I'm really trying to cut down time to make some parts. So last night I gave trochoidal tool paths a shot with the deep DOC and low WOC. Go into FSWizard put in my parameters.

Material: 6061 aluminum
TOOL: 0.5 in dia, 2 flute, HSS, 1 in flute, 1.5 in stickout, 0.375 in shank.
Engagement: 0.375 in DOC, 0.05 in WOC, 4000RPM

It spits out 42IPM feed rate! Only 0.3 HP though, I thought it was a bit fast so I cut it to about 75%, 30IPM and thought F it, if I break something I will just fix it, its worth the experiment. Well that feed rate was just too fast. Either the spindle doesn't have enough torque, or it doesnt respond fast enough cause it would bog down pretty fast. I dialed it down to 40% feedrate (~12IPM) and it was a lot happier, but still would dip down to 3800RPM on some of the cuts mostly where it initially makes contact with the work piece, and stalled at one point where the cut was approaching that of a slot.

It cut down the time substantially though. As this operation took only 1 hour (even with slow rapids) vs 2 hours. For the next set I was thinking of switching to a 3/8" endmill and roughly same parameters 0.375 in DOC , 0.0375 in WOC, 4000RPM, maybe 20IPM. Or run the same 0.5 in endmill, and 0.25 in DOC, 0.05 in 15IPM.

Maybe my cuts are too aggressive? I didn't notice any chatter, so I'm suspicious that the spindle motor just isn't up to the task. Maybe there is a pot on the controller I can adjust (the motor gets pretty warm already though)? I really wouldn't mind upgrading it with something with some more oomph that I can interface with mach, maybe VFD controlled? I did some searching, and didn't get into the build threads, but it seems that most of the inquiry's don't provide any part numbers. I also looked on bf20.com/projects2 and most of the links were broken, but searched the part numbers and found them. Still I'm not sure what to go with.

What have you guys used to upgrade the spindle motor, what would you recommend? If you have something in your build thread please leave a reference.