[Ripthorn]

I have a MaxNC 15 that I recently got up and running. I tried running my first piece through it today and found that my z measurements were all wonky. I found that it is because it seems the Z stepper is missing steps during it's last inch or two of travel in the negative direction. I am running LinuxCNC and tuned the motors, but I did all that with the Z at the middle of its travel where it does not seem to miss steps. What should I check? Also, my max speeds seem really low, like 6 ipm for z, 10 or 15 for x and y with low accelerations of like 1 in/s2. Just wondering what to check to get this all up and running. Thanks.

[pws]

Sounds like your Z axis ball screw is out of alignment and binding. I would give a go at aligning it end to end.

[Ripthorn]

I turned it by hand some and found that it took more force to turn near the end of the travel. Lubed it up and it helped some. Then I checked my driver board again. Turns out it was set for too little motor current, so I upped it and it seems to be working just fine now. Though the ball screw probably could stand some alignment.

[wizard]

Ball screw or ways. To isolate you need to disconnect the screw in such a way that it doesn't impact manual sliding of the saddle on the ways.

Either way you need to find the problem as excessive binding will lead to rapid wear. Worst your lost steps could end up random if it binds just enough to cause problems from time to time. The low driver currents on the motor board may of been a good thing for you if they caused you to look at the mechanics like this.