# Laser cutting thin aluminum



## Oznog (Nov 5, 2008)

I need to cut thin flat aluminum, like 0.015". It will be painted black on one side. I'm a little concerned about the edges of the paint getting burned though. It might be necessary to do the painting after being cut so I can't totally depend in the higher absorption of a black surface.

I have a Taig CNC mill.

What sort of laser would be required to cut this? AFAIK it's going to need to be an IR but I've no idea of the wattage needed. Is there any cheap solution, like one of the super-powerful laser diodes?

I'm a smart guy and would research the necessary safety precautions, and then actually do them. I can deal with all that.

I saw a 15W CO2 tube on eBay. 34mm beam width but focusing optics should be able to fix that. Would that cut thin aluminum? It would be nice to avoid the long glass and high voltage though if a laser diode could work. Water cooling's not such a problem.

Waterjet would be nice, but I don't see any cheap way to get there from my setup.


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## comozo (Nov 6, 2008)

looky here click the FAQ at the bottom of the page
http://www.parallax-tech.com/cutting.htm


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## RDZombie (Nov 6, 2008)

15w of co2, even well focused wont be enough, id say for any kind of speed you will need at least 100w


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## InTheDark (Nov 6, 2008)

Does it have to be laser? You're looking at quite a bit of unneccessary cost to cut some pretty thin material. Also, painting it black probably won't have as much of an influence as you might think with IR lasers, the wavelengths absorb differently than visible light. The composition of material is the main factor, color and even surface finish isn't as much of a factor. A quick search on google shows 5% absorbtion for c02 on aluminum, so that means whatever minimum power you think you need, multiply by 20X. That doesn't even account for the high thermal conductance of aluminum, which would increase your power requirements even more.

Why not get a plasma cutter? Even the smallests one will cut through that thickness aluminum faster than you can move the torch, at a fraction of the cost


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## Oznog (Nov 6, 2008)

comozo said:


> looky here click the FAQ at the bottom of the page
> http://www.parallax-tech.com/cutting.htm



Huh ok yeah that suggests I'd need way more power to be able to cut thin aluminum. 

I do need to make fine cuts and holes. The problem I expect is that mechanical routing may damage the edge of something flimsy like this but I haven't tried. And I wanted to make very fine holes but- duh- a CO2 laser like that isn't going to be able to make a really fine beam even with focusing. At least not as good as my carbide PCB drills.

Actually the laser came up because I'd wanted one for general-purpose burning wood and leather or whatever. This application was kind of a side note.

How fine of a line can plasma cutting do, anyways? I've browsed and see lots of moderately expensive cutters but I assumed they had a pretty big kerf for this job but I'm not sure.

Actually, this is conductive material... EDM machining makes sense.


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## RDZombie (Nov 7, 2008)

the 15W co2 would work decently for wood burning (still a bit slow tho). My miller plasma cuts a line about 2mm wide, decently clean cut. For thin aluminum, a used CW yag (much better for metals than CO2) head can be had for relatively cheap on that online auction site.


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