Z-Axis skips

[Clarity 0]

Hello everyone.

Having UM2 Extended for about a week already, and generally it's fine.. Except ABS clogging and one more trouble getting me every few prints. When I leave printer unattended, almost every time at the random layer, platform jumps a good 5 cm down ruining the print. Anyone had this issue? I searched and found only hardware-related issues. but mine seems fine when lowering/raising platform.

Also I'm using cura and sometimes S3D when I need supports. It seems this happens while using S3D, but I'm not completely sure.

Thanks in advance!

[gr5 2,229]

The Z axis jumping suddenly is a new issue and it seems to be related to overheating of the *driver* on the board under the printer. Most people fix it by lowering the current slightly. The issue possibly is *not* temperature related as some people claim cooling the board doesn't help yet lowering the current *does* help. Anyway try adding this gcode to see what happens:

M907 Z1000

That sets the Z stepper current to 1000ma. Default is possibly 1300? I forget. Also consider removing bottom cover, printing with printer at 45 degrees (it will print at any angle and even upside-down just fine) and have a fan blow gently on the underside.

Experiment and let us know what works so I can tell other people. It's really a small percentage of people with this problem (guessing 1% but don't really know) and it's a new issue (something different about the driver chip maybe or just the hot weather?).

[ChrisSalzburg 12]

Thanks! Setting the z-axis current in the ultimaker settings from 1300 mA down to 900 mA totally worked for me