ExtrudoWhy is my 3D print nozzle clog mid-print?
Nozzle clog mid-print is usually caused by debris or heat-damaged plastic is blocking the nozzle, often from heat creeping up the melt zone. Extrusion slows or stops completely partway through a print, even though the printer keeps moving
Photo coming soon — this slot fills in automatically when a maker opts in to share a diagnosis of this defect.
Quick reference
| Defect | Most likely cause | First thing to try |
|---|---|---|
| Nozzle clog mid-print | Debris or heat-damaged plastic is blocking the nozzle, often from heat creeping up the melt zone | Do a cold pull |
What it looks like
Extrusion slows or stops completely partway through a print, even though the printer keeps moving
Most likely cause
Debris or heat-damaged plastic is blocking the nozzle, often from heat creeping up the melt zone
How do I fix nozzle clog mid-print? Step-by-step
- 1
Do a cold pull
Heat the nozzle, then let it cool to about 90°C and pull the filament out firmly to remove the blockage.
Done when: The pulled filament tip is clean, not burnt or ragged
- 2
Check the cooling fan on the heat break
Make sure the small fan that cools the area above the nozzle is spinning and unobstructed — if it fails, heat creeps up and jams the filament.
Done when: Heat break fan spins freely and blows air when powered
- 3
Inspect the PTFE tube
If your printer uses a PTFE tube, check it isn't scored, deformed, or gapped from the nozzle — replace if damaged.
Done when: Tube is smooth inside and seated firmly against the nozzle
Frequently asked
What causes nozzle clog mid-print in 3D prints?
Debris or heat-damaged plastic is blocking the nozzle, often from heat creeping up the melt zone
How do I fix nozzle clog mid-print on my printer?
Follow the step-by-step fix above, starting with "Do a cold pull". Each step includes a "done when" check so you know whether it worked before moving on.
Is this fix confirmed by other makers?
This entry is part of Extrudo's seeded defect library. Confirmation counts appear once real users report the fix worked.
Not sure this is your problem?
Upload a photo of your print and our AI will diagnose the exact defect, cause, and fix in under 30 seconds — free, and no account needed for your first case.
Diagnose my print