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Prusa Mini Bearing Maintenance  

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OutlawECHO
(@outlawecho)
Eminent Member
Prusa Mini Bearing Maintenance

My Prusa Mini seems to be getting a little loud on both X and Y movements. I think the bearing need lubricated. I looked at the Prusa maintenance, https://help.prusa3d.com/en/guide/printer-maintenance-tips_23200/, but can't help thinking I am missing something. These are sealed bearings right? So shouldn't the bearings be removed and lubricated on the ID instead of just grease smeared on the rods? I would appreciate any input, tips, and tricks.

Along the topic of X and Y movement noise, can someone explain belt tensioning. Everything I have read has been pretty vague; "Tighten to a good tension, but not over tight" or "it should sound like a low bass when plucked". As a novice, neither of those are super helpful. Any tips on belt tensioning would be appreciated as well.

 

Thanks!

Best Answer by karl-herbert:

Posted by: @outlawecho

My Prusa Mini seems to be getting a little loud on both X and Y movements. I think the bearing need lubricated. I looked at the Prusa maintenance, https://help.prusa3d.com/en/guide/printer-maintenance-tips_23200/, but can't help thinking I am missing something. These are sealed bearings right? So shouldn't the bearings be removed and lubricated on the ID instead of just grease smeared on the rods? I would appreciate any input, tips, and tricks.

Along the topic of X and Y movement noise, can someone explain belt tensioning. Everything I have read has been pretty vague; "Tighten to a good tension, but not over tight" or "it should sound like a low bass when plucked". As a novice, neither of those are super helpful. Any tips on belt tensioning would be appreciated as well.

 

Thanks!

The linear bearings of my Mini did not last long either. Already after 2 weeks one was defective. If you want to stay with linear bearings, I would exchange them for Misumi linear bearings and lubricate them according to manufacturer's recommendations.
How to tighten a belt ideally is hard to explain in words. The best way is to press the belt with your thumb and index finger with little effort until both toothed surfaces touch each other.

Misumi linear bearings

belt tension

 
Posted : 05/10/2020 3:07 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Prusa Mini Bearing Maintenance
Posted by: @outlawecho

My Prusa Mini seems to be getting a little loud on both X and Y movements. I think the bearing need lubricated. I looked at the Prusa maintenance, https://help.prusa3d.com/en/guide/printer-maintenance-tips_23200/, but can't help thinking I am missing something. These are sealed bearings right? So shouldn't the bearings be removed and lubricated on the ID instead of just grease smeared on the rods? I would appreciate any input, tips, and tricks.

Along the topic of X and Y movement noise, can someone explain belt tensioning. Everything I have read has been pretty vague; "Tighten to a good tension, but not over tight" or "it should sound like a low bass when plucked". As a novice, neither of those are super helpful. Any tips on belt tensioning would be appreciated as well.

 

Thanks!

The linear bearings of my Mini did not last long either. Already after 2 weeks one was defective. If you want to stay with linear bearings, I would exchange them for Misumi linear bearings and lubricate them according to manufacturer's recommendations.
How to tighten a belt ideally is hard to explain in words. The best way is to press the belt with your thumb and index finger with little effort until both toothed surfaces touch each other.

Misumi linear bearings

belt tension

 

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 05/10/2020 5:35 pm
OutlawECHO
(@outlawecho)
Eminent Member
Topic starter answered:
RE: Prusa Mini Bearing Maintenance

@karl-herbert

Thanks for the response Karl. Do you recommend a specific Misumi bearing? Part number? Looking through the website I can select Misumi bearings ranging from $3 to $20 for the specific replacement of the Prusa LM8UU. Is the $3 Misumi an upgrade or do I need to spend 25% of the cost of the mini to replace all the bearings?

Posted : 05/10/2020 6:03 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Prusa Mini Bearing Maintenance

@outlawecho

Of course there are also clones of Misumi's LMU8, but I would not recommend them. But a good Misumi linear bearing should not cost more than 5 Euro:

https://www.roboter-bausatz.de/3135/misumi-lm8uu-lmu8-linearlager

If someone knows better sources - please share them.

20 Euro rather cost the SKF bearings: https://www.zitec-shop.com/de/lbbr/p-G1635000070

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 05/10/2020 6:52 pm
OutlawECHO
(@outlawecho)
Eminent Member
Topic starter answered:
RE: Prusa Mini Bearing Maintenance

@karl-herbert

Thanks again Karl. From Misumi, the basic LMU8 is about $8USD. There were just many options so I wanted to confirm that the basic is an upgrade. 

Posted : 05/10/2020 7:31 pm
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