I experimented slight defect in my printed part, spécially along the y axis when printing perimeters, along the x axis every thing was fine but on the y axis ... (see the picture )
as the size of the ondulation were exactly the same as my t5 belt teeth i tried to slightly thighten it and bingo (look at the pictue the upper part (no more ondulation, and a straight wall.
the way to tighten the belt ? only get the bolt loose one the front rear threaded rod adjust the inner bolts , rethighten the outside ones, you can do that during a print test to see the différence
that was a "from the defect to the caus and (possibly) the cure"
have a nice day
