laser ploter "cnc"

hey i just had a thought any input appreciated

i am a glass artist by trade and i think i can build a laser tube i say i think
only because i have yet to do so

how hard would it be to build a 2 dimensional plotter to carry the laser say for cutting sheet goods, or the like ?

if it is not too difficult to build i might start in on building one soon

thanks for any and all of your creative input in advance

austin

You can buy 'em from the Chinese for about $750 these days, last time I looked. The only drawback is that they're a bit like HP printers. The laser is full of Helium, iirc, and you have to replace it about every 4-6 months at a cost of about $250 because the helium leaks out.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Forest do your remember where you saw one for that price? Depending on how they handled some of the complexities like focusing and laser power level, it may be worth it to me to pick one up. When the tube goes out replace it with a high quality tube.

I looked into building my own a month or so ago. I was planning on just purchasing a sealed tube here in the US. However, after staring to deal with the complexities of mirror alignment, focusing, and most important the safety features it got put on the back burning until I have more time.

cptwinder Wrote:
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> Forest do your remember where you saw one for that
> price?
>

IIRC, Adrian sent around a spec sheet on that cheap laser cutter. I thought seriously about buying one, but decided that having and using one would keep me from actually creating a proper reprap machine to do that kind of work. You might want to ask him.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

There is a cheap 40W machine direct from China [cgi.ebay.co.uk]|66%3A2|65%3A12|39%3A1|240%3A1318 for £919. I can buy something that looks the same locally [cgi.ebay.co.uk]|66%3A2|65%3A12|39%3A1|240%3A1318 for £2000! Although it seems to be the same spec the first one quotes the cutting depth in acrylic as 3mm but the second one 5-8mm. 3mm would not be much use to me but 5-8mm would so I am a bit confused as to how much power I need.

Not that I am particularly thinking of buying one, but if I was to make one it would have to be powerful enough to cut 6mm acrylic I think.

Edited 1 time(s). Last edit at 03/03/2009 04:27AM by nophead.

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[www.hydraraptor.blogspot.com]

That is the same spec that Adrian circulated. I should have said UKP 750 instead of US$ 750.

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Forget about the tube, I'd be more interested to see if one could make the optics for the tube. FYI, low end laser cutters use about a 25 watt laser, I found a 25 watt laser diode on ebay for about $100.

Hi Gene Hacker,

15 years ago i built some laser-plotters with 5 Watt RF-CO2-tubes. Here i mounted the laser to the basis, used some metal-coated mirrors for feeding the ray along the moving axes and in the prototype a germanium-lens, later ZnSe-lenses with 10mm diameter and 20mm focal length.

For a 8Watt pigtailed diodelaser i lathed some tubes as housing and distancers and assembled two quartzglass-lenses with 15mm diameter, 60mm spacing and 15mm/20mm focal length. The glass-fibre-core was 0,1mm in diameter and the cutting focus nearly the same size ...

Viktor

Hi Viktor,
How deep will 8W cut into plastics like PMMA and POM?

Chris

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[www.hydraraptor.blogspot.com]

Hi Chris,

... i limited the power around 4 Watts because of life-time and used the laser mostly for micro-welding of gold- and platinum-powders on gold-pads.

My tests with black ABS and some thin sheets of plastic went fine but i was interested only in the range up to 0.5mm - it cut's deeper when moving slower but you have to exhaust the fumes and the cutting efficiency is highly dependant of the colour (or absorption) of the material.

With a 10Watt-Laser of nearly the same wavelength and smaller spot-size i carved v-groves in aluminium and silizium and 'drilled' some deeper holes in plastic around 0,5mm in diameter and 5mm deep by using the spot like a millhead of 0,02mm diameter. But you have to exhaust the smoke too or it will block the ray ...

Viktor

Gene Hacker,

That was my thought originally as well, pick up a cheap diode on ebay and get around the hassles of dealing with long, fragile, and expensive tubes. However, the more research I did the more I realized that wavelength has a lot to do with how well you can cut certain materials.

The wavelength of CO2, 10.6 μm, is well absorbed by organics and not so well absorbed by metals. This isn't to say you can't cut metals, as it is done all the time. You would be "wasting" a lot of the energy via reflection of the beam. There is another laser medium, that completely escapes me at the moment, that has just the opposite attributes.

Also, as Viktor pointed out, you can control the depth of the cut by either keeping the laser focused on that spot longer and sucking/blowing the gasses out of the way or you can make multiple cuts like you would do with a milling head.

The standard disclaimer needs to be applied. I haven't taken a physics class since high school and the closes thing I get to lasers in my day job is when I install software from a DVD. So I could be completely wrong.

Jeremy