Z-axis Stepper motor missing steps

Hello all, While I am new to the Zortrax M200, I have built many printers and maintained several more.

I am on my 4th print and it is clear the z-axis stepper motor has started skipping steps. On any other printer this would be a sign of too much friction, bad acceleration curves, or just having the current on the stepper motor turned down too low. The missing steps only happen when raising the platform and I can cause a step loss by lightly pressing down on the bed. I have already checked the coupling since others have had an issue there, but I am quite familiar with the sounds a stepper motor makes when it is missing and making steps and so am 95% sure it is missing steps, not just spinning in the coupler. I will say that the issue mostly happens at one particular point in the rotation of the ball screw and only for large moves. During printing everything is fine because all moves are down and even the up moves are small. But right now during the start of a new print, after calibrating at the middle and the corner it lowers more than 5mm and so needs a full rotation to begin the print and always fails, the print head hovering 2-3mm off of the bed. On any other printer I would have opened the board and adjusted the pot on the z-axis stepper driver to increase the current going to the motor. On a closed machine like this I am unsure.


Check the connector on the motor. I think julia had a bad connector there once.

There’s definitely something wrong if you can stop it so easily with your finger. My platform lifts up very strong.

All, thanks for the consideration, I figured out that the z-axis couplings (didnt know there was a second one underneath) had come slightly askew and thus made the ball screw seize slightly once per rotation. I re-aligned everything and we are back in the game.