I have a visable wobble, which prob equates to about 0.5-1mm of runout on my y axis. If I loosen the step motor a little from its mounts you can see the motor wriggling as the ballscrew turns.
I bought the router as a pre built kit, the only part I did myself was wire up the electronics. As the machine is still under warrenty Im a little nervous about removing the ballscrew to check to see if the runout is only in the machine section of the screw.
Would runout be a potential cause of my motor stalling? The manufacture assures me with my setup I should be able to go as high as 7m/min yet I cant go much higher than 2m/min without the motor stalling.
Current is set as high as possible 3amps and the micro stepping is as per the manufactures suggestions.
Slowing the acceration appear to have no effect on the motor stalls.
I would hope that you have mis-alginment, not run out. Alignment can be adjusted, runout would mean that the screw is no good. Old indian trick is to loosen the screws mounts and run it to the motor end, snug that end up. Then run down to the other end and tighten it up, then back to the motor end and tighten. That should roughly align the screw. I only work on metal cutting machines but the theory should be the same. Good luck!
Thanks, I have tried that old trick already unfortunately but worth trying again I think before removing the screw. Its actually a small desktop-ish machine so it can be done without the motor attached and physically pulling the machine back and forward by hand. It was when doing this last time I noticed the wobble in the motor coupler. Because the machine freely travel up and down the full stroke of the axis now I am worried the alignment is prob ok.
If the screw itself turns straight, the coupler may have that runout or the screw end machining. If it is bad enough it might stall the motor and eventually break the motor shaft due to fatigue.
But I suspect the 7m/minute may just be an "optimistic" spec. What is the screw pitch? If it is e.g. 5mm that would be 1400 rpm and pretty high for a stepper.
I agree with Jerry, if the screw runs without any binding it must be close to aligned. Pull the coupler off and indicate the screw end, maybe its not true.
If you have a solid coupling you might want to consider geting a three piece coupling with a softer spider and see if that helps. Also, it is possilbe that the bore of the coupling is too large, and when clamped moves the coupler out of alignment.
I prefer the spider type couplers because they allow me to remove the motor without unbolting the coupler, and along with aiding misalignment the spiders also absorb some shock and vibration, as well as "decouple" the motor from the screw...
Ball screw runout causing motor stall?
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