Grinding noise Nextruder when printing PETG
Hi all,
I have my Core One kit assembled for about a month now.
When printing with (Sunlu) PETG, after some time my print head is making a grinding noise...As if material is squished (or gears grinded) when the extruder motor is turning.Print quality is fine, so no things like under/over extrusion, blobs etc. happens.
Somehow I can not upload media on my post to show it in action, but here is the link:
https://storage.googleapis.com/prusa3d-content-prod-14e8-wordpress-forum-prod/2025/08/826eb0d7-pxl_20250804_133715568.ts_.mp4
The squeaking sound does not happen at the start of a print, but after approx 10 minutes and then it will continue.However, the noise is not continuous and is a bit rythmic (as if gears are lubed and then bare again)For longer strokes, e.g. perimeter walls, it will continue making the noise, at shorter strokes (infill) it is this rythmic occurance.
I have checked and re-lubricated the gears, tried to lower the print speed and/or filament flow rate, but so far no luck to resolve the issue.There are teethmarks on the filement when unloaded, but I guess that is a good thing in terms of grip to pull the material into the extruder, right?
When printing with PLA, no problem at all!
My ideas:- Loosen the filament grip somehow?- Play with the flow of material (maximum volumetric flow?) so the flow of filament is smooth and not pushing new filament into the printhead with too much torque, tips?
What are your suggestions to fix the issue?
Thanks!
RE: Grinding noise Nextruder when printing PETG
With a bit of help of Prusa customer service and self-digging, I have found (and resolved) the problem:
Turned out that the plate at the back of the gearbox (the one with 3 holes and 1 cutout for the idler thred-screw) was ever so slightly misalligned, that when temps on the lubricant went up (less resistance?) the gear wheels 'brushed' the back plate with a scraping noise. Maybe the gap also created the possibility for debris to build up behind the plate.
Misalignment might have happened because the idler screw was tighly screwed in and 'pushed' the plate upwards (the screw was touching the plate, it was not just in the middle of the cutout), resulting in the back plate not being perfectly flush with the motor and gearbox.
I have removed all screws (including idler screw). Loosely screwed the idler screw back in, relubricated the gearbox, screwed the 3 screws back in and sound was gone.
Just a notice for when somebody in the future has the same grinding sound issue.