I’ve seen this problem on and off with my MPCNC and another one I built for my Dad. However, I’ve recently been trying to cut aluminum which is causing the issue every time. The z-axis will drop several millimeters mid cut causing me to abort. It usually happens 10ish minutes in. You can see how it gouged the aluminum while adaptive clearing in the picture. It happens with gcode generated by both Fusion 360 and FreeCAD. The end mill is not dropping out of the spindle (can happen when it heats up and the nut isn’t tight enough). Also, my machine is as low as possible. I have maybe 1.5" of workable Z. It’s almost like the z-motor cuts out for a second. I didn’t feel how hot it was getting but the motor isn’t under much stress.
Any help would be appreciated. Thanks.
Arduino + Ramps 1.4
DW660 (also happens on my 52mm spindle)
Single flute 1/8" flat end mill (the one from the V1 store)
Nema 17 motors (2A, 59Ncm)