I have tried the materials test and at I cannot figure out how to cut orange acrylic that is only 3mm thick. Does it need to be a different color or something else? Burning and cutting with wood works just fine. I cut wood up to 6mm thick with no problem. Just having a problem with orange acrylic. I think I need clear lol as the orange around the laser is for protection. Yes I am a newbie. I did the materials test using 10% power and 60mm/sec up to 100% power using 380mm/sec. No cutting done and just melting most areas.
Nevermind I found out that a diode laser is the worst to use when cutting acrylic. Unfortunately I do not have a C02 laser.
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Simple fact if the material is clear and you are using a visible laser, it won’t work at all.
If the acrylic has an additive to make it black or another color the visible light is absorbed by the additive, that heats, which heats the acrylic. This is indirect lasing… same as a coating on glass.
The problem is exacerbated by the color additive being near the laser light color as that, by nature, is highly reflective at the beams frequency…
Thanks for posting the solution. You figure it out on your own 
I think much of this is from advertising that the visible laser will cut/engrave acrylic, when it really can’t. Acrylic is naturally clear.
Welcome to the forum… if you don’t know, use the search feature 
if you can’t find anything relevant, then post under on the areas for your laser. Yours is a grbl machine and has it’s own area… This allows people with more expertise in that area to see your post quicker.
Do the best you can, is all we ask, same with keywords, it can be moved if it’s an issue, but don’t let it keep you up at night…
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10w diode, Red 2.82mm acrylic (same stuff I use for my viewing windows. Files attached for viewing and LB settings…
LaserMikeyStuffSign.lbrn2 (72.5 KB)
I home-made my stencil font (rectangle and Boolean fix) for the “a” and “e” letters.
Ya I tried it and still just melts my orange transparent acrylic. I have a Fox Alien 40w with a 10w output. I think I need a Co2 laser to do acrylic. What laser do you have?
This was done on a Sculpfun S30 Pro (10w output). Air assist was on. I think the trick is to melt the plastic and blow it out of the groove. I see a lot of fine plastic filaments along the cut path.
Ya I tried it with air assist on and off still no luck
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I have not only found, but have been advised, on the co2 to use as low air pressure as possible when doing acrylic… Seems to work much better, but the co2 is vaporizing the acrylic and it doesn’t sound like the diode can put enough energy in the material to do that.
You’re trying to do something that is on the verge of not really viable anyway, so use what you can to get the best results you can.
Good luck
It may be the composition of the plastic made the difference, and I just plain got lucky.