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Cracking sound from extruder, bad print, MK3s+  

New Member
Cracking sound from extruder, bad print, MK3s+

Hi, I've assembled MK3S+. The example prints on the attached SD card were printed beautifuly, but other prints are horrible. Also, the printer is making weird cracking electrical sound from extruder (motor I believe) after the initial layers - attached video.

I'm slicing in PrusaSlicer 2.3.0 with following settings:

Printer: Original Prusa i3 MK3S and MK3S+

Filament: Prusament PLA (I've also tried Prusament PET - the same)

Print settings: 0.30 mm draft

I'm using original Prusament PLA and Prusament PET.

As I said, the attached SD gcodes are printed without a problem with no sound.


Does anybody know what's the problem?

Thank you!

I can't embed the video. Here's the link:

This topic was modified 3 years ago 3 times by Krystof
Posted : 09/02/2021 3:40 pm
Dan Rogers
Noble Member
RE: Cracking sound from extruder, bad print, MK3s+

Interesting noise.  My hearing is not the best, but it sounds almost like the teeth on the extruder gears are barely engaging.  Have you checked the tension adjustment on the extruder arm?  It would have been one of the adjustments you made during assembly.

Another possibility is your live Z is just way too low - or maybe both.  The pictures look like the print head is dredging through the prior layers

If you go back to the PRUSA test piece, you can go back to it and it prints perfect, but when you try and print your own design, you get that filament mess?


Posted : 11/02/2021 8:33 pm
New Member
Topic starter answered:
RE: Cracking sound from extruder, bad print, MK3s+


Exactly. When printing the test prints attached on the SD card - it prints perfect.

Using the same filament (original PLA Prusament) and slicing it in the latest Prusa Slicer, I'm getting the bad results.

You mentioned extruder gears. Do the pictures look like over extrusion? Because if so, the printer might be over extruding with extruder not able to keep up melting the plastic, thus would be skipping gears and making the weird sound. Is that possible?

As I've mentioned, I'm slicing with the default MK3S+ printer profile with the default PLA prusament profile in the latest PrusaSlicer. It's just tiny bit odd that the slicer would be generating something wrong if all the parts (slicer, printer, filament) are original Prusa.

Posted : 11/02/2021 10:08 pm
kurt _hectic
Active Member
RE: Cracking sound from extruder, bad print, MK3s+

I have exactly the same problem. I was scared that maybe plastic was expanding inside and making such cracking noise. 
I'll try to find a tutorial, adjust the tension screw and will come back with the result. 

@krystof-2, did you manage to fix it?

Posted : 08/11/2023 8:40 pm
Reputable Member
RE: Cracking sound from extruder, bad print, MK3s+

The assembly manual explains how to check and align the extruder.

Prusa assembly manuals

Posted : 09/11/2023 11:12 pm