Lesson Learned I hit the jackpot on some name brand extruded acrylic.

Lasers
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Lesson Learned

I hit the jackpot on some name brand extruded acrylic. I live next to a large university that has a surplus shop available to the public. I found 12 sheets, 3 mm thick, 18 x 24 inches for a total of $20! Anyway I started to cut them and was surprised that the settings I was using on thicker acrylic was not working. I need to mention that I had left the protective paper on the acrylic as not to scorch it. Increasing the power and slowing the speed did not do much good. Multiple cuts no go. I removed said protective paper and it cut like butter! I am not sure what the paper is made of but it sure messes with the process. Took a few cut to figure it out.

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More than likely a UV protection film to keep it from discoloring and scattering your beam

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@Alex_Krause , the K40 is a C02 laser. Unlike the other lasers producing visible or short near-IR light, the output of a CO2 laser is medium-IR radiation at 10.6 um.