Undersized Stepper Motors?
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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°
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Voltage ( V
8 -
Current ( A
0.5 -
Resistance (Ohms): 19
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Inductance (mH): 32
Z-axis:
2x 2.4 kg-cm NEMA 17 (# 42BYGH011)-
Step angle: 1.8°
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Voltage ( V
11.2 -
Current ( A
0.33 -
Resistance (Ohms): 34
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Inductance (mH): 48
Additional Printer Properties:
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Cartesian printer
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12V Power Supply
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8mm linear rails and M5 lead screws
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X-Carriage: E3D Titan Aero with pancake stepper and V6
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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).
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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.
