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noisy dual Z

Posted by jens53 
noisy dual Z
July 13, 2019 02:37AM
A quick question .... my x and y axis movements on a CR10-S5 are very quiet, presumably due to micro stepping.
The Z axis sounds very much like my other CR10 with the normal creality controller that doesn't offer micro stepping - very noisy.
Could someone confirm for me that this is normal ? Is the fact that two z motors are in series causing this issue ? Has anybody else noticed that ?

It doesn't affect operation but I thought I would figure out why it is the way it is.
X, Y and Z are all set for 1.5A maximum current, Z is 400 steps per mm. X and y are set to 80 steps per mm
Re: noisy dual Z
July 13, 2019 05:20PM
It used to be the case that it was always better to connect dual Z motors in series, when they had similar characteristics to the X and Y motors. However, many 8-bit controller boards made the mistake of providing dual parallel Z motor connections, and some printer manufacturers have recently been using low current high inductance Z motors to mitigate the disadvantage of parallel connection. If Crealty has done this on the CR10, then you may be better off either connecting them in parallel, or connecting them to separate driver outputs. Being noisy could be a sign of this. Are there labels on the Z stepper motors that identify the model number of the motors?



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: noisy dual Z
July 13, 2019 05:32PM
The only identifying marks are "Creality 42-34" .... so not much help there.
Is there anything I can try to do without re-configuring the entire printer? Would disconnecting one stepper tell me anything ?
Would measuring phase resistance tell me anything ?
Most important, is it likely to hurt anything if I carry on running like that ?

Thanks!
Re: noisy dual Z
July 14, 2019 02:02AM
If you measure the phase resistance and also the length of a Z motor, you can search stepperonline for other motors with similar length and phase resistance, which will give a good idea of the rated current and inductance.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: noisy dual Z
July 14, 2019 04:26AM
Quote
dc42
It used to be the case that it was always better to connect dual Z motors in series, when they had similar characteristics to the X and Y motors. However, many 8-bit controller boards made the mistake of providing dual parallel Z motor connections, and some printer manufacturers have recently been using low current high inductance Z motors to mitigate the disadvantage of parallel connection. If Crealty has done this on the CR10, then you may be better off either connecting them in parallel, or connecting them to separate driver outputs. Being noisy could be a sign of this. Are there labels on the Z stepper motors that identify the model number of the motors?

Very interesting, I've always run my Z-motors in parallel because Ramps just allows you to in that way. I'm using the same motors in my whole machine. Does this mean that I should run then in series? They are Nema17 2.5A 2.8deg steppers. X/Y is run with TMC2208 and Z/E are run with A4988.


http://www.marinusdebeer.nl/
Re: noisy dual Z
July 14, 2019 03:19PM
A4988 drivers in stepstick format are only good to about 1.4A or possibly 1.5A peak current because of the tiny PCB area. So your parallel Z motors will be getting maybe 0.7A each. That's very low for a 2.5A motor. If you have very fine pitch Z screws then it may not matter. But you would get more torque if you wire them in series.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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