cutting conditions for 5/16 aluminum "FO3015 Amada laser? 2

I have never cut 0.312 but this is my condition for 0.375 hope this helps
FEED 15 ipm
PWR 4000
FREQ 2000
DUTY 100
GAS PRESS 0.6 Mpa
gas shop air
focus -0,25

I agree with maayhemm's recommendations with the only variable being the focus point in relation to the material. In thick aluminum cutting (specially anything thicker than 0.25") you want to have a shallow focus point in order to not only cut but pierce easier as well. The dross on the material will be longer (almost shark-teeth like) but will be easier to remove. I would recommend cutting it with nitrogen although shop-air does well on this material but the oxygen percentage in it will make the dross a bit harder to remove.

I would certainly use a 4.0mm double-nozzle as well.

Good Luck.