I have built a little 3D corner object to test the alignment of my UMO. Interestingly, the print is strongly tilted x-direction in the bottom layers (3mm) only, the y-direction looks fine. I have already strongly tightened the pulleys as recommended in older posts. This effect appeared from one day of happy printing to the other...
I am curious to learn your interpretation why this tilt is so much z-dependent.
Thank you,
Mattias