Under-Extrusion
Under-extrusion produces prints with gaps between lines, weak infill, missing layers, or rough textures. Walls appear thinner than expected and the print feels fragile.
Example
Root Causes
Partial or full nozzle clog — most common cause
Print temperature too low — filament not melting fast enough
Print speed too high — extruder can't keep up
Extruder tension too loose — filament slipping on drive gear
PTFE tube degradation creating friction (Bowden setups)
E-steps not calibrated — extruder not pushing correct amount
Filament diameter variation — thicker sections resist extrusion
Validated Solutions
Perform a cold pull to clear partial clogs (heat to 200°C, cool to 90°C, pull firmly)
Increase print temperature by 5-10°C to improve flow
Reduce print speed by 20-30% to give extruder time to keep up
Check and increase extruder grip tension
Calibrate E-steps by measuring and adjusting extrusion multiplier
Increase flow rate / extrusion multiplier by 5% in slicer
Replace PTFE tube if degraded (yellowed or rough interior)
Perform atomic pull and then hot tighten nozzle while at temp
Slicer Settings to Adjust
Print Temperature
5-10°C
Print Speed
20-30% reduction
Flow Rate / Extrusion Multiplier
5% increments
The AI uses this knowledge base when analyzing your prints. Upload a photo on the Analyze tab to get personalized recommendations for your specific print.