Grinding Filament

In most 3D printers, a small drive gear works by gripping the filament and pressing it against a bearing. This gear has sharp teeth that dig into the filament, pushing it forward or backward depending on the gear's rotation. However, if the filament gets stuck while the drive gear continues to spin, the gear can strip away so much material from the filament that nothing is left for the teeth to grip onto. This is often called "filament stripping," as too much plastic has been worn away, preventing the extruder from functioning correctly. When this happens, you may notice small plastic shavings around the area, and the extruder motor may spin without pulling the filament through the system.

Common Causes and Solutions:

Aggressive Retraction Settings

The first thing to check is the retraction settings on your extruder. If the retraction speed is too high, or if you're retracting too much filament, it can place excessive stress on the extruder, making it difficult for the filament to keep up. To test if this is the issue, cut your retraction speed in half and observe whether the grinding stops. If it does, your retraction settings were likely causing the problem.

Increase the Extruder Temperature

Increasing the extruder temperature by 5-10 degrees may help the plastic flow more smoothly if the filament continues to grind. Higher temperatures can make the filament more fluid, reducing resistance and helping to prevent grinding.

Printing Too Fast

If adjusting the retraction settings and increasing the temperature doesn’t resolve the issue, the next step is to slow down the printing speed. A slower print speed reduces the workload on the extruder motor, allowing it to rotate more gradually and reduce the chances of filament grinding.

Check for a Nozzle Clog

If the filament continues to grind after adjusting the temperature and print speed, there may be a partial clog in the nozzle. Refer to the Clogged Extruder article for guidance on diagnosing and resolving this issue.