Messages

7761

General Mach Discussion / Re: PWM and routers?

« on: August 20, 2010, 10:46:13 AM »

If you toggle the IJ mode setting to Inc (config / general config) that should do it.

Tweakie.

7762

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« 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  ).

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

Tweakie.

7763

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« 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  .

Tweakie.

7764

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: August 19, 2010, 08:13:18 AM »

Hi Dan,

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.

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.

7765

FAQs / Re: newbei: what to buy for my 1st CNC ?

« on: August 19, 2010, 07:25:14 AM »

Sure is Rich.

When you do these things and it is all fresh in your head you don't need a schematic but a few years down the line .......
I got the idea from some other machine photos I saw here somewhere.

Tweakie.

7766

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« 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.

7767

General Mach Discussion / Re: Power Supply for Motion Controlling

« on: August 19, 2010, 02:41:45 AM »

My apologies to p j for hijacking his thread.

Yes Ian - I hate it when someone steps on my nuts  

Yes Sam, I can reduce power / increase speed and cut in to any depth. Because the kerf is extremely narrow any engraving is better viewed at an angle. This keyring was the prototype for some made for my musical buddy Terry Batt. (thanks to your help I can now obtain better edge finish than this   )
The best effects with acrylic are by raster etching the surface - this does stand out quite well when side lit. When I get some spare time today I want to raster etch an owl picture using the Mach Impact/laser plugin and I will post some pics of the result.

Tweakie.

7768

Show"N"Tell ( Your Machines) / Re: X machine-Like

« on: August 19, 2010, 02:19:08 AM »

Amir,

There are quite a few ideas here  http://www.machsupport.com/forum/index.php/topic,13486.0.html

Tweakie.

7769

FAQs / Re: newbei: what to buy for my 1st CNC ?

« on: August 19, 2010, 01:32:06 AM »

Red arrow indicates the junction board incorporating pull up resistors used for terminating my limit switch wiring.
1) Solid State Relay used initially for switching the spindle motor but can be used for anything.
2) Rear of 3 pin socket for connecting items that will be switched by the SSR.

Hope this helps.

Tweakie.

7770

Show"N"Tell ( Your Machines) / Re: X machine-Like

« on: August 18, 2010, 11:27:26 AM »

Excellent Amir.
Looks like a lot of work but it could be a very nice machine.

Tweakie.