It looks like you have done your homework and are already getting pretty good results, so I’ll just add a few miscellaneous notes:
- a jet of air directed at the cut will be a long way to clear chips and get uneventful cuts. You don’t seem to be using one ? (at least in that video).
- bonus points for having a mister installed that will inject a small percentage of lubricant in the airflow
- single flutes are excellent for cutting aluminium: better chip evacuation, less chip recutting.
- you could cut with a deeper DOC since you are using adaptive clearing. I use helical ramping always.
- I probably wouldn’t use a 20% optimal load myself, I’m more comfortable in the 10% zone for metals.
- note that the actual chipload is lower than you mention, due to chip thinning, due to the 20% stepover.
- which means the #201 chipload is probably a bit low (below 0.001") and hence the risk of melting, especially with a three-flute uncoated endmill. The actual #278Z chipload sounds right (after chip thinning)
- I would have advised checking my intro to feeds and speeds, but it looks like you already know about all that?
- slotting is always hard, and harder in metals: avoid whenever you can (i.e. use a smaller endmill and adaptive-clear a channel, to make the slot)
- consider using a feeds and speed calculator to optimize your cut parameters ?
@gmack produced the worksheet that rules them all, see :
Speeds, Feeds, Power, and Force (SFPF) Calculator