Can polycarbonate (e.g., Lexan) twinwall be cut? References indicate that the cut edge of polycarbonate will char. I can live with that, but I’m wondering if the laser beam will diffuse cutting through the first layer and make a poor cut on the bottom layer.
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If you can cut a solid sheet of the same thickness then I don’t think the air pocket in the middle will make it any harder to cut through.
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Diffuse, no. But remember that the laser is not collimated for cutting - what this means is that the sides of the shape of the beam are not parallel to one another, indeed they form a proper cone, where the very finest point of the cone is the point of maximum cutting power. The further away from this focal point a material is, the less performant will be the beam for cutting.
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Had to look that up 
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That’s a big “depends”. It can catch on fire and release chlorine gas which will corrode your electronics in the laser. But in thin sheets it can cut or can also slag. Lesser amount of chlorine gas the thinner the sheet.
It’s usually (but not always - see Epilog) on the “don’t laser this” list.
I had to look this one up too. It doesn’t seem to be universally recognized yet.
I don’t think there is any chlorine in polycarbonate. It’s molecular formula seems to be C16H18O5. Any chemists?
I’m not a chemist but am positive that PC contains no chlorine.
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Sorry about that, that’s probably from work jargon.
Sorry, sorry. I sometimes get all carried away.
Please don’t apologize for making me learn something new! What would be the point of being here if I knew everything I read already?
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Thanks for the warning
Not sure if this helps alot, but here is a link on Polycarbonate
Thin Polycarbonate Sheeting (<1mm) - Very thin polycarbonate can be cut, but tends to discolor badly. Extremely thin sheets (0.5mm and less) may cut with yellowed/discolored edges. Polycarbonate absorbs IR strongly, and is a poor material to use in the laser cutter.
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it’s true there’s no chlorine, but it’s always worth checking msds for a supplier when possible to make sure they’ve not added something weird to the blend (maybe a uv stabilizer, etc).
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The ATX guide says chlorine. Wonder why if the MSDS doesn’t indicate that. Could be why Epilog doesn’t say “no”, just that it doesn’t lase cleanly.
Most Makerspaces I’ve been to use the ATX guide though.
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I think you might have read the section above the Polycarbonate/Lexan
Polycarbonate is often found as flat, sheet material. The window of the laser cutter is made of Polycarbonate because polycarbonate strongly absorbs infrared radiation! This is the frequency of light the laser cutter uses to cut materials, so it is very ineffective at cutting polycarbonate. Polycarbonate is a poor choice for laser cutting.
I did find a link that refers to non-chlorinate Lexan:
Here is another reference to chlorine-free (which I take to mean that Lexan has chlorine and non-chlorine formulas):
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Fair enough! 
Yeah. Which means you’ll need the MSDS for the particular batch you’re using.
Such a pain. 
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