Undersized Stepper Motors?



  • Each time I home an axis, I get a very loud buzzing sound from the stepper motors with no motion, followed by very slow, "strained" motion. I've only gotten motion out of the Z-axis once. After that it's just been the loud buzzing. I've tried numerous combinations for current and speed settings, but nothing has had a significant impact or improvement. I'm wondering if the steppers do not have a high enough current rating and/or too high of an inductance for the drivers. Any thoughts or ideas would be much appreciated.

    X and Y-axis steppers:
    4.2 kg-cm NEMA 17 (# 42BYGH4807)

    • Step angle: 1.8°

    • Voltage ( V 😞 8

    • Current ( A 😞 0.5

    • Resistance (Ohms): 19

    • Inductance (mH): 32

    Z-axis:
    2x 2.4 kg-cm NEMA 17 (# 42BYGH011)

    • Step angle: 1.8°

    • Voltage ( V 😞 11.2

    • Current ( A 😞 0.33

    • Resistance (Ohms): 34

    • Inductance (mH): 48

    Additional Printer Properties:

    • Cartesian printer

    • 12V Power Supply

    • 8mm linear rails and M5 lead screws

    • X-Carriage: E3D Titan Aero with pancake stepper and V6

    • Y-Carriage: 6" x 6" x 1/2" MDF with aluminum build plate on top

    If you're wondering why I chose these motors, I recently dismantled my Printrbot LC when the Printrboard died and tried to keep as many of the leftover, non-wood parts as I could when I rebuilt (the steppers being among them).


  • administrators

    You are using motors with very high inductance and low current ratings. These are a poor choice for a 3D printer because they need high voltages to drive them at speed. With 12V power you stand almost no chance of getting them to work well enough for a 3D printer. With 24V power it would be better, but the speeds achievable will still be low. Use the EMF Calculator at http://reprapfirmware.org/ to work out the speeds at which torque will start to drop.

    The two Z motor outputs on the Duet are connected in series because that is generally better for low inductance motors. For your high inductance Z motors, connecting them in parallel would work better. Or, if you are not using the E1 motor output, you could connect one to Z (with the 2 jumpers in the spare Z connector) and one to E1, then use the M584 command to assign them both to Z.


Locked
 

Looks like your connection to Duet3D was lost, please wait while we try to reconnect.