The technical or scientific name for acrylic is polymethylmethacrylate.
Most of us that use CO2 machines are in mm/s but if you convert 3 in/s, it’s 76mm/s. I cut Acrylic at 14mm/s at 60%. You are probably ‘speeding’. Mine is a 50 watt (lol), just cut a .75" disk out for a project. One pass with this material
If the material passes (or reflect) the emissions of the laser it will NOT do any damage to the material. The material must absorb (block) the energy to excite (heat) the molecules.
Any material that blocks the transmission of the emf from a laser, will suffer damage to the material. How much damage depends on the amount of emf absorbed. My glasses are polycarbonate, makes good safety glasses and can be cut. Polycarbonate does not produce good edge results and isn’t used very often. It is very durable and is used in fighter canopies. It is as safe as acrylic to cut.
The window in my machine is acrylic as far as I can tell. Polycarbonate is more expensive, so I doubt these low cost machines put that in the window, where acrylic does just as well.
I keep a pair of polycarbonate safety glasses around for visitors who don’t wear glasses.
What isn’t absorbed is UVB that is sometimes generated.
