Instructables

Poly, PETG, Acrylic? How to tell?

Hi all!

First, this is my first post to the forums. Hi. :)

I have a friend with a laser cutter, and he said that he can only cut Acrylic or PETG. No Polly.

First, why is that?

And second, I already have some plastic, so how can I tell what kind it is? I bought it a long time ago...

I'd rather not buy more plastic if I can help it, but I will if necessary.

Thanks!

~Mark

kelseymh2 years ago
First, the reason is that polyethylene gives off fumes when burned (which is how laser cutters do their cutting). Those fumes can recondense onto the optical components of the laser system, permanently damaging them. What I don't know is why acrylic plastic or PETG don't give off similar fumes. The owner's manual for a laser cutter will specify what materials can or cannot be used safely.

Second, identifying a random sample of plastic unambigously is non-trivial. If it's consumer packaging, you can look for the "circle of triangles" recycling symbol. The number inside will tell you what kind of plastic it is. Failing that, there's not a lot you can do if you don't have a record of the purchase (yeah, right...).