For Christmas my daughter got a Ukulele from my mother. It seems like every waking moment since then she walks around the house playing it and making up songs. She wanted a pick for it so we decided to try making one out of some 1/32" acetal plastic I had and wanted to test with anyhow. I’d already created a Reuleaux triangle shape for a rotary engine design I was working on and decided to use that. It even had a hole in the middle with gear teeth that might be interesting. I made an alternate one with a simple star pattern in the middle as well which was good in the end since it worked better. Turns out the many tiny gear teeth of the original one pushes too much heat and just melts out the center (and maybe starts burning the rest of the material away a bit until you blow it out ). I also had my original settings too high with power 100 and speed 30 (very melty), then 50 (still too melty), then 80 (pretty close but still a smidge melty), then 100 (not quite enough to get through in all spots) and finally at speed 90 which worked well.
Here are some of the first attempts with different speeds and scale adjustments.
In general acetal seems to be a more melty material than acrylic is so the edges can often round at the corners (always makes me wonder what would happen if you tried to laser cut shrinky dinks… ) These were done at speed 50 and the star pattern was usable, but the gear one was just a mess (but being a non-stick material, it was easy to clean up!)
This one was done at speed 80 and turned out better.
Here’s the two next to each other
Then, because I’m a dad, I made this one and told her it was a pick-achu