Skipped Layers and Gaps¶
The term "skipping layers" often describes a print defect where it appears that one or more entire layers are missing, leaving visible horizontal gaps in the model and making it extremely weak.
Is it a Z-axis problem or an extrusion problem?
While it might look like the Z-axis failed to move up, this issue is almost always a severe case of under-extrusion. The printer did move up to the next layer, but it failed to extrude any plastic (or extruded very little) for that period.
Primary Cause: Severe Under-Extrusion¶
This problem shares all the same causes as regular under-extrusion. The issue has simply become so severe that extrusion stops completely for a short time.
The most common culprits are:
- A Partially or Fully Clogged Nozzle: Debris inside the nozzle is preventing the flow of plastic.
- A Dirty Extruder Drive Gear: The gear that pushes the filament is slipping because its teeth are clogged with plastic shavings.
- Heat Creep: Heat is traveling too far up the hotend, causing the filament to soften prematurely and jam before it reaches the melt zone. This is often caused by a failing hotend fan.
- Incorrect Temperature: The printing temperature is too low for the filament, making it too viscous to be extruded properly.
How to Fix It: See the Under-Extrusion Guide
Because this is an extrusion issue, the solutions are covered in detail in a separate guide.
➡️ Please refer to the Troubleshooting: Under-extrusion
guide for a complete step-by-step list of solutions.