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Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
x-axis stuck

Hi! I got this issue after some time printing.  What's wrong?

 

 

Posted : 07/05/2020 11:15 am
Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
Topic starter answered:
RE: x-axis stuck

Posted : 07/05/2020 11:16 am
stoofer
(@stoofer)
Estimable Member
RE: x-axis stuck

@ak-1

Hi,

I can't see the video. I recently had a sticky X axis causing failures. I thought it was the grooves worn into my smooth rods. After replacing all those and the bearings, the issue persisted.  If I moved the extruder by hand, I could feel inconsistent resistance.  If I did it quickly enough, I could hear a "clack" noise like bearing failure. 

It turned out to be that the X idler bearing (on the right of the printer as you look at it from the front) has failed, and was causing enough resistance for the steppers to detect crashes / fail to home.

Posted : 07/05/2020 12:35 pm
Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
Topic starter answered:
RE: x-axis stuck

Updated the video permissions.

It's really hard to push it to the left, while pushing it to the right is easy.

Posted : 07/05/2020 12:56 pm
Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
Topic starter answered:
RE: x-axis stuck

Not sure if the video above works, but maybe this direct link does? https://drive.google.com/file/d/1UkJH0nSq2rgiARv15RnvWSz7eBBEpJBj/view?usp=sharing

Posted : 07/05/2020 2:29 pm
DJ
 DJ
(@dj-6)
Trusted Member
RE: x-axis stuck
Posted by: @ak-1

Updated the video permissions.

It's really hard to push it to the left, while pushing it to the right is easy.

Given the asymmetric nature of the resistance, I’d check the rubber bearing seals on either side of all 3 X-axis bearings; one of those seals may have rolled causing extra friction in one direction.  Unfortunately, unless this is not the cause, this will require disassembly of the X-axis either to inspect the seals between the 2 upper bearings or to replace the bearings if damaged. I’d try looking for other causes first.

This post was modified 4 years ago by DJ

DJ

Posted : 07/05/2020 5:03 pm
DJ
 DJ
(@dj-6)
Trusted Member
RE: x-axis stuck

Edit timer is too short! 

Maybe remove the belt and see if the asymmetric resistance remains.

DJ

Posted : 07/05/2020 5:10 pm
stoofer
(@stoofer)
Estimable Member
RE: x-axis stuck

It sounds like bearing failure to me in the video.  Get your head in there and listen to it, see if the sound is from the extruder direction or the idler direction.

Posted : 07/05/2020 5:12 pm
Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
Topic starter answered:
RE: x-axis stuck
Posted by: @djspathis
Posted by: @ak-1

Updated the video permissions.

It's really hard to push it to the left, while pushing it to the right is easy.

Given the asymmetric nature of the resistance, I’d check the rubber bearing seals on either side of all 3 X-axis bearings; one of those seals may have rolled causing extra friction in one direction.  Unfortunately, unless this is not the cause, this will require disassembly of the X-axis either to inspect the seals between the 2 upper bearings or to replace the bearings if damaged. I’d try looking for other causes first.

This seems to match.  I disassembled and the lower bearing was stuck in one direction, and I could see something moving on the side of the bearing.  I guess I have to buy a new bearing or is this fixable?  I've only printed 1kg with this device.

If I need to buy one of these:  https://shop.prusa3d.com/en/mk3mk3s/140-linear-bearing-lm8uu.html   I would rather buy on amazon as they ship faster.  However there are so many brands.  Which brands are OK to buy?

This post was modified 4 years ago by Alexander Kjeldaas
Posted : 07/05/2020 7:14 pm
Alexander Kjeldaas
(@alexander-kjeldaas)
Active Member
Topic starter answered:
RE: x-axis stuck

How the bottom bearing moves: https://drive.google.com/file/d/1dbHg9E5T0-cee1v_GMvYbcdYFxytmQpP/view?usp=sharing

Posted : 07/05/2020 7:23 pm
DJ
 DJ
(@dj-6)
Trusted Member
RE: x-axis stuck

Normally Amazon delivery is unmatched here in the US; I've had much longer delays recently.  You might try the Prusa Chat customer service (when logged into the Prusa store, a pop-up dialogue box appears in the lower right corner).  They might be able to ship you a set of bearings in a reasonable amount of time and the bearings might still be under warantee. I'd replace all on this axis and save the undamaged ones as spares.  Also, I strongly recommend  greasing all the bearings prior to installation; please search these forums for various thoughts on this. As for what manufacture of bearings is best, I really can't say as I only have my original Prusa supplied bearings.

This post was modified 4 years ago by DJ

DJ

Posted : 08/05/2020 3:28 pm
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