How to fix filament grinding

In this article you will learn to fix issues that result in the filament being damaged before reaching the hotend




grinded filament

BCN3D printers extrude the filament by pushing it between two gears that spin. The gears bite into the filament to move it up, but in the case the filament gets stuck, the gears will continue spinning and consequently damaging the filament. You can identify this problem by looking at the filament after it has passed through the motor.


In this article, you will find the most common problems and some tips to fix it.


Material configuration

bcn3d stratos interface

In most cases, the wrong Stratos profile configuration can cause underextrusion or other printing issues that result in the material being grinded.

underextrusion caused by hostile retraction settings Stringing in the model by a worse configuration of the retractions


Note: BCN3D Stratos profiles have been tested by our laboratory team to achieve the best print quality and avoid the most common printing issues. If you are using third party filaments, you can use the generic profiles or get in contact with the manufacturer to get the best configuration.

Hostile retraction settings

retracciones1 Cropped

The retraction settings are usually tweaked to avoid printing issues like stringing but a very high retraction speed or a very long retraction distance can cause grinding issues. We recommend a maximum retraction distance of 7mm. You can also try to reduce by 10mm/s the retraction speed to see if the issue is solved.

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If you want to learn more about the retraction settings and how to modify them, visit the following article: BCN3D Stratos: Retractions.

Low printing temperature

temperatura Cropped

If the material is not being melted at enough speed, it will get stuck on the hotend while the motor keeps pushing which results in it being grinded, try to increase the temperature by 5ºC or 10ºC to help the filament melt in time.



Warning! Check the datasheet of your material before increase the temperature, a high temperature can burn the filament inside the hotend and clog it.

If you need the technical sheet for the BCN3D filament, you can check the filament category in our knowledge base: Filaments

Printing Speed

Printing at high speed means that the gears on the motor will spin faster. During long time prints, the filament can get grinded by the friction between the components of the extruding system and the high speed of the motor. To fix it, you can reduce the printing speed allowing the extruder motor to work at lower pace; try to reduce the speed by 50% to check if the problem is gone or decrease the speed in steps of 10mm/s.



Mechanical issues

The configuration is not the only cause of the grinding problems, if you have already checked the steps above, the following steps will help to solve any mechanical issue that cause grinding.

Hotend clog

hotend cleaning epsilon series

If you use different materials or the wrong configuration, parts of the filament can get stuck on the hotend and produce grinding on the filament, to avoid and solve it, is recommended to clean the hotend frequently; these guides will help you through this process:

How to clean the hotend (BCN3D Sigma)

How to clean the hotend (BCN3D Sigmax)

How to clean the hotend (Epsilon Series)

How to clean the hotend (Sigma Series)

How to unclog a hotend

Maladjusted extruder motor thumbscrew


If the extruder motor is not properly adjusted, the gears might not be able to grab the filament or the filament gets crushed by the high pressure. To adjust it properly, fully screw the knob and then loose one turn.



If you have the R16|R17 extruder motor the screw needs to be positioned at the same high as the block.


Damaged bowdens

bowdens Cropped

The filament travels through the bowden which causes some friction during all its curve; if the bowden is damaged, the friction at the damaged point can cause the filament to get stuck. Visually check if the bowden has a notch. Insert a filament through the bowden to check if it can flow easily.

Get in contact with your distributor or with the BCN3D support team to get a new one in the case that it is faulty.



Remember to clean the extruder gears if you had experimented this issue:

How to clean extruder motor (BCN3D Sigma)

How to clean extruder motor (BCN3D Sigmax)

How to clean extruder motor (Epsilon Series)

How to clean extruder motor (Sigma Series)


If you still experience filament grinding issues, get in contact with our support team by filling this form.

Forum community 

The repair didn’t go as planned? Check out our forum community for troubleshooting help.


It's important to keep your printer in good shape to make the most out of it. In this chart, you can find a list of the extruder maintenance procedures and how frequently these should be done. 

Maintenance Plan (BCN3D Sigma)

Maintenance Plan (BCN3D Sigmax)

Maintenance Plan (Epsilon Series)

Maintenance Plan (Sigma Series)


bcn3d-recycle  Take your e-waste to a certified recycler. Check how we do it in BCN3D.



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maintenance eng


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