dual z motor setup

hello i am trying to figure out whats wrong with this dual z motor setup, the motor vibrate when at low amp .5 voltage or at .8 voltage . i disconnected the stepper motor from the 8 mm acme screw so the motor are free from any bind and still have the shake after few sec spin. i use a temp power supply of 12 volt 5 amp, i tested with the hot-end on and off same thing. X and Y axis nothing wrong , maybe i little warm after 20 minutes stay on. need help ???.

Edited 1 time(s). Last edit at 04/10/2018 09:02AM by magnetos.

helloweneedmoreinformationaboutyoursetupwhichdriversandwhichsteppersdoyouuse?howdidyouconnectthesteppersparallelorserial?

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o_lampe
helloweneedmoreinformationaboutyoursetupwhichdriversandwhichsteppersdoyouuse?howdidyouconnectthesteppersparallelorserial?

What we really need is more punctuation!

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Here is what I have to set my steppers to make them work.

Using Nema 17 / 42mm Steppers with a4988 stepper motor driver
On my 12V 30amp supply
dual Z steppers 1.395
Single XY Steppers 0.695

On my 24V 20amp supply
dual Z steppers 0.710
Single XY Steppers 0.395

Question of jerk or question of a jerk ? That is the question !

Edited 1 time(s). Last edit at 04/11/2018 12:39PM by MKSA.

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"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)

hi, here the spec i find it about the motors : nema17 bipolar 2a 84 oz 4 wires, i think are in serial connected.
Main board Arduino2560 Ramps1.4, step driver dvr 8825 , power supply 12vdc 19amp pc-supply , i replaced from a 5amp to a much stronger power supply
z connector - different color check polarity on both motors , try swap in diffrent polarity same problem.
z connector

-- dvr8825 socket set to 1/16 step
step drive set 1/16

try to calibrate the step of z axis to above 804 steps and at 1557 what should be to move a 100mm the motors (both) make a halt noise not moving, but the move down in slow 1mm increment with no noise. i set the step driver to .550mVolt to .800 mMVolt
if i keep the step x mm under 804 no noise when i press home or move up and down. (not calibrate it).


1st print with the 1.2 nozzle , no hotbed installed

Edited 2 time(s). Last edit at 04/11/2018 02:19PM by magnetos.

thank you Robert, i will test with a 1.395 volt on the drv 8825.
i was afraid of fry the drv or the motor. will test later..

post it info stop.
thank you for reply stop

The DRV8825 has a different formula to calculate Vref than A4988. See here

And once you fix the current in the DRV8825, fix the step skipping at low speeds problem.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Ok, so far i got the motor to move with out grinding noise.
changed the pot voltage to a .800 and changed the step/mm to a 1557 , no noise up and down.
i believe two wire on one z motor where solder in the wrong direction causing to short the other motor plus the low voltage on the drv 8825.
Now its time to calibrate the Volcano nozzle. and nozzle height to print.
thank you for the help..

Quote
magnetos
thank you Robert, i will test with a 1.395 volt on the drv 8825.
i was afraid of fry the drv or the motor. will test later..

I would not just jump to the 1.395 v ref, I would adjust the voltage up until steppers function correctly.

This should occur around double the V-Ref as a single stepper. I have installed heat sinks on all drivers, and using a fan to cool the circuit.

Previously posted link appears to be dead. See: [www.reddit.com]

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

i like this TL-Smoother i will get a set to test on my small printer first. is some kind voltage filter. thx