Need Help: Print is Offsetting in X-Y direction

[Kadu 0]

I have an Ultimaker 2 Extended. I have printed about 30 successful large prints prior to this issue. I repeated the print as I thought it was a fluke but the same issue re-surfaced.

In the above image the item is supposed to be straight in the vertical direction, but it is printing the S curve about 1cm up from the start position. The above was repeated 2 more times in which I decided to post this asking for help.

One thing to note, I noticed that on the X and Y motor some Black Residue, not sure if this is part of the problem or not.

Thanks

Phil

[DidierKlein 729]

Hi and welcome to the community

This is most likely a problem with a loose pulley, can you check if all of them are tightened?

Also check if no belts are rubbing against something (the side panels for example)

[Kadu 0]

After using Sewing Machine Oil on the axis bars the problem is resolved. It seems there must have been sticking while sliding along the rods and the oil fixed it.

Thanks

Phil