I’m making a control panel for an electronics project and so I’ve been trying to cut some reasonably thin acrylic (0.093″) using my mill. My approach has been to cut it using multiple passes through the material, taking anywhere from 0.005 to 0.01 off in each pass, using a feed rate between 5 and 6. I’ve tried a few different kinds of bits (1/8″ mill end, 1/8″ round burr and v-shaped), but the results seem to be the same: once the bit is about half-way into the material, it gets heated up to the point where it starts to melt the acrylic. :( Occasionally I’ll get a good cut, but those results aren’t repeatable. Does anyone have any tips for cutting acrylic without melting?
Paul, as with any material, the bit makes all the difference. This becomes especially apparent with acrylic.
Generally speaking, you want a bit that clears away a good amount of material to minimize heat. A bit with one or two flutes is a good start. Also you’ll want to use a relatively slow spindle speed, and a faster feed rate (you’ll probably need to experiment as this will depend on a lot of factors).
Here are a couple good sources for bits specifically made to cut plastic:
You could also try exporting multiple toolpaths that start at different heights in the material. With this solution you’d run each file and wait for the bit to cool in between. You could also look at adding “dwells” at different parts of the .NC file by hand, but you’d want to make sure the dwell happens out of contact with the stock to be cut.
Example: G4 P5, where G4 means “dwell” and P5 means 5 seconds.