PLA filament was jammed in the extruder gears in the middle of the printing process

PLA filament was jammed in the extruder gears in the middle of the printing process  

New Member


I recently purchased (on 20/4/2020) a fully assembled i3 MK3S printer from Prusa company.

The printer worked without any problem with a very large number of prints.

Recently, using Prusa's Galaxy Silver PLA filament, the PLA filament was jammed in the extruder gears in the middle of the printing process : printing continued but no filament was coming out of the nozzle.

I disassembled the extruder block according to the site's recommendations, removed the pieces of cooled PLA tangled around the gears and replaced the Teflon tube. I reassembled everything and re-calibrated the first layer.

Everything worked fine for several prints, then the same problem appeared again.

I then ordered on Prusa site a complete new "assembled hotend E3D (MK3S)" that I replaced.
I redid a complete calibration.

Two correct prints and then again the same problem: the PLA filament is completely wound in the extruder gears and the printing is no longer done at 4/5 of the model (while the continuous printer worked until the end of the printing process).

I only use PLA, the metal printing sheet is the original smooth model, printing times are 2 to 5 hours.

Can the problem be related to the way I tighten the screw with a spring when I remount the extruder gear block?
Does this spring loaded screw need to be tightened completely?

Thank you in advance for your answers and advice.




Posted : 07/07/2020 10:15 am

the sprint tension needs to be very light. 
My tension screw is barely engaged...  

over tightening the screw can lead to feed problems and filament jamming. 

using PLA in a very hot room or enclosure can also lead to jamming... 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 07/07/2020 11:47 am
New Member


Dear Joan,


Thank you very much for those informations.
I guess the screw with the spring at the extruder gears is much too tight.

On the other hand the problems also occurred after I placed the printer in a closed insulating cabinet (to reduce the noise and to maintain a more stable temperature during the few ABS prints).
I guess the printing with the PLA filaments didn't support this hermetic cabinet.

I'll loosen the screw with the spring, keep the door of the hermetic cabinet opened and redo a print test.

Best regards from Belgium



Posted : 07/07/2020 4:58 pm

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