Missing Z Steps

[cmcd2820]

Unfortunately, it doesn't happen in the same spot and is not reproducible. I will try to get a picture of the other good prints and the fails to explain better. It seems to be more a 'motor heating and then skipping randomly' error. I did check the pots before I adjusted them and they were at .61 VDC. Can log term overpowering cause permanent damage to the steppers? So now when they get a little hot they skip? Also, I just remembered I have the tubing on the shafts, no zip ties or anything holding them.

That might be it!!!! As the motors heat up, the tubing slips? I'll try that. Is there a suitable coupler I could print? Most that I have seen are metal.