Last night I developed an intermittant Y axis layer shift issue. Mechanically, I have the belt very tight, the teeth all look intact, the set screws on the 16 tooth pulley are all down tight and in the correct spot, the idler and the tensioner is all tight and not missing any parts, and the belt clips under the heated bed are screwed down and intact. The print head isn’t hitting anything, and none of the cables are getting snagged. I’m kind of at a loss as to what could be causing it. Is there anything electrical in the motor or controller that could cause an occasional shift like that? I’m not printing any faster than I have been for moths now and nothing else has recently changed. Any ideas? I do notice that the Y axis Nema motor gets warmer than the others.
Nevermind, turns out my tensioner was cracked on the back side where I couldn’t see it, and was holding tension enough for most operations, but would occasionally shift. Put the backup back on, and now it seems to be fine. Remind me to make a stouter one of those.