Blanking...

[tikka308]

What's it called when material (e.g. aluminum) builds up between the flutes? For some reason the term is eluding me...

[tauntdesigns]

Galded

not sure how it's spelled

[Stepper Monkey]

Galling is the term you are looking for I think.

Some aluminum alloys like to do that, some of them are downright gummy. You aren't trying to machine on "found" aluminum are you? If so, just try again on a known alloy designed to be machinable. Some aluminum alloys out there are just not practically possible to machine no matter what you try to use on it.

[tikka308]

No, I'm using 6061 from speedymetals.com. I just ran it too long without coolant and the part got really hot - definitely my fault.

Galling huh? I was thinking the term was "chip welding"

[blades]

Galling is the result of what it does to your surface finish. The material build-up on the end mill was always refered to as "loading up" when I was machining for a living.

When machining aluminum, I used to use a 50%-50% mix of thread-cutting oil and mineral spirits. Always made for a nice surface finish as well. An oil-based cutting fluid will help prevent gummy aluminum from sticking to the end mill more so than a water-based coolant. Of course this may not be practical if you have a dedicated coolant return system in place on your mill.