Layer shifting: the print slides partway up

Likely causes

In order: the most frequent cause comes first.

1. 01The head collided with the part — usually with an area lifted by warping — and lost steps
2. 02Slack belts or loose pulleys on the axes
3. 03Acceleration or speed beyond what the mechanism can take
4. 04An overheated motor or driver losing torque
5. 05A mechanical obstruction: a cable, a dirty rail or a seized bearing

How to fix it

Apply one fix at a time and reprint the same test part. Changing three settings at once tells you nothing about which one worked.

1. 01

   Check belt tension and pulley grub screws

   Medium

   With the printer off, move the head by hand: it should glide with no tight spots and no play. Pluck the belt: it should sound like a taut string, not slack. Check the pulley grub screws are tight on the flat of the motor shaft; a pulley spinning on its shaft produces exactly this failure.

2. 02

   Lower speed and acceleration

   Easy

   Cut print speed by 30 % and acceleration by half, then run the part again. If it no longer shifts, the problem was mechanical over-demand, and you can raise things gradually again until you find your machine's real limit.

3. 03

   Eliminate the warping that causes the collision

   Medium

   Many shifts are not an axis fault but the consequence of another problem: a lifted corner gets in the head's way and pushes it. If the shift coincides with the height at which the part began to curl, tackle the warping first.

4. 04

   Clean and lubricate rails and rods

   Medium

   Dust and hardened plastic debris on the rods increase friction until the motor loses steps. Wipe with a lint-free cloth and apply the grease or oil the manufacturer specifies, never WD-40, which washes the original lubricant away.

How to prevent it

• —Check belt tension every few weeks of heavy use
• —Do not raise speed and acceleration together: change one parameter per test
• —Stop warping before it grows enough to get in the head's way
• —Keep the rails clean and apply the recommended lubricant

Sources

1. [1]Layer shifting | Prusa Knowledge BasePrusa Research · Manufacturer · accessed July 27, 2026