Pancake Stepper On Extruder Resonating.



  • So I just got a pancake stepper to put on my Bondtech BMG extruder. I have verified that it is wired correctly. When I try to extrude though the stepper is not moving. When I apply a small amount of force on the drive gear though the stepper kicks in. My understanding is that this is caused by stepper resonance. I am having a hard time finding reliable recommendations on what to do when this happens.

    Here are my current settings from config.g related to the extruder:

    M350 E16 I1
    M92 E417
    M566 E120.00
    M203 E2400.00
    M201 E250.00
    M906 E700.00 I30


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    @cthulhulabs said in Pancake Stepper On Extruder Resonating.:

    So I just got a pancake stepper to put on my Bondtech BMG extruder. I have verified that it is wired correctly. When I try to extrude though the stepper is not moving. When I apply a small amount of force on the drive gear though the stepper kicks in.

    That can also be caused by only one phase of the stepper motor receiving current.



  • @dc42 said in Pancake Stepper On Extruder Resonating.:

    That can also be caused by only one phase of the stepper motor receiving current.

    That was my first though, but I checked for that. I unplugged the connector from the Duet and used a multimeter on the wires. A+ to A- reads continuity and B+ to B- reads continuity which means the coils are connected. Also RRF is not throwing an error about a coil being disconnected like it does when a connector is lose.



  • I am not sure what this could mean, but I just measured the resistance of both coils on this stepper motor. One is reading 5.8ohms the other is reading 2.6ohms. The other stepper motors I have checked that on have had basically the same resistance on each coil (+/-0.4 ohms).



  • Chect the motor spec sheet but looks like one pair of wires is energising one coil and the other is doing two. That would definately result in no motion and one reading is very neatly double the other!

    5.6ohm is getting on for a high resistance motor for 24V. You'd generally expect to see a high inductance too which vould make it a bit on the sluggish side.



  • This is the stepper:

    https://www.omc-stepperonline.com/nema-17-bipolar-18deg-18ncm-255ozin-07a-29v-42x42x25mm-4-wires-17hs10-0704s.html

    Spec says 4.2ohms per coil. So it looks like a coil is shorted out.

    As for the inductance, I'm running 24v so that's not an issue. I ordered the e3d slim stepper as a replacement.



  • Looks like one of the reviewers on that site had a similar problem.


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