Traditionally, 2 flute end mills have been the preferred choice for Aluminum. However, 3 flute end mills have proven to be more successful in many finishing operations, and with the right parameters they can also work successfully as roughers
Is 2 or 3 flute better for aluminum?
Material Considerations
The widely accepted rule of thumb was to use 2 flutes for machining aluminum and non-ferrous materials, and 4 flutes for machining steel and harder alloys.
What is the best coating for aluminum endmills?
The diamond and DLC coatings result in a very smooth chemically inert surface. These coatings have been found to significantly improve tool life when cutting aluminum materials. Diamond coatings were found to be the best performing coatings, but there is a considerable cost related to this type of coating.