Nicolinux, Thank you for your suggestions. Thought I'd follow up to close it out for any who may find this. It was effectively an issue with the stepper motor and belt that controls that direction. We tried printing cylinders and variously sliced objects that did not reproduce the issue. It was in a region of the plate where the friction on the pulley belt changed quickly. As best as we could figure, having changes in direction in that region messed with the motors ability to return to the same position, thus it skew the parts in that area. A cylinder didn't have the issue because it would never stop/start in that orientation, just go round and round. It was very subtle.
We "loosened" the tension on the belt a little to reduce the effect of the friction change and the issue went away. Shortly after we replaced the belts and haven't seen it since.
Thanks again (a year later)
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Nicolinux 288
Hi,
first - there is no logic in the forum software to categorize posts. Maybe another admin moved it here because this issue is so much in the "WTF?!?!?" realm that one is not sure where to categorize it
So did you slice with Cura 15.x and 2.x and you got the same skewed model? Then you can rule out the slicer.
Did you print other models just to see if the problem occurs at the same height? If yes, then it might be a hardware problem (loose pulleys if you didn't regard them already).
Another idea could be overheating stepper drivers which cause the motors to stutter and miss steps. I am not sure how the UM2 board handles this, but with a another board on another printer I have seen this behaviour.
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