product is available here in the UK but awareness to the existence of this product is sadly lacking.  :-\

Tweakie.
Title: Re: The Laser Project.
Post by: ThomasCB21 on October 16, 2012, 10:11:11 PM
Ethyl . . . BAD!  Propyl . . . GOOD!
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 08, 2012, 06:52:10 AM
Another image produced on Obechi using the Mach3 Impact / Laser Engraving plugin.

Tweakie.

Title: Re: The Laser Project.
Post by: Ya-Nvr-No on November 08, 2012, 07:39:22 AM
Sexy ... I like
Title: Re: The Laser Project.
Post by: bartabac on November 10, 2012, 07:30:51 PM
Hello, and thank you for this forum, which gives me a lot. :)
I'm French and I use a translator, thank you to excuse my bad qualities words. :(

A big thank you to Tweakie for your site "http://www.cooperman.talktalk.net" and for your participation in numerous forums. I learned a lot. ;)

I realized your PWM controller and I use the program V16.2
Manually everything works perfectly. ;D
But with Mach3, I get a varying voltage S0 to S1000 but I can not seem to have a constant voltage and frequency is not fixed on 5khtz. Which side can come the problem? Is that I made a mistake or Mach3 is that I can not solve
Thank you for helping me because I'm not experienced with Mach3 :-[
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 11, 2012, 02:09:21 AM
Hi Bartabac,

Some while back I did try using the Mach3 PWM output for laser control but it was not very successful. Perhaps it depends on the type / specification of PC used but I found that the small, periodic, frequency variations of the PWM produced quite large changes in laser output power. This is not noticeable when cutting but it can spoil engraving work etc. so I abandoned the idea in favour of manual control for maximum laser current.

Tweakie.
Title: Re: The Laser Project.
Post by: bartabac on November 11, 2012, 05:37:21 AM
Hi Tweakie, :D

 Thanks 1000 times answered me so fast
Your answer reassures me because I try for several days without results
At the same time it is sad because I can not find my PWM laser.
But I still very happy with your system because I can control my 40W CO2 laser in manual low.  With a potentiometer I could not do it in low voltages. Your control installation works perfectly.  ;)
Thank you very much for your work ;D

For now I use Mach3 PWM montages that works more or less
"Http://www.sonelec-musique.com/electronique_realisations_conv_pwm_tension_001.html"
I changed the diagram 001ab R4 and R5 by 470ohm this may help some people can be.
But if someone has a solution for the PWM with Mach3 and a laser I would be happy.
In any case a very big thank you.
Continue to make me dream :D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 11, 2012, 09:44:19 AM
Hi Bartabac,

I am pleased that you are making progress with your laser control. Perhaps you could post some pictures of your work, setup etc.

I am following with great interest the work being produced and shown by the guys in the Diode Laser thread here http://hobbycncart.com/forum/63-151-11  Really excellent work.

A couple of images I just had to try with the CO2 laser – Jeff’s train engraving was produced using GCode generated by John’s PicLaser software using the Sierra algorithm and Amator’s craftsman engraving was reproduced using the Mach3 plugin.

Tweakie.


Title: Re: The Laser Project.
Post by: Ya-Nvr-No on November 11, 2012, 03:34:29 PM
Tweak; Where are you finding the engraving images, they would be good for me to Palm Engrave? Love the Train Engine. Thanks
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 12, 2012, 01:43:52 AM
Hi Craig,

The train image was taken from the thread mentioned in the last post but if you PM Jeff directly (JJWMACHINECO) he could, I am sure, provide you with a better resolution image for your palm engraving.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 13, 2012, 03:49:59 AM
Something that made me smile…

This guy obviously thought it would be fun to laser engrave the sausages !!.

After the fire this was the mess he had to deal with.

Tweakie.
Title: The Laser Project.
Post by: Fastest1 on November 13, 2012, 09:04:23 AM
Now that is funny!
Title: Re: The Laser Project.
Post by: BR549 on November 13, 2012, 11:14:34 AM
HEY Tweaks, Can you track and shoot down ICBM's yet ?

You are having WAY too much fun.

(;-)TP
Title: Re: The Laser Project.
Post by: bartabac on November 14, 2012, 05:29:21 PM
Hello everyone ;D

I managed to stabilize the Mr. Tweakie PWM controller with Mach3 ;)
 "http://www.youtube.com/watch?v=N8I5QgCz-lo"
With the same G-code, I managed to burn the image to the center (2.5 mA) and cut out the leaves of the tree and the framework (19 mA) I am happy. :D

If you want you can see the beginning of my work here"http://www.laserfreak.net/forum/viewtopic.php?f=107&t=52456&hilit=cnc+laser+bleu"
But I still have much work to have the same quality as you

Thank you all for your work ;)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 15, 2012, 01:54:16 AM
Hi Bartabac,

I am pleased that you have sorted the PWM issue. Thanks for posting the link showing your machines and work.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 15, 2012, 05:01:46 AM
HEY Tweaks, Can you track and shoot down ICBM's yet ?

You are having WAY too much fun.

(;-)TP

Hi Terry,

Given the distance and thus small angles involved I am sure Mach3 could handle the task but I think I would need a Damn Great Big Laser.   ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on December 28, 2012, 05:52:47 PM
I'm finally getting my laser diode machine tuned in.  Burned this today.  It's a little too dark, but caused by wood type.  I need to replenish my good wood (Baltic Birch) supply.

Happy New Year All,
John Champlain
www.picengrave.com
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 29, 2012, 06:15:35 AM
Excellent work John, I am pleased to hear that you have your new electronics, for the laser power control, all up and running – there will be no stopping you now.  ;D

(For others following this thread who may be interested in using diode lasers with Mach3 there are some more pictures and discussion on the techniques, hardware, development and progress in this thread http://hobbycncart.com/forum/63-151-8 )

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 31, 2012, 04:05:02 AM
Can Llithophanes be produced with a laser ??

The answer is definitely “yes” but not, I suspect, with the same degree of quality as produced by spindle machining.

I had to give it a try and this was my first attempt. It is not that good but I am sure the results could be improved once I have discovered the reason for the unwanted background ‘noise’ which is spoiling the effect.

Has anyone else here tried creating Lithophanes using a laser ??

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on December 31, 2012, 05:34:23 AM
This is an interesting approach, Tweakie. Never thought about this.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 31, 2012, 08:20:16 AM
Hi Dan,

The previous Litho was produced a while back but this one was made this morning. One big advantage is that they only take a fraction of the time to make (some 15 to 20 minutes for this one, which is 100mm wide) but the secret, if there is one, is to set the laser power so it does no cut right through the acrylic.  ;D

I don’t think laser produced Litho’s will ever get up to the quality that can be produced by spindle engraving but who knows ?

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on December 31, 2012, 08:43:41 AM
I don't know, Tweakie, that is pretty detailed to me, that looks great!

Dave
Title: Re: The Laser Project.
Post by: Dan13 on December 31, 2012, 11:49:35 AM
Tweakie, I agree with Dave, the last one shows pretty fine detail. May be in reality it looks different though.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 31, 2012, 12:38:04 PM
Hi Guys,

I don’t think there is any problem with resolving the detail as the laser beam can be focussed to a spot size almost similar to the point of an engraving bit.

The main issue appears to be that I am unable to get a smooth surface finish. In itself this is relatively unimportant as far as light transmission is concerned but it can trap some of the residual powder particles (filler creating the opal appearance) and when it does this creates an unwanted dark spike. I should say that I am not yet 100% certain that this is the cause of the dark spikes but it is looking more than likely.

I dusted some black toner onto a background area in the first Litho (this should be flat as it is all the same pixel value) so you can see a better close-up picture of the surface finish I was obtaining. This has improved slightly since changing the laser modulation method but it still looks a bit like the surface of an orange.  ;D

There is just so much to learn.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on December 31, 2012, 12:51:23 PM
Wow, great picture, and if anyone's going to figure it out, it'll be you-
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 05, 2013, 05:45:31 AM
A recent, accidental, discovery (not by me) when laser cutting a mask in preparation for paint spraying revealed that the adhesive and or mask somehow fuses with the ceramic surface glaze on wall tiles.

Obviously I had to give it a try and this is the result of my first test. I am not certain about the long-term durability but this has been through my dishwasher once without any noticeable degradation – if it survives say 10 cycles through the dishwasher then I would say that it is pretty permanent. An interesting discovery.

Tweakie.

Title: Re: The Laser Project.
Post by: balsa burner on January 05, 2013, 06:03:15 AM
That interesting, i was just about to try and mark out a pattern into some litho or try to cut it. (if 80w will do that)
I've seen some spray on stuff to mark alli with a laser, but it's so expensive I've not bothered with it.

What adhesive did you use and have you tried it on any other materials ? I've often thought about trying to melt a covering onto a metallic background but haven't had time to try it yet.

Nice work tho. the detail looks good, lets hope it lasts.

  Bry
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 05, 2013, 06:27:37 AM
Hi Bry,

The original discovery was made whilst using the blue 'Painters Tape' but I am uncertain if this contains PVC so it would need to be ‘burn tested’ before trying - just to be sure.

I used the paper transfer tape, as used for the application of vinyl signs. Different tiles and possibly different makes of tape will produce slightly different shades - this was one of the super white tiles which have a slightly bluish appearance the standard white tiles produce more of a sepia shade. As far as I am aware it only works with ceramic glaze.

I would be most interested to see / hear of others results with this.

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on January 05, 2013, 07:31:55 AM
I love the effect of the "scrimshaw" look that you get with that. I'm imagining the old oriental carvings or the scenes that sailors on ships would do on ivory teeth/tusks.

Interesting technique indeed!
Dave
Title: Re: The Laser Project.
Post by: Dan13 on January 05, 2013, 08:45:17 AM
Interesting idea. The result is real cool!

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 05, 2013, 10:56:33 AM
I love the effect of the "scrimshaw" look that you get with that. I'm imagining the old oriental carvings or the scenes that sailors on ships would do on ivory teeth/tusks.

Interesting technique indeed!
Dave

Hi Dave,

I agree with you, they certainly can look really old world.

Something I want to try is a circular, rotating, panoramic view around a cylinder and since Terry created the Y to A cylindrical mapping screen this project has started to look a whole lot easier to do. I have seen pictures, in old books, where this sort of thing was done on lamp shades but I am thinking more of incorporating it into the base of a lamp. All I need is time  ;D

Tweakie.  

Title: Re: The Laser Project.
Post by: Dan13 on January 05, 2013, 11:17:45 AM
Think I saw someone over here done a cylindrical lytho with a candle lighting from the inside. The result was fantastic.

Dan

EDIT: It was Greolt I think I recall.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 05, 2013, 11:19:55 AM
Hi Dan,

Thanks, I will do a search and see if I can find it.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on January 05, 2013, 11:24:15 AM
Ah... and here is the link to is Youtube video:

http://youtu.be/dblNnF4JJGk

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 05, 2013, 11:44:57 AM
Thanks again Dan.

That led to video showing almost exactly what I want to do  http://www.youtube.com/watch?v=5NFk4Yv_ePc&NR=1&feature=endscreen

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on January 05, 2013, 11:50:11 AM
Yes, these are beautiful, Tweakie.

Dan
Title: Re: The Laser Project.
Post by: PicengraverToo on January 05, 2013, 04:00:07 PM
Tweakie,

Try doing a Lithophane using a 360 degree panoramic photo and mate the ends together seamlessly. The calculations have to be perfect and the machine setup has to be very precise. I was able to accomplish this on the second lithophane I ever made. The image never ends. ;D

http://www.vectric.com/forum/viewtopic.php?f=16&t=6321

 http://www.youtube.com/watch?v=ki_tPourVTA

http://www.youtube.com/watch?v=LnZVNVN7LqY

Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 06, 2013, 12:16:46 PM
Thanks Jeff.  8)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 12, 2013, 06:10:07 AM
Hi Guys,

Thanks to suggestions from others I have been able to improve my technique and this is the latest Lithophane, laser cut into Corian.
As there is no Z axis movement I was able to use a constant velocity of 4000mm / min for the X axis (excepting the acceleration and deceleration zones for each line scan). The final work does need backlighting (unlike opal Plexiglas) so it looks like I will be making a few of John’s (PicEngraver) LED / diffuser light frames when I get a chance.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: budman68 on January 12, 2013, 07:40:00 AM
Very nice Tweakie, do you have a link to Johns frames? Not sure I saw those.

Dave
Title: Re: The Laser Project.
Post by: Picengraver on January 12, 2013, 08:07:42 AM
Dave,
PDF here: http://www.picengrave.com/downloads/Lithophane%20Light%20Panels.pdf
Regards,
John Champlain
www.picengrave.com
Title: Re: The Laser Project.
Post by: budman68 on January 12, 2013, 08:32:21 AM
Thanks, John, I see I set mine up "almost" like yours (http://www.machsupport.com/forum/index.php/topic,22972.0.html ), but I see you added the light diffuser as well.

I bet that would even out the light a bit more across the back of the image for sure. Nice touch, and I will have to add that to my toolbag for future use.

Thanks for sharing-
Dave
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 12, 2013, 08:34:44 AM
Thanks John, I have been searching for that link for ages  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 02, 2013, 07:23:49 AM
At the risk of rambling on a bit, I have been closely following the absolutely excellent and quite pioneering work which is being done with low power diode lasers by John, Jeff, Dave and others in different parts of the world - for those that may be interested these threads relate;

http://www.machsupport.com/forum/index.php/topic,23456.0.html
http://www.machsupport.com/forum/index.php/topic,23584.0.html

Whilst I am quite certain that it can be done, replicating their work using a CO2 laser is not without it’s difficulties (cracking a nut with a lump hammer comes to mind) but, hopefully, I will get there.  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: yywind on February 14, 2013, 10:47:27 AM
A picture of a very good friend, laser etched using GCode produced with the free software DotG.

Tweakie.

Hi Tweakie,

I am newbie for laser engraving, I just completed my cnc router recently and am immediately interested in the laser engraving after reading some of your posts. You guys are genius!!!

I have a couple question about dotG & your post processor,
1. How does it control the 'on time'(duration of laser on) of the laser? Is it achieved by changing the Z axis feed rate while X axis is in constant feed rate for each 'dot'?
2. Is it sharing the same idea as Art's impact/engraving plugin? So dotG is basically outputting a TTL signal to trigger the laser?
3. Could you paste several lines of GCode to help me understand how it works? Unfortunately I am not able to install dotG at the moment, it gives me 'cannot create file' error, will sort it out later.

Thanks so much.

Yanxin
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2013, 12:44:11 PM
Hi Yanxin,

DotG has been designed for reproducing a one bit, ‘dot-dithered’ image (one with a varying density of equal sized dots to create the illusion of shade) and when set in ‘dot’ mode the laser is only fired when the X and Y axes are stationary.

To fire the laser I am using the M11P1/M10P1 command set together with an imaginary B axis and my Post Processor (see posting #641) essentially creates this code for each dot in the image:-

B0

M11P1 B1
M10P1 B0

B0 is at the start of the code and makes sure the imaginary B axis is in position 0.

M11P1 turns on Output #1 (as soon as the B axis starts to move). Output #1 is mapped to an LPT (parallel port) output pin which is in turn connected to my laser TTL(L) trigger.
Because the imaginary B axis takes time to move from position 0 to position 1, I have adjusted (by trial and error) the steps per unit, Velocity and Acceleration of this axis to produce the required time delay (laser on time).

M10P1 turns off Output #1 and thus the laser trigger as soon as the B axis starts to move back to position 0.

I hope this answers your questions.

Tweakie.
Title: Re: The Laser Project.
Post by: yywind on February 14, 2013, 11:50:51 PM
Thank you for the detailed explanation, Tweakie, I understand how dotG works now, it's like a real PWM. If I understand correctly, the impact/engraving plugin is doing "fixed time" pulsing(60us?) with variable reasonable repetition rate.

Hope I can show off my first art piece one day:) Still a long way to go. Thanks again!

Yanxin
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 15, 2013, 04:04:40 AM
Hi Yanxin,

I am looking forward to seeing some pictures of your work.

(You are quite correct about the Impact / Laser plugin - it uses a fixed time interval (PWM) of 40uS and a variable repetition frequency (PRF) of between 0 and 12.5 kHz and, of course, fires the laser whilst the axis is moving).

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 15, 2013, 04:08:59 AM
I have been following recent work (done on another forum) with low power lasers producing images using printer Toner.

I had to give it a try using my 40W CO2 laser and this was my first successful test run on a scrap piece of Oak.

IMPORTANT - It should be noted that it is unwise to experiment with fine powders in a confined space so for any that follow please observe the necessary safety precautions and always have a suitable fire extinguisher standing by.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 17, 2013, 08:27:24 AM
Something that just had to be tried…

As mentioned earlier, others have a lot of success using lasers to melt / fuse printer Toner onto the surface of wood and I just wondered if it would work with copper clad PCB material.

There are a couple of difficulties to be overcome – firstly getting a thin and even layer of the toner powder onto the copper surface and secondly getting a low enough power level from a 40 Watt laser so as not to completely vaporise the toner.

Once these challenges have been overcome – it is a breeze.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on February 17, 2013, 10:36:32 AM
That's nice Tweakie. I am picturing a lot of mess after dealing with the toner ;)

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 17, 2013, 12:35:02 PM
Hi Dan,

You are not wrong - the mess was not as bad as I was expecting it to be, but I would not want to be doing this as my day job.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 18, 2013, 08:11:51 AM
One more test using the dreaded Toner.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 07, 2013, 12:03:21 PM
The Parliament Building is probably the most photographed building in Hungary. It's symmetry is just outstanding.

This laser produced rendering is just 50mm square and I think, makes for a good example of the detail that can be reproduced within lithophane’s in general.

Produced from a standard JPG image which I cropped to make it rectangular then using the Mach3 Laser / Impact plugin I scaled it to fit the Corian blank, set the max. laser power to approx. 30% and hit Cycle Start.

By the time I had finished off a can of beer it was done.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on March 07, 2013, 06:38:55 PM
Very nice Tweakie.......... your just showing off now............. and I like it.  

Brett
Title: Re: The Laser Project.
Post by: Sam on March 08, 2013, 05:47:43 PM
Wow. Very nice Tweaks. Awesome as usual.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 09, 2013, 03:32:21 AM
Thanks Guys, but I can’t help thinking that Art deserves the credit here.
 
Although, over the years, I have made a few minor changes to the code (basically to suit the operation of my own machine) the Impact / Laser Engraving plugin was written by Art in 2007 – long before we even had a laser to test it with. He certainly has foresight and his software never ceases to amaze me.

My current worries are that I will become a Dinosaur - because this plugin works so well, I will never be able to leave Mach3 for Version 4.  ;D

There was some discussion (in another thread) where I doubted that laser produced lithophanes could actually produce a resolution equal to spindle engraved versions but since getting hold of some genuine Corian to try - I now think that it is possible to get extremely close.
The big advantage is that the laser takes half an hour to produce a small, 0.1mm step-over, litho that may take half a day with spindle engraving.

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on March 09, 2013, 12:02:40 PM
YOU become a dinosaur? doubtful. I feel like a T-Rex because I don't even have a laser. Definitely on the 'to do' list, and climbing closer to the top.
Title: Re: The Laser Project.
Post by: TOTALLYRC on March 09, 2013, 06:35:53 PM
+1 on laser climbing the to do list.
Mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 27, 2013, 05:02:02 AM
I have been asked to do a few laser’d tiles for a friend (non-commercial work).

Following a bit of experimentation, it was evident that pen and ink line drawings (which use hatching to create the illusion of shade) produce better results than the pencil sketch drawings and this is the result of one of the tests which I thought I would share.

(I should point out that I have no rights to use this image. It was solely used as a test and this tile was destroyed after the photo was taken).

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on March 27, 2013, 08:56:23 AM
that looks very good tweak any chance in the future you show some close up images of the dot pattern? Do you have to seal the tile after you burn it?
Title: Re: The Laser Project.
Post by: Chaoticone on March 27, 2013, 09:27:36 AM
Very nice Tweakie!

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 27, 2013, 09:48:15 AM
Hi Craig,

I don’t know if this image helps because there is not really a dot pattern as such to see.

The tile was produced from an 8 bit image using the Impact / Laser plugin and this fires the laser at up to 12,500 times per second so with a feed-rate of just 3,500 mm/min most of the dots appear on top of one another (overlapping).

The marking is essentially carbon soot which has, for the most part, been integrated into the surface glaze. I still have some different samples outside in the weather and what little sunshine we have had lately - whilst others have now had many dishwasher cycles so I am thinking the marking is reasonably permanent.

The lasering process will certainly destroy the surface integrity of the glaze but tiles are not usually glazed on their edges and I doubt that grouting compound is totally moisture resistant. But, like most of my stuff, it is early days yet and time will tell.

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on March 27, 2013, 10:51:56 AM
Thanks, I do like the detail.
I know when I put down tile, I was advised to apply a grout sealer. Thought that might be a good idea in this case too.
If you were to rerun the program several times does it etch into the tile deeper?
Also wondered about applying rub-n-buff for an added effect. You could mask and color areas for effect.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 27, 2013, 12:43:36 PM
Hi Craig,

Thanks for your suggestions / ideas, they really are much appreciated.

Quote
If you were to rerun the program several times does it etch into the tile deeper?

I don't know, possibly it would - but the secret is not to completely destroy the surface glaze, just to heat it, creating the micro fractures / melt which capture the carbon soot (if that's what it actually is).

Quote
Also wondered about applying rub-n-buff for an added effect. You could mask and color areas for effect.

I have tried rub'n'buff after etching and yes colours could be produced but rub'n'buff is easily removed with many different household solvents and the finished tile, although looking good would perhaps not be so durable (I doubt it would survive too many dishwasher cycles).

Others are currently experimenting with coloured enamelling powders and laser fusing these onto / into the tile surface (similar to my toner experiments shown earlier). So far, the results are not that spectacular but I think the idea has great promise and definitely needs further investigation.

Tweakie.



Title: Re: The Laser Project.
Post by: yywind on April 03, 2013, 06:17:23 PM
Recently I have completed my D/A converter, tested with A axis and seems to be working fine. My home made diode driver is based on Die4Drive, I changed the sense resister to 0.3ohm, this gives me roughly 1.5A max output current, the diode I am using is M140(supposed to do 1.7w ~ 2w) and a three element lense. See below pictures. The voltage on diode is about 4.65v, with slight modification the drive could work on other types of diode too.

I only tried it on a metal cookie box with paint, seems to be powerful enough. Have not tried to burn a real image yet, looks good so far:)

Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 04, 2013, 01:56:35 AM
Hi Yanxin,

Excellent work my friend, you are certainly making good progress on this project.  8)

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on April 04, 2013, 05:10:28 PM
Tweakie,
Nice job, as is always the case with your work.  I don't know much about ceramics, but wondering if burning an image before firing in a kiln would allow lower power to be used - ala laser diodes  :).   I have some old greenware (?) left by the previous owner of my weekend home that I didn't want to throw away, so it looks like another experiment has now been added to my list.


Yanxin,
Nice work indeed.  It looks like your DAC is similar to what a couple of us are also using, just with a different IC.  If you haven't already, please join our group at: http://hobbycncart.com/forum/63-151-29.

Regards All,
John Champlain
Title: Re: The Laser Project.
Post by: yywind on April 05, 2013, 01:58:17 AM
Hi Yanxin,

Excellent work my friend, you are certainly making good progress on this project.  8)

Tweakie.

Hi Tweakie,

I learned a lot from you guys(you, Dave,Jeff,etc.), I have to admit that I love laser more than spindle ;D, Less noise and more fun!
I generated a gcode file off a small image(our lovely Drew, downloaded from google), sharpened and converted to 8bit gray scale using IrFanView, then fed into BMP2CNC(sounds like no one has tried this for laser yet) and generated the gcode. The file size is 10cmx15cm, consists a total of 70k lines, the max depth is set to 0.0253", 0.0001" per step, tool tip size is 0.007" and line spacing is 0.007" too. Have not tried to burn it yet, may just work right out of the box ;D, will try it soon and report back once get a chance.
Title: Re: The Laser Project.
Post by: yywind on April 05, 2013, 02:10:01 AM
Tweakie,
Nice job, as is always the case with your work.  I don't know much about ceramics, but wondering if burning an image before firing in a kiln would allow lower power to be used - ala laser diodes  :).   I have some old greenware (?) left by the previous owner of my weekend home that I didn't want to throw away, so it looks like another experiment has now been added to my list.


Yanxin,
Nice work indeed.  It looks like your DAC is similar to what a couple of us are also using, just with a different IC.  If you haven't already, please join our group at: http://hobbycncart.com/forum/63-151-29.

Regards All,
John Champlain


John, thanks for your kind words, I am getting closer:)
Yes, I am using Dave's DAC circuit, it's simple and I can get 8bit 0~5V output. I have to say I am surprised by soldering skills while building those circuits, I have soldered 4 tiny cop-8 chips without any problems. 
Just checked your forum, sounds like another great place having fun, will register soon.

Yanxin
Title: Re: The Laser Project.
Post by: Picengraver on April 05, 2013, 11:45:08 AM
Yanxin,
Dave's circuit works slick, but you will lose the lower bits of output because of the threshold requirements of laser diodes.  I added a second op-amp to the output from the DAC so I could set a bias of about .2(?) volts minimum.  This lets me have the complete 256 bits usable over the full range of the 0v to 5v signal.  I typically modulate my diode between .3 amps min. and 1.6 amps max.  I'm not sure if I could go higher or not - don't want to risk blowing another diode.  I have a 0 to 2 amp meter hard wired in the leads to my diode so I can monitor its current draw.

Hope this helps,
John Champlain
Title: Re: The Laser Project.
Post by: Dan13 on April 05, 2013, 01:44:14 PM
Hi John,

I am curious, can you actually see the difference of a few bits? I actually was playing with the above mentioned IrFanView (which is a great program, by the way, thank you) and I could see no difference at all between depth of field 256 and 100. Actually, somewhere at 20I already struggled to see the difference. Either this program implies some other units or I am testing on wrong photos. Otherwise I can't tell any difference.

Dan
Title: Re: The Laser Project.
Post by: yywind on April 05, 2013, 03:24:02 PM
Yanxin,
Dave's circuit works slick, but you will lose the lower bits of output because of the threshold requirements of laser diodes.  I added a second op-amp to the output from the DAC so I could set a bias of about .2(?) volts minimum.  This lets me have the complete 256 bits usable over the full range of the 0v to 5v signal.  I typically modulate my diode between .3 amps min. and 1.6 amps max.  I'm not sure if I could go higher or not - don't want to risk blowing another diode.  I have a 0 to 2 amp meter hard wired in the leads to my diode so I can monitor its current draw.

Hope this helps,
John Champlain

John, thanks so much for your suggestions, will try that later. The driver board I built has a bias pot too, I have set it to 0.16a(probably should set a little higher) minimum for my M140 diode, would that have the same effect of adding a second op amp at DAC side? The max current I am getting from the driver is around 1.55a, very similar to yours, increasing the bias current will increase the  max current too.

- Yanxin
Title: Re: The Laser Project.
Post by: Picengraver on April 06, 2013, 04:53:26 AM
Hi Dan,
Losing a few bits from the bottom of a 256 bit image is not the same as reducing total bit depth of an image.  To me, my images were burning darker with the lower bits missing, but YMMV.  When I was able to use the full 256 bits, my results seemed to improve, hence my recommendation.  In truth, image engraving with analog modulation of laser diodes is still evolving, and we are all learning new things frequently.

Yanxin,
If you increment (jog) your diode control by one step at a time until your diode current starts to increase from your set minimum, this will tell you how may bits (if any) are being 'lost'.  Your driver may respond differently than mine, and you may not need the full 0 to 5 volt signal to get good results.

More here about my circuit (message #320): http://hobbycncart.com/forum/63-151-16

Best Regards,
John Champlain
Title: Re: The Laser Project.
Post by: yywind on April 06, 2013, 07:02:21 AM
Hi Dan,
Losing a few bits from the bottom of a 256 bit image is not the same as reducing total bit depth of an image.  To me, my images were burning darker with the lower bits missing, but YMMV.  When I was able to use the full 256 bits, my results seemed to improve, hence my recommendation.  In truth, image engraving with analog modulation of laser diodes is still evolving, and we are all learning new things frequently.

Yanxin,
If you increment (jog) your diode control by one step at a time until your diode current starts to increase from your set minimum, this will tell you how may bits (if any) are being 'lost'.  Your driver may respond differently than mine, and you may not need the full 0 to 5 volt signal to get good results.

More here about my circuit (message #320): http://hobbycncart.com/forum/63-151-16

Best Regards,
John Champlain

Thanks John, now I understand. I was assuming the current will start to increase based off the bias current at 1st step, looks like it's not, steps will be lost, I will prove that later.

I burned my first MDF today, no practice at all, first laser burned wood in my life, very excited, not good quality but at least it proves my DAC,driver and diode works as expected, and shades look good. See below pictures, burned too dark, and lines not merged(need to de-focus laser?), and possible backlash.

Yanxin
Title: Re: The Laser Project.
Post by: Dan13 on April 06, 2013, 07:12:51 AM
Hi John,

Thanks. I think I see what you mean.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 06, 2013, 07:24:30 AM
My congratulations Yanxin, this looks like you are well on your way to producing some stunning images.  8)

A really excellent job my friend.  ;)

Tweakie.

Title: Re: The Laser Project.
Post by: Picengraver on April 06, 2013, 09:15:56 AM
Yanxin,

Yes to Tweakie's comment - a really excellent beginning.  MDF burns dark, but your image shows very good image tonality.

The lines are something I also have a problem with.  Are you using 1/4-20 (or similar) lead screws?   That's what I believe is causing the lines, and I have just started building a small belt-drive machine to see if I can eliminate them.  Our friends who use ball screws don't have the lines.

John Champlain
Title: Re: The Laser Project.
Post by: Chaoticone on April 06, 2013, 10:33:23 AM
 :)  Yanxin, your coming right along............ makes me happy.

Brett
Title: Re: The Laser Project.
Post by: Picengraver on April 06, 2013, 12:04:16 PM
Brett,
Are you not hooked yet?  Guys, we need to team up on him ;)
Title: Re: The Laser Project.
Post by: Chaoticone on April 06, 2013, 12:42:14 PM
John, I have been hooked for a while.  A good friend of mine was one of the guys that helped Artcam with path generation for Lithophanes.  Loved the idea and now the availability of parts and information enabling us to use lasers really excites me.  I often wonder what will be next and find some others efforts truly inspiring.  Many of those others have posted in this thread.  Marcel Beaudry's tiny cubes in cubes and a host of others come to mind.  Tom Hubbin was working on 3d laser scanning before he passed.  In a world where most refuse to think for themselves in order to accomplish trivial things, I come here and see the exact opposite.  That is what I love.  People who push to be above average and refuse to let the standard deter them from accomplishing their goals.  Tweakie has always made my day in that respect.  So, will I ever get to play with lasers.......... no idea but if I live long enough I'll have at least one of everything.  ;D

Brett
Title: Re: The Laser Project.
Post by: yywind on April 06, 2013, 10:12:37 PM
My congratulations Yanxin, this looks like you are well on your way to producing some stunning images.  8)

A really excellent job my friend.  ;)

Tweakie.


Thanks, Tweakie, you are the one that always motivating me. A good start:)
Title: Re: The Laser Project.
Post by: yywind on April 06, 2013, 10:14:52 PM
:)  Yanxin, your coming right along............ makes me happy.

Brett
Thanks Bret, still a long way to go, those genius setup a really high standard, hard to keep up with:)
Title: Re: The Laser Project.
Post by: yywind on April 06, 2013, 10:32:02 PM
Yanxin,

Yes to Tweakie's comment - a really excellent beginning.  MDF burns dark, but your image shows very good image tonality.

The lines are something I also have a problem with.  Are you using 1/4-20 (or similar) lead screws?   That's what I believe is causing the lines, and I have just started building a small belt-drive machine to see if I can eliminate them.  Our friends who use ball screws don't have the lines.

John Champlain

Yes, I am using 1/2-13 lead screw, Y axis is not stainless steel lead screw, I have been planning to replace it and now I think it's time to do it, the other two are high quality stainless steel lead screws.  Maybe next build will be ball screws.

I reduced the power and bias current, de-focused the laser a little bit, burned another MDF, lines are still there, image is better but it's losing details at lighter color because of the lower bias current(I'll definitely implement your DAC circuit soon). Next will try de-focus more, reduce line spacing to see if I can make it better. Maybe it's the way this piece of MDF reacts with laser, will try one other type of wood too to see if lines are still there. I am having a lot of fun:)

See below picture. Sorry the MDF was a little dirty, some marks on it, looks like there are three flies on Dew's nose.

Yanxin
 
Title: Re: The Laser Project.
Post by: yywind on April 07, 2013, 08:18:44 AM
Lines are gone once I reduced the line spacing half, in order to retain all shades, I had to burn MDF darker, it's still burning, will take 4 hours to complete.

Yanxin
Title: Re: The Laser Project.
Post by: yywind on April 07, 2013, 09:39:18 AM
Lines are gone once I reduced the line spacing half, in order to retain all shades, I had to burn MDF darker, it's still burning, will take 4 hours to complete.

Yanxin
Too early to say that, it shows up as it burns more, sounds like the lead screw problem.
Title: Re: The Laser Project.
Post by: PicengraverToo on April 07, 2013, 09:52:06 AM
Yanxin,

I'm the one that developed/invented this process by varying the power to laser engrave 8bit shades and I do have to say, very good job!

Why don't you jump over to the Hobby CNC Art laser diode thread and post your results? This is a CO2 laser build thread that Tweakie started. Just a suggestion.

Jeff
Title: Re: The Laser Project.
Post by: Picengraver on April 07, 2013, 10:06:10 AM


Yanxin
[/quote]
Too early to say that, it shows up as it burns more, sounds like the lead screw problem.
[/quote]

Yanxin,
You might try to chase the threads of the lead screw with a sharp (new) thread die if you have one.  It might help. 

John Champlain
Title: Re: The Laser Project.
Post by: yywind on April 07, 2013, 09:21:33 PM
Yanxin,

I'm the one that developed/invented this process by varying the power to laser engrave 8bit shades and I do have to say, very good job!

Why don't you jump over to the Hobby CNC Art laser diode thread and post your results? This is a CO2 laser build thread that Tweakie started. Just a suggestion.

Jeff

Thanks Jeff, I read your threads before, lots of my ideas are coming from you, have not got a chance to say hi! I tried to register the forum you and John mentioned but I do not understand the language(hungarian?), will try again, I'll move to that thread once registered.

Yanxin
Title: Re: The Laser Project.
Post by: yywind on April 07, 2013, 09:24:43 PM


Yanxin
Too early to say that, it shows up as it burns more, sounds like the lead screw problem.
[/quote]

Yanxin,
You might try to chase the threads of the lead screw with a sharp (new) thread die if you have one.  It might help. 

John Champlain
[/quote]

I do not have the tools, I actually swapped the X and Y axis by swapping X and Y within the gcode and run it again, the lines is still the same direction, so my Y axis does have problems, it does not produce even lines, sometimes the spacing is larger. X is fine, no lines.

Yanxin
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 26, 2013, 01:13:19 PM
In preparation for the arrival of Mach version 4 (which does not support parallel port operation) I have been experimenting with the Smooth Stepper (external motion controller) and how it performs when controlling my laser.
Greg at Warp9 has done a great job with this product and the USS software plugin already supports the use of the M10 / M11 command set so it should have been a straight forward ‘plug and play’ exercise but unfortunately this was not to be the case.
I was getting occasional ‘wrong direction’ axis movements and after making many changes to the various USS settings nothing could cure the problem.
It transpires that my rather ‘old technology’ Alegro based stepper motor’s driver was experiencing signal related issues. After a bit of experimentation I fitted additional Schmitt trigger outputs (including a 150nS delay) to the direction signal lines from the USS and hey-presto there are no longer any axis ‘wrong direction’ moves.
Ahh - the mysteries and the wonders of electronics.  :D
Still some more investigation to do but I am hoping to determine just why this rather crude fix has cured my problem.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on May 26, 2013, 02:16:56 PM
Tweakie, I'm glad you have it sorted but interested in your on going investigation.  Can you elaborate any more on how you pinned the problem down and what components you used for the fix? 

Brett
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 27, 2013, 03:37:48 AM
Hi Brett,

I have sent you a PM but some more information for those that follow;

Initially (and as Jeff at the Warp9 forum suggested) I investigated electrical noise / incorrect earthing etc. (USB cables seldom have a screen to carry the PC earth via the USS to the Parallel Port cable screen) - once electrical noise / earthing had been ruled out my next thoughts was one of timing where the direction pulse was not being seen soon enough. Delaying the step pulses (to give the direction line transition more time) made the situation a whole lot worse so it definitely was not that.
In my mind there was always the possibility that if tri-state logic had been used in the SS design my stepper's driver could be picking up a false logic state in relation to the direction signal transitions so I tried delaying the direction signals and it worked.
Obviously, and as mentioned earlier, more investigation is required because 150nS is hardly worth considering as a delay so it may just be the Schmitt Trigger outputs which are doing the trick. As time permits I will look at this issue in more depth and post my findings.
The circuit I am using just consists of eight TTL gates, daisy chained for each direction line.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on May 27, 2013, 09:53:06 AM
Thanks Tweakie, Great find BTW.  This is one of those problems that could drive a man mad.

Brett
Title: Re: The Laser Project.
Post by: Sam on May 27, 2013, 11:34:08 AM
How do you keep so much knowledge and know-how in your head, Tweakie? I think your part Borg. I have trouble tying my shoes most days.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 27, 2013, 12:21:46 PM
 ;D ;D ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 28, 2013, 02:06:43 AM
Hi Sam,

Cast your mind back a while to when I was starting out with this project and having problems laser cutting acrylic with smooth edges.

Who was it that took the time to look at my GCode and discovered that my CAD/CAM created tool-paths were rubbish ?

Before your help. http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21730;image (http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21730;image)

After your advice. http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21738;image (http://www.machsupport.com/forum/index.php?action=dlattach;topic=12444.0;attach=21738;image)

You can’t tell me that you are having troubles with shoe laces.  ;D  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: Sam on May 28, 2013, 02:10:55 AM
Yeah, but..... that don't even compare. I think the answer to that problem was just so simple, you overlooked it. :)
Title: Re: The Laser Project.
Post by: Chaoticone on May 28, 2013, 07:34:31 AM
 :)

Brett
Title: Re: The Laser Project.
Post by: Picengraver on May 28, 2013, 09:11:28 AM
Tweakie,
From what I have seen of your projects and designs these past few years, I'm convinced that you have to be a descendant of Merlin. :)
John Champlain 
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 05, 2013, 01:15:47 PM
Thanks guys you are far too kind.  :)

As I learn more from others it is nice to re-visit the things I have done in the past and see if improvements in my techniques can be made.

This is only my second attempt at laser etching photographic images into the rear surface of a mirror and thought you may like to see the result.

It’s a bit on the dark side (too much contrast) but I think I can improve that for the next attempt.

I used 'PicEngravePro' to create the Mach3 toolpath - thanks John (Picengraver) for such excellent software and all the time and effort you have put into making it what it is today.

Tweakie.
Title: Re: The Laser Project.
Post by: Chaoticone on June 05, 2013, 03:06:58 PM
As usual, very Nice Tweakie!  The whole lot of you guys have made a lot of progress and are turning out some very impressive results.  :)

Brett
Title: Re: The Laser Project.
Post by: Picengraver on June 05, 2013, 08:24:09 PM
Tweakie,
Very nicely done, as is usual with all your work.  Thank you for the kind words and all your support.

Brett,
Thanks, too, for your very appreciated comments.  Still waiting for you to join us.  Must be some way you could justify a laser for your business.   ;)

John
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 22, 2013, 12:21:10 PM
Although there are still only a handful of us worldwide that are using the Mach3 Impact / Laser Engraving plugin I thought you may all be interested in the latest update.

Because the output from the plugin is bi-directional, the exact registration of the horizontal lines produced is dependant on device activation speed and from version 1.1 to date this line registration had been set to a compromise between the speed of a laser trigger and the speed of an impact magnet trigger.

Arising out of necessity, I have recently had to adjust this line timing to better reproduce some fine detail work with Lithophanes and in order to preserve the plugin’s compatibility between Laser and Magnet operation I thought it would be wise to include a user adjustable horizontal alignment feature.
To this end I have now added a group of 4 buttons to the GUI - these new buttons will allow the registration of the raster lines to be advanced by +1 or retarded by up to -2 image pixel widths (with the default being zero) and this should now be sufficient adjustment to cater for the correct operation of both devices.

I still have a bit of tidying-up to do (I always seem to get into a terrible mess between the manual coding and the automatic coding from the wizards when using Microsoft’s Visual C++), and I need to do some more testing but the latest version of the plugin (1.2c) will shortly be freely available to any that are interested.

Tweakie.
Title: Re: The Laser Project.
Post by: Picengraver on June 24, 2013, 08:51:45 AM
Nicely done, Tweakie.

Would it also be possible to alter (or make user selectable) the pulse timing of the output for possible use with laser diodes?
 
John Champlain
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 25, 2013, 02:38:01 AM
Hi John,

Thanks, that is a very good suggestion and something I will look into.
Basically, my initial thoughts are that for diode laser operation (slower feed-rate) changing the calculation ratio between output power (amount of ‘dot-gain’) and feed-rate will achieve the desired result (a bit like the way in which the ‘greyscale compression’ function currently works for the CO2 laser). Anyway this is something I will investigate, as time permits and report back.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 28, 2013, 07:44:07 AM
Well, after a bit of experimentation, I think I can now safely say that the Mach3 Impact / Laser plugin can be used with low power diode lasers.

My design criteria was for a 1 Watt, blue-ray diode laser using a feed-rate of 1000mm/min but as I only have a 100mW, 655nm diode laser available for my tests I scaled back the feed-rate and the following work was produced at just 100mm/min. The results are, I think, acceptable and demonstrate that, in principle, it is possible and that the system works but like my school reports always used to say – “could do better”.

I have used this particular .jpg image many times before (for testing purposes) as using the same image helps me with comparisons between different settings and methods etc. The .jpg has been dithered (using John’s excellent software PicDither), my diode laser was triggered using the TTL method and the total job time was around 3 hours for this 50mm x 50mm example.

The Mach3 plugin basically works by a system which has been termed ‘dot gain’ - firing individual dots on the digital trigger output at up to 12,500 times per second. A great many of these dots appear on top of one another (overlapping) and the more dots that occur in any one place the darker the work is burned.

The maximum duty-cycle for the digital trigger output from Mach3 is 50% (pulse on time / pulse off time) and although this is just fine for a higher powered CO2 laser it was necessary to increase this duty-cycle to around 90% for diode laser operation.

If there is any interest in this, I would be pleased to provide the details of just how it was accomplished.

Tweakie.
Title: Re: The Laser Project.
Post by: TOTALLYRC on July 28, 2013, 09:06:19 AM
As usual, excellent work from the house of Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 03, 2013, 12:44:40 PM
Thanks Mike.

I had to do a bit more acrylic cutting so while I was at it I made this - one can only dream.  ;D

Tweakie.
Title: Re: The Laser Project.
Post by: TOTALLYRC on August 04, 2013, 09:47:44 AM
Hi Tweakie,
I saw the demo of Mach4 at cabin fever and was impressed. It looks like it will be worth the wait.

Speaking of waiting, hopefully I will get some time this winter to work on adding a laser to mu router. I looked at a 3D printer but I don't think the resolution is fine enough for me to build one. Maybe after the laser.

Mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 04, 2013, 11:36:39 AM
Hi Mike,

Adding a laser to an existing machine is not difficult to do but it does entail quite a lot of work so perhaps it is best left for the winter months.  ;)
It would be great if you start a project build thread on this – I, for one, look forward to following your progress.

Tweakie.
Title: Re: The Laser Project.
Post by: TOTALLYRC on August 06, 2013, 07:12:17 AM
Hi Tweakie,
I will probably do a thread on the Zone. If I really get ambitious I will update all my other threads as well.

The first thing I need to do is buy some laser stuff and get it working on the bench. Any ideas on what to buy?

Mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 06, 2013, 08:29:14 AM
Hi Mike,


Assuming you are going for a CO2 laser then…

1) Laser tube and matching high voltage PSU (most likely from China).

2) Gold plated FS mirrors and suitable, adjustable, mirror mounts (the USA made product is superior in quality).

3) Focus lens - GaAs is more hard wearing but I use ZnSe most of the time. Short focal length (small spot size) is good for engraving, longer focal length (larger spot size) is good for cutting (again the USA made product is superior in quality).

4) Water circulating pump for tube cooling – others generally use a submersible pump in a tank of de-ionised water. I use a closed loop system with forced air radiator.

5) Water flow sensor and means of water temperature monitoring.

6) Oil-less compressor to provide ‘air-assist’ when cutting and also to keep the detritus off the valuable lens.

7) Countless number of other bits and stuff to cobble it all together.

Hope this helps.

Tweakie.
Title: Re: The Laser Project.
Post by: TOTALLYRC on August 06, 2013, 10:53:48 AM
Thanks for the info Tweakie.
Looks like the most expensive parts will be the tube and power supply. I can cobble up a cooling system just from all the stuff I have lying around.
I thinks I need to save up a few more $$$$$$$$$$$$.

Mike

Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 18, 2013, 06:41:19 AM
Following a request, on another forum, I have developed another little device.

This unit records actual laser tube emission time, as opposed to machine run time, and is intended to provide an indication of tube lifetime. It uses RF technology to detect the laser tube emissions so requires no electrical connection to the host machine and will be suitable for use with all makes and models of commercial laser machines which use a dc excited glass laser tube.

Laser tubes have a finite lifetime which can perhaps be likened to draining a tank-full of water – just how long it lasts depends on how wide the tap is opened, however, this unit should be useful in providing averages.

The initial ‘rats-nest’ model has clocked up some 15 hours now and I am looking forward to some serious testing of this, the first prototype.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on September 18, 2013, 07:19:45 AM
Tweakie,

Would it not be easier to use a small engine hour meter?

Like this person did. http://www.fullspectrumengineering.com/forums/viewtopic.php?f=3&t=1441

Those can be picked up fairly cheap!

http://www.amazon.com/Inductive-Meter-Marine-Motorcycle-Waterproof/dp/B00A43PKOE/ref=sr_1_5?ie=UTF8&qid=1379503092&sr=8-5&keywords=small+engine+hour+meter

Jeff
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on September 18, 2013, 07:35:19 AM
That is some might fine work. I like it. What are you using to monitor beam on and at what frequency?

Can you add data storage system that monitors & collects beam; on time, emission power and temperatures at tube, coolant and ambient. And then display it in a spread sheet that can be used to predict life cycle? ;D
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 18, 2013, 08:17:14 AM
Quote
Would it not be easier to use a small engine hour meter?

Maybe Jeff.


Quote
Can you add data storage system that monitors & collects beam; on time, emission power and temperatures at tube, coolant and ambient. And then display it in a spread sheet that can be used to predict life cycle?

It's all possible Craig and I am sure it would not be too difficult to do if there was a requirement. Perhaps another project is on the horizon.  ;D

Tweakie.


Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 22, 2013, 02:41:44 AM
An example of testing and early failures…

I built a small test rig which gives off similar RF emissions to an operating laser tube so I could test run the unit without using the laser. After a couple of hours the clock stopped. Cutting the clock apart revealed a long plastic shaving caught up in the gear train and although the mechanism was beautifully constructed the Chinese manufacturers of this device seem to have absolutely no idea of quality control. Cleaning, removing the debris then gluing it all back together seemed to have resolved the issue and the 24 hour test then continued without fault.
Prototype #1 is now off on it’s travels for further testing with professionally manufactured laser machines whilst prototype #2 is now running 24 / 7 until destruction.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 17, 2013, 03:10:03 AM
PWM (Pulse Width Modulation)

The following is just a brief summary of PWM and how it is manipulated to control the output power of CO2 lasers. Where appropriate, I have included the full title of the various acronyms solely for the benefit of those who are not yet familiar with these abbreviations.


PWM is essentially a stream of rectangular, digital, pulses comprising of three separate components – Amplitude, Duty Cycle and Frequency.

Amplitude is never a variable and it is generally fixed at 5Volts but for some, later, equipment this may be at the more recent TTL (Transistor – Transistor Logic) standard of 3.3Volts.

Duty Cycle is usually expressed as a percentage and it is basically the ON / OFF time of the switching signal. For example; with a 50% Duty Cycle the laser output is on for half of the time period and off for the remaining half of the same time period. However, as the variable component in the Duty Cycle is the Pulse Width then Duty Cycle can, on occasion, also be expressed in terms of time – typically in uS (microseconds).

Frequency is the number of times per second the Duty Cycle is repeated. This component is commonly termed the PRF (Pulse Repetition Frequency) and is generally expressed in kHz (kilohertz).The frequencies most commonly used are between 5kHz and 20kHz with 20kHz (20,000Hz) being considered to be the upper operating frequency limit for most laser Power Supply Units (PSU).


The following diagram depicts a typical PWM waveform (as would be seen using an oscilloscope) and this is essentially a graphical representation of Voltage versus Time.
As most (not all) laser PSU’s operate from an Active Low signal, in this and the following examples, the area above the graph (as shown by the shaded portions) represents the laser ON time.

(http://www.cooperman.talktalk.net/pwm1.jpg)

As the speed of light is (essentially) a constant, in the above example, we are unable to change the 12.5 kHz PRF without it changing the 80uS time period of one complete cycle and visa versa because Frequency and Period are reciprocals of each other but there are two distinctly different ways in which the laser ON time and thus the apparent laser output power can be controlled by manipulating the PWM.

Consider the following example where we initially have a 25% Duty Cycle and we wish to double this power output setting to 50%. We could either double the pulse width from 50uS to 100uS or we could keep the pulse width at 50uS and double the PRF from 5kHz to 10kHz. Both these solutions will result in a 50% Duty Cycle.

(http://www.cooperman.talktalk.net/pwm3.jpg)



Quite obviously there are an almost infinite number of combinations of Pulse Width and Frequency which we could use to achieve a 50% Duty Cycle but, depending on the material being worked, each combination may produce different results in the finished product. Bit of an abnormality perhaps but there are reasons for this behaviour, possibly to be described at a later date.

Some words to the wise…
There are constraints on the manipulation of PWM (to avoid a situation where the safe internal photon density of the tube is not exceeded) but provided the Duty Cycle is never greater than 95% and the Frequency does not exceed 20kHz then almost anything goes.
Commercial laser machines generally incorporate safe settings limits within their software / firmware to prevent the user from accidentally over-driving the tube and for this reason it should be considered most unwise to override or change any password protected settings.

As with everything, there will always be exceptions. For example, my DC excited laser can be operated at 100% PWM which is essentially CW (Continuous Wave) mode but only because it has a preset ‘maximum tube current’ control. My RF excited laser does not have this option so 95% PWM is its maximum safe limit. With both lasers my highest operating Frequency is still regarded as being 20kHz.

Tweakie.
 
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on November 17, 2013, 07:33:19 AM
Have to start calling you "Professor Tweakie"  ;D

Nice Job, thanks for taking the time, sharing and teaching.
Title: Re: The Laser Project.
Post by: Picengraver on November 18, 2013, 08:09:22 AM
Thanks Tweakie.  Very informative and understandable (even to me  ;D).
John Champlain
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 19, 2013, 08:02:34 AM
Thanks guys.  :)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 21, 2013, 07:04:23 AM
Knowing how we all like gadgets I thought you may be interested in this little device I put together last week. It is essentially a basic (and more robust) version of the commercially available ‘home energy monitor’ but it’s my hobby to always build as much of my own stuff as I can so thought I would share the experience.

Simple and quick to construct using a combined voltage / current meter display (bought via the bay from China at about £7 inc. postage) 13 Amp plug, socket and cable plus a project box enclosure.

Its purpose is just to get an idea of the combined electricity running cost of the laser, air supply, cooler, extractor etc. under average / normal operational conditions for different types of job.

The first picture shows the readings I get with my Koi air pump, cooling system and laser running at low power during an engraving job. My compressor (only used for cutting thick stuff) and ducted fume extraction system were each measured separately.

As Watts = Volts x Amps my machine, during the average engraving job, uses (237 x 1.7) 402.9 Watts which is 0.4029 kW per hour of job time. Adding to this the figures obtained from the fume extraction system and using the price per kW hour from my energy provider I can get a pretty good idea of the machine running cost (at least as far as the electricity usage is concerned).

I don’t intend for the gadget to be permanently left in circuit, although it may be handy to monitor any possible voltage drop on my supply at peak usage times, it is just used to establish the average electricity usage for different types of jobs.

The second picture shows the readings I get when cutting thin acrylic.

Tweakie.
Title: Re: The Laser Project.
Post by: Jammerm on December 28, 2013, 12:31:30 PM
Would there be any way to connect this to a computer to monitor voltage over time? For some reason our electric into our home seems to fluctuate a lot. It also goes of about once a week, very aggravating, resetting all the clocks drives me nuts! About the time I'm cutting a job on the CNC and the power goes out for a couple seconds, I won't be happy. I'm just thinking of having a time line to show the power company.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 29, 2013, 02:04:31 AM
Hi Jammer,

I think one of the the commercially available 'home energy monitors' would probably be a more suitable device for your particular application. (typically, something like this perhaps  http://www.amazon.com/Weanas-Energy-Voltage-Electricity-Monitor/dp/B00DTMQ1S6/ref=sr_1_1?ie=UTF8&qid=1387628051&sr=8-1&keywords=watt+amp+meter ).

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on December 29, 2013, 08:42:24 AM
I use the "TED 5000" and love it, was a little struggle with getting it set up.

http://www.theenergydetective.com/

Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 30, 2013, 07:01:24 AM
Excellent piece of kit Craig, although a bit pricey for my budget I would love one of those.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Ya-Nvr-No on December 30, 2013, 08:42:20 AM
Use some of that income you received for your cmm touch probe design.  ;)

Thou I  never seen it come to market. They just buy it to kill it ???

As far as the Ted 5000:
I installed a big central vacuum this past month for my shop and noticed that my projected electric bill will be going up.  :o
But being able to live dust free and work the winter months, priceless.  ;D
Really an education on the energy hogs and teaches you to shut things off or use timers. (Air compressors & Water Heaters,  :'()
Title: Re: The Laser Project.
Post by: NODEGAMRA on December 31, 2013, 07:15:43 PM
Hi guys and thank you Tweakie for this great plug-in.
Total NOOB here and I am just getting started with laser engraving.
I have tested it by engraving simple shapes and it works perfectly.

I do have a question...
Is there any way to make the engraving from top to bottom, instead of bottom up?
 
Any info would be greatly appreciated.
Thank you.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 01, 2014, 03:12:00 AM
Hi Nodegamra,

As it stands the pluglin is configured to only engrave from the bottom up.
Perhaps, at the next revision, I will consider adding selectable origins (centre and each corner) for the X0, Y0 starting position as, for me, a centre origin would be useful.

Armagedon  ;D

Tweakie.

 
Title: Re: The Laser Project.
Post by: texaspyro on January 26, 2014, 01:31:20 AM
I built a couple of laser diode heads for my desktop mini-mill.  One uses a 3 watt 445 nm multi-mode blue laser.  The other uses a 0.7 watt (driven at 0.5 watts max) 405 nm single-mode near-ultaviolet laser.  Single mode lasers can be focused to a smaller spot than multi-mode lasers.  My main application is cutting solder paste stencils.

Here is a Tweakie Bike cut from 0.032" bassword (0.063" balsa cuts the same) using the 405 nm laser.  Cutting was at 8"/minute.  Two passes were used to assure that the bits fell out... otherwise residual fibers can cause them to hang and punching them out can break things (particularly in balsa) due to the tiny features.

I converted Tweakies g-code to DXF and then converted the DXF to Mach3 gcode to control my laser.  Laser power is set via the "S" spindle speed word.  Spindle power mcodes control the laser power supply and coolant mcodes control the co-axial assist air (via a small 12V diaphragm pump).

The features in the DXF are 1mm wide.  After cutting,  the features measured 0.98mm...  works out to a kerf width of 0.0005" !  The laser lens is 4" from the cutting surface.  With a shorter throw,  the spot can supposedly be focused to 0.01mm

(http://imagizer.imageshack.us/v2/800x600q90/543/6364.jpg)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 26, 2014, 02:14:32 AM
Excellent work my friend, I look forward to seeing some pictures of more of the things you make.

Tweakie.
Title: Re: The Laser Project.
Post by: texaspyro on January 26, 2014, 02:41:34 AM
Here is a solder paste stencil cut in vellum paper.  The pads on the QFN20 packages are 0.5mm apart.  This one was cut without assist air.  The air really helps to reduce over-burn of the edges.  Without it the edges seem like they want to smolder some, expanding the size of the cutouts.  Sorry for the bad focus... it's all the camera will do.

With visible light lasers,  the color of the material greatly affects the cutting ability of the laser.  White or purple does not cut well at all (well being defined as faster feed rates and lower powers).  Red and black cuts well,  green a little less,  and yellow a little less.  Most cutting of stencil materials is in the 4"/minute and  1/3 to 1/2 power range.  Lower feed rates tend to work better since mill acceleration effects are minimized (i.e. small features cut the same as longer ones) and lower powers cut better (less over burn and longer laser life).  White papers cut very inconsistently...  some pads cut perfectly,  others hardly at all...  on the same sheet. 

Paper vellum (a translucent plasticized cotton paper) is one of the best materials that I have found for solder paste stencils.  It cuts very cleanly and is the proper thickness (0.003") and is very cheap (50 cents/square foot). It holds up well for small prototype runs.  I have also had good success using an orange colored copier paper from Staples.  It is a little over 0.004" thick and dirt cheap.   I can cut Kapton,  but not as well as vellum... plus it costs a bundle (over $15 sheet)  Mylar sucks...


(http://imagizer.imageshack.us/v2/800x600q90/13/2xyc.jpg)
Title: Re: The Laser Project.
Post by: Fred27 on January 26, 2014, 03:42:27 PM
I've never heard of vellum for solder stencils. That sounds interesting. I've successfully cut Mylar with a 40W CO2 laser (an eBay special with a Chris Circuits controller board) but it did suffer a little from the edges thickening where it melted. Covering with masking tape (both sides) before cutting and some gentle fine sanding afterwards helped and and it worked fine.

Incidentally, how do you control the laser power using the S command? I'm thinking of doing something similar to mine - maybe adding PPI control from gcode. I'm happy to custom design a controller but still not sure how best to get the setting from Mach3 to my board. Modbus seems to be a bit outdated and need serial in addition to parallel. PWM isn't really what I need. Getting into plug-in development seems a bit over the top. Ideally I just want some data sent via a parallel port pin. Any helpful hints?
Title: Re: The Laser Project.
Post by: texaspyro on January 26, 2014, 05:29:27 PM
I am using a Flexmod P3 driver.  It has analog modulation.  I use the MACH3 spindle speed PWM feature to make an analog control voltage (via a Gecko G540 controller).  The Flexmod driver has pots that set the minimum and maximum laser diode current.  I have the minimum set to what the laser needs to just get cranking (around 5-10 mW output).  Spindle speed S0 produces 0V and S9000 produces max laser current.  Theoretically S5000 should be max power/5V output,  but probably due to light loading on the Flexmod input,  my laser power maxes out at somewhere between S6000 and S9000.

The laser power supply (a 9V regulated wall wart supply) is plugged into the mill controller spindle relay.  I use the spindle M-codes to switch the laser power supply ON/OFF and the coolant relay to control the air pump.  The Flexmod has a 7 second soft-start delay between applying power and allowing full laser output.  My gcode puts in an 8 second dwell after switching on the laser power supply and air pump.  That delay and the pump noise also provide some safety warning in case you forgot your laser goggles...
Title: Re: The Laser Project.
Post by: texaspyro on January 26, 2014, 06:07:23 PM
I've never heard of vellum for solder stencils. That sounds interesting.

I have tried just about everything that looked like it might work for stencils (and a few that didn't).   So far the best results (cutting tiny features that hold up to the Toothbrush Scrubbing Test From Hell) have been with the vellum and the Bright Orange (24 lb?) copier paper from Staples.  They both seem to hold up will with use (but I've only done maybe a dozen boards with one stencil) and couldn't cut cleaner.  I have cut  0.15 mm pads spaced 0.15mm.

Something else that works very well cut-wise is self-stick vinyl.  But it makes nasty vapors.  Also the sticky had some advantages (keeps it in place on the board) and some dis-advantages (hard to align, particularly on larger boards).

I first found the vellum a Michael's on clearance...  and it looks like they have stopped carrying it.   I found the red vellum at Hobby Lobby.  This place also looks promising:  http://www.hyglossproducts.com/Vellum-Translucent-Paper-p/58203-1.htm

For very nice Kapton stencils for cheap try OSHSTENCILS.COM   Kapton stencils are good for several hundred boards.
Title: Re: The Laser Project.
Post by: texaspyro on January 27, 2014, 02:45:36 AM
I did the "Engrave TWEAKIE in a grain of rice" test.   Not having any rice,  I marked a piece of Kapton.  I can read the 100 micron tall letters with a hand lens,  but the 50 micron ones will need a microscope.  I can tell there are individual letters, but can't make them out.  I could probably improve things with some proper attention to focusing.  the laser is just focused by (remaining) eye right now.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 27, 2014, 03:24:08 AM
 :)

Tweakie.
Title: Re: The Laser Project.
Post by: texaspyro on January 27, 2014, 04:32:58 PM
I tried cutting some scaled down Tweakie-bikes out of .032" basswood.  The half scale and quarter scale (250 micron features) ones turn out great.  Basswood is not up to the task of 1/8 scale Tweakie-bikes.  They cut out,  but the bike is essentially made out of 125 micron wide ash and falls apart.

One issue with cutting things at this scale is the tendency of the assist air to blow the cutout bits all over the place.  I even have a couple of quarter scale Tweakie-bikes gone with the wind...
Title: Re: The Laser Project.
Post by: frasej on January 27, 2014, 05:59:28 PM
Finally got the Arduino to do the  laser power modulation.  ;D Did the usual Drew picture test:  http://www.flickr.com/photos/jayfrase/12180276666/ (http://www.flickr.com/photos/jayfrase/12180276666/)
When blown up you can see that my spacing is a little off.  Used PEP and had the spacing set at 0.009.  I tried it at 0.007 but got overlapping lines.  Guess I should have used 0.008.  Oh well, that's for next time.
The one problem I'm still having is the Arduino is getting off by the end of the print.  The file said the power level should have been 98 and the Arduino said it was 70.  Low by 18 steps.  I'm not sure why this is happening.

Title: Re: The Laser Project.
Post by: frasej on January 27, 2014, 06:21:05 PM
Didn't get a chance to attach the file.  Warning... Large file ahead.
Title: Re: The Laser Project.
Post by: Chaoticone on January 27, 2014, 06:50:37 PM
I tried cutting some scaled down Tweakie-bikes out of .032" basswood.  The half scale and quarter scale (250 micron features) ones turn out great.  Basswood is not up to the task of 1/8 scale Tweakie-bikes.  They cut out,  but the bike is essentially made out of 125 micron wide ash and falls apart.

One issue with cutting things at this scale is the tendency of the assist air to blow the cutout bits all over the place.  I even have a couple of quarter scale Tweakie-bikes gone with the wind...

 ;D
Title: Re: The Laser Project.
Post by: texaspyro on January 27, 2014, 09:22:32 PM
I got the tiny text test under a microscope...  the 50 micron tall text is barely legible if you know what you are reading (after all the beam is maybe 12.5 microns wide (about one wavelength of a CO2 laser beam)).  100+ micron text is readable.  I am seeing a little lag in switching the beam off due to using the MACH3 spindle speed command to control the laser (PWM generator is running at around 25,000/256 Hz so it takes a little while for power changes to take effect).  My gcode maker can put delays in before/after switching on/off laser, but I was not doing that so getting little light tapered wisps between chars.

I did a little calculation and figured for engraving images it would take around 3 hours per square inch (my mill/controller/power supply maxes out motion at around 20"/minute)...  but the resolution should be awesome!
Title: Re: The Laser Project.
Post by: Picengraver on January 27, 2014, 10:01:22 PM
Jay,
Very good for a beginning with an experimental controller.  Definitely shows promise.

Perhaps using a different wood would help some as well.

John Champlain
Title: Re: The Laser Project.
Post by: texaspyro on January 27, 2014, 10:15:52 PM
Here is another image of Tweakie-bikes cut with the 405nm laser in 1/32" basswood.  Focused beam width looks like it is around 12.5 microns (close to a single wavelength of a CO2 laser).  Full sized bike tubes are 1mm across.  Smallest one is 250 microns.   Tried to cut a 1/8 scale one,  but at 125 microns wide,  the bike structure is basically ash...  falls apart.  All bikes cut with two passes at 500 mW/6" per minute, assist air on...  final pass needed to make sure the cutouts fell out...  without it you tend to break things pushing out the pieces due to faults in the wood grain being weak places.

(http://imagizer.imageshack.us/v2/800x600q90/62/hbcw.jpg)
Title: Re: The Laser Project.
Post by: frasej on January 28, 2014, 09:32:35 AM
Looks incredible, and incredibly fragile.
Title: Re: The Laser Project.
Post by: texaspyro on January 29, 2014, 10:33:23 PM
Here is some gratuitous 405nm laser cutlery.  It is the EMC2 FLOWSNAKE pattern.  The flowsnake is a fractal like pattern known as a Gosper curve.  This one is around 1 inch across.  The edge measure 10.9 inches long and has 3077 facets averaging .0035" long.  You can't see most of the tiny detail in the photo...  crappy camera.

I generated the MACH3 gcode for this pattern from a 40 line long recursive program written for EMC2 based machines using my gcode processing program.  It can translate between the languages of about 50 different milling machines plus DXF, HPGL, GPGL, and a few others.  It can also generate time optimized 2D cutting paths.

(http://imagizer.imageshack.us/v2/800x600q90/839/yf5j.jpg)
Title: Re: The Laser Project.
Post by: texaspyro on February 01, 2014, 08:14:39 PM
I did some tweaking on the feed/power level when cutting the .032" basswood and have been able to cut tweakie-bikes where the features are 175 microns wide.  At 150 microns wide they are a bit too fragile to handle... the structure is barely more than ash.  I need to find some material that the 405 nm light does not char like wood does or melt/fuse like most plastics.

I've also been engraving some desktop name stands for some friends... on small wooden matches with 500 micron tall letters... I am becoming a connoisseur of dollar store match sticks.  One side is always finished quite well.  The others are usually rather rough.  Plus the boxes are handy for transporting teeny-tiny tweakie-bikes.

A friend is getting me some UV curing resin to try some stereo lithography.
Title: Re: The Laser Project.
Post by: frasej on February 02, 2014, 12:04:48 AM
Try craft foam.  The 2mm style cuts very easily with little to no charring.
Title: Re: The Laser Project.
Post by: frasej on February 18, 2014, 06:56:12 PM
Can anyone explain the following... Below are two images, one is an extreme closeup of the other image.  Notice that instead of straight lines, the lines appear to be wavy. This was burned onto balsa wood and I was wondering if it's the grain that is causing the waviness?
Title: Re: The Laser Project.
Post by: Picengraver on February 18, 2014, 08:47:31 PM
Are you perhaps using all thread rod (machine screw thread) for lead screws?
John Champlain
Title: Re: The Laser Project.
Post by: frasej on February 19, 2014, 09:18:57 AM
Eww, no.   All Chinese lead screws.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 19, 2014, 09:32:19 AM
Loose lens or mounting perhaps ?

Tweakie.
Title: Re: The Laser Project.
Post by: frasej on February 19, 2014, 09:54:39 AM
Loose lens makes more sense.  I have it wrapped in Teflon plumber's tape but it is still easily moved.  I may need to add some more.  I hadn't thought of that, thanks.
Title: Re: The Laser Project.
Post by: Picengraver on February 19, 2014, 02:34:23 PM
Well, a warped screw and slight play in bearings might explain it.  Would probably not be noticeable when using a spindle.  Does it change when switching from a horizontal engraving to a vertical?
John Champlain
Title: Re: The Laser Project.
Post by: frasej on February 19, 2014, 04:06:12 PM
I wrapped more tape around the threads of the lens and put it back on.  There is still a little wobble in the burn, but not nearly as much as before.  The lines don't seem to cross each other any more.  So it probably was just a loose lens.  I've never tried going perpendicular to the direction I was burning in.  I'll have to give that a go and see.
Title: Re: The Laser Project.
Post by: balerion on June 03, 2014, 05:32:22 AM
Hi texaspyro, I'm very impressed by your results. Can I ask you how you managed to get such a tight focus? Also, would you recommend your setup to cut ~mm sized features in kapton?
Title: Re: The Laser Project.
Post by: texaspyro on June 03, 2014, 12:58:09 PM
Hi texaspyro, I'm very impressed by your results. Can I ask you how you managed to get such a tight focus? Also, would you recommend your setup to cut ~mm sized features in kapton?

The laser that I used is a 405 nm single mode laser.  Single mode lasers can be focused to very small sizes and their beam is much less rectangular than the typical laser diode beam.   I focused the beam manually by eye (use proper goggles) and then tweaked the beam by rasing and lowering the laser head on the mill.  (One way is to place the material on a sloped angle and draw a line on some easily marked material like Kapton.  Then examine the mark with a magnifier and see where the mark is thinnest).   But the location that I came up with was pretty much the same as the manual focus point I came up with.  I can't see much focus diffeence over a +/- 0.25" change in laser height.

I can cut Kapton,  but not very well.   It chars and the char seems to block the beam.  Using enough power to cut the material limits the feature size and quaility of the cuts.

Also,  after I bought my 700 mW laser (which I run at 500 mW max),  a new 1+ watt laser is now availabe.  I have not tried it yet...
Title: Re: The Laser Project.
Post by: balerion on June 04, 2014, 04:01:53 AM
Thank you very much for sharing. Is it against forum rules to ask for your laser source?
Title: Re: The Laser Project.
Post by: texaspyro on June 04, 2014, 11:37:21 AM
Thank you very much for sharing. Is it against forum rules to ask for your laser source?
DTR laser shop...  google will find it.  My .5 watt laser is from a 12X Blue ray writer.  The new 1 watt is from a 16X blue-ray writer.  I also built a 3 watt 445 nm head.  It has a beam around 5 mils wide.  I run it around 2.5 watts max.  He has a new 5 watt diode,  but the beam is even bigger.

Those G2 lenses produce the highest output power from these lasers.  There are some 3 element lenses that can produce a smaller beam from the 445 nm lasers,  but they seem to do it by clipping off then ends of the rectangular beam.  You lose around 30% of your power with the 3 element lenses.

My laser driver is a Flexmod P3 from Illumination Supply.  I power the lasers with a 9 volt regulated 3 amp wall-wart type power supply from Ebay.

Oh,  and don't forget you MUST use proper laser safety goggles!!!!!!  Mine are made by Eagle Pair...  DTR has a link on his web site.
Title: Re: The Laser Project.
Post by: balerion on June 04, 2014, 11:46:30 AM
Thanks! I will use my lab's goggles, don't worry  ;)
Title: Re: The Laser Project.
Post by: texaspyro on June 04, 2014, 03:37:12 PM
Thanks! I will use my lab's goggles, don't worry  ;)

Make SURE that they block the wavelength of your lasers...  not all goggles work at all wavelengths...
Title: Re: The Laser Project.
Post by: balerion on June 04, 2014, 04:34:18 PM
Quote
Make SURE that they block the wavelength of your lasers...  not all goggles work at all wavelengths..
Thorlabs LG10, 190 to 534 nm, OD = 7+, they should be fine. We are all very scared by our laser (not the 405nm one), hence the expensive goggles.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on June 26, 2014, 06:04:05 AM
Something I keep getting asked about is CO2 laser output power control by using the Mach3 generated PWM signal and the S********* command in the GCode program. This is not something I prefer to do as I always treat engraving and cutting toolpaths as two different operations separated by a tool change. However, PWM control had to be done.

Well, pre-set laser output power is not a constant – it will vary dependant on tube temperature and it’s cutting / engraving ability will also vary dependant on ambient temperature as well as the type of material and it’s moisture content etc. etc. As a result a GCode program with a defined power setting may run just fine today but may need some adjustment to run just as well tomorrow.

There is always more than one way to accomplish anything but this is the best solution I have come up with so far. It does however need a bit of extra hardware to function but this is simple enough to make and just fits inline with the LPT cable to the machine.
The maximum laser power is still manually set and the GCode S********* command controls the actual laser output power between (approx.) 0% to 100% of the maximum that has been set. This allows for the laser output power variations, mentioned above, to be compensated for and adjusted on a day-to-day basis without having to make any changes to the GCode program.

This method basically gates together the Mach3 PWM signal with the M11P1 / M10P1 command codes on Output# 1 just by using a pair of opto-couplers and the LED series resistor values have been chosen to present a loading on the LPT port of no more than 5mA per pin which is well within it’s capability.
This method negates the set-up time delay associated with switching the PWM signal with the M3 / M5 commands by leaving the Mach3 PWM signal constantly running then just applying it as required with the M11P1 / M10P1 commands. Provided any changes to the laser output power are commanded by entering the S********* command on a separate line in the GCode no delays in changing power levels have been noticed and engraving / cutting within the same program is easily accomplished.

The circuit is extremely basic and can be easily made and fitted to an existing machine (which is controlled by the LPT port, of course) and the following pics. Show just what I have done.

(It should be noted that the Vcc required for the opto-transistor is provided by the pull-up resistor included within the laser PSU’s TTL(L) input. If this is not available then a 10k pull-up resistor to +5 Volts may need to be added).

My Mach3 set-up is as follows (please note - your pin numbers may be different).

PWM base frequency 500
Minimum PWM 0
Relay – M3 Output #2
Spin up / down delays all 0
Spindle √  17  0  X  X  1  1
Output #1  √  1  16  X

Spindle pulley 1 Min speed 0  Max speed 100 Ratio 1

The GCode program uses M3 followed by S********* (0 to 100) which is essentially percentage of full power. Thereafter changing power by entering a new S********* command and the laser is switched on / off by the M11P1 / M10 P1 commands. The program then has M5 at the end.

Nice little project for a rainy day perhaps ?

Tweakie.


Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 07, 2014, 06:07:01 AM
Some further thoughts on this…

By changing the active state of Output #1 to ‘active low’ the circuit can be simplified as shown below.

Tweakie.

Title: Re: The Laser Project.
Post by: wdwkr53 on July 17, 2014, 11:12:00 PM
I followed this thread & was able to get my laser mounted on my CNC spindle to work.  Thanks so much for all the information.  I use Aspire to generate vector gcode for Mach3.  I have to manually insert the E1P0/E1P1 where appropriate for shutting off the laser.  Works great, but labor-intensive in the edit gcode mode.  Is there a plug in or way of "find-and-add" the commands faster?  I downloaded the Impact Engraving plug in, but I would like to do vectors.  Any suggestions would be appreciated.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 18, 2014, 01:20:48 AM
Nice work wdwkr53.

Locate your Vectric post processor ( C / Documents & Settings / All Users / Application Data / Vectric / Aspire / ... ) and modify it to insert the M11P1 / M10P1 commands as appropriate. I have attached a typical example of one of the pp's that I use if it's any help.

Tweakie.
Title: Re: The Laser Project.
Post by: Jammerm on July 24, 2014, 12:46:52 PM
Tweakie, have you seen this article. A diode laser that is strong enough to cut steel. I haven't read it all but it sounds promising. I wonder if any cooling is required. I'll look at it closer when I get back from town.

http://phys.org/news/2014-07-direct-diode-laser-bright-weld-metal.html
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 27, 2014, 07:42:38 AM
Hi Jammer,

Thanks for posting the link – there is no doubt that laser development, new thinking and technology advancement is cracking on at an alarming pace and that article made very interesting reading.

One thing that’s often not made very clear in press releases is that laser beams do not actually contain any heat – they are just a coherent stream of photons (having no mass) and it is the reaction of the molecules in the material they come into contact with which actually creates the heat. Another point that is often overlooked is that when cutting metals it is the high pressure assist gas (often Oxygen) which actually does the cutting (much like oxy-acetylene or plasma work) and the laser beam is merely the catalyst.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on July 27, 2014, 08:02:46 AM
Just a short 1 minute video of the combined engraving / cutting toolpath using a logical AND between PWM and laser trigger as described in posts #856 / #857

 http://www.graytel.talktalk.net/Darwin 2.wmv (http://www.graytel.talktalk.net/Darwin 2.wmv)

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 06, 2014, 02:04:24 PM
Hi Guys:


   Im starting to monitor this thread as Im finally doing laser experiments myself. I have my synrad
running on my workbench. It stopped lasing the other day and I found by slightly tweaking the
frequency with the cap that it works again. I tuned for 6 amps at 100% duty cycle. ( If anyone can tell
me the actual draw of a synrad j48 at 100% duty Id appreciate it, or a tuning proceedure. :).

   This project Im doing starts with a diagnostics and remote control panel ,now built ,and ends with a new engraving plugin
for Mach3/4 or any CNC system. (We'll see how that goes :) ). The control panel seems to work fine, It does 1us
tickle pulses, any frequency and pulse count can be dialed up by buttons, and a fire button starts to blink. You can
dial up from 1 - 5000 pulses or CW mode. Pressing fire shows the count countdown till 0, at which point laser shuts off,
and the counter reads zero. This shot pattern counts down at the dialed up frequency.. then Tickle resumes. Removing your finger from the button stops the test fire and it can resume by repressing. A reload button reloads the last count for another run. A photo is attached before a mask is applied over the top. (It will end up resembling a wooden control panel. :) )

   Internally, the PWM is controlled in 3192 steps from 1 - 99% power. (Though I suspect the synrad will probably make that 100 steps internal to itself.). Everything seems to be firing well, so Ill be starting the next phase to allow an engraving algorithm to
be uploaded for any engraving. The panel is built from an arduino YUN, the 400mhz unix system takes care of the SD card and will accept engraving command files wirelessly. The 16mhz arduino will control all firing pulses. This allows me to send a large file of commands for an enraving run OR simply use the panel as a smart spindle controller for on/off types of work.

  The plan is to connect the Yun to the step/dir inputs to any breakout board on X, Y and A. They will be monitored by the Arduino which will then reach into a command file to find the power level, frequency or dither pattern to be put out for the current virtual location of the laser in cartesian space. This means Ill have to write an engraving command program to take a photo and create a command file for various types and resolutions of engraving. It will also put out a GCode file which really will be nothing more than a raster scan with perhaps high and low res areas in that scan. The command file, already sent wirelessly in to the SD card of the YUN will interpret current location of that raster scan from the step pulses and make a very high res, multi power level engraving step by step. It may have to use fractalization to make an image larger to match the step count for the highest res. possible.

  Well, thats the plan.. we'll see what works or if it all just drives me nuts.. :) . Ill be posting the source code and schematics as open source,as well as any program thats written to create command files.. its all pretty cheap with the exception of the YUN, but one could use a simple leonardo... I just wanted mine to be wireless for ease of use..and the unix side makes it very powerfull for any size file to be used up to 100gig or so... you can even remote mount the sd card for this arduino onto your desktop.

  The whole point here is to give the pulsing and power waveform performance of a DSP laser system with just Mach or other cnc doing the motion...

Heres the panel as a photo... comments or suggestions welcome. Should be interesting..


Art


  
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 07, 2014, 02:08:47 AM
Hi Art,

That Gearotic laser control looks like a very interesting project indeed and I look forward to following your progress.

Regarding the engraving plugin you may be interested in work by TomTom in Japan - he has produced raster and vector plugins (based on your original engraving plugin) and these videos relate...

https://www.youtube.com/watch?v=o-BHEPkvaVI

https://www.youtube.com/watch?v=5L_xaxfXNjM

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 07, 2014, 07:08:47 AM
Tweaky:

   He's done very well.  My problem with the current way fo doing things is the limits on power. At 5Khz you get only
4 -5 power levels from Mach. I think we need much more if we want to do 3d sculpting type of engraving. For that
Id like to see at least 50 -100 levels of power. The question is always how to get the power functions into
the motion stream. The trick of sending in a stream of 1's and 0's as I did with that original plugin was OK..
but I really want to see what happens when you get much greater control of the power and trigger stream.

  SO instead of 1's and 0's, I propose a stream of byte data for power, combined with a set of variables that
control the ratio'ing of that power from point to point.  Kind of a curve fitting for engraving lines.. It may cause a small
delay at each end of a engraved line.. but we'll see. My main concern is if a Arduino can control the changes
fast enough during an engraving. Perhaps Darwin could send data over an output line or something..

Anyway..thanks for the links, it shows great stuff has been done, and that theres interest for such things, all
things I like to see when I start down such a road. :)

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 07, 2014, 11:48:48 AM
Hi Art,

I agree, the 4 – 5 power levels will not be enough. Just a thought but could you not just run at 10kHz and limit the duty cycle to 50% (the original plugin only achieves, at best, a 50% duty cycle at 12.5khz).

Quote from Synrad docs…
In most cases, the laser does not achieve full depth of modulation when driven by Command signal frequencies over 5kHz at duty cycles greater than 50%.

Scrub that thought - it would not enable more power levels in just half the band.

However, I don't understand quite how you are going to do it but I like the idea of byte streaming power levels.  :)  External PWM generator ??

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 07, 2014, 12:27:38 PM
Tweakie:

 >> the laser does not achieve full depth of modulation when driven by Command signal frequencies over 5kHz at duty cycles greater than 50%.

Im really not sure what to make of that statement, like many of their statements on PWM its a bit ambiguous. I "think"
it means that above 5khz and as you appraoch 20khz the modulation turns into an average of the pwm incoming width. So
running 50% at 10Khz for example would still only give 1/2 power output. Im experimenting here to see how true all that is,
its why the panel I built had to have the capability of repetative pulseing by pulse count, width and frequency..so I could see
the effect on various materials.

   The original plugin was binary really. It sent a string of 1's and 0's that turned the laser on or off at each step location, but the
power was always at the PWM frequency of the S word. 1 of 8 levels or so( I know you know this, I mention it so it will be in the
 record of the thread..)
  My thought at the time was that by triggering on step with a dithering frequency or other method of injecting grey scale the
engraving would be the best we could do. So basically what Im looking at doing with this panel is uploading a file into it before
the scan. ( The original plugin kinda did this too, it sent one line of binary to the printer port driver to use as triggers of off
or on , one for each step. ).  A printer port driver ( Darwin included) can do that , but its only control is on or off. So what
Im doign is adding a level between Darwin ( Or the m3 pp driver) and the laser. This panel is smart, so Darwin ( or m3) wont send that
digital stream anymore, instead we'll send a file before the scan. TO illustrate.. heres the old method..

 
 1) Plugin loads photo and calculates a line of binary off/on data. Sends data to printer port driver.
 2) Plugin sends one line of motion to CNC. Memory limited to one line of scan data as binary
 3) During motion, port driver uses binary stream on a per step basis to turn laser on or off.
 4) Plugin repeats process for each scan line till end of photo..
 
 Heres what Im trying to do.
 
 1) Standalone program loads photo. Creates entire x/y cartesion scan power levels file for each step of a
    scan of the photo. File may be up to 8Gig or so in size. Its sends this wirelessly to the SD card in the smart
    panel.
 2) Program puts out scan Gcode file. A simple raster file, with tighter closer scan lines where hiresolution is desired,
    and looser scan lines where less lasing needs to be done. This makes the raster scan faster overall.
 3) As the Gcode runs ( In mach3, 4 whatever..) the panel is tied to the step and direction lines. Its interrupt driven
    so it knows whenever the CNC system moves an axis. It looks into the SD card file and figures out what power level to
    shoot on each step ( X or Y..). the file has 3000 power levels possible per step location. Since its created by a standalone program
    the data levels can be quite complex. For example nonlinearity of the beam can be considered with more power in certain grey
    levels. For 3d scupting, you coudl use a calibrated power curve for depth.. a lot of things can be done with a smart control panel.
 4) Mach ( or whatever) has no idea a laser is running, doesnt have to control power levels at all, it just has to turn on the laser output
    which tells the arduino panel that it must lookup a value for each step and fire the laser at that power. The CNC unit simply runs
    Gcode of an XY raster.. or spiral raster..or whatever shape one wants..
   
    Well, thats the thought.. Im not sure my arduino can do all this fast enough, but I think it can. It also means youd simply build a smart
    panel for alaser, hook it up to a breakout baord so it gets the step/dir signals paralleled from the stepper driver. Of course
    a secondary mode will simpyl do on/off for traditional laser usage..
     
    Hope that explains it better.. Hope even more its all possible. :)
   
    Art
   
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 07, 2014, 01:08:18 PM
Hi Art,

Thank you for the detailed explanation - you make it all sound so simple  ;D

Seriously though, I think I understand your intention and it seems just terrific - I especially like the possibility of a non-linear response curve, as you say different materials behave differently and certainly not all in a linear manner. Another thing comes to mind - when raster scanning, ignoring the areas where the laser is not firing (not scanning those areas) speeds up through-put a great deal.

Keep up the good work my friend - I wish I had your brains when it comes to software development  :D

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 07, 2014, 03:22:09 PM
>>I wish I had your brains when it comes to software development

 I think its more lack of brains that makes on jump into this type of project. :)

Seriously, it will be interesting to see the effects of several things once we have
a greater level of power control.. Ill be implementing a test pattern to try to show the effects
of power, frequency and pulse count on various materials. Ive searched the forums and I see
all kinds of questions about the three variables and their effects, but with frequency ranging from
 0-5000, power from 0-100 and pulse count per pixel perhaps as much as 1000 pulses per location
( a function of speed vs frequency) , that's about 500 million variable combinations. Im always
 interested  when I get to explore things like that.  So as long as this laser continues to work Im
really interested in what we can do.

Art
Title: Re: The Laser Project.
Post by: ART on August 07, 2014, 05:32:16 PM
Tweaky:

 By the way, it occurs to me its pretty simple to get this arduino to convert a 100hz pwm to 5Khz pwm.. So with one of these
Mach3 could easily be converted to allow for 100 power levels... just by adding a cheap arduino as a pwm up-convertor..Hadnt thought of
that before for some reason..

Art
Title: Re: The Laser Project.
Post by: ART on August 22, 2014, 02:03:28 PM
Hi Guys:

   I jus finished hooking up the new control panel. It now takes a 50hz PWM and converts it to 5Khz PWM. So now I have Mach4
so I can type an Sword from 1 - 100 and get 0-100% power in 100 steps. Thats was job 1. I also have an override for that by a pot on the panel so I can override the Gcode program on the fly by turning the pot like a brightness pot to control the output.
   Also, rather than actually turn on the laser, the PWM , when sensed, just tells the laser to be prepared to fire at that power, if PWM is not sensed
but the Spindle on command goes high, the panel then uses just th epot for power. SO when Darwin ( or mach3) commands Spindle on, the laser gets
ready. The panel is also wired to the X and Y step and direction lines. ( you have to hook up 5 wires from the panel to the breakout baord.).

   SO now, when an step is sensed on X or Y, the laser will trigger off a shot of n pulses set by the user on the panel. When it exhausts those n pulses
it stops. Each time it sees a step it resets the counter, so if you move slow or fast, the power per step is the roughly the same, this should make grey scales easier as in this method speed is not as important.. more as I do more testing...

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 23, 2014, 03:46:19 AM
Hi Art,

It’s all sounding very exciting and as you say, that system should certainly make greyscale working a lot easier to implement.

Just something, mentioned before and to keep in mind, which only affects laser operation and makes no noticeable difference to spindle operation…

Mach4 makes the changes to the S word (and the subsequent PWM output) considerably faster than Mach3 and as near as I can measure, changes occur up to 50mS before the completion of the preceding line of Gcode (the actual period in mS being dependant on the execution time of this Gcode line).

In the attached pic. of one of my earlier test samples, there are two changes of S word occurring when switching from an ‘engraving’ to a ‘cutting’ toolpaths and in both instances the increase in PWM pierced the work (shown by the arrows) at the end of the ‘engraving’ toolpath.
This fooled me a bit to start with but thanks to help by Craig and Scott adding a delay in the Mcode switching macro’s resolved the issue. Just how this can be resolved when using an axis direction pin for laser switching I have yet to discover but it is all part of the great learning experience.

I would just like to take this opportunity to offer a big “thank you” for setting such a low price for the Darwin pre-buy license. Keep up the good work my friend.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 23, 2014, 07:29:12 AM
Tweaky:

>>In the attached pic. of one of my earlier test samples, there are two changes of S word occurring when switching from an ‘engraving’ to a ‘cutting’ >>toolpaths and in both instances the increase in PWM pierced the work (shown by the arrows) at the end of the ‘engraving’ toolpath.
>>This fooled me a bit to start with but thanks to help by Craig and Scott adding a delay in the Mcode switching macro’s resolved the issue. Just how this >>can be resolved when using an axis direction pin for laser switching I have yet to discover but it is all part of the great learning experience.

  Cant happen in this method, no laser is emitted when turning on the PWM, the panel gets the new power within a few ms.. but even that time doesnt
matter as radiation only happens as the step pin pulses. The step pin, resets the pulse counter which then allows radiation only for a set number of pulses
and then stops..unless another step pulse comes along. The next step pulse resets the counter and radiation starts again..or continues as it may have still
been shooting as a result of the last pulse. 

  In other words you can turn on the spindle , go for a walk, come back and then jog, the laser cuts only during motion.. Its my hope this cures many ill's
in terms of early trails and such.. mainly because you can enter a spindle delay.. a few ms will do it, and your power will always be proper no matter
if your in Mach3 or 4. This panel is designed to work as easily on M3 as M4 or EMC.. all you need is the 5 wire hookup to the breakout board.

 I hope to turn on power this week and test rather than just look at numbers, so we'll soon see if Im barking up the wrong tree. :)

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 23, 2014, 08:24:51 AM
Hi Art,

In my mind, I know you are right but I will be interested to hear if you run into any issues with timing when changing the PWM duty cycle between low to high levels within a running Gcode.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 23, 2014, 10:18:36 AM
Tweaky:

 lol, yes as we all know the path to hell is paved with good intentions.. ( and idea's..).

  Ill show in a video how it all works out..

Art
Title: Re: The Laser Project.
Post by: ART on September 02, 2014, 10:47:40 AM
Hi Guys:

(Copied from printer port forum.. wrong spot :) )

 First laser engraved photo done with Darwin. Darwin sent 40 levels of power ( of 100 possible) via
serial dataclock transmission while engraving at 7000mm/min.

https://plus.google.com/u/0/photos/118339423221700707274/albums/6054479007323314049/6054479008542443554

 Theres a video on the page as well. Im still just developing a method for darwin to do engravings or pin
punching.. I find surprisingly that my servos have a terrible following lag only noticable because of the lasers ability
to fire instantly on any step command at any power. SO if I cut in both directions, I get a "Carrot on a stick" problem
where the laser fires on the step pulse, but the servo doesnt get there for another 10mm's of travel.
  So Ill either have to put in a following error calculation for slow servo's.. or replace them if I wish to engrave in both directions.
Cutting isnt so much an issue. The photo shows quite an impressive quality for laser on melemine , and at least verifies that
adding a simple arduino, and hooking up 4 wires to the breakout board allows a large amount of laser control..

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 02, 2014, 11:33:29 AM
Great work Art, the project is all starting to take shape now you are into the actual 'power on' testing stage  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: zann68 on November 03, 2014, 09:02:23 PM
Hi Guys,

This is the little sub-panel fitted in it's place on the controller board. I used a couple of spots of cyno to fix it's position on the IC's before making the through connections to the main board. The function of these two switches will be software programed to control such things as ‘last setting store and retrieve’, 'PRF frequency', 'menu selection' etc. What started out as a simple project just keeps growing  ;)

Tweakie.

Hey,

Do you have a build file like the J48 Controller for this addon? I got my hands on a 30w J48-1S-LSI laser. We were throwing it out and wanted to project it instead of landfilling the laser.

Thanks Tweakie
Title: Re: The Laser Project.
Post by: dude1 on November 03, 2014, 10:04:56 PM
have a look here this is what Tweakie, Art and a few others are doing

http://gearotic.com/ESW/FavIcons/index.php?board=16.0
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 04, 2014, 04:10:01 AM
Hi Zann,

The version shown on my website works ‘as is’ without the additional switch panel (which was added later to enable extra menu items selection).

As mentioned above by Daniel, the Arduino based design by Art may be a much easier project for controlling your J48 – I am certainly following it with great interest and hope to get it working with my CO2 laser in the not too distant future.

Tweakie.
Title: Re: The Laser Project.
Post by: zann68 on November 16, 2014, 11:49:28 AM
Looking into that as well. Thanks Guys
Title: Re: The Laser Project.
Post by: Tokamak on November 21, 2014, 01:52:53 PM
Tweekie,
Help!!
After reading your build I decided to install an 80W laser on my MechMate. All works fine except turning on the Laser from Mach3.

I cannot get pin 16 to go active. Configured output #1, Port 1, Pin 16

My G code looks like this:

N70G00G20G17G90G40G49G80
N80G70G91.1
N90 (End Mill {0.006 inch}MDF)
N100G94
N110F40.0
N120G00X0.1001Y0.1072M10P1
N130G1M11P1
N140G1Y0.8572M11P1
N150G2X0.1314Y0.8885I0.0313J0.0000
N160G1X0.6314M11P1
N170G2X0.6626Y0.8572I0.0000J-0.0313
N180G1Y0.1072M11P1
N190G2X0.6314Y0.0759I-0.0313J0.0000
N200G1X0.1314M11P1
N210G2X0.1001Y0.1072I0.0000J0.0313
N220G00M10P1
N230G00X0.0000Y0.0000
N240M30
%

Mach3 Ver R3.043.066

I gotta be missing something simple.


Title: Re: The Laser Project.
Post by: Tokamak on November 21, 2014, 02:57:41 PM
Tweekie,
Sorry for the hijack. Digging further I found a charge pump issue disabling the outputs on my PMDX board. Laser works!
Tokamak
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 22, 2014, 01:50:26 AM
I am pleased you found the problem.  ;)


Tweakie.
Title: Re: The Laser Project.
Post by: sitzme on December 09, 2014, 07:55:09 PM
"Well, after a bit of experimentation, I think I can now safely say that the Mach3 Impact / Laser plugin can be used with low power diode lasers."
"If there is any interest in this, I would be pleased to provide the details of just how it was accomplished."

I am trying to get a KaleCNC diode laser working with the plugin.  It works in gcode and when using the plugin I do get pulses but not enough power to mark.  I am interested in how you got it to work.
Thanks for your efforts on this topic in general.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 10, 2014, 03:35:15 AM
Hi Sitzme,

The plugin’s ‘fire pulse’ width is limited (it is essentially the axis step pulse) and as feed-rate is reduced the spacing between pulses increases thus producing the ‘lack of power’ problem you are experiencing.

My solution was to use an external microprocessor (PIC chip) to digitally detect the ‘fire pulse’ then extend it’s width. The prototype is a bit crude (based on a partially populated circuit board designed for my RF laser controller) and whilst I have every intention to refine this design and post it as a project, like most things, work interferes with play-time and it has been pushed to the back of the queue. The design could, I am sure, be simplified (by not having the display) as the microprocessor automatically stores the last setting (for future use) and it is easy enough to set-up by experimentation with a test sample. It requires no changes to the machine as it connects in series with the 25 way LPT cable and is just used when required.

Some while back another member posted an analogue design for pulse stretching and this works well but had limitations on the range of available pulse widths so I opted for a digital solution which can easily extend the fire pulse width right up to the start of the next pulse no matter how slow the feed-rate. His design is here http://www.prutchi.com/2012/02/04/co2-laser-engravercutter-addition-to-a-cnc-retrofitted-sieg-x2-mini-mill/


I am working on another project at present and this will probably keep me busy until the springtime but if you can wait until then I will post full constructional details of a re-designed pulse extender before the summer.

Tweakie. 
Title: Re: The Laser Project.
Post by: sitzme on December 10, 2014, 06:59:27 AM
Thanks Tweakie.  I understand the work/play issue.  Would it work to slave the unused B axis with X at a ratio and fool Mach3 into seeing a high pulse rate for the X axis but put out a reduced rate to actually drive the axis?  I am going to look at this tonight but have to go make a living now. ;^)
Title: Re: The Laser Project.
Post by: sitzme on December 10, 2014, 04:13:03 PM
Please disregard most of my last post.  Mach3 does not support gear ratios on slaved axis.  Having dug a bit more (someone correct me if wrong) it appears that the engraving plugin outputs a frequency with a 40ms pulse width and the diode laser TTL needs a PWM signal.  Either a software change/addition to the plugin or additional hardware is needed to use a diode laser if I understand.  Given the availability of low cost, higher power diodes these days, there will probably be more interest.  The PWM works great if you treat the laser as a spindle so hopefully someone will figure out a way to do it in software for the plugin.  Would it be possible to use an Arduino Uno to convert from pulse frequency to PWM in this instance?
Title: Re: The Laser Project.
Post by: ART on December 10, 2014, 04:38:06 PM
Hi:

 Check the laser control panel thread in the forum at gearotic.com for information on such a project for mach4. The box there creates a PWM
signal for cutting or engraving photos..

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 01, 2015, 08:35:28 AM
A bit of experimentation here…

It is not possible to cut soda-lime glass with a CO2 laser but, some while back, I read a couple of patents which cover a ‘fracture technique’ where the laser is used to heat the glass (causing compressive stress) and then the glass is cooled (causing tensile stress) which in turn creates a fracture along the defined toolpath.
Obviously I have much to learn here but needing 2 x 20mm diameter, opaque glass, discs I thought this process may be worth a try.
I found that straight line fractures are relatively easy to achieve but circular fractures needed a bit more thought.
On my first attempt I found it impossible to remove the discs so using slightly more power on the second run I created radial fractures in all directions and I now have the two required discs which fit the intended application perfectly. The edge quality is not that good (but that is unimportant for my application) although I think refining the technique will lead to better quality results.

Just thought I would share the info for any others that may be interested in experimenting with laser glass cutting.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 01, 2015, 08:55:25 AM
Tweaky:

Excellent. I had been discussing the thought of that a few months back with Bob.. SO you cut small lines like normals coming out from the circle?
How'd you cool it? Air?

Art

Title: Re: The Laser Project.
Post by: Chaoticone on April 01, 2015, 10:52:20 AM
Very Cool Tweakie! I had to learn how to cut glass when working on a Sunburst light/window over a door casing that was built sometime before 1865. They were shaped like wedges and I wasted a lot of glass on the ends that came to a point before I figured it out. I have thought of a piece a local glass shop had displayed on their wall since I first saw it (younger than 10) and even more since working on the window. It was a mirror that was shaped like 3 doughnuts stacked to form a triangle. The entire perimeter was a series of arcs with round holes in the center. A few times when that magic mirror crossed my mind I have almost researched it to figure out how it was done. I have come to the conclusion I really don't want to find out, not like that. That mirror has become my Santa clause. I'm pretty sure I know a few gifts I will see in the bag if I peek. I just caught a glimpse of you putting presents under the tree.

Brett  
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 01, 2015, 11:46:47 AM
Thanks for the encouragement guys, it is much appreciated.

If only I knew the secrets of shaped glass cutting it would all have been a lot easier insofar as selecting the correct toolpath for the job. In my ignorance I just used a standard toolpath (as shown in the top of the picture) and although the glass cracked, with that layout it is not going to come apart any time soon. Brute force (more power) worked but it is not really the right way to go about it.

To cool the glass I used cold air (passed through half a dozen turns of tubing submersed in an ice bucket) with the glass resting on a milling machine parallel which had previously been placed in the deep freeze for a few hours.

There has to be a better way – it’s just a matter of dreaming it up.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 01, 2015, 12:01:45 PM
>>There has to be a better way –

 There almost always is. :)

Art
Title: Re: The Laser Project.
Post by: BR549 on April 01, 2015, 10:56:30 PM
I think you may want to play with the focal length. I studied 3d glass engraving for a while. The secret was to have the focal length set to the INSIDE  of the glass. FOr cutting/scribing I would think the Focal length needs to be either on the top surface of the glass OR the bottom surface.

In manual glass cutting a bottle circumference you scratch the outside surface then run it under boiling hot water a little at a time and you can get a perfect seperation 99% of the time.  So well defined that you can reset the two pieces back together and it will not leak water

From Cold to HOT (;-) the glass expands and fractures at the Scribe line.  From Hot to cold it tries to contract and most times cannot contract enough to do the fracturing due to compression.

Just a thought, (;-) TP
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 02, 2015, 03:17:00 AM
Hi Terry,

Many thanks for the suggestions, they are gratefully received.

You are, of course, absolutely right about behaviour with a scribed line ( I have seen your excellent demonstrations with bottle cutting) but, unfortunately, CO2 lasers don’t produce the right kind of line. Because of the wavelength the CO2 beam is absorbed into the material causing some surface micro fracturing and some melting with the bottom of the kerf being randomly rounded and this prevents the glass from breaking along the line (many before me have tried this method without success).

The patented idea of ‘tensile stress cracking’ turns the tables, so to speak and relies on the laser beam being out of focus to heat the glass rather than mark it and it is usual to cool the glass some 10 or so mm behind the passage of the beam. For me, this is OK for straight lines but the toolpath starts to get extremely complicated for shaped working (where tangential control may be necessary for the air/water mist cooling nozzle).

With my experiment I attempted to create as much thermal shock within the glass as I could manage and it sort of worked (at least I got the discs I needed) but I found that it was necessary to create a fracture at an edge for it to follow the toolpath line and there is a technique to doing this. Perhaps, when I get more time to spare, I will investigate this further and hopefully be able to produce better quality results.

It is certainly a subject for thought.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: stirling on April 02, 2015, 05:52:38 AM
I'm wondering if increasing the temperature gradient in both stages would help.

e.g. put the glass in the freezer prior to lasering and then warming it in the oven/hot water whatever, before hitting it with a freezer spray.

remember the safety glasses - it'll probably explode...  :o

You could also try increasing the number of radial lines maybe.

Ian
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 02, 2015, 06:47:49 AM
Hi Ian,
 
Pre-heating or pre-cooling the glass is something I will have to try.
Perhaps tangential lines may make it easier to remove the parts - I don't know but I suspect that the fracture produced in radial lines may continue in a straight line rather than following the shape - something else for me to try.
Thanks for the suggestions.

Tweakie.


(There are more details of the tensile stress cracking technique in this document  http://www.jklasers.com/images/ZeroWidthGlassCutting.pdf )
Title: Re: The Laser Project.
Post by: ART on April 02, 2015, 07:46:18 AM
Tweakie:

 In my imaginings, I had planned on drilling a small hole in a peltier element I have here. They are semiconductor slabs really so
drilling a hole shouldnt hurt them. then if the gantry pulled the peltier along while burning the glass though the peltier, I might
be able to get a very large thermal gradient. Ive never gotten to test that theory yet,
 but I have a 2" square peltier laying here.... someday soon maybe. Im think at that point motion speed is then a gradient control
instead of just heat control, it also would give me a pot to turn to increase gradient or lower it. ( Things always work better when you have
a pot to turn.. lol )..seriously though .. a peltier with a hole in it could give a very large gradient , these things get very very cold when you have an
appropriate heat sing and fan on them, and it should be possible to right through a hole in the heatsink and a hole in the peltier.. I think
dragging one across glass may work...

Art

Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 02, 2015, 09:00:56 AM
Good thinking Art - although it may be risky drilling a hole through a Peltier as it is my understanding that each of the individual elements are connected in series (see diagram). You may get away with a small hole but I think it would need to be at least 3mm dia. ?

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 02, 2015, 09:50:45 AM
Tweakie:

 You could be right, on the one I have in front of me, it looked more like the serial connection was upwards in thin slabs that are the full size of the square..
but then Ive never opened one..

Art
Title: Re: The Laser Project.
Post by: dude1 on April 02, 2015, 06:23:38 PM
I plan on doing something simaler art my mum likes to do mosaics with glass or cut glass bottles to make something with them I am making a bottle cutter what I am planing to do is have a peltier sitting under it  so when it gets turned the glass get cut and cold at the same time so then you can take the bottle out and put it in hot water.

when I get my laser going I will try with that as well

Title: Re: The Laser Project.
Post by: BR549 on April 02, 2015, 07:52:40 PM
Just a bit of reference reading.

(;-) TP
Title: Re: The Laser Project.
Post by: JTW on April 04, 2015, 08:36:09 PM
Just to confirm, drilling the peltier is not going to work. Major risk to break the series connections inside but the plates on each end are usually ceramic and the pressure from the drill will just shatter it. You can get circular peltiers with holes already in them though.
Title: Re: The Laser Project.
Post by: ART on April 04, 2015, 09:40:56 PM
Thx

  Saves me from busting one. :)

Art
Title: Re: The Laser Project.
Post by: Vogavt on August 01, 2015, 09:13:17 PM
........... I need to do some more testing but the latest version of the plugin (1.2c) will shortly be freely available to any that are interested.

Tweakie.


I'm interested if this works with the impact engraving too!

Thanks in advance,
Vogavt
Title: Re: The Laser Project.
Post by: ART on August 02, 2015, 07:08:59 AM
Hi:

   I suspect it would, but I m no longer persuing this as a viable project in favour of making a controller to do it as a native
function. While my arduino controls my laser great in XP under Darwin, Im working on Auggie, an augmented Gcode controller
specifically designed for lasers and impact engravers as I no longer use XP myself.
   More will be published on this by end of summer. This project will stay here for those that wish to stay in XP and run it, but
for most I think XP and printer ports are going away, so the Auggie project will replace this one.

Art
Title: Re: The Laser Project.
Post by: ART on August 02, 2015, 07:09:48 AM
oops, sorry guys, wrong thread for that last reponce. :)

Art
Title: Re: The Laser Project.
Post by: Vogavt on August 16, 2015, 06:32:31 PM
........... I need to do some more testing but the latest version of the plugin (1.2c) will shortly be freely available to any that are interested.

Tweakie.


I'm interested if this works with the impact engraving too!

Thanks in advance,
Vogavt


Well, I've purchased a 445nm laser kit so I'd like to have the latest available version. I've scoured the net to see if it had been posted in other forums or threads here, but either I'm overlooking it (the v1.2c) or it hasn't been posted. Is there a later version than this one?
Title: Re: The Laser Project.
Post by: dude1 on August 16, 2015, 06:44:19 PM
http://gearotic.com/ESW/FavIcons/index.php?board=16.0
Title: Re: The Laser Project.
Post by: Vogavt on August 16, 2015, 08:34:00 PM
Well, I looked at all the threads there, but again, unless I missed it, the v1.2c was no where to be found.
I suspected it might be there if I registered for the site and it then it might reveal a "files" area, but today the registration process is/was closed.

I did see info regarding Mach4 and some info for using an Arduino; not really what I am looking for (I don't think).

Thanks anyway.

Maybe the illusive dll will rear its head sometime. LOL!

Vogavt
Title: Re: The Laser Project.
Post by: dude1 on August 16, 2015, 10:14:10 PM
 tweakie stuff is here or on his web site http://www.cooperman.talktalk.net/ I could not find what you are looking for ever
Title:
Post by: Vogavt on August 16, 2015, 10:25:42 PM
OK thanks for looking for it as well. I'm familiar with his awesome build site and was one of the first places I looked too. No joy.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 17, 2015, 01:45:19 AM
Hi Guys,

It was posted but I can't find it either now.  ::)

The attached zip contains version 1.2c of the DLL which is the latest version.

(n.b. although I have made a number of changes to Art's Engraving DLL over the years compatibility between Impact and Laser use has always been maintained).

Tweakie.
Title:
Post by: Vogavt on August 24, 2015, 08:40:07 PM
Thank you!

I got the 445nm 2W laser in the mail and the correct wavelength glasses. Applied 12vdc to the driver board and moved a wooden board back and forth to get an idea of where my focal point was (after playing with the lens adjustment ferrule and getting as small of a dot I could get). Then the beam went dim and I could no longer get any burning of wood.

I checked the back of the power supply again and it was 12vdc / 850 mA. So I dragged out my multi-tester and found it was around 19 volts! Seems though that I recall that the true reading should be taken when under a load.

Now I don't know what do. The fan was running on the end of the laser's case and it never even got warm.

It is giving off a faint blue light but nowhere near what it was for about a minute.

Any testing procedures I could try? It came with no instructions.

 Help?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 26, 2015, 03:47:52 AM
Sorry to say this but the symptoms you have described exactly match those of a blown laser diode.  :'(

Tweakie.
Title: Re: Laser turns back on at end of program
Post by: wl888 on November 01, 2015, 01:29:23 AM
Hi Guys
Have been a watcher on these pages for some time and have learn't a lot, but i am now branching into a laser add on for my bench mill.

Have got the signal to fire and to turn off with the M10P1 and M11P1 commands, no problems, but when the program ends, the unit fires again.
I have gone thru dozens of threads, here and on other sites, tried the suggestions, no luck.

Am using output1 pin 9 active high.
I wish to keep the use of the Z axis for zeroing and focal adjustment, have already  got the screen extras up and running.(that was a fun learning curve)
(Have also tried this on the std 1024 screenset, no luck)

The interface is a DIY LPT breakout, nothing flash, no smarts, and works perfectly.
I have it set up with a series of LED's on all the outputs for testing.
the S.... command is correctly reflected in the Dro.

Below is a sample code i have been using.

Like most when learning a new skill, i have provably missed the obvious.
any and all help appreciated.
Doug

;Rem
s75
M11P1
X60.0Y0.0
M10P1
X50.0Y0.0F550
M11P1
X60.0Y3.3333
M10P1
X60.0Y-3.3333F550
M11P1
X59.7435Y-6.1296
M10P1
X49.8497Y-4.6761F550
M11P1
X54.561Y-5.3683
M10P1
X55.7668Y-6.9893F550
X56.0995Y-8.0008
X55.8919Y-9.4142
X55.2823Y-10.2872
X53.7997Y-10.5507
X49.0884Y-9.8586
M11P1
X58.0144Y-15.3154
M10P1
X57.4297Y-15.6496F550
X57.764Y-16.2343
X58.3486Y-15.9
X58.0144Y-15.3154
M11P1 g0 x0y0z5   (it does turn off here during the move)
s0                         (S0 works)
M30                        (Signal turns back on here)
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 01, 2015, 02:06:45 AM
Hi Doug,

Config / General Config / Pgm End or M30 Rewind - look to see if Turn off all Outputs is checked.

Tweakie.
Title: Re: The Laser Project.
Post by: wl888 on November 01, 2015, 03:12:55 AM
Thanks Tweakie, you are quick.
Yep, had that one ticked
Doug
Title: Re: The Laser Project.
Post by: wl888 on November 01, 2015, 03:17:34 AM
Is there a setup file i could send you, and if so how do i post it, just drag and drop??
Doug
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 01, 2015, 03:57:38 AM
Hi Doug,

That's a good suggestion.

I don't know which Screen you are using but bottom right of the 1024 set shows the Profile you are using. Locate the .xml file <your profile> .xml (typically Mach3Mill.xml) in the Mach3 folder - copy it to the desktop, rename the copy to a unique name (wl888.xml would be good) then using the Additional Options (at the bottom of the reply pane) attach it to your reply.

I will check you settings and hopefully be able to suggest a solution.  ;)

Tweakie.

Title: Re: The Laser Project.
Post by: wl888 on November 01, 2015, 04:26:04 AM
Ok, that was the name, but as you will see there are the extra buttons i've added, but as i mentioned before, i also tried it on 1024
file attached.
Meanwhile i will continue searching at this end. :)
again , thanks for the quick support.
Doug
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 01, 2015, 05:03:28 AM
Hi Doug,

The only thing I can see (without testing it on a machine) is that you have Output#1 configured as Spindle. This may be causing a conflict with the M10P1/M11P1 commands. Try using a different Output# for one or the other and see if that resolves the problem. Also uncheck Use WatchDogs (Config / General Config).

Tweakie.
Title: Re: The Laser Project.
Post by: wl888 on November 01, 2015, 06:55:36 AM
 Ok...I think I have it now...
A combination of errors...

1. Output 1 was set as active low.(ticked)
2. M10P1 and M11P1 were inverted in the program.
3. End result was that pin 9 Output 1 was always on.

have now set Output 1 to active High (crossed) and swapped the M codes around.

5 days to find this. Will test it some more tomorrow morning (now 10:50pm), but i think thats it. ;D

that's straight cutting, next step is to figure PWM for Grey Scale engraving.

Thanks Tweekie  :D

Doug
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 01, 2015, 07:41:03 AM
Pleased you got it sorted Doug.  :)
Just shows how observant I am - didn't notice M10 / M11 were transposed.  ::)

Tweakie.
Title: Re: The Laser Project.
Post by: wl888 on November 01, 2015, 03:54:05 PM
LOL.. :D ....I figured it had to be something basic, I was just too close to the problem to see it, but talking it out with You moved my focus.

Also I think You corrected some other errors I had along the way.

Anyway....maybe these posts will help someone else with tunnel vision.  :o

Thanks

Doug
Title: Re: The Laser Project.
Post by: wl888 on November 02, 2015, 09:04:13 PM
Hi All
Now that's sorted, I am moving on to the connection cable, this is still a work in progress. My main concern is at the bottom of the listing where I propose to join wires together to increase current capacity, not being a able to see the wires (sealed cable) I am wondering if anyone have seen this done (successfully) before or is  it a really bad idea. ???
I am also looking at using a heavy USB cable, the ones with larger power wires, for the Laser power supply. These cables are both shielded. From a previous post I noted that shield is connected at controller end only.
All Limit wiring will also be via USB cables.
Attached file.

Thanks in advance :)
Doug
Title: Re: The Laser Project.
Post by: wl888 on November 03, 2015, 04:29:21 AM
 :-\OK...Trash the above, had another look at it after some sleep....total dribble..please disregard. :'(
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 03, 2015, 05:10:25 AM
 :)

Tweakie.
Title: Re: The Laser Project.
Post by: wl888 on November 06, 2015, 02:52:48 AM
Hi All
Have been working on the control side,the aim is to operate the steppers at 24v and control thru Mach3. looking at the DRV8825 Arduino style module, needed a way to interface it with my DIY printer out board without full Arduino, tried a host of ideas, even asked the manufacturer, no luck. So...I just put 3 signal diodes inline with the Enable/Dir/Step terminals and hoped.. It worked. So if You could look at this to see if I have missed the obvious and there is risk of damage etc.
The signal diode stop a 0.4 to 0.5vdc feedback from the controller.
attached 2 pics.
thanks
Doug
Title: Re: The Laser Project.
Post by: kmin on January 16, 2016, 09:34:36 AM
Hi,
I have been reading the most of this long topic and things have been living during this 6 years, so what's the way to go at the moment?
I need to do vector engraving mostly but would like to experiment with grayscale as well.
Is engrave plugin modified by Tweakie still the way to go or there is something better. How should I get the modulation from Mach3?
 
I have 2w laser diode with russian analog/pwm driver (similar to Flexmod P3) and Mach3 control board with pwm output and analog 0-10V output.

Should I combine pwm S-commands and M11/M10 with opto-coupler like Tweakie did or is there out  something more advanced at the moment?
I saw Art was building nice pulse-distance control for mach4,  something similar built I have seen also for grbl and for linux cnc, but I don't have the knowledge to bring it to Mach3...
How are you engraving with your lasers at the moment (without encoders, dac, etc.)?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 16, 2016, 11:19:12 AM
Take a look at PicLaserLite http://www.picengrave.com/ it is, I think, more suited to diode laser operation than the Mach3 plugin.

Tweakie.
Title: Re: The Laser Project.
Post by: kmin on January 16, 2016, 01:01:43 PM
Thank's Tweakie!
I already had a look at it but noticed it was more about grbl setups. Can it be fitted to Mach3 setup?  I have laser fitted to my router and I mainly need it for vector engraving so I would rather add something to my setup than change it. I'm using Aspire for generating the gcode.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 17, 2016, 01:45:43 AM
Quote
I already had a look at it but noticed it was more about grbl setups. Can it be fitted to Mach3 setup?

I think it can (at least it did when I last used it) but you would have to check with them.

For your vector engraving why not just modify the Aspire post-processor to include the M11/M10 commands for the On/Off operation and use your control board's PWM output to control the power level.
Another possibility...
If your control board was set-up so that 100% PWM was full power and 0% was no power or Off then the M11/M10 would be unnecessary and you could control your laser just by the PWM (assuming it is capable of switching fast enough).

There is plenty of room for experimentation so perhaps just try various methods and see what suits you best.

Tweakie.
Title: Re: The Laser Project.
Post by: kmin on January 17, 2016, 06:51:53 AM
Thank's Tweakie,
you mean by combining M11/M10 and pwm like you did with optocoupler?
I haven't tried just with pwm, but according to the threads I have been reading, there is too much delay  with S********* commands to switch the laser on and off....
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 17, 2016, 10:47:49 AM
Quote
you mean by combining M11/M10 and pwm like you did with optocoupler?

At the moment I don't see a better way.

You are probably right about the S### delay in Mach3 although in Mach4 the S### is, if anything, too fast  :)

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 12, 2016, 12:00:19 PM
Hi Tweaky:

  Thought you might like to see my initial testing with 3d sculpting in wood..  :)

Art
Title: Re: The Laser Project.
Post by: ART on April 12, 2016, 12:01:32 PM
ohh, thats with a 14 watt laser output at 8000mm/min, using distance step correction for acceleration and deceleration correction.

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 13, 2016, 01:26:24 AM
Excellent work Art, I look forward to seeing more of this.

The 8000 mm/min is particularly impressive, that's galvo performance.  ;)

Are you using a variable PWM (linked to axis speed) to provide the Acceleration / Deceleration changes in laser output power ?

Tweakie.
Title: Re: The Laser Project.
Post by: TOTALLYRC on April 13, 2016, 06:35:00 AM
Way cool guys,
If I only had a laser and the time to work with it. Maybe when the other 40 projects are done.

Mike
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 13, 2016, 06:40:57 AM
Way cool guys,
If I only had a laser and the time to work with it. Maybe when the other 40 projects are done.

Mike

Mike, how can you possibly live without a laser ?   ;D

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 13, 2016, 07:12:00 AM
Tweakie:

  >>Are you using a variable PWM (linked to axis speed) to provide the Acceleration

  The PWM is controlled on a 1ms waypoint basis. So each time I sent waypoint data, I also
send a PWM for that ms. The program looks into a database for each location to get its power
point for that ms ( an image in this case), and then scales that power by a formula based on
feedrate and euclidian distance of the upcoming ms's motion. So for example, if an F8000 is in effect,
 and 50% laser power is selected, the program calc's the energy per mm going out, and maxes at 50% when we
hit 8000/ 60000 = .13mm's per ms. So all power is then scaled from 0 - .13mm/sec with .13 being
50% power output, this is recalcuated each ms.
   All that fixes very well accel and decel and keeps power very smooth here for the most part,
but I intend now to add a quadratic correction formula to the power curve to smooth it more
to take into account nonlinearity of a particular laser.
    I know Ill never make it perfect, but Im of the feeling the more calibrations you have, the better
it "should" get. Its not a bad initial testing for only a 10 watt engraver.. Thats 2mm deep, Im
aiming for 19.  :) , doing multipass should let me get results more similar to a 100 watt..just slower.

Art

   

Title: Re: The Laser Project.
Post by: ART on April 13, 2016, 07:13:46 AM
>>The 8000 mm/min is particularly impressive, that's galvo performanc

  :), actually, I slowed it down for 3d, my photos are now done at up to 25000 mm/min.

Art
Title: Re: The Laser Project.
Post by: ART on April 13, 2016, 07:14:39 AM
>>Mike, how can you possibly live without a laser ?   Grin


 How can anyone???? lol

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 13, 2016, 11:04:23 AM
Wow !

Great stuff Art, keep up the good work my friend.

Once I have finished-up on the paid work (it must run out soon) I will be back with the laser experimentation.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on April 13, 2016, 02:02:29 PM
Heres one at 12,000.

:)

Art
Title: Re: The Laser Project.
Post by: TOTALLYRC on April 13, 2016, 08:03:41 PM
Way cool guys,
If I only had a laser and the time to work with it. Maybe when the other 40 projects are done.

Mike

Mike, how can you possibly live without a laser ?   ;D

Tweakie.

Barely getting by but somehow I manage. :)
Title: Re: The Laser Project.
Post by: ART on April 17, 2016, 04:21:19 PM
I leave you with a final test image in teak,

 40mm x 40mm , 475inches/min

Art
Title: Re: The Laser Project.
Post by: Dan13 on April 18, 2016, 01:05:15 AM
It's fantastic, Art! But how is it that the wood maintains its natural colour and doesn't look burned?

Dan
Title: Re: The Laser Project.
Post by: ART on April 18, 2016, 07:24:30 AM
Dan:

   Laser machining uses the same concepts as normal CNC. I consider the focal point to be a small
ball endmill of .1mm id diameter. Like nay endmill, if you go too slow you burn, at the right speed you dont.

 This photo shown was with a 10 watt laser, run fast, and many passes (8). the photo is how it came of the table,
no cleaning was necessary.. so long as the speed is right, it doesnt burn.

Art
Title: Re: The Laser Project.
Post by: Dan13 on April 18, 2016, 08:45:33 AM
COOOL!!!!

Interesting, how good of a surface finish can achieved using this method? Also if other materials (acrylic for instance) can be machined equally well or even, may be, some are better?

Dan
Title: Re: The Laser Project.
Post by: ART on April 18, 2016, 10:21:38 AM
>>Interesting, how good of a surface finish can achieved using this method?

To be honest, I dont know. these are images from initial testing of the mode. Im finding things I wish to add more code to correct,
and lessons to be learned on how to best organize an image for burning. I suspect these initial images will be far surpassed as I
get further into learning how to deal with it. There seems little published on laser in a 3d context, most work seems focused on powerful
lasers ( 100 watt or more) to do 3d, but they do it in one pass. This is fine, but the bottom of their cut is likely very low power
as it would be 3.5mm away from focus, so this multi-focus method allows a set power at every level.. takes longer ,but the results
should be as good or better as the focus is also tight at all levels and power requiirements are much lower, Ive done them in pine at 5 watts.
 It does require a Z table motion though..

  I have tested acrylic, it also works there, but I dont have a good example to show as I find they need to be quite deep
to be photographed well. Here is an early test though in plexiglass...

Art
Title: Re: The Laser Project.
Post by: Dan13 on April 18, 2016, 03:46:11 PM
Interesting to follow your investigation in this field.

Dan
Title: Re: The Laser Project.
Post by: PicengraverToo on April 19, 2016, 11:45:39 AM
Here is a 3D engraving we did in Poplar using a 3W 445nm Laser Diode with an Air Assist.
Title: Re: The Laser Project.
Post by: Dan13 on April 19, 2016, 01:17:26 PM
Wow! That' impressive. The depth looks substantial. Could you post a snippet of the Gcode you used to do this? I am curious how it's done.

Hard to judge on the quality from the photos, but looks as though it beats any attempt to 3D engrave with a conventional bit in terms of speed and detail level...

Dan
Title: Re: The Laser Project.
Post by: PicengraverToo on April 19, 2016, 01:45:00 PM
Thanks Dan,

The Z axis commands control the laser power and the variable feedrate slows in the higher laser power (darker) areas to cut deeper.

This is not a fast engraving process by no means. It's only a 3W Laser Diode, but the focal point is around .005" so it does get fairly good detail.

The depth of cut was a little over 1/8". This is not from the exact gcode file to make it, but you will get the idea.

X2.511 Y1.048 Z-0.0138 F47.5
X2.518 Y1.055 Z-0.0143 F46.4
X2.525 Y1.062 Z-0.0139 F47.3
X2.532 Y1.069 Z-0.0132 F48.9
X2.539 Y1.076 Z-0.0187 F36
X2.546 Y1.083 Z-0.0240 F23.5
X2.553 Y1.09 Z-0.0239 F23.8
X2.56 Y1.097 Z-0.0221 F28
X2.567 Y1.104 Z-0.0214 F29.6
X2.574 Y1.111 Z-0.0217 F28.9
X2.581 Y1.118 Z-0.0217 F28.9
X2.588 Y1.125 Z-0.0216 F29.2
X2.595 Y1.132 Z-0.0222 F27.8
X2.602 Y1.139 Z-0.0216 F29.2
X2.609 Y1.146 Z-0.0208 F31.1
X2.616 Y1.153 Z-0.0199 F33.2
X2.623 Y1.16 Z-0.0199 F33.2
X2.63 Y1.167 Z-0.0199 F33.2
X2.637 Y1.174 Z-0.0197 F33.6
X2.644 Y1.181 Z-0.0191 F35.1
X2.651 Y1.188 Z-0.0190 F35.3
X2.658 Y1.195 Z-0.0194 F34.4
X2.665 Y1.202 Z-0.0191 F35.1
X2.672 Y1.209 Z-0.0192 F34.8
X2.679 Y1.216 Z-0.0191 F35.1
X2.686 Y1.223 Z-0.0191 F35.1
X2.693 Y1.23 Z-0.0191 F35.1
X2.7 Y1.237 Z-0.0192 F34.8
X2.707 Y1.244 Z-0.0191 F35.1
X2.714 Y1.251 Z-0.0191 F35.1
X2.721 Y1.258 Z-0.0191 F35.1
X2.728 Y1.265 Z-0.0192 F34.8
X2.735 Y1.272 Z-0.0191 F35.1
X2.742 Y1.279 Z-0.0191 F35.1
X2.749 Y1.286 Z-0.0192 F34.8
X2.756 Y1.293 Z-0.0195 F34.1
X2.763 Y1.3 Z-0.0198 F33.4
Title: Re: The Laser Project.
Post by: Dan13 on April 20, 2016, 10:21:26 AM
Hi John,

So you control both the feedrate and the Z depth... but why do you need them both? And how do you correlate/sync them? Isn't it easier having just one parameter to control?

Are you using your PicEngrave software for the Gcode?

Dan
Title: Re: The Laser Project.
Post by: PicengraverToo on April 20, 2016, 01:29:45 PM
Hi Dan,

Yes, we control both the feedrate & the laser power and you can set them independent from each other. The variable feed rate is done by a set percentage of the full feedrate based on the laser power values. It helps using both because you can expand the cutting depth range based on the shades in the image. Lighter shades has less burning power and speeds up the feedrate to cut shallower, where darker shades burn with more laser power and slow down the feed rate to cut deeper. A Depth Map image is being used. It's also possible to have the Z axis move the laser's focal point down into the deeper cut areas, use a A,B or C axis command to control the laser power and have a variable feed rate on each line of gcode also. 

Yes, PicEngrave is being used to generate the gcode for our 3D laser diode engraving.

Here is another example in Poplar and it's about the same max depth of cut.

Jeff

   
Title: Re: The Laser Project.
Post by: Dan13 on April 21, 2016, 01:35:22 AM
Jeff,

So the Z axis commands do actually move the Z? I got the opposite impression from your previous post where you said they were controlling the power of the laser.

Still don't get it - why you can't control just the feedrate and have the same effect. Is there not enough resolution/range for the feedrate?!

Thanks for the photo, I really like the results you're getting.

Dan
Title: Re: The Laser Project.
Post by: PicengraverToo on April 21, 2016, 07:34:38 AM
Dan,

There are many ways to setup your machine for this process.

A US Digital MA3 shaft encoder for analog or PWM laser modulation timing belted to the Z axis stepper would allow the Z axis down movement and laser modulation at the same time, but they would be synchronized together. A variable feedrate can be used also.

Or, you can use a switch for different stepper motors. Set the Z axis focal height, then switch to the MA3 stepper to control the laser modulation with Z axis commands. A variable feedrate can be used also.

Or, you can use a DAC or a MA3 as a 4th axis. Z axis down movement commands & A,B or C axis laser modulation commands can be set independently, but still on the same line of gcode. You can also vary the feedrate.

There are other options and somewhat similar, but they are out of Mach3's ability. It consists of using X, Y axis moves and then S commands for the laser's modulation. A variable feedrate can be used with it also.

You can try just using a variable feedrate, but by using both variable laser power and variable feedrate combined together, it gives you more control of the outcome as you can see in my examples.

Jeff
Title: Re: The Laser Project.
Post by: Dan13 on April 21, 2016, 08:59:08 AM
Thanks for explaining it, Jeff.

Dan
Title: Re: The Laser Project.
Post by: ART on April 21, 2016, 03:55:17 PM
Jeff:

    Thx for the photo's, they really are great engravings. I hadn't thought of adjusting feedrate, Ill add that to the PWM to see if perhaps using all 3, feedrate, PWM and
Z height will produce better.

Art


Title: Re: The Laser Project.
Post by: PicengraverToo on April 21, 2016, 06:54:28 PM
Thanks Art,

I'm sure it's allot easier to tame a 3W laser diode, then a CO2. :-)

Jeff
Title: Re: The Laser Project.
Post by: Honlarneau on June 20, 2016, 08:16:23 AM
When using the Impact / Laser Engraving plugin, I have found that the initial preparation of the image or photo is key to success. A free program which has just come to my attention is FotoSketcher by David Thoiron. http://www.fotosketcher.com/download.htm
(When installing use the advanced options unless you want to install the unwanted toolbars etc or else download the portable version).
This program is capable of producing some quite stunning results and in some ways can be better than the Photochop plugin I have been using to date.

Tweakie.

To prepare photos well, another photo post processing goodware is image filter editor (http://www.watermark-software.com/photo-filter-fingertips.html), which supports fast adding photo protections as well as well editing.

(http://www.watermark-software.com/imgs-style2016/photo-filter-fingertips/photo-filter-fingertips-4.jpg)


Title: Re: The Laser Project.
Post by: DeserEagle on April 09, 2017, 07:08:27 AM
Hey. Greeting from far away! I'm from Belarus from the city of Minsk.
Sorry for my bad English. I use google translator.
For half a year I have been studying the theme of a solid-state laser. I did a lot of experiments and achieved good results. I have a channel on youtube. There is a video about my progress. I can post a link to the video only with your permission. You're the master here) I read almost all of the 97 pages of this topic - using an interpreter. I even began to understand the humor on the forum) Your projects are everywhere) Everything is pretty well written! Thank you for your work.

Closer to the point)

a)
I managed with your help to run the plugin Engraving DLL v1.2s - works fine. Thank you ! But there was a problem. Laser power adjustment is required, and in this plug-in this is not possible. I need laser engraving on natural skin. And there it is necessary to regulate the depth of the burn. Moreover, the plugin does not behave correctly on my machine. It makes a move to the right, then immediately to the left, and then a pause of about 500 milliseconds. This greatly slows down processing. What G code is used in the plugin - I have not found it anywhere. Therefore, I can not edit it. I realized that the principle is based on changing the pulse frequency of 40 microseconds in length. Do you have a G code from the plugin for example? To understand his work?
I tried changing the processing speed and accuracy to 0.1 millimeter. But this is not enough.

B)
I tried to create my G code with DotG v0631. I tried to manually adjust the laser power. This also did not work ... I still did not understand how to check whether my Mac3 sees the commands M11P1 and M10 P1.

I have version Mach3 R3.043.066 - it is higher than version Mach3 R3.043.056. So these teams should work. But this does not happen - my homemade CNC machine runs in jerks - which was not the case with Plug Engraving. Here is an example of my code:

(- DotG program -)
(X = 0 to 160 Y = 0 to 100)

G17 G21 G40
G80 G90 G94
F1000
M10P1 b0
G0 X0 Y0


G0 X151 Y5.25
M11P1 b1
 
G1 X150.75 F1000

M10P1 b0

G0 X151.25 Y5.5
M11P1 b1

Is it correct? My machine brakes at each of these points.
How can I check whether the M10P1 and M11P1 commands work?
How to create a normal code with M10P1 / M11P1 commands?

at)
Of course I want the best of options. To control the laser power at each point of burning. I read a lot of your articles. And I saw that you use command C *** for power adjustment where S0 is 0% power, and S1000 (or S100) is 100% power.
But as soon as I add the S *** command - the CNC machine starts working slowly at once.
It's strange why this does not happen when working with a palagin.
What does your G code look like? Show me your example.

Conclusion. The plugin works fine, but there is no power adjustment and pauses in 500 microseconds. M10P1 b0 and M11P1 b1 I think they do not work for me. The control of the spindle command (PWM) slows down the machine.

You would have helped me a lot.
Thanks for the help !
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 09, 2017, 09:06:18 AM
Hi Desert Eagle,

Welcome to the forum.

DotG was originally intended for impact engraving so the actual ‘dot’ is produced when the X axis is stationary. The axis motion is basically stop – start.  To enable DotG operation with a laser then a dummy axis (axis B) was used to trigger the M10/M11 commands. This article attempts to explain the M10/M11 commands and how axis movement (any axis) is necessary for their operation.  http://hobbycncart.com/publ/cikkek/mach3_temaju_cikkek/switching_a_laser_under_mach_control/8-1-0-29 (http://hobbycncart.com/publ/cikkek/mach3_temaju_cikkek/switching_a_laser_under_mach_control/8-1-0-29)

Mach3 version .066 may not be the best version for you to be using. The overall opinion of the forum is that version .062 is best. ftp://anonymous:guest@ftp.machsupport.com/Mach3/Mach3Version3.043.062.exe (ftp://anonymous:guest@ftp.machsupport.com/Mach3/Mach3Version3.043.062.exe)

The plugin delay, after the movement to the left, is something I have been meaning to correct but, like so many other things, it never happened – perhaps one day I will do it. You can make a reduction in this delay by operating the plugin in constant velocity mode.
The plugin writes directly to the Mach3 engine so no separate Gcode is available for viewing or editing.
The plugin uses a constant 40uS pulse width (this does not change) it is total number of pulses per pixel (determined by the pixel value) which regulates the laser power or burn.

Hope this helps.

Tweakie.
Title: Re: The Laser Project.
Post by: DeserEagle on April 10, 2017, 01:20:34 PM
Thanks for the nice reception on the forum!
Thanks for the link to Mach3Version3.043.062. I was looking for an older version with respect to .066, but I did not find it. Soon I'll try it in action.

By plugin. I have a fixed speed. But this does not take away the delay.
The plugin program is good.
It's a pity there is no tuning of the power of burning.

But with control via the virtual axis B nothing happened.
More precisely, the virtual axis itself works. But the CNC machine still works jerky.
The article you dumped - I also read and translated.
But I do not really understand how the virtual B axis changes something.
It seems to me that DotG does not correctly calculate the X axis movement.
Maybe you have an example of a working code - which works fine without jerking. I can try it for myself. True, I have a limited desktop size of 200x450 millimeters.

Thank you in advance.) Nikolaj
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 11, 2017, 01:18:34 AM
Hi Nikolaj,

The DotG X axis motion is 'stop-start' so, in operation, it will be 'jerky'. This can, top some extent, be reduced by selecting a suitable feed-rate / Acceleration.
The 'virtual B axis' movement is necessary to trigger the M10 / M11 commands whilst the X axis is stationary (the M10 / M11 commands will only take effect at the instant of an axis movement).

Hope this helps.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 12, 2017, 02:34:05 AM
Hi Tweakie,
I think it was here that I saw someone who used the Z motor coupled to an encoder to do analogue control of a laser power. Wanted to review his work and try to implement this idea for impact engraving. Do you remember who it was and do you have some reference?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 12, 2017, 03:04:38 AM
Hi Dan,

It was Jeff (Picengravertoo) and he now resides here https://www.picengrave.com/forum/

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 12, 2017, 03:45:47 AM
Thanks Tweakie!

Got a link to his work with the encoder?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 12, 2017, 05:18:30 AM
Hi Dan,

Not that I can remember but I think all the information is in these two threads somewhere if you have the time to browse. Maybe quicker to ask Jeff directly on the previous mentioned forum though.


http://hobbycncart.com/forum/63-151-1
http://hobbycncart.com/forum/63-236-1


Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 12, 2017, 05:34:44 AM
Thanks Tweakie!

Dan
Title: Re: The Laser Project.
Post by: DeserEagle on April 13, 2017, 03:21:07 AM
Hi Nikolaj,

The DotG X axis motion is 'stop-start' so, in operation, it will be 'jerky'. This can, top some extent, be reduced by selecting a suitable feed-rate / Acceleration.
The 'virtual B axis' movement is necessary to trigger the M10 / M11 commands whilst the X axis is stationary (the M10 / M11 commands will only take effect at the instant of an axis movement).

Hope this helps.

Tweakie.


Hey. Tweaks.
Now I understand why these commands are used.
Their task is to turn on and off when the X axis is not moving.

But I do not have a solution at the moment.
Dotzh is not suitable for preparing the G code even with postprocess for M11P and M10P commands.

I've tried many other programs to prepare G-code. I even tried the program for burning with the filament of CHPU. But nothing happened.

Is there a program that prepares G - with M11P and M10P - without jerks?
Paid? Free use? Maybe an article about her is somewhere on the forum?

But still I have a little progress, I used the program ArtCAM 2008 to get G code for engraving. The essence of using a small movement of the Z axis - which can be replaced by the virtual B axis and even in pair with the M11n / M10P command. It works, but not as qualitatively as a plugin.
I still have not figured out how to correctly replace the data from the Z-axis with data with the M111 / D1 / M10n1 command.

Can you tell me? Help?

I will attach the successful G code to the message.

https://drive.google.com/drive/folders/0B2Yl5soaDkgmUDJpZDNoWUhXcm8?usp=sharing (https://drive.google.com/drive/folders/0B2Yl5soaDkgmUDJpZDNoWUhXcm8?usp=sharing)

Spare link to google disk:
https://drive.google.com/drive/folders/0B2Yl5soaDkgmUDJpZDNoWUhXcm8?usp=sharing

Sorry, I could not attach the file directly)
Language barrier) I think you understand me.

And by the way, here is my e-mail number deserteagle3113@gmail.com

Thanks for the help.

Nikolaj.
Title: Re: The Laser Project.
Post by: Dan13 on April 13, 2017, 05:10:14 AM
Hi Nikolaj,

Did you check PicEngrave at www.picengrave.com ?
It may do what you want. It does have the option of variable feedrate, but not sure about the M10/M11. Haven't used it for a long time, but I am sure Tweakie will soon chime in and give you a better reply.

Dan
Title: Re: The Laser Project.
Post by: Dan13 on April 17, 2017, 05:49:08 AM
Hi Tweakie,

From the link you referred to above:
http://hobbycncart.com/forum/63-151-1

Your post #2 you mention a video with a constant 50Hz engraver. What video are you talking about? Do you have a link? Is it a CNC with constant frequency engraver? What would the Gcode look like?

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 17, 2017, 06:20:32 AM
Hi Dan,

Sorry, but that was a few years ago and so much has happened since I just can’t remember it’s content.
The video will still be lurking on the forum somewhere – I initially transferred a number of discussions from the Hungarian areas to start the English section and obviously the link to that video didn’t follow. I will see if I can track it down but don’t hold out too much hope as it may remain illusive.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on April 17, 2017, 06:39:45 AM
OK, thanks Tweakie. Would be interesting to see if you find it.

Dan
Title: Re: The Laser Project.
Post by: DeserEagle on April 17, 2017, 12:33:26 PM
Hi Nikolaj,

Did you check PicEngrave at www.picengrave.com ?
It may do what you want. It does have the option of variable feedrate, but not sure about the M10/M11. Haven't used it for a long time, but I am sure Tweakie will soon chime in and give you a better reply.

Dan

Thank you ! I looked at your link. There is no trial version of the program. I'm afraid to pay for what might not work with my laser ...
I do not know what to do.
Tweak did not answer me.

E-mail number deserteagle3113@gmail.com
Tweakie for the help.
Nikolaj.
Title: Re: The Laser Project.
Post by: Dan13 on April 17, 2017, 01:22:33 PM
Did you try to download and install it? I think it will allow you to play with it without a licence, but will put watermarks on your image.

Dan
Title: Re: The Laser Project.
Post by: DeserEagle on April 17, 2017, 03:50:03 PM
Did you try to download and install it? I think it will allow you to play with it without a licence, but will put watermarks on your image.

Dan

http://prntscr.com/exkn5o

There are watermarks.
But when I try to press the launch, a window for entering the key pops up.
I can not try.
I can only buy and use immediately.
Maybe I'm doing something wrong?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 18, 2017, 01:44:30 AM
Hi Nikolaj,

PicLaser demo version can be downloaded from here http://www.piclaser.com/
Try it to see if it meets your needs.

Tweakie.
Title: Re: The Laser Project.
Post by: PicengraverToo on April 18, 2017, 06:12:15 AM
Did you try to download and install it? I think it will allow you to play with it without a licence, but will put watermarks on your image.

Dan

http://prntscr.com/exkn5o

There are watermarks.
But when I try to press the launch, a window for entering the key pops up.
I can not try.
I can only buy and use immediately.
Maybe I'm doing something wrong?

After loading an image, select the Tutorial PDF button for instructions.

Dan,

The Encoder information is in the PicEngrave Pro 5 Help PDF.

Jeff
Title: Re: The Laser Project.
Post by: DeserEagle on April 20, 2017, 09:04:00 AM
Hello everybody. Thanks for the links and help.
Two days of experiments gave nothing.
Picengrave PRO5 works so dramatically that my machine almost fell apart.
With the configuration and instructions, I figured out - after loading in MACH 3 the machine trembles tremendously.
Dotg - it turns out to be not so bad. He works abruptly, but engraves.
Maybe I have with the settings of parameters Mach 3 that something is wrong?
How to properly adjust the laser for the laser?

Its settings attached.

https://drive.google.com/drive/folders/0B2Yl5soaDkgmU0kzRUY2SXF2aVU?usp=sharing

Thank you !
Title: Re: The Laser Project.
Post by: DeserEagle on April 20, 2017, 09:13:20 AM
Hi Nikolaj,

PicLaser demo version can be downloaded from here http://www.piclaser.com/
Try it to see if it meets your needs.

Tweakie.


Hello everybody. Thanks for the links and help.
Two days of experiments gave nothing.

Tweakie -  i found such a photo.  http://prntscr.com/eypaj9      Where can I get a postprocessor with that name   "Tweake M10-M11.dgp"   for Dotg?
Title: Re: The Laser Project.
Post by: DeserEagle on April 20, 2017, 09:25:46 AM
https://drive.google.com/file/d/0B2Yl5soaDkgmdzd2MUVOWHdsTlE/view?usp=sharing
https://drive.google.com/file/d/0B2Yl5soaDkgmLXJwYm05ODdDZ3c/view?usp=sharing

Here's a video of how the machine shakes:
Title: Re: The Laser Project.
Post by: PicengraverToo on April 22, 2017, 08:22:48 AM
Try selecting Insert G61/G64.

This is not the place for product support. Use the Contact & Links page on our web site.

Thanks.
Jeff
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 18, 2017, 04:38:36 AM
I needed to engrave a number of assembled parts which were too deep to fit beneath my laser nozzle. The solution would be a time consuming disassembly and re-assembly of the items or modification to my laser lens system.
As the combined mirror / lens assemblies (usually fitted to the commercial laser machines) are cheap to buy (from China) I decided to give it a try. Making a small bracket to fit the new mirror / lens assembly to the machine (in place of the existing lens assembly) replacing my vertical laser beam with a horizontal laser beam and creating a new Mach3 profile to swap the Z axis with the Y axis everything worked beautifully.
There are safety issues with having a horizontal laser beam on an open frame machine and I have not yet worked out the best / most foolproof solution but I am working on it.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 18, 2017, 07:37:38 AM
Nice work Tweak.  Safety issues aside, its not a bad solution to that problem.  Parts are indeed quite reasonable these days.

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 18, 2017, 08:09:21 AM
Thanks Art.

I used a GaAs meniscus lens in this attachment (first time I have used one) and I must say that I am really impressed with the tiny dot size that it can produce.
Now to change out my other GaAs Plano-convex for a meniscus.  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 18, 2017, 08:28:39 AM
Really? Ill have to try that.. smaller the better...

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on September 12, 2017, 05:38:41 AM
Something that may be of interest to others…

Mach4 has the commands M62P# and M63P# (where the # denotes the Output# number) which both only operate, or take effect, consistent with an axis movement.
So the Gcode…
M62P1 would turn on Output #1 at the instant of an axis movement and M63P1 would turn off Output#1 again, at the instant of an axis movement.

As of Build 210 the Ethernet Smooth Stepper plugin allows for multiple instances of the M62/M63 commands to be stacked and operated jointly upon an axis (any axis) movement.
So please consider the following snippet of Gcode…
G21 F4500
M62P1
M62P2
M63P3
M62P4
M62P5
M62P6
M63P7
M62P8
G1 X0.001
%
At the instant the X axis moves the Outputs# 1 to 8 would contain the binary data 1 1 0 1 1 1 0 1 (assuming you are reading the bits from the same direction as me). Obviously any combination could be set from 00000000 to 11111111.

The interesting part, and the point of all this, is that Outputs# 1 to 8 could be interrogated by a simple controller (to convert the bit pattern to an 8 bit decimal value from 0 to 255) which could then be used to control / vary laser output power from within Gcode which is running at constant velocity.
It is basically a way to output 8 bit numbers from within a running Gcode and having no noticeable effect on Axis Velocity or breaking the constant velocity chain.

I have not fully tried this yet but it could offer a considerable reduction in the process time when laser engraving 8 bit images (currently using the S### command to control / vary laser output power).

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on September 13, 2017, 09:27:14 AM
Interesting! Writing a postprocessore for one of the program out there, doesn't seem fun though ;)

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on October 07, 2017, 07:06:14 AM
The making of this was mentioned in another Topic but for those following this thread…

A wall hanging picture, laser engraved into 20 mm thick Birch plywood using the ‘old-faithful’ Mach3 Impact / Laser Engraving plugin.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on December 13, 2017, 08:15:29 AM
Something for others who may be interested in halftone techniques…

SquiggleDraw (https://github.com/gwygonik/SquiggleDraw) is an App. which runs inside Processing (https://processing.org/). It is quite easy to set-up and use and it produces an .svg image which can be converted to Gcode within Inkscape (https://inkscape.org/en/) or other vector software such as Aspire9 (http://www.vectric.com/products/aspire.html) .

Here is an .svg generated image converted to .dxf (http://ul.to/vo1uiw3x)
 and the associated Mach3 Laser toolpath (http://ul.to/gqg1inuc)
 

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 10, 2018, 05:19:40 AM
Over the years this thread has been running I have been contacted by many users of the K40 Laser Cutter / Engraver. They do not use Mach3 or are even likely to use it in the future but they have come here to gain knowledge and information. Because I am happy that the following software is not in any way in competition with Mach I have posted this information as it may be of interest to followers of the thread.

I am a great admirer of Scorch and his excellent software solutions. He was the first to enable free V-Carving for CNC routers and now he is setting the standards for free K40 compatible laser software.

K40 Whisperer is an alternative to the Laser Draw (LaserDRW) program that comes with the cheap Chinese laser cutters available on E-Bay and Amazon. K40 Whisperer reads SVG and DXF files, interprets the data and sends commands to the K40 controller to move the laser head and control the laser accordingly. K40 Whisperer does not require a USB key (dongle) to function. K40 Whisperer also handles Gcode files.

K40 Whisperer is a free open source program released under the GNU General Public License (GPL).

http://www.scorchworks.com/K40whisperer/k40whisperer.html (http://www.scorchworks.com/K40whisperer/k40whisperer.html)

Tweakie.


Title: Re: The Laser Project.
Post by: ART on January 10, 2018, 07:40:55 AM
Thanks Tweaky:

   I wasnt aware software existed that uses the LaserDRW protocol. Nice to know. Also handy to have archived so
K40 users have some options.

Art
Title: Re: The Laser Project.
Post by: ART on January 10, 2018, 07:43:52 AM
 
Tweaky:

 >>Because I am happy that the following software is not in any way in competition with Mach

 Theres never any problem if you wish to discuss competition to Mach3, While Im proud to have written
it I have no proprietary interest in Mach3, so its just one of many options available these days. On this board nothing
is really off topic for discussion.  Im always interested in hearing the various options available to folks.

:)
Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 11, 2018, 05:07:36 AM
With Art’s permission…

For many years now I have successfully used Art’s Mach3 Impact / Laser engraving plugin for CO2 laser engraving 8 bit photographic images onto wood (and other materials). Unfortunately, due to the nature of the pulse timing this plugin will only operate via the PC’s Parallel Port, which is rapidly becoming obsolete, so an alternative was desperately needed.

Art never seems to tire of software development and along with a small handful of others I have recently been trying out ‘Auggie’. This FREE software started as an extension of Gearotic Motion but now stands in it’s own right. It is a very basic (trimmed down) CNC solution which incorporates the beautiful ‘S-Curve’ acceleration / deceleration of the Tempest planner (which really should have been incorporated into Mach3 but never was) and it has been designed around the 57CNC USB and Ethernet CNC controller.

Although Auggie would be equally at home with basic CNC milling, routing, etc. it has some advanced features designed specifically for laser use and it can support RF, DC, Diode and most other types of lasers. It does not stop there as Auggie has many more interesting features which, for the most part, are described here;  http://gear2motion.com/auggie (http://gear2motion.com/auggie)

For me, the most important thing about Auggie is that it has the ability to process 8 bit photographic images and although it is a very different process to the old plugin the final results appear very similar. I am still working on how to get the best results with an electromagnet but Auggie can also be used for Impact Electromagnet operation.

In the following pics, one was produced with my CO2 laser and the other with my impact electromagnet.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on January 11, 2018, 08:07:16 AM
Tweaky:

  lol, you know, when I wrote Mach3, it was the result of wanting something personally to
engrave photos. The responce was so overwhelming I ended up making very few photos's over
the intervening years as Mach was built up. Ive learned to live vicariously through the
artistry of others. :)
 
  So it pleases me no end to see your success with it, your photos are definitely better than any
Ive output.

  Keep up the great photo work, nice to see impact is coming along and that Auggie can at
least get you started with experimenting in it..

Art

 
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 12, 2018, 02:48:33 AM
Thanks Art for the kind words. I thought my post would make you smile.  ;)

Back in the day, I started out with Mach2 then moved on to Mach3 – although I have Mach4 set-up and ready to go (using the Warp9 ESS) I am now having my doubts that I will ever use it for any serious work. Currently, Mach3 still rules. Somehow, I need to get more free time so I can get stuck into learning the protocol and application of Auggie scripting then who knows the direction of the future.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on January 12, 2018, 08:17:50 AM
Tweakie:

   I see Mach3 as the hobbyist package ( I use M3 on my workshop router still.), I have M4 setup for testing,
but I dont run it much as its pretty pure on its own, its a pro level no nonsense CNC controller.Doesnt need much
help from someone like myself.
     Auggie is for experimentation and easy access to hardware not typically supported
like a laser, and so will suit the very few of us who like to work at a lower level of access to hardware.
  Its from such things that idea get developed though, and it wouldn't surprise me if someday packages like
Mach4 support PWM as an output.  When it does its because of things like Auggie and persons like you who
play and do such nice work. I see the ESS has added PWM, so with the Pokeys and ESS now having a pwm option
it may just be a matter of time till the more pro end of software supports it, and thus more controllers. Its a circular
loop of chicken and egg.  The ability to control a PWM signal from the position within a data set virtual to the
tool location is something thats handy in a few area's, not just lasers.

{
( My suggestion for the archive..in case the M4 writers read this :)  )

  I think all CNC controllers should have some sort of command that attaches a datafile to a pwm signal with a
rectangular dimension settings. Like Attach( "Mydata.dat, XSize,YSize, BYTE_COLOR); The PWM would then reflect
at all G1 moves the value within that file (0-100%)  based on type of data,in this case 3 byte color data. 

}

  I always found if you offer it, people will adopt it if its a good idea. As you've mentioned before, the engraving plugin
at first was greeted with a yawn when I wrote it, but over time its been popular with a lot of people judging by the
size of this thread.

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 13, 2018, 04:21:30 AM
Hi Art,

I still get many emails and questions about the original plugin and 8 bit image reproduction (from folks all over the world).
Although the plugin is easy enough to use it is not always that easy to achieve good results. The overall set-up is perhaps a bit too complex.
On the other hand, with Auggie (and of course the 57CNC) it is very easy to get good 8 bit image results first time.
I agree, the M3 enable then ON with feed-rate moves and OFF with rapid moves combined with a system to allow changes in the PWM duty cycle without breaking the CV chain is definitely the way forward. I think this method of control is by far the simplest and as you have said, would equally apply to many different systems, not just laser.

Tweakie.


Title: Re: The Laser Project.
Post by: Dan13 on January 14, 2018, 07:44:30 AM
Very nice photos you engrave there Tweakie!

I have a 15W Chinese laser diode machine (450nm), but can't engrave any photos on wood. The laser mainly curves the wood, but not burns it to different shades of gray. Only have ever tried soft wood (pine), could be that on harder wood it would work better, I don't know.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 14, 2018, 08:32:42 AM
Hi Dan,

I don't really know if hard woods perform better or not, certainly a lack of the hard growth rings (often found in pine) is preferable. I think you just have to try different woods and see.

Just thinking out loud...
The original Mach3 plugin was only able to provide a maximum 50% pulse duty cycle so lower powered lasers could struggle to achieve the best results. Auggie has adjustable PWM pulse duty cycle (0% to 100%) so I am confident that good results could be achieved with as small as a 150 mW diode laser (although feed-rate may be painfully slow).

As we have already said Auggie is free software but it requires the 57CNC which incidentally is also an excellent motion controller for use with Mach4.

Tweakie.

Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 14, 2018, 08:45:33 AM
Hi Dan,

If it helps...
I know nothing about wood but as a comparison, the image in post #1001 is on plywood which was purchased as Birch Ply and the image in post #1003 in on what Ger21 suspects is Beech.

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on January 14, 2018, 11:24:47 AM
Hi Tweakie,

Just tried on some plywood and at least got something that looked like the original photo. But it's still far from the work you do. I am getting the feeling that the more denser the wood and the finer the surface, the better result you'll be getting.

Dan
Title: Re: The Laser Project.
Post by: ART on January 14, 2018, 01:15:35 PM
Hi Dan:

  I find its wood and focus. Being in focus sometimes hurts you, sometimes helps. Try just a bit off focus to try to
create a grey scale effect from power... In focus sometimes can just remove wood cleanly with no burn..

Art
Title: Re: The Laser Project.
Post by: Dan13 on January 15, 2018, 02:54:36 AM
Hi Art,

That's an interesting suggestion. Thanks. I didn't think that way. Will experiment with this.

Dan
Title: Re: The Laser Project.
Post by: Dan13 on January 18, 2018, 07:10:27 AM
Tried to adjust the laser out of focus slightly. Can't say that it helped to produce more shades of grey. If find that trying to engrave a photo on wood is inconsistent and since the wood is not uniform I usually see different tones for shades that had to be the same. The darker shades work better the lighter usually are not seen at all. Increasing power burns the dark spots too deep.

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on January 18, 2018, 08:22:59 AM
Hi Dan,

Hopefully third time lucky trying to attach everything to this post. :)

The .zip file has my .aug and .tap files for this image that I have engraved onto Birch ply. Please try it and see if you can get similar results.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on January 18, 2018, 08:38:00 AM
Hi Dan:

 Variations caused by wood grain are usually desirable as they identify the wood its on. Your problem may be more
related to absorption profile. UV lasers dont work the best on organic matter. The higher the frequency
or shorter the wavelength of a laser the less it is used for organics, and more for marking metal.
  CO2 and Yag ( either end of the infra red spectrum) are easily absorbed by organic matter like wood ( or skin
or corneas) while UV  absorbs differently than the others. For example if you hit your
eye with a CO2, its probably fixable as the burn occurs on the outside of the eyeball, whereas UV will go
through the first layesr and damage the retina at the back of your eyeball, and may not be fixable.

   So while UV will burn wood, its a smaller portion of the energy that's doing the burning. Its why UV is used more for
engraving a photo on metal than wood, and you may find the photo looks better on an aluminum plate or metal
surface of some kind, though grey scale may suffer as that's a property of the surface material.

  UV lasers also suffer from optics, an LED isnt easy to focus to a tight focal spot, the optics are difficult
so the typical lower end laser dont have great optics on them usually. This can limit its ability to get sharp
results. You may want to try on a white painted surface and finding the power levels that best produce a
grey scale. Paint tends to darken on a more linear scale.

   If your using Auggie, in its config there is a setting of minimum power and max power. Setting that properly, by setting
minimum to the level at which you begin to see burn, and max to the power where its dark enough will allow Auggie
to create a grey scale that's best for that laser as it will scale power to between those two levels.

  I'm sure a UV can do photos, but I suspect you need to treat the wood with something that assists the absorption
like a resin or paint ( wood conditioner maybe), then using the proper power range should allow a grey scale.

  I don't use UV yet, I'm all CO2 here, so I'm no expert on such matters, but all this may give you some things
to consider. I'm just hooking up my third CO2 laser now ( I have a 10w and a 40w, I'm adding a 48w)
 and building a new cabinet for it, so Ill be playing more with photos myself in the future,
though I'm more interested in cutting paper with my new one, than burning it.
    :)

Art



Title: Re: The Laser Project.
Post by: ART on January 18, 2018, 08:38:55 AM
Nice photo Tweakie. :)
Title: Re: The Laser Project.
Post by: Dan13 on January 18, 2018, 09:06:19 AM
Thanks. That was my guess too regrading the wavelength. It's not UV here, but just violet at 450nm.

I am using the software that came with the laser. The controller doesn't seem to work with any other sowftare. It either does photo or accepts Gcode. But the way it uses Gcode is not common to all others - on G1 moves the laser turns ON and on G0 it turns OFF. This is the only way to switch the laser on and off from within Gcode. I will look into the gcode you sent Tweakie and see if it I can adapt it.

Dan
Title: Re: The Laser Project.
Post by: ART on January 18, 2018, 10:06:11 AM
>>on G1 moves the laser turns ON and on G0 it turns OFF.

  Auggie works the same. It saves a lot of switching statements and I find it preferable
to other types of control statements. As your probably ocked into a set power range for a photo
unless you can set the power level range, you may want to experiment with various treatments to
the material to perhaps get a better range.

Art
Title: Re: The Laser Project.
Post by: Dan13 on January 19, 2018, 06:33:51 AM
That's good to know Art. I have never used Auggie. Have had Gearotic since its first days, but never got to see what Auggie was all about.

Tweakie, I cannot understand the Gcode you attached. There doesn't seem to be any laser control commands, just G1 moves side to side. No G0's or anything.. either I am missing something in the way you control your laser, or it is the wring file.

Dan
Title: Re: The Laser Project.
Post by: ART on January 19, 2018, 07:46:45 AM
Dan:

>>There doesn't seem to be any laser control commands, just G1 moves side to side.

  Its because the Gcode loads an Augment file at the start and that sets photo mode.

   Thats standard GCode for Auggies Photo engraving setup. The laser in Auggie's photo
mode only turns on in G1 mode moves AND only when the x,y position is in the extents
of a loaded photo. This allows one to accelerate toward the photo with burning starting
automatically as the laser enters the photo and stopping as it leaves. This allows for constant speed
photo engraving which smooths out any aberrations caused by accel and decel of the laser head.
  Since power and speed are semi-linearly related in laser cnc, having a constant velocity can
help when burning a photo. Although in general use Auggie will vary the power as a linear function
of actual velocity, the correction is not quite linear enough on most lasers for photos, so for photos
we do this acceleration rejection method to make them clearer.

Art


Title: Re: The Laser Project.
Post by: Dan13 on January 19, 2018, 08:14:46 AM
I see. Pretty neat. But afraid I will not be able to use it. My laser has a USB dongle which does the communication between the machine and PC. So can only use their supplied software. Which would accept Gcode file as input or images.

Dan
Title: Re: The Laser Project.
Post by: ART on January 19, 2018, 08:41:42 AM
 Yup, typical problem. Best to just keep playing with material and such to find one that gives a
good grey scale on your machine, then photos shoudl start to look better.

Art
Title: Re: The Laser Project.
Post by: Spandex on February 13, 2018, 05:18:44 PM
This may be a stupid question, but why was the laser attached in such a way as to require all the complex juggling of mirrors? Why not just stick it down like the spindle?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 01:35:47 AM
Not a stupid question at all.

Mounting a CO2 laser tube vertically does work and many have done it but it's life expectancy is considerably reduced.

Unlike diode lasers the CO2 lasers produce a certain amount of detritus during operation (some from the gasses but mostly from the electrodes). If the tubes were mounted vertically this waste material would settle on to the output coupler, burning-in, cause overheating of this component and ultimately lead to the early failure of the tube.

Various tube manufacturer's (such as Synrad) withdraw their warranty if their tubes are mounted beyond a defined angle to the horizontal.

Tweakie.


Title: Re: The Laser Project.
Post by: Spandex on February 14, 2018, 03:56:11 AM
I see thanks.
Title: Re: The Laser Project.
Post by: Spandex on February 14, 2018, 04:33:38 AM
Hmm it looks like you can't modify posts. Just wondering what laser you would suggest? I'm only at the stage of reading about the two types, diode and carbon dioxide. I'm reading diodes are dangerous to your eyes and I'm not sure why but apparently the carbon dioxide varieties are much more commonly used.

Given that you've got some experience using your laser and it looks like you've even replaced it once already, do you have any suggestions on which one to get? I'm looking into hot rodding my CNC machine just like you did but recommendations would be much appreciated.

P.S. Found the post modification button, I'm guessing it gets locked out after a time limit.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 05:27:35 AM
Because the wavelength of the laser beam is different between CO2 and Diode lasers the effect of a minor, accidental, exposure to the eyes is also different. A CO2 laser will cause damage to the cornea (similar to welders arc-eye) and this may be repairable whereas a Diode laser beam will travel through the Cornea and be focussed by the lens onto the Retina which may not be repairable. I am extremely happy to use a CO2 laser with just standard eye protection but when I use a diode laser I always wear the full goggles with an OD 4+ rating to match the wavelength of the diode.
Having said that and much to my suprise, there have been extremely few, genuine, reported cases of eye damage caused by lasers.

When I started this thread Diode lasers with enough power to do anything useful where rare and extremely expensive. Nowadays, since the advent of blue-ray players and recorders, the diode price has fallen and they now offer a much cheaper and easier entry into laser work as compared to CO2. However, you must consider the type of work you wish to do as the wavelength of the laser will determine its action / reaction upon different materials.

I have and use 3 different types of laser – Diode, RF excited CO2 and DC excited CO2 and they each have their own strong and weak points. The only thing I can suggest is that you read-up as much as you can before making the decision.

Tweakie.

(the post edit function was being abused so the function has been time limited)
Title: Re: The Laser Project.
Post by: Spandex on February 14, 2018, 05:52:57 AM
Gocha. Yep reading about this stuff as we speak. Mostly forums for now, hopefully will find some good links along the way.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 06:09:26 AM
I can't possibly keep up with all new developments so if, in your travels, you find anything good please share the info.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 06:31:16 AM
Pictures always speak louder than words and (as you all know) I just love pictures.
Not to everybody’s liking but this is my take on changing the pin allocation and polarity of a PWM signal on a DB25 ribbon header cable connecting my CNC machine to the controller.

Tweakie
Title: Re: The Laser Project.
Post by: ART on February 14, 2018, 07:18:52 AM
>>Various tube manufacturer's (such as Synrad) withdraw their warranty if their tubes are mounted  beyond a defined angle to the horizontal.

   75 degrees to the vertical is the maximum allowed with SynRads.

(nice circuitry on a cable Tweak.. very tidy way to do it.)

Art


 
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 07:50:03 AM
Thanks for the info. Art.

One thing that concerns me is that I have learned so much over the years (lots from you) that if it is not shared with others now then one day it may all be lost.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on February 14, 2018, 07:57:26 AM
Tweakie:

  Yes, I try to post in for archival purposes when I can so others following will have some data to find. Laser information can
be hard to find and hard to research.

  (btw: I now have my galvos working as step direction wiring and happily jogging around with Auggie and even homing nicely.. My problems now I think are mainly the damn theta lens, one of those things with very little information to go on. )

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 14, 2018, 08:18:51 AM
Quote
My problems now I think are mainly the damn theta lens, one of those things with very little information to go on.

Hi Art,

Not something I would tackle - mathematically correcting for the scale and pincushion distortions sounds like hard work compared to my simple linear engraving work and drinking beer.

I am pleased you have your galvo head working OK – I am still thinking along the lines of linear Y axis and galvo X axis but yet to construct the prototype.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on February 14, 2018, 09:40:45 AM
Ive learned quite a bit on the galvo's.. I can see where the real problem is the F-Theta thing. Its
really not that expensive to do the rest. Ive used an arduino to convert step/direction to analogue
values and a DAC to control the galvos. Easy enough, but the pincusion and focus will be the real
challenge.. Ive a lot to learn there..

Art
 
Title: Re: The Laser Project.
Post by: Spandex on February 15, 2018, 01:15:30 AM
Has anyone done any assessment on how good at depth control one of these lasers are? I'm not talking about $10K priced lasers that definitely can control depth very well. What can you reasonably expect form a cheap CO2 laser?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 15, 2018, 01:41:05 AM
Hi Spandex,

Depth control is a weak point.
Comparative depth and repeatability is generally good but trial & error is usually used to arrive at the correct initial settings.

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on February 15, 2018, 02:18:09 AM
Hi Spandex,

Depth control is a weak point.
Comparative depth and repeatability is generally good but trial & error is usually used to arrive at the correct initial settings.

Tweakie.


Sounds workable. Wouldn't it be cool if along with laser cutting, it also had a sensor that gauged depth at the same time! And I'm guessing getting your hands on TOMTOM isn't really possible? I haven't been able to find any links other than his blog:

https://blogs.yahoo.co.jp/tomtchi (need chrome to translate) but there's no links to the plugin.

Another update for the Impact / Laser Engraver plugin (v1.2a).

Image aspect ratio;
I have re-instated the ‘maintain aspect ratio’ function (somehow lost along the way) which is now operated in a slightly different way to which it was originally. There is a new screen button “Calculate Parameters AR” and this automatically sets the vertical (Y Axis) height based on the, user input, horizontal (X Axis) width information and the original image aspect ratio. This new function works alongside the original “Calculate Parameters” function and provides a choice of either locked or free aspect ratio.

Changing the Mach mode of motion;
If the original image detail extends to the vertical sides of the canvas it has been found best to process the engraving in the Exact Stop mode whereas if the image detail stops short of the edges there is a small but significant gain in process speed if Constant Velocity mode is used.
By default the plugin now operates in Exact Stop mode and I have added a new check box “CV mode” so that Constant Velocity can easily be used, as and when required. (Without having to open the Mach General Config page to change the settings there). On exit the plugin returns Mach to CV mode.

I have also updated the PDF file to reflect these changes.

Engraving.dll   http://www.cooperman.talktalk.net/Engraving.dll

Engraving.pdf   http://www.cooperman.talktalk.net/Engraving.pdf

Tweakie.


What is the difference if any between this plugin and DotG?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 15, 2018, 02:24:28 AM
Quote
Wouldn't it be cool if along with laser cutting, it also had a sensor that gauged depth at the same time!

Something for you to design perhaps ?

The Mach3 plugin will reproduce 8 bit images (true shades of grey).
DotG produces 1 bit images (illusion of shade by dot-dithering).

If you contact Tomura directly he will send you a copy of his TomTom plugin.

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on February 15, 2018, 03:03:27 AM
Something for you to design perhaps ?

Maybe one day. I can't think of a use for such a contraption for me at the moment. I think trial and error will suit me just fine.

Thanks, will get in touch with him.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 15, 2018, 05:17:28 AM
Hi Art,

Thought you may be interested in this which is something I had not seen before. It is a 3 axis scan head which can scan very large areas by obviating the requirement for an F-Theta lens system. https://nutfieldtech.com/3xb-3-axis-scan-head/

This pic. is of a Nutfield 3XB. Obviously the beam angle changes dramatically during the scan but the focus remains constant.

Certainly something for me to investigate further.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on February 15, 2018, 08:38:38 AM
Hi Tweaky:

   Thanks for the photo of the Z axis lens. I was aware of, but hadnt seen one. Synrads newest also uses this, they use a voice coil
lens to move it the required theta distance as the mirrors sweep.  The real problem I think with Galvos is the distance vs focus spot
formulas. For a TEM0 laser like the RF ones, focus size is  (4*wavelength*focal distance) / (PI * inputdiameter). InputDiam is ually around 2-3mm for a co2, but with an expander mine is 12mm or so.

   I have a beam expander to try to get the smallest dot possible. The formula shows how important the expander and focal distance is though. You can double the effective power of a laser by expanding its beam prior to focus or simply by using a smaller focal distance.
So galvos have it rough, to get a 12" field for example if that field requires a 12" focus length,  thats (4 * .01 * 304) / (3.14 * 12mm) = .322 and thats if its a good lens. When a focus gets that large you need alot of power as power reduces 4 times faster than its growth in distance.  Its this balance that Im currently working on as I puzzle out the size matrix I want from my galvo. I always knew smaller focus
distances were better, but till I crunched the numbers I didnt realize just how much better and why.

  When it comes to Depth engraving, I shoot one level, leasure the distance engraved, and then do multiple levels
using that initial test pass's depth as the multiplier for pass depth. It produces 3d images to a very close desired depth I find that way.
Each material being different, its only a guide but allows pretty good 3d.

Title: Re: The Laser Project.
Post by: Spandex on February 19, 2018, 04:17:21 AM
Judging by the photos that you posted, you never did quite get to the same level of fine detail in terms of cutting out the bicycle as the pros? How fine can your setup get do you think?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 19, 2018, 04:55:23 AM
Judging by the photos that you posted, you never did quite get to the same level of fine detail in terms of cutting out the bicycle as the pros? How fine can your setup get do you think?

Strange comment to make. Perhaps you need to read a few more of the posts.  ;)  http://www.machsupport.com/forum/index.php/topic,12444.msg102590.html#msg102590

Tweakie.

Title: Re: The Laser Project.
Post by: Spandex on February 19, 2018, 05:04:48 AM
Ah I think I missed the size of those bikes when I saw the pic.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 06, 2018, 06:35:06 AM
A couple of laser produced images from the same .jpg - there must be an infinite number of variations possible by using different techniques / settings, the problem is deciding which one I like the best.  ;D

Tweakie.


Title: Re: The Laser Project.
Post by: Dan13 on March 06, 2018, 07:26:08 AM
Nice. The first one must be a dithered image used with DotG or the like. The second one a very nice grayscale and the third seems like a poor attempt at grayscale  ;D

Dan
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 07, 2018, 04:00:06 AM
 :)

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on March 11, 2018, 10:13:24 PM
1st one is the best.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 13, 2018, 05:28:55 AM
Hi Spandex,

I think Dan13 has summed it up well.

The first one was created from a ‘dithered’ image (which creates the illusion of shade by varying the density of individual dots) and this is the most common form of laser image reproduction. It is easy to do and it is quick.
Generally a specialist software (such as PhotoGrav) is used to create the 1 bit  ‘dithered’ image which is then sized and adjusted to match the d.p.i resolution of the particular laser being used. I used 200 d.p.i. here as it is usual to limit the image resolution to 200 or 300 d.p.i  (there is little point in specifying a smaller pixel size than the laser is actually capable of reproducing).

There are a few of us who are interested in producing true 8 bit gray-scale images (as the second picture) but it is not so easy to do as different materials react to the laser in different ways and the production time is much longer.

As he previously mentioned, Art is currently building a galvo scanning system which can work at much higher axis feed-rates than standard linear systems such as mine and I am eagerly awaiting the results of his initial tests before I start on building something similar.

The third image is very much ‘work in progress’ as it is probably the best of the three but it needs far more contrast - who knows, perhaps one day I will succeed.

Tweakie.
Title: Re: The Laser Project.
Post by: ART on March 14, 2018, 03:03:35 PM
Tweakie:

    Just starting to test..

https://www.youtube.com/watch?v=5bOzb-32pa8

  Im impressed so far, but you know I see nwo speed wont help in photos at all.
The Laser is controlled in 1ms packets, so if you raster a photo at 1 second across,
it will have a resolutoin of 1000 pixels. At .5 seconds, only 500. Faster you go the
less res you have. In theory a 4k image at 4 seconds per raster sweep is the highest res.
one can get ..

  I'm finding galvos are great at vector works, infinite acceleration helps.. but for photos
I think speed is my enemy..

Art



Title: Re: The Laser Project.
Post by: Tweakie.CNC on March 15, 2018, 02:51:32 AM
Wow that is quick.

Nice work Art  (I notice that the beam is not turning off during the rapids  :D).

Tweakie.
Title: Re: The Laser Project.
Post by: Dan13 on March 15, 2018, 05:02:17 AM
 That is fantastic, Art!!

What is the visible red dot? Did you also build the hardware??  :o

Dan
Title: Re: The Laser Project.
Post by: ART on March 15, 2018, 07:14:01 AM
All G1's.. I turned off rapids for that test :)

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on April 25, 2018, 07:11:12 AM
An echo from the past.  ;D

https://www.flickr.com/photos/tweakie-cnc/27822699768/in/dateposted/

This demo was made in the early days, before the M62/M63 commands were included within Mach4. The laser was switched using the A axis direction pin and machine control was by the LPT parallel port using Darwin.

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on May 06, 2018, 09:03:03 AM
Hi Spandex,

Depth control is a weak point.
Comparative depth and repeatability is generally good but trial & error is usually used to arrive at the correct initial settings.

Tweakie.


Still thinking about depth quality. Do you think a laser that's reasonably priced would have a depth of cut accuracy to be able to take off a layer of paint? So I'd I have a few coats of primer and then a few layers of top coat, would it be reasonable to expect to go through the top coats and say half way through the primer?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 06, 2018, 10:45:40 AM
I am sure it is possible but it is not something I have ever tried.
I suspect that the final result would be far from satisfactory as there is bound to be some scorching / charring of the edges of the topcoat and the entire surface (and quite possibly the entire thickness) of the undercoat.
Perhaps a subject for experimentation ?

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on May 07, 2018, 09:59:02 PM
I am sure it is possible but it is not something I have ever tried.
I suspect that the final result would be far from satisfactory as there is bound to be some scorching / charring of the edges of the topcoat and the entire surface (and quite possibly the entire thickness) of the undercoat.
Perhaps a subject for experimentation ?

Tweakie.


Spent a few hours researching this, couldn't find an answer thus far so perhaps experimentation might be the order of the day.

What's your take on Fiber lasers? I'm only starting looking into them, but they appear to be superior to CO2 lasers at least for thin materials. Although they appear to be a fair bit more powerful than CO2 lasers which doesn't bode well for simple engraving work. The main thing that interests me with fiber lasers is the fact that you don't need to spend a long period of time setting up all the mirrors (and are therefore also more reliable in exploitation) and they appear to last longer as well, so these seem to be a much cheaper alternative all around.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 08, 2018, 04:12:20 AM
Fiber lasers open up a whole new chapter, their different wavelength enables metals engraving and many other things that can’t be done at the CO2 wavelength. However, CO2 lasers can do many things that Fiber lasers can’t so best to decide on the final product required before choosing the laser type – or perhaps have both types, after all it’s only money  :D

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on May 14, 2018, 06:55:00 AM
Hi Tweakie, do you have any info in relation to laser wavelength selection?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 14, 2018, 11:23:37 AM
It's such a broad subject and documents I have seen only cover limited aspects of photon properties at various wavelengths so best to Google the subject and see what you find. The various laser manufacturers websites will often detail what their machines are capable of so that should be a start.

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on May 17, 2018, 03:30:28 AM
I think I found the answer, looks like it's as simple as, the optimal wavelength is the wavelength that is absorbed by the material.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 17, 2018, 07:12:28 AM
I think I found the answer, looks like it's as simple as, the optimal wavelength is the wavelength that is absorbed by the material.

Never really thought of it that way but it certainly sounds like a very good rule of thumb.

Tweakie.
Title: Re: The Laser Project.
Post by: Spandex on May 17, 2018, 08:29:58 AM
Well, I never did get any response from Tomura Kazuki with his TomTom plugin, so I guess it's out of the question. I do wonder however whether the Mach3 plugin or DotG are smart enough to not stupidly scan the entire area line by line thereby going over large areas where engraving isn't necessary?
Title: Re: The Laser Project.
Post by: Tweakie.CNC on May 17, 2018, 08:37:55 AM
Quote
I do wonder however whether the Mach3 plugin or DotG are smart enough to not stupidly scan the entire area line by line thereby going over large areas where engraving isn't necessary?

Nope  :'(

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on August 04, 2018, 11:16:12 AM
Warp9 have now added the ability to laser reproduce (raster) 8 bit photographic images using their ESS and the v221 release Mach4 plugin. It is still very much in the beta stage and does not have a GUI but an excellent and detailed ‘setting-up’ tutorial has been prepared which should get any potential users up and running in no time. It equally supports vector laser work and is suitable for use with Diode, RF and DC excited CO2 lasers.

I have not had a chance to try it out yet but for those who may wish to do so, the full documentation and further details can be found here;  https://warp9td.com/index.php/faq/faq-mach4#LaserSetup

Tweakie.
Title: Re: The Laser Project.
Post by: ART on August 04, 2018, 11:23:12 AM
Tweakie:

  Thx, nice to know. Nice to see lasers getting some respect. :)

Art
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 02, 2018, 07:13:02 AM
I had been hoping that other Mach4 users with lasers and an ESS may have tried out the laser raster image reproduction but overall there does not seem to be much interest.

Considerable improvements have now been made with the latest ESS plugin Build 227 and Mach4 Build 3882 but the plugin is still lacking a GUI and key runtime features such as vertical step-over adjustment and image scaling.
 
Currently the vertical step-over seems to be set at one pixel, making the scan lines clearly visible and there is a definite issue with horizontal registration although this can possibly be improved by gating the laser PWM and adjusting the gate timings – something I have yet to try.

So far, this is the best I have been able to achieve – it can only get better  ;)

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 05, 2018, 06:20:03 AM
Thanks to Andy at Warp9 who explained to me how to fine tune the delays it was just a matter of trial and error before I was able to set the horizontal registration for my chosen feed-rate.
After 3 or so attempts it is now pretty close.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on November 06, 2018, 07:27:19 AM
Although I am using mach4 a bit more often nowadays I just had to try the same fox image using Mach3.

Tweakie.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 18, 2019, 02:43:21 AM
Way back in 2014 I posted the simple solution I use for controlling my laser output power using the Mach3 generated PWM signal. https://www.machsupport.com/forum/index.php?topic=12444.msg194200#msg194200
That method, although just fine for me, is not suitable for lasers which use an Active High TTL input so an alternative was investigated.
Although it is a little more complicated because a 5 Volt power source is required, using a basic logic IC the Mach3 generated PWM can easily be gated ON / OFF using the M11 / M10 command set thus controlling laser output power.
I have attached schematics for both TTL(High) and TTL(Low) versions of the same concept.
By referring to the truth table you can see that condition C would be used for laser OFF with condition D used for laser ON (at the designated PWM) and condition F would be used with 100% PWM for full power laser output.

Food for thought perhaps ?
Title: Re: The Laser Project.
Post by: MN300 on February 18, 2019, 12:51:35 PM
The 74LS00 is a NAND gate so there should be a circle on the output to represent the logic inversion. This would make the difference between the PlanB and PlanB2 more obvious.
The unused gates could be paralleled to increase the output drive.

Using 4000B series CMOS would allow for 5V or 12V logic levels. The MC14011BDG NAND gate has twice the output current (8.8ma) as the average 4000 series gate (3.4ma). That's slightly more than the 74LS00 (8ma).
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 19, 2019, 01:29:26 AM
Thanks for the info.  :)
I have now corrected the NAND outline in both schematics as your suggestion - thanks again.
Title: Re: The Laser Project.
Post by: Tweakie.CNC on February 25, 2019, 07:16:37 AM
I have just been contacted by a Mach3 user in The Netherlands who does not like to post here because he says that he does not have good English. Well:  Zijn Engels is een stuk beter dan mijn Nederlands.

He uses a Chinese motion controller which will output spindle PWM but it does not support the M11/M10 command set and up till now he has just been using an imaginary Axis Direction pin to switch his laser ON/OFF and controlling output power manually.
He has now tried the gating concept shown in post #1067 and he discovered it has an unexpected benefit…

For a while, a few years back when the M11/M10 command set was broken, I used the B axis direction pin to switch my laser ON/OFF – although this worked just fine EStop would not automatically turn the laser OFF and this really did represent a fire hazard.
Because Mach3 allows all Outputs to be switched OFF upon EStop (and this includes the PWM signal) gating an Axis Direction signal with PWM will always switch the laser OFF when an M5 or M30 or EStop is encountered. Brilliant.

This is something I had not considered – thanks Joost for the heads-up on this one (we never stop learning).

Tweakie.