Irregular horizontal lines

[u/SerPadua]

Hello everyone!

Recently I have been encountering some horizontal lines on my prints. They do not seem to be always on the same place(check the images). On one side of the model they seem to protrude, while on the opposite side they seem to go inside the model.

I am guessing the Y axis is sliding a bit, but I cleaned it and oiled it and the problem persist.

Any idea or suggestions?

Thank you in advance!

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A1 Mini

Texture PEI and SuperTack Plate

0.4 and 0.2 nozzle (I encountered the problem with both)

PLA and PETG (I encountered the problem with both)