Hi JazzCNC,

Thanks for the fast reply. Now I understand the situation. OK, here is what I would do if I have to use a single flute cutter for aluminium:
My rule specially for aluminium is Fz=D/100 or for example if you have 6mm diameter cutter your feed rate will be Fz=0.06mm/rev. And if you have available 10000 rpm, your feed rate will be F=600mm/min. I would not go more than DOC=1D
and WOC=1D.
Always helical plunging if it is possible as F=1/2 for the plunging. The single flute should go straight plunge (drilling) with no problems. Finally, It really depends of the carbide grade of the cutter. It might not be suitable for high speeds. Recently, I did a custom order for 3 flute uncoated cutters for aluminium. I made 12mm cutter with 45deg spiral. The tool has 24mm working length and 80mm total length. The carbide material of this cutter is WC25, a grade for stainless steel processing. This cutter works since four weeks, it is still in use and it works with S=10000rpm and F=3800mm/min.
So, if the single flute cutter brakes on the recommended cutting conditions, I am sure we can fix this problem with custom made tool. The good part is that the price is the same as the standard one, but there is a requirement for min 5 cutters.
I have one of those 12mm cutters left. If you want I will send you to try it or to some friend of you.