A customer was trying to decide whether to use a 2-flute or 4-flute carbide end mill for his job on aluminum. One important question before spending the extra money for a high-performance tool, is how many parts are you making?
I think one you
might look at is our part number 136475. This is 1/4" x 4" long with
a 1" length of cut. The number of flutes is a trade-off between better
finish and better chip evacuation. Sometimes with softer grades of aluminum the
flutes could get clogged up, but as long as that is not an issue for you a 4
flute will give you a better finish and do more work per rotation of the tool. I
think a lot of people are using this tool for doing a similar application. There
is also a popular one with the gunsmiths that is specifically for aluminum. The
part number is 150104 (150027 for uncoated). This is a high-performance tool
that is capable of doing long production runs and much high speeds & feeds
than the standard tool, but if you are not doing a large quantity it would
probably be more than you need. The high performance ones have 3 flutes, a
deeper clearance between the flutes for better chip evacuation and an optional
ZrN coating specifically for aluminum and other non-ferrous metals. The
high-performance also has a 45 degree helix instead of the standard 30 degree.
This provides a better finish due to a shearing action of the flutes and also helps
get the chips up and out. The main reason carbide end mills fail is when the
re-cut a chip from the previous machining, so the chip evacuation is important,
but if you are doing a smaller quantity you can try to use air of fluids to
keep the cutting area clear from chips.