Strange vibration

[Demitrius]

I understand, vibration is difficult question.

If I try slow or fast speed - looks god, minimal vibration, but vibration increase when motor works on middle speed. Who knows, which GRBL settings may affect vibration or need I check belt, motor, or something else? (hardware)

PS: Simple Nema23 step motor, no encoder

[terjeio]

I understand, vibration is difficult question.

Resonance is a likely culprit - search for stepper motor damping.

Who knows, which GRBL settings may affect vibration

Microstepping (steps/mm).

[Demitrius]

You mean add dampfer or remove?

I have one dampfer under motor mount

[Demitrius]

[terjeio]

Here is one of the links from the search above. Many tips in that post. I have no idea what will work for you - however, increasing the microstepping worked for me when I recently switched to grblHAL from a Mach3/Smotstepper combo for my router/mill.

[darkfibre-nl]

Here is a bit more info about what you describe,: https://www.geckodrive.com/support/mid-band-instability/