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Y-axis bearings shot in  

John Stone
New Member
Y-axis bearings shot in

Hi, all. My Mk3s+ has been remarkably plug-and-play until yesterday, not quite 60 days after receiving it. I had a print failure due to crash detection with the first three layers skewed by 50% of the print length. When I cleaned things up and ran a belt test, it failed with a "Y axis length error." I tried moving the bed manually and noticed it was very hard to move.

I took it apart and got the Y frame off and notice that while the single-bearing rod moves freely (perhaps too freely/sloppily for my taste) the two-bearing rod was binding with what felt like hydraulic lock/sticking.  After removing the bearings from the frame, I can move all three of them up and down the rods without issue and I don't see any scoring on the rods or dirt or buildup. I do however notice that one of the three bearing end seals has flaked off part of it, which looks suspiciously like heat damage.

The only thing I've done different in the last few days is printing ASA from an enclosure (one of those Creality zip-up tents) where I had been doing it with just a draft skirt before. Total print time in the enclosure before failure was about 12 hours or so over two days. The ambient temp in the enclosure never got above 103F(39.4C) so I expect it should have been well under any harmful temps. That said, since those bearings are right next (and attached) to the build plate which is set to 105C for ASA, I'm wondering if these Misumis are exceeding their 20-80C rated temps. 

Surely I'm not the only one that has had issues with this? Total print time per the Statistics screen says 6 days 47 minutes, so less than 150 hours of printing. 

Any ideas as to what causes this kind of issue or how to prevent it? Do I need to be lubricating it a lot more often or with a special lubricant? Do I need to try and source the LMUF or SLMUS all-metal bearings instead of the standard ones with plastic retainer material?

Posted : 24/10/2021 5:23 am

Did you lubricate the bearings with the white lithium grease that Prusa supply in their kits during the build?
if not, give that a try now?

the flaking seal sounds a bit odd, have a word with Prusa chat, in the eShop pages,

Note, the chat window appears about 3 seconds after the page loads... 

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK...
Posted : 24/10/2021 7:48 am