Annoying stepper's sound

tommylight wrote: You can use these to dampen the sound and vibrations, i use plenty of those.

They will not totally remove the noise and vibrations, but they will make everything a lot quieter and more pleasing to the ear.

Thanks Tommylight !!! It is an excellent suggestion.
Now, regarding the variable audio frecuency sound; it is helpful this motor damper? this sound is all the time, and is more evident when the stepper not rotate. Really is very annoying.
Thanks for your answer.

That is the noise produced by the drive PWM current limiting so here are some tips:
Try a different power supply, cheap power supplies produce way to much ripple.
Adding 220 to 470uf capacitors directly to each drives power terminals should lower or completely get rid of that noise.
As a side note, the TB6xxx series drives will need also some 0.1 to 0.47 uf capacitors in parallel with power supply, or even betteter said capacitor should be added inside the drives connected between ground and the "VRef" input to IC.

tommylight wrote: That is the noise produced by the drive PWM current limiting so here are some tips:
Try a different power supply, cheap power supplies produce way to much ripple.
Adding 220 to 470uf capacitors directly to each drives power terminals should lower or completely get rid of that noise.
As a side note, the TB6xxx series drives will need also some 0.1 to 0.47 uf capacitors in parallel with power supply, or even betteter said capacitor should be added inside the drives connected between ground and the "VRef" input to IC.

Thanks Tommylight, I understand all your suggestion. I'll open the drivers box and I'll analyse the electrical circuit. As I told you is an "almost home made" router.
Thanks. a lot.

Opening the drives is a last resort, you have plenty to test with without opening them. Do test at the exact order i wrote them above. Chances are you will get satisfying results before reaching the "open the drive" point.
Opening them would require good knowledge of electronic and schematics and soldering skills, or the magic smoke will escape from them !
Anyway you decide to go, i will be here to help, just do not hope you will completely get rid of it, you won't.
FYI, i never did try to remove that noise, i just like it and it reminds me that one of machines in ON. I can hear even some connected to some high tech stepper drives made by LAM Technologies, as they are de facto the best drives i had in my lifetime. I have used plenty of the DS series, have a look
www.lamtechnologies.com/Resources/Doc/DS10_BRUK.pdf