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Making a laser cutter
« on: April 05, 2010, 01:23:16 PM »
Hi there,

I have built a cnc with about 60*60 dimensions. I'm using a dremel hand tool instead of a spindle motor to work less noisy but it still works too noisy for an apartment. I thought that maybe I could use a laser so I could use my cnc anytime I want. But I don't know much about lasers. I'm generally cutting 5-8 mm plexyglass, or making pcbs. What kind of laser that I need to use? And is it possible to make pcb with laser? If yes, is it possible to make it with the same laser that I can cut plexy? And also what kind of troubles I might see while the prosses of changing my machine to a laser cutter?

thanks.
« Last Edit: April 05, 2010, 01:25:20 PM by furkan »

Offline Tweakie.CNC

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Re: Making a laser cutter
« Reply #1 on: April 06, 2010, 03:01:35 AM »
Hi,

It's a very involved subject and the discussions between diode laser and CO2 laser will run for eternity. There is lots of laser info on Sam's Laser FAQ here http://www.repairfaq.org/sam/lasersam.htm

When it comes to adding a laser cutting head to an existing machine this is a link to my progress so far http://www.cooperman.talktalk.net/files/27.htm
The cold weather has halted progress lately but I hope to continue with the project sometime soon.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

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Re: Making a laser cutter
« Reply #2 on: April 23, 2010, 06:11:12 AM »
Hi Furkan,

After a bit of experimentation I really do not see that making PCB’s with a laser is even a remote possibility (but perhaps someone may prove me wrong).

There are a number of reasons, that I can see, why this is not a practical proposition:–

1)   Copper is such a good conductor of heat that a lot of energy would be dissipated either side of the intended kerf .
2)   Copper is also probably the best reflector you can get for energy at 10600nm. (CO2 laser).
3)   Because the laser beam is focused to a point the size of a pin prick the isolation kerf produced would hardly be wide enough to be of any practical use.
4)   Assuming there was enough available laser power then once it penetrated the copper layer it would then still have sufficient energy to cut right through the GRP board as well.

It was a good thought though.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.

Offline Tweakie.CNC

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Re: Making a laser cutter
« Reply #3 on: May 12, 2010, 07:25:52 AM »
Just out of interest, I have recently read a suggestion that is basically as follows:-

Coat the copper side of the PCB material with a very thin layer of photocopy toner. Use the laser to draw the intended circuit and thereby melt/fuse the toner onto the copper surface (low power setting). Remove excess toner and acid etch the PCB. Remove toner with wire wool and tin PCB etc.

Anybody like to try this and see if it works ?.

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Making a laser cutter
« Reply #4 on: May 12, 2010, 07:42:32 AM »
Hi Tweakie,

Thanks for your answers and suggestions. And sorry that I  couldn't look at here for so long.

As I searched making PCBs with laser is something expensive, difficult and a bit dangerous in home conditions.

Your suggestion can work. But if I will again use acid, I prefer to use a PCB pen with cnc as I do now.

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Re: Making a laser cutter
« Reply #5 on: May 12, 2010, 08:19:46 AM »
Hi Furkan,

If you haven't tried it already then I think 'Isolation Routing' is the way to go for PCB's - no more acid, no more mess.

   http://www.cooperman.talktalk.net/circuit5.wmv

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.
Re: Making a laser cutter
« Reply #6 on: May 12, 2010, 08:54:59 AM »
hmm. So did you isolate the spindle motor with that black box?

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Re: Making a laser cutter
« Reply #7 on: May 12, 2010, 10:52:05 AM »
 ;D ;D ;D

Not sure I fully understand but the laser lens assembly is lifted out and the spindle motor fitted in it's place when I need it. The black tube surrounding the spindle motor is it's air cooling jacket (there is a fan in there, at the top).

Tweakie.
Success consists of going from failure to failure without loss of enthusiasm.  Winston Churchill.