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Z axis loud and doesn't move evenly  

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jd14
 jd14
(@jd14)
Active Member
Z axis loud and doesn't move evenly

I just finished assembling my Mk3, the self test ran fine; the z axis sounded funny, but when I tried to manually step the z axis up/down it moves funny. Everything looks connected properly, but it seems like the right stepper is either not running or is slower than the left. What should I be looking at to try to fix it?

https://photos.google.com/share/AF1QipMHXy6yHIzV84sc91-LIpsUnn467_AHooLv_DnWSOTQfeY9ZpX1zBOO6ZNX2N9ZCw?key=WHNmUTRaeU15V2RpUzVuUkwxbHVkUEFCUTFQVkV3

Posted : 09/04/2018 3:17 pm
john.n13
(@john-n13)
Estimable Member
Re: Z axis loud and doesn't move evenly

Could the small black cover at the bottom of the right lead screw be turned down too far so that it's tight against the motor case?

Posted : 09/04/2018 3:27 pm
jd14
 jd14
(@jd14)
Active Member
Topic starter answered:
Re: Z axis loud and doesn't move evenly

I don't think the black cover is stuck, it moves pretty freely.

Posted : 09/04/2018 3:37 pm
smithkt
(@smithkt)
Eminent Member
Re: Z axis loud and doesn't move evenly

Could there be a misalignment of one of the threaded or smooth rods? I've seen some suggest loosening the screws holding the mounts at the top and bottom. Move the Z axis up to the top and tighten the screws on the top mounts. Then move the Z axis to the bottom and tighten the bottom mounts. See if the Z axis now moves smoothly.

Posted : 09/04/2018 4:40 pm
jd14
 jd14
(@jd14)
Active Member
Topic starter answered:
Re: Z axis loud and doesn't move evenly

Seems like my right stepper on the z is not working. Worked with Prusa tech support and tried running with one stepper at a time and in both slots, the right stepper didn't move properly. Replacement on the way. I guess I waited this long I can wait a bit longer.

Posted : 09/04/2018 5:15 pm
Peter L
(@peter-l)
Honorable Member
Re: Z axis loud and doesn't move evenly

Try loosening the screws that hold the trapezoidal nuts to the Z carriage slightly (maybe 1/8 to 1/4 turn). Apparently if you clamp them down too hard they do that.

I'm not sure exactly why this happens, but I suspect that the surface of the printed carriage isn't quite exactly flat enough, and tightening the nuts too hard can make them skew a tiny bit.

Anyway, I had the same noise and this was the fix.

Posted : 10/04/2018 12:17 am
jd14
 jd14
(@jd14)
Active Member
Topic starter answered:
Re: Z axis loud and doesn't move evenly

I removed it completely and ran with the right axis removed and it wouldn't turn. It jittered, but did not turn. Waiting for replacement...pondering if I could give printing a shot without one of the Z steppers so I can pathclear the next issue....

Posted : 10/04/2018 6:39 pm
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