Took a couple tries but finally got it.
I started off trying to break a bit. I did something like 3mm end mill, 1.5mm doc, 8mm/s. It didn’t like that.
Then I went back to trochoidal milling and was much better. The bit and piece were room temp immediately after the cut. @Michael_Melancon Thanks for this Guide to Milling Aluminum Plates for MP3DP v5 with EstlCAM
This also helped me identify that my core was a little loose. I had to tighten the bolts because I could rock it back and forth.
I think I’ll test for dimensional accuracy next time. Then maybe I can cut out aluminum strut plates.
I did get this onion skin on the bottom of the cut. I can’t figure out why. The aluminum is ~4.8mm thick, and I did like 6mm doc. 0.3mm finish pass. This bit might be a little dull though