Under-extrusion (gaps, thin walls, weak parts)
Walls have gaps or holes, top surfaces look porous, and the part feels weak and snaps easily.
Easy under extrusion underextrusion gaps in walls thin lines
Likely causes
- Clogged or partially clogged nozzle
- Extruder slipping or grinding the filament
- Flow / e-steps set too low
- Printing too fast for the hotend to melt plastic
- Nozzle temperature too low
- Filament diameter out of spec or tangled spool
How to fix it
- Do a cold pull or replace the nozzle to clear a partial clog.
- Check extruder tension and look for ground-up filament dust near the drive gear.
- Calibrate e-steps / rotation distance, then fine-tune flow with a flow test.
- Reduce volumetric flow: slower speed, bigger nozzle, or a high-flow hotend.
- Raise nozzle temperature by 5–10 °C and re-test.
- Measure the filament with calipers at several points; replace if it varies more than ±0.05 mm.
Work through it in order
The fastest path to a fix
Change one thing at a time and print a small test. Start with the first fix listed — it is the most common cause.