Layers shifted sideways
The print suddenly steps sideways part way up, so the top half doesn't line up with the bottom.
Also described as layer shift, shifted layers, print offset, staircase, misaligned layers, skipped steps
Try these in order
Most likely and quickest to check first. Change one thing at a time so you know what fixed it.
Nozzle hitting the print
- Fix curling edges and overhangs that catch the nozzle.
- Turn on Z hop for travel moves.
Loose belt or pulley
- Tension the belts and tighten the grub screws on the motor pulleys (one should sit on the flat of the shaft).
Too fast or too much acceleration
- Lower the travel speed and acceleration until the shifts stop.
Stepper current set too high or too low
Too little current and the motors skip steps on fast moves. Too much and the drivers overheat and cut out for a moment, which often shows up only after the print has been running a while.
- Check the electronics fan works and the board isn't sitting in a hot enclosure.
- If the motors are too hot to keep a hand on, lower the driver current a little. If they stay cool but skip on fast moves, raise it a little.
Something blocking the movement
- Make sure cables and the filament can't snag at the far ends of the bed or gantry.