So I was just working next to my printer, when I heard a buzzing sound coming from the printer. Whenever the steppers are energized, my Z2 Stepper (back right) is vibrating slightly. It's not enough that you can see or feel it on the gantry, but when touching the exposed motor pulley in the skirt, you can feel it quite obviously. Could this be due to noise from other electrical components, or is it more likely an issue with to be an issue with the driver/MCU?
#Stepper Z_2 Vibrating when stationary
tidal totem
woven pumice
Some combinations of stepper drivers, stepper motors, and settings seem to do that, but I don't think I've had it happen enough that I've noticed it since I stopped using ancient hardware with A4982 drivers.
I think it's due to the fact that whenever the stepper motor is holding still at something that isn't a full step (i.e. one of the many microsteps in between), the driver has to have both motor coils "partially on" which is does by basically switching them off and on many times per second, and that can cause them to "buzz" and vibrate by a tiny fraction of a step. That's just me guessing though.
tidal totem
I have TMC2209s for all corners, and all 4 have the same settings, and interpolation is off. I can try turning it on but I thought interpolation was the setting that allowed to take microsteps
Well I tried turning it on for all 4 Z motors, and now after restarting and homing again the Z3 motor is vibrating (although much less than Z2 was before)
woven pumice
Interpolation just means that whenever the stepper driver is told to move (even in between microsteps), it will do that move in several smaller steps, down to as small as it's highest microstep setting. It shouldn't have any effect when holding still, only when moving.
what's your stepper driver config like for these motors?
tidal totem
## Z2 Stepper - Rear Right
## Connected to MOTOR_4
[stepper_z2]
step_pin: PF9
dir_pin: PF10
enable_pin: !PG2
rotation_distance: 40
gear_ratio: 80:16
microsteps: 32
[tmc2209 stepper_z2]
uart_pin: PF2
interpolate: true
run_current: 0.8
sense_resistor: 0.110
It's the same for each motor, just obviously different pins.
woven pumice
If it were me I'd probably just fiddle with settings and see what happens. With/without interpolation, smaller/larger microsteps, and spreadcycle or stealthchop.
And if it seems to be happening mostly in certain motors, double check that everyting is tightened down properly and not making the vibrations sound worse. Some small amount of vibration will always be there just due to how microsteps work, but usually not noticeable
tidal totem
So I just tried moving it up and down in Z by 10mm, and whenever it's up Z2 vibrates moderately, but whenever it's down Z3 starts vibrating again a little bit, so it's repeatable
woven pumice
only real reason to use interpolation I think is if the printer is too noisy (when moving) without it, even if the systemic positioning error it introduces is usually tiny.
tidal totem
Is there a chance it's a current related thing? I have all 4 Z motors set to .8A, the same as my A and B motors. I'm not sure if my MCU (Octopus v1.1) has a limit to how much current it can send to all motors combined?
Just kinda grasping at straws, maybe I'm thinking of that because I'm trying to set up reducing run current for sensorless homing rn lol
Either way since it doesn't seem to be really affecting anything I'll just do the classic "leave it until it breaks something"
woven pumice
Holding a stepper steady at 0.8A is a relatively tiny amount of power (a couple watts), shouldn't be an issue. It's possible the vibrations will change with run/hold current (probably mostly the latter if it is when not moving), only way to find out is to test.
I'm guessing you're not doing sensorless homing on Z anyway?
If the noise doesn't bother you, leave it be. If it does, see if some different stepper driver settings makes it better. And if it only ever happens on Z2 and Z3, something might be loose and rattling more than it needs to.
tidal totem
No, I'm not doing sensorless homing on Z. Is that even possible with 4 Z motors? But yeah doing some more testing, moving by different increments, it's always one of the four Z motors that vibrates. I've managed to get it on all of them by moving in ~1mm increments.