Loud steppers when moving



  • I've been using my Duet wifi for over half a year now. Coming from a RUMBA board with TMC2130's installed I expected the Duet to be about as quiet as the previous combo but alas.

    I'm using two NEMA17 steppers on my CoreXY platform labeled:

    TYPE: 42BHH48-151K-24B

    I believe these are 4.2V 1.5A 4.8mH 2.8Ohm 1.8 degree steppers, I've read references online that indicate that they also go by this type.

    I've made a video demostrating the noise viewable here. In this video they are running 100mm/s but they are noisy at all speeds, up to 500mm/s. When running them with TMC2130 they were completely silent.

    They are configured as followed.

    M350 X16 Y16 Z16:16 E16 I1
    M92 X80 Y80 Z1600:1600 E401
    M566 X1800 Y1800 Z600:600 E1500
    M203 X30000 Y30000 Z1500:1500 E6000
    M201 X10000 Y10000 Z250:250 E7500	
    M906 X1100 Y1100 Z800:800 E1000 I25
    

    Disabling interpolation does increase the noise but only minor.

    The Duet is running on it's own dedicated 150W 24V Mean Well power supply. Other steppers are also noisy, they are using the same stepper motors.
    I would like them to be as silent as before or at least as silent as I've heard (or not have heard) in other people's videos.


  • administrators

    I have a few suggestions:

    1. What current were you running the motors at when you were using TMC2130 drivers? At 1.1A current they would have been getting very hot; so I am guessing that you were using a lower current.

    2. For some combinations of motor and supply voltage, the chopper control register value for the TMC2660 drivers needs to be adjusted to make them quiet. This page https://duet3d.dozuki.com/Wiki/Reducing_Stand-Still_Noise is about reducing standstill noise, but the same techniques can reduce motion noise too.

    3. The TMC2130 drivers implement stealthchop, which makes the motors very quiet but tends to screw up big time at higher movement speeds. If you only ran your printer at low speeds, perhaps you were using stealthchop mode? The TMC2660 on the Duet WiFi doesn't implement stealthchop, but a similar effect can be achieved using coolStep. The disadvantage is that it has to be tuned manually, whereas stealthChop tries to tune the settings automatically.



  • Thanks for your quick response! I'll answer your suggestions.

    1. I think I was running them at 850mA with active cooling but that is RMS and Duet uses peak right? So about 1200mA peak.
    2. I though the registers were only for standstill as the title suggested indeed. I will look into that.
    3. I ran the 2130s in stealthchop until about 150mm/s I think and then had them switch over to spreadcycle.

    I'll report back with my findings, thanks again.



  • @dc42 I've read the post you've linked to about reducing idle noise. Changing the steppers to TOFF 1 does reduce noise somewhat but it's still not perfect and have a distinct stepper noise. I've also tried changing some of the hysterisis values and blank values with C commands to write to the registry but I don't have a oscilloscope available right now and the guide kind of relies on it. Also, trying out different values for these registers does change the sound a little but nothing dramatical.


  • administrators

    Are you certain it was 850mA RMS that you were using, not 850mA peak? Before the days of Trinamic stepper drivers, motor currents quoted in 3D printers were always peak. That's why the values set by M906 are peak in RepRapFirmware. I think Marlin on RAMBo boards uses peak too. Trinamic tend to refer to RMS current in their datasheets, but it's up to firmware developers whether to specify the parameters to motor current setting commands as RMS or peak.



  • From configuration_adv.h in marlin:

    #define X_CURRENT          800  // rms current in mA. Multiply by 1.41 for peak current.
    

    Maybe the 2208s have different values because that section has it defined as MAX_CURRENT. Also, not that it matters I think since Marlin is universal, I was using a RUMBA board and not a RAMBO.



  • @dc42 Any more suggestions? I notice a definite improvement with the TOFF parameter but I'm curious if there's a better way to tune the other parameters.


  • administrators

    The TMC2660 chopper register settings are described in section 9.1 of https://www.trinamic.com/fileadmin/assets/Products/ICs_Documents/TMC2660_datasheet.pdf. There is a separate section on coolStep configuration.


 

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