Knocking sound from extruder stepper

There is this knocking noise from extruder stepper. I couldnt figure out the problem.

I removed the filament and noise didnt stop. It it not about hotend.

Please help me.

SKR 1.4 Turbo + TMC2209 ( vref=0,8V ) + Marlin 2.0.9.3


[youtu.be]

I've never encountered that one before. Usually knocking sound is either motor wired wrong, or overloaded and missing steps. But it's turning properly so the wiring is good, and removing the filament proves that it's not overloaded. Try removing the whole extruder assembly so you can hold the motor alone in your hand and see if it still does it. Although it probably won't be as loud without the frame to radiate sound. So you could try touching the motor to the frame and to other objects to amplify the sound. It's possible that the motor isn't vibrating in any problematic way, but something else on the printer is slightly loose and happens to resonate at the frequency of the motor's vibration.

Edited 1 time(s). Last edit at 02/22/2022 05:34PM by dekutree64.

They can knock with a loose mounting screw, or if the driving gear is out of line with the filament.

Thanks for the reply.

Here is the list of what I did to solve this,

I removed filament
I changed TMC driver
I changed connection port on mainboard ( used E1 port instead of E0 port )
I unplugged steppers cable and plugged to x / y and z steppers , this time sound transferred to that stepper.

As I understooed, extruder stepper is making tiny and sudden retractions during the xy direction changes of nozzle while printing. That knocking sound comes from that little retraction moments. It is not effecting print quality but very disturbing and loud.

In ther video that retraction moments can clearly be seen.

[youtu.be]

Edited 1 time(s). Last edit at 02/24/2022 03:15PM by utkudemir.

Hmm, perhaps it is indeed missing steps, but not due to filament pressure. I had some trouble with missed steps on retraction recently when trying out a new extruder design using a NEMA 14 stepper, and the solution ended up being to reduce the max extruder speed. I never did figure out exactly why that fixed it. I would have thought acceleration, jerk, and motor current would be the settings to adjust, but they didn't seem to affect it.

Another thing you could try is going into the Tune menu during a print and setting the linear advance K factor to 0. That's probably what's inserting all the small retractions, so disabling it will likely eliminate most of the noise, but it will still do it when retracting before travel moves.

WOW ! Thank you magic man. Until now I wasnt aware of what advance K factor is!!
All my problems are now solved. Thank you soooo much