Alignment issues?
I've got two i3 MK3 printers and one of them seems to have trouble aligning the layers correctly along the Y axis. (See images below for details.) I've checked the belts (their tension values are just about even at 272/277), but it keeps "drifting" when I try to print something. What's causing this?
Re: Alignment issues?
The belt cal tension values are - in my opinion - at best "in the ballpark" values. I can swing the tension from too loose to too tight and not see much change in the reported values. I think of the tension as a "gain" value for the axis. Tighter, or even stretched, means a longer print axis. Looser, means wobbly head placement. Maybe printing a 200x200 plane to ensure the design size matches print size is a better way to tension the X & Y belts.
Thinking out loud, a random wobble could mean belts are too loose, with the part exhibiting a few overhangs or even a few lean spots. But I'd expect this would also show up on layer 1 uniformity. This seems to fit the issue in the fist photo, where it looks like X and Y are dithering.
The second photo looks to be some other issue. It looks more like drift rather than dither. Misaligned Z axis rods changing X tension as the head raises? Or something below the bed rubbing the Y belt as the bed moves to that end?