High pitched noise from the extruder (not from fans)

High pitched noise from the extruder (not from fans)  

New Member

Hi, I have brand new Prusa i3 MK3s (which I built from the kit). And while printing (in the stealth mode) there is a (really annoying) high pitched noise coming from the extruder, somewhere between 16kHz and 20 kHz (see attached image). It is NOT coming from the fans, when I stop them the noise is still there unchanged.

Is there something I can do about it?



Posted : 18/02/2020 1:15 am
Estimable Member

I find that stealth mode sometimes generates resonances that are much louder than normal mode. It depends on what you print. I typically print in normal mode and it’s quiet enough. 

This post was modified 9 months ago by mdaneman
Posted : 18/02/2020 6:38 am
Noble Member

You're probably hearing the PWM/stepper drive noise. I hear it too and it stops when the stepper idle timeout occurs and the motors shut off. Not much you can do about that, though it is reduced in stealth mode due to reduced motor currents. 


Posted : 18/02/2020 2:14 pm
New Member

I have this EXACT same problem, and I can't find any additional info on it. Did you ever figure it out? Would buying a different stepper motor help?

Posted : 28/08/2020 9:07 am
Noble Member

Don't worry its something that goes away when you get older lol.

Posted : 28/08/2020 9:15 am
New Member

Hopefully this will be useful to someone, as there isn't a lot of information about this issue online:


I've replaced the extruder motor with the Moons' MS17HD2P4100 one, which is a drop in replacement (no different firmware or anything else necessary), and the 16kHz and above noise levels, while still present, significantly dropped. 


Just make sure to do the wiring correctly:



From: https://github.com/PrusaOwners/prusaowners/wiki/Moons_stepper_motors



The audio in the following screenshots was _NOT_ recorded under the 100% exact the same conditions, however it is very close to it. The second screenshot also shows average rates from the samples, and the first one the realtime one. First one had more noise in the lower frequencies, but the higher ones are the same (i.e. not a lot of external factors).


Before, with the stock extruder motor:


After, with the moons' motor. Keep in mind some of the higher frequencies come from other motors that are moving, as well as the PSU. But on my printer the extruder one was significantly louder in higher frequencies than others. Since I have 2 more moons' motors, I'll probably replace another 2.


Posted : 08/09/2020 7:20 am

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