Y-Axis Stepper runs rough  

RE: Y-Axis Stepper runs rough

Posted by: @brett-bowden

I've been doing a few prints with my new Mk3 and found the odd pattern in the picture.  The lines are perpendicular to the direction of the print head and are inconsistent.  Also, when placing my fingers on the Y-Axis stepper, I can feel a noticeable roughness as compared to the X-Axis. 

I believe I have a bad bearing in the Y-Axis stepper and need to know how to get a replacement.

 

Did you lubricate the linear bearings? Is the belt tension in tolerance range, u-bolts not too tight?
Check this and try to move the Y-axis with switched off  printer and observe any changes.

Misumi replacement bearings are available from Prusa and various other distributors.

RE: Y-Axis Stepper runs rough

@karl-herbert

I took the belt off the Y-Axis and rotated the stepper by hand and it is rougher than the X-Axis so that eliminates belts and bearings.

Thanks.

RE: Y-Axis Stepper runs rough

@brett-bowden

Not really. If you assemble the drive gear improperly, or try to set belt tension with those silly LCD numbers, you can have print issues. Also, improperly set bearing - lack of grease a primary, and over tightening the mounting bolts/screws a secondary cause of funny axis movement.

In any case - you should probably be asking Prusa, not users - how to get something warrantied.  They have email, the store chat, and probably a phone number.

RE: Y-Axis Stepper runs rough

@tim-m30

Tim,

Thanks for the feedback...  I'm sorry I wasn't clear, other than the normal cogging effect of steppers, the Y-Axis stepper when removed from everything has areas of rough rotation as compared to the X-Axis stepper, also removed from the machine.

As far as support, I looked for a contact on the Prusa site and this forum was the only thing I could find so I assumed this was how Prusa did their support.  I'll take another look to see if I can find a warranty contact.

Thanks!

RE: Y-Axis Stepper runs rough

@brett-bowden

The easiest way to handle warranty claims is to use the Prusachat. Log in with your account and select the eshop. After a few seconds the chat window appears in the lower right corner. Prusa would like to have videos, so I might prepare something there already.

RE: Y-Axis Stepper runs rough

RE: Y-Axis Stepper runs rough

I'm having this same problem on 2 of my MK3's. It would result in inconsistent reliability on Y axis crashes and layer shifts.

Greased/Lubed everything, and it was still there, moving the Y axis back and forth manually, you could feel rough patches in the rotation cycle in the stepper itself. I removed the belt, and the Y axis is smooth as butter. I ordered a Y axis replacement stepper ($35ish) and that one failed as well. Was there a bad batch recently?

Now, my MK3/MMU2 is starting to act up on the Y axis in a similar way..

RE: Y-Axis Stepper runs rough

Tried to get this troubleshot with tech support, but they're giving me the runaround on the exact culprit (these Y steppers are bad), I ordered some replacement steppers (for half the price) off Amazon ( https://www.amazon.com/gp/product/B07GDD2X4B/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1) and replaced the bad Y axis steppers on both my systems and resolved all woes.

The three bad Y steppers that I got through Prusa are all noticeably hard to spin smoothly all on their lonesome and are definitely the source of the problem. If you're seeing odd Y axis shifts and rough sliding on your Y axis not tied to bearings/pulleys, spin your Y stepper (off power) and see if that's your problem too.