I am losing steps on my z axis.Belt tension seems OK. The pulley is not slipping on thhe motor shaft. When the machine is on but not running, I can move the z axis up and down somewhat easily by hand. Nothing is slipping - the stepper motor is turning. I can’t do this to the other axes - with a lot of force they don’t move.
Please check and see if your static pulley is slipping (you’ll probably have to disassemble) — it may or may not have a pulley set screw in place, depending on when it was put together — if you don’t have one, might want to consider one, standard M3 grub screw from a hardware store — might be able to make a regular M3 BHCS of suitable length work.
Thanks for the reply! There are no grub screws in the static pulley and I will install some, but I don’t think that it the problem. The stepper motor rotates when I pull on the z-axis hard enough to move it. It doesn’t seem like I am pulling that hard. Could this be a problem with the stepper?
It -should- move in all axis when the power is off, and shouldn’t take much force. If it takes a lot of force when power is off, something is wrong.
If it moves without a LOT of force when the power is on, something is slipping.
As @mikep noted, the motor should hold w/ all of its torque — please check the wiring — if that’s all sound, turn off homing, power down, swap the X and Y connectors and see if the behavior swaps between the motors. Contact email@example.com and we’ll work out getting your machine running properly.