So we’ve been encountering a problem with one of our prusa i3 MK3i’s for …like a year now, in which there’s rather horrible layer shifting. Today’s most recent example:
It hasn’t gone away. Some interesting things of note is that it always seems to happen around the same spot ~15 layers up or so. however, i’ve also ran a test print of a really small pillar that went up past the z-level it typically happened with no issues.
Is the printer in stealth mode? usually it would detect a layer shift and rehome, but thats disabled in stealth mode.
You should also debug bearing tension (from surrounding hardware) and verify theres no scoring in the rails. I’ve also seen prusa bearings fail from not being re lubricated.
I solved this problem with my Creality printer once by adjusting the wire management… at a certain height, the wire sleeve was catching behind the printer sometimes and could catch enough to cause the shift. This was an abrupt rather than gradual shift, so I’m not sure this could be your problem, but seems worth mentioning.
Are you running from octoprint/a computer or from SD? In the past I’ve had a number of layer shifting issues when printing over USB through octoprint that went away when I switched to using an SD card. It seemed especially common with small round objects which would have many g-code commands of linear movements to form the arcs.
I don’t think anything catches on anything, I’ve watched the print shift without seeing anything immediately sus.
I also don’t think it’s the gcode’s fault (but not too sure on that); this problem has followed us across slicers - Cura to prusaslicer
Though this iteration of the issue is a bit different from before - before it was an abrupt shift of a few layers of ~3mm and then back to it’s original, repeatedly
Hey! I’ve built a rep rap so I am familiar with all failure modes of 3d printers! This is probably one of three things, stepper is getting too hot and skipping steps (probably not). The stepper driver is getting too hot and shutting off (maybe), or most likely, your stepper current is too low, try adjusting the potentiometer on your main board, clockwise is usually more current. Best of luck, if that does not work it is a loose connection to the stepper. I have had this problem before, let me know if that fixes it!
For what it’s worth, Prusa support is extremely responsive and knowledgeable and has helped me a number of times. Definitely worth contacting them if you haven’t already.
