Small waves instead of straight lines printed!

[Othman 1]

We started to have this problem recently. Instead of straight walls, we get small waves! See pictures attached.

I think it is a hardware problem but I am not sure where exactly is the problem and what to do.

If you have any idea please comment.

Thank you.

[IRobertI 521]

Possibly the infill showing through to the surface. Try un-checking "Infill before walls" and see if that helps.

[Othman 1]

Possibly the infill showing through to the surface. Try un-checking "Infill before walls" and see if that helps.

 

This option is un-checked already.

[IRobertI 521]

Does it happen with every model or just some? If you look at the layer view in cura, what does it look like? The ridges seem to line up with the little "spikes" on the top, maybe there's something weird going on in the exported model that is causing it?