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0.4A Stepper motor vs 1A stepper motor using A4988 drivers? Motor Stalling problem

Posted by jcdrbm 
0.4A Stepper motor vs 1A stepper motor using A4988 drivers? Motor Stalling problem
February 05, 2017 05:02AM
I'm having a problem with my extruder stepper motor stalling for retraction speeds over 10mm/s. I still have retraction problems so would like to increase this if possible. I don't have problems with stalling on my 0.4A X,Y,Z stepper motors.

I'm using a Greg's Wade extruder for Prusa i3 with a Nema 17 Bipolar 40Ncm 12V 0.4A Stepper Motor.

My extruder Pololu A4988 stepper driver is tuned to .16V. (Vref = I_TripMax * 8 * Rs) (Vref = .4*8*0.05 = 0.16).

Relevant settings in Marlin:

DEFAULT_MAX_ACCELERATION {1000,1000,100,10000}
DEFAULT_RETRACT_ACCELERATION 3000
DEFAULT_EJERK 5.0 // (mm/sec)


Would I have more luck with a 1A stepper motor?

Is the current rating of my motor the limiting factor to my retraction speed?
VDX
Re: 0.4A Stepper motor vs 1A stepper motor using A4988 drivers? Motor Stalling problem
February 05, 2017 06:10AM
... its the current and the voltage together, what's defining the max possible speeds - higher voltages allow faster steps, and lower inductivity (with lower coil resistance or higher current ratings) too.

So try with 24V instead of the common 12V for your stepper drivers (if they can handle this) and/or a motor with lower inductivity/higher current ratings ...


Viktor
Stepper motors are normally operated at 8-20X the rated voltage. Your 12V motor can't deliver its rated torque at speed because the power supply voltage is too low. Look for a motor rated for 2-3V and current 1.5-2.5A range.

Turn down the extruder acceleration.


Son of MegaMax 3D printer: [www.instructables.com]
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