Engraving Acrylic

[badboys cnc]

I do a lot of lighted acrylic signs. I'm using a carbide 45 or 60 degree cutters. I cut between .o15 to .o35 deep. I have tried spindle speeds of 10,000 to 14,000 RPM, and feed rate of .3 per second. I installed a mister on the shopbot and run water and a little bit of Johnson baby oil in it. This has helped 90 percent to stop the chips from sticking in the groves. But still not 100 percent. I then have to try and scrape the rest out by hand or with air hose. If I'm not careful I will scratch the acrylic. Not good. Any ideas? thanks

[coryatjohn]

I'm guessing the basic issue here is insufficient heat removal. Either increase the feed rates or decrease the RPM's to increase the heat rejection. The chips are sticking because they are partially melted.

[garyb]

As coryatjohn noted above your not hitting the chipload with your feed and speed.
for acrylic, 48ipm 8000rpm for small letters (.5), 60ipm 10000 for larger
then you don't say what tooling your using, not all v-bits are suited to cut plastics so your tool selection maybe a hindrance to your cut as well.
Gary

[jerry_stanek]

Are you using cast or extruded acrylic that make a big difference

[badboys cnc]

Which is better. I can get both. Thanks

[Rick W]

Which is better. I can get both. Thanks
Cast acrylic is best.

Rik

[coryatjohn]

Cast is also usually more expensive... I don't think there's much 1/4" cast acrylic around.

[jerry_stanek]

Cast is also usually more expensive... I don't think there's much 1/4" cast acrylic around.

I use a lot of 1/4 cast acrylic many different colors Most I cut on my laser but I do some on the bot. Easy to get cast if you order from a supplier