Y axis failing selftest, bent stepper motor axis?
 
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Y axis failing selftest, bent stepper motor axis?  

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Pneumatic
(@pneumatic)
Active Member
Y axis failing selftest, bent stepper motor axis?

I've seen others saying that adjusting the belt tension and lubricating the slide berings as ways to address a y axis that is failing self-test, but that hasn't helped me.

I notice that when I move the y axis by hand, that it goes through sections that are easier and some that are stiffer as I move it, roughtly in sync with the rotation of the stepper motor.  I'm wondering if somehow I could have bent the axel coming out of the stepper motor and that's causing the motor to have variing levels of belt tension.

Is that possible?

Posted : 09/08/2024 11:37 pm
Pneumatic
(@pneumatic)
Active Member
Topic starter answered:
RE: Y axis failing selftest, bent stepper motor axle?

I meant to say "bent steppar motor axel?" in my original title

Posted : 10/08/2024 12:00 am
Diem
 Diem
(@diem)
Illustrious Member

First work through:

https://help.prusa3d.com/en/article/regular-maintenance-mini_133222

Especially make certain the smooth rods are clean and lightly lubricated.

In addition, temporarily loosen the Y belt and check the Y idler is not clogged, out of line or the bearing failing; then try turning the stepper by hand - you should feel the steps but otherwise it should be smooth, no grating.

If the problem persists, come back - those axles are unlikely to bend.

Cheerio,

Posted : 10/08/2024 4:56 am
_KaszpiR_
(@_kaszpir_)
Honorable Member
RE: Y axis failing selftest, bent stepper motor axis?

If the uneven areas are small ( something about every 5cm?) then maybe non centered belt pulley?

See my GitHub and printables.com for some 3d stuff that you may like.

Posted : 10/08/2024 6:39 am
vhubbard
(@vhubbard)
Estimable Member
RE: Y axis failing selftest, bent stepper motor axis?

Bent shaft is possible, but I would take a hard look at the gear drive that is on the stepper motor shaft.  If it is drilled off center it will wobble causing what you describe also.    

Posted : 10/08/2024 3:00 pm
Pneumatic
(@pneumatic)
Active Member
Topic starter answered:
RE: Y axis failing selftest, bent stepper motor axis?

 

Posted by: @vhubbard

Bent shaft is possible, but I would take a hard look at the gear drive that is on the stepper motor shaft.  If it is drilled off center it will wobble causing what you describe also.    

I'll take a look at both that gear and the idler gear at the other end, but this is an emergent behavior (i.e.. it didn't used to do this.). I can't explain what might have caused it to get bent (I haven't dropped it or anything, and that shaft looks like 5mm of stainless steal, so it would take a lot to bend it.)

I ordered a replacement stepper motor because it's relatively cheap, and I would like a spare anyway.

 

Posted : 12/08/2024 4:03 am
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