Microstepping and torque?

  • Hi all,

    I know very little about these stepper motors I use in so many projects! I updated my extruder from an ungeared feed to a bondtech which is 1:3 geared. Because of the gearing, I figured I could get away with using a small 0.9 pancake nema17 I had since I tried an e3d titan extruder (which was junk by the way). With the .9 and the 3:1 and my microstepping (which I can't actually remember and I'm not home to check), my steps/mm are something ridiculous like 800+. What I miss about using a full size 17 and 1:1 extruder was the ability to retract at ridiculous speeds. This setup necessitates slower jerk and presumably lowers my torque, as it seems I can't print quite as fast as I used to with the ungeared rig. Would I get more torque by lowering the micro-stepping (and thus my steps/mm)?

  • Microstepping reduces current by maybe 30% which reduces torque as well.

    Since the motor coils are spending less time at peak current you might be able to bump the current limit to offset the microstep current loss. If you try this carefully monitor motor temps to ensure they are stable.

    Since you are geared 3:1 you should still have plenty of torque on the output. Your accel/jerk/max velocity values will have to be quite a bit higher to get the same response on the geared output. This might be your limiting factor.

    You could try just increasing the max speed / accel / jerk value until you run into step loss issues before trying to lower the microstepping.

  • Moderator

    Bowden or direct?
    What are your accel, jerk, speed settings for the extruder?

    Why is 800+ steps per mm ridiculous?

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