Ultimaker 1+ build but... you have to see this one for yourself...

[valentt 0]

Any ideas what is happening here?

[fbrc8-erin 176]

Well, that looks fun.

Is this a UMO+ or a UMO with a heated bed kit?

It looks like you probably have a loose pulley on your Y-axis, so the motor is missing steps. Check all of the set screws in your pulleys and on the Y motor itself to make sure they are tight. If you try to home the head, does it move smoothly, or does it struggle?

If your XY axes haven't been lubricated recently, you may want to check and make sure they are; the motor can miss steps if it can't move smoothly.

[Titus 170]

Micheal Jackson Smooth Criminal lean!

Check this out

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#shifted

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#leaning

[anon4321 16]

Awesome overhangs though!

If you don't find a loose pulley, although less likely, check that the steps per mm are the same for both X and Y.

[valentt 0]

Thanks, there were few screws loose on pulleys. Everything works great now.