I know how frustrating it can be when your 3D printer suddenly stops extruding filament. However, there are several things you can try to get it working again. With a bit of troubleshooting, you’ll likely be able to identify and fix the issue.
Check for Physical Obstructions
The first thing I do when my printer stops extruding is check for any physical obstructions preventing the filament from being pushed through.
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Examine the extruder gear to make sure filament is making contact with the gear teeth and being gripped properly. Remove any small bits of filament that may be stuck in the gear teeth.
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Check that the filament path through the extruder and hot end is clear. Look for clogs or jams and clear them out.
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Verify the filament spool can unwind freely without snagging. Untangle any filament that may be wrapped around the spool.
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Disassemble the hot end and extruder to inspect for clogs if needed. Be very careful not to damage any parts while disassembling.
Thoroughly checking and clearing the extruder path is often enough to get filament flowing again.
Adjust the Extruder Spring Tension
If no obstructions are present, another common issue is improper extruder spring tension.
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The extruder arm spring needs to grip the filament tightly, but not so tight that it flattens the filament.
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To adjust tension, turn the screw on the spring to compress or decompress it slightly.
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Do small increments of a quarter or half turn at a time.
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You want enough grip to avoid slipping but not so much it squashes the filament.
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After adjusting tension, try to manually push filament through the hot end while the extruder motor is disengaged. It should have some resistance but still be pushable.
Getting the spring adjustment right usually fixes extrusion problems for me when changing filament types and diameters.
Increase Nozzle and Extruder Temperature
Another issue may be that the nozzle and/or extruder temperatures are set too low for the specific filament type you are using.
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Refer to the filament packaging for the manufacturer’s recommended temperature range.
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Increase nozzle and extruder temperatures 10-20°C above the minimum recommended temperature as a test.
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Give the hot end time to fully heat up at the new temperature before trying to extrude filament.
I find some filament types need temperatures towards the higher end of the recommended range, especially for the first layer. Increasing temperatures helps filament melt and flow easier.
Check for Slippage Problems
If filament is moving through the extruder but not coming out the nozzle, there may be slipping or stripping issues:
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The extruder gear needs good grip on the filament to push it through the hot end without slipping.
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Check for smooth or shallow teeth on the extruder gear that may be worn down. Replace the gear if damaged.
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Lubricants or additives on certain filament types can reduce grip and cause slippage. Try wiping the filament clean before loading.
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Too much spring tension can flatten the filament and cause the gear to slip instead of grip. Loosen tension if needed.
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Stripping occurs when there are gaps between melted filament in the hot end. This prevents a solid column from being pushed through. Increase hot end temperatures to improve melting.
Addressing these slippage problems will improve the extruder’s ability to grip and drive the filament.
Check for Heat Creep Jamming
Heat creeping up from the hot end into the cold end can cause jamming issues. Signs of this include:
- Filament getting stuck in the throat/cold end above the melt zone.
- Clicking sounds as the extruder tries to push filament.
- Having to increase retraction settings to avoid clogging.
To help prevent heat creep:
- Improve cooling on key parts like the extruder, cold end, and stepper motor. Direct fans, heat sinks, and thermal paste can help.
- Slow down print speeds to reduce heat buildup.
- Consider upgrading to an all-metal hot end which is less prone to heat creep.
Controlling temperatures is crucial to avoid softening filament prematurely before it enters the melt zone.
Check for Clogged Nozzle
A partial or full clog in the nozzle itself can also obstruct filament. Some ways to clear and prevent nozzle clogs:
- Perform an atomic pull by heating the nozzle to printing temperature, then allowing it to cool slightly before quickly pulling out the filament. This can help dislodge debris.
- Replace the nozzle with a brand new one to ensure a perfectly clear opening. Use proper tools to avoid damaging hot end parts.
- Increase nozzle temperature by 10-20°C to allow filament to liquify more easily.
- Slow down print speed to reduce pressure and shearing forces in the nozzle.
- Install a nozzle with a larger 0.5mm opening that is less prone to clogging.
It takes patience, but carefully breaking down, checking, and cleaning the extruder components will usually get your printer extruding happily again. Don’t give up!
