After some thought I think the motor tuning on the machine caused the shaft failure.
I used a function generator to create an instant forward / reverse so I could see the wave form at the G320 test point on the scope. That's all fine when there is nothing being driven by the motor. But ... I left the belt hooked up so I was instantly reversing about 30 - 40 pounds of ball screw and 400 lbs. of bed. I'm thinking all that that inertia against the instantaneous torque of the motor, effectively at stall, was enough to start the failure. Didn't help that the 1/2" shaft was turned down to 3/8" and the inside of the shoulder is very sharp on these motors.
So ... when I go to tune the others I will remove the belts and sheaves. Found some replacement NEMA 34 motors @ CNC4PC and they are on order.
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Re: Update on X-Axis
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