I have been trying to machine these extrusions for awhile now with no success. I work at a door manufacturing company and we recently purchased a CNC machine. The extrusions can be anywhere between 30"-96" in length and typically 1"-6" in width/height depending on the piece. Throw in some dove tails and these are a nightmare to machine if you are new to this. I have been using a single "O" flute endmill for a lot of the machining and then a double flute pocket endmill for the pockets. Both are 3/8" and that is all I really have access to at this time. I don't have to make any arbitrary shapes or anything just simple holes, squares and rectangles so our prep devices can fit inside of the extrusion. I can machine most of what I need but I am not getting nearly enough tool life. I have broken both bits quite a few times now. The "O" endmill leaves a nice finish and the harmonics are not bad. The pocket em leaves chips embedded into the finished piece but the harmonics sound fine. Both endmills are carbide. I am at a loss.

I run the "O" EM at:

16,500 RPM's
10 IPM
5 down feed

Double flute pocket EM at:

18,000 RPM;s
15 IPM
5 down feed

Thank you,