From my experience with cutting aluminium I believe coolant and amount of coolant is very important. It is not only cooling factor, but chips removal and lubrication as well.
I use plain diesel, strait from petrol station as a coolant. It's cheap, available, does not cause corrosion and it is not likely to get bad. In fact it protects my machine against rust.
As an example, to cut my aluminium plate for my PC cooling system I used 4 flute HSS 3mm dia end mill available from UK online shop. There was no clogging and broken end mills at all. I don't remember feed rate and DOC( it was few yars back), but most certainly I wasn't creating alu dust.
Obviously using two or single flute carbide bit would be advantageous, but milling in a way I did proves significance and necessity of coolant.