Author Topic: The Laser Project.  (Read 792213 times)

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Offline Spruft

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Re: The Laser Project.
« Reply #310 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  ???

Online Tweakie.CNC

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Re: The Laser Project.
« Reply #311 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Online Tweakie.CNC

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Re: The Laser Project.
« Reply #312 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Overloaded

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Re: The Laser Project.
« Reply #313 on: February 04, 2011, 09:20:40 AM »
You are an inspiration Tweakie, beautiful work as always.
Thanks for the update,
Russ

Online Tweakie.CNC

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Re: The Laser Project.
« Reply #314 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Overloaded

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Re: The Laser Project.
« Reply #315 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

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Re: The Laser Project.
« Reply #316 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Online Tweakie.CNC

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Re: The Laser Project.
« Reply #317 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

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Re: The Laser Project.
« Reply #318 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.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Jennifer

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Re: The Laser Project.
« Reply #319 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


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