I'm looking at milling some parts from 6082 Aluminium, however they involve 2mm radius corners and 8mm depth, so I'm looking at 2x cut depth to diameter ratio, if I go for a single slot.

In steel this wouldn't bother me, as I'd just use a bit occasional WD40 application combined with yhe occasional blast with the airline to keep as much of the swarf out the cut zone, however I know this technique doesn't work well when dealing with aluminium that prefers to stick to cutter edges for the slightest reason and start a terminal spiral for cutter life.

My current thinking is use a 5mm cutter to do a rough profile (I'm using a 5mm as it's the best compromise for a few surface features I need to do first), leaving 0.1, and maybe 0.5mm depth, then swap to a 4mm cutter for a couple finishing passes, with the last being at full depth.

I know the best option is flood coolant, however it's not an option on this mill.

So any hints/tips from anybody who's dealt with deep slots in aluminium without flood coolant?