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Under-extrusion means the printer is not depositing enough plastic. Check for a partial clog, filament drag, low temperature, worn nozzle, bad flow calibration, or extruder slipping.
Under-Extrusion Fix Path
Fix Under-Extrusion and Weak Lines Fast
Fix under-extrusion with checks for clogs, extruder grip, filament drag, flow calibration, temperature, slicer profile errors, and material-specific feeding issues.
Fix 3D Printer StringingFix Bed Adhesion ProblemsFix First Layer ProblemsStop 3D Prints From WarpingFix Layer Shifts on 3D PrintsFix a Clogged 3D Printer NozzleFix Over-Extrusion, Blobs, and Rough WallsFix 3D Printing Support ProblemsFix PETG Printing ProblemsFix TPU Printing ProblemsFix Resin 3D Print ProblemsNeptune 4 Pro Troubleshooting HubOrca Slicer Troubleshooting and Settings HubDiagnose Failed 3D PrintsFix Z-Banding and Repeating Layer Lines
What this page helps with
under extrusion, gaps, weak lines, missing extrusion, extruder clicking, flow calibration.
Use this as a landing page first, then jump to the most specific detailed guide below.
What it looks like
- Gaps between walls or infill
- Weak brittle parts
- Extruder clicking
- Thin top layers
- Inconsistent line width
What usually causes it
- Partial nozzle clog
- Filament path resistance
- Temperature too low or speed too high
- Flow rate not calibrated
- Extruder gear dirty or tension wrong
Do this in order
- Confirm the nozzle is clean and material flows smoothly.
- Check filament path drag, spool friction, and PTFE tube condition.
- Run temperature and flow calibration for the exact filament.
- Inspect extruder gear teeth and tension.
- Reduce speed until the hotend can keep up.
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Useful tools
Tools and checks that may help
Nozzle cleaning kit
Flow calibration model
Spare nozzle
Digital calipers
Tool suggestions are context only. Fix the symptom first, then use the right tool if the diagnosis actually points to it. Some recommended-tool pages may include affiliate links with disclosure.
FAQ
Fast answers
What should I check first?
Under-extrusion means the printer is not depositing enough plastic. Check for a partial clog, filament drag, low temperature, worn nozzle, bad flow calibration, or extruder slipping.
Should I change many slicer settings at once?
No. Make one controlled change, test again, and save the working result in Profile Vault. Random setting changes make print failures harder to diagnose.
When should I use AI Doctor?
Use AI Doctor when the symptom is unclear, when the print failed in multiple ways, or when you want to connect a failed-print photo to the right guide path.