Milling acrylic

A friend wanted 90 silhouettes of the State of Illinois for part of a trophy:

Getting 90 of them milled was quite the learning experience. Here's what I learned along the way.

I used Easel to do the design, because milling a simple SVG doesn't require the functionality of Fusion 360. Plus, I was able to hand the design off to my friend to edit under Easel, something that would have been much more difficult with Fusion 360. The pre-set millings were helpful too.

Lessons:

• You really do want cast acrylic rather than extruded. The extruded acrylic melted, producing cuts that were a bit rough and the bit almost always pulled the acrylic up.
• Tabs are you friend if you want to mill a lot of pieces. But with acrylic the broken off tabs are nasty sharp. I put tabs on the outside of the silhouettes but not the inside, so that the visible part of the design would be clean (the outside is hidden in the final assembly).
• Getting the acrylic from a plastic distributer --- Petersen Brothers Plastic --- worked out better than getting it from a big box store. Cheaper, easier, and better selection than Home Depot.
• My machine was able to cut the 1/8" acrylic in 3 passes, but every now and then the bit would pull the acrylic up off my cutting board. I settled for 4 passes at 45 inch/min, which is 5 inch/min faster than Easel's recommended setting.