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x-axis creaking and cracking. Bad bearings?  

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sammythesquibb
(@sammythesquibb)
Active Member
x-axis creaking and cracking. Bad bearings?

Hi all,

I have the i3 MK3S+ that I assembled from the kit. I have done over a hundred hours of trouble-free printing but recently, and suddenly, the extruder assembly has developed a creaking sound.

I have preformed the recommended maintenance including cleaning and lubricating the rods, checking for scratches (none), cleaning the bondtech gears (already very clean), and ensuring that the pulleys are free and mobile. The belt tension is 264 for both the x and y axes.

Here's a video of the sound: creaking sound

Prusa have recommended that I disassemble the x-axis and inspect the bearings. No ball bearings were lost during assembly, but they seemed to suggest that balls could be knocked out of place within the bearing itself when inserting the rods.

Do you have any recommendations for this issue, particularly regarding the disassembly as the x-ends required a lot of my weight on them to insert the rods and they're unlikely to come apart easily! Prusa will send me new bearings once I confirm that they're bad, although I'm not entirely sure what to look for other than a row of bearings that has a gap in the channel from missing balls?

All the best,

Matthew

Posted : 04/09/2022 9:03 am
cwbullet
(@cwbullet)
Member
RE:

Bad bearings or your screws are too tight.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 04/09/2022 11:29 am
sammythesquibb
(@sammythesquibb)
Active Member
Topic starter answered:
RE: x-axis creaking and cracking. Bad bearings?

I forgot to mention that even with the extruder carriage back plate loosened the sound still occurs. What can I do differently in future? 

Posted : 04/09/2022 12:00 pm
Diem
 Diem
(@diem)
Illustrious Member

Check your X axis idler bearing.

Cheerio,

Posted : 04/09/2022 12:05 pm
fuchsr
(@fuchsr)
Famed Member
RE: x-axis creaking and cracking. Bad bearings?

Sure sounds like bearings. 

Posted : 04/09/2022 12:23 pm
Artur5
(@artur5)
Reputable Member
RE: x-axis creaking and cracking. Bad bearings?

Last year I had the same sound on the X avis of my MK3S+.

My bet is that this is a case of  bad bearings like cwbullet and fuchsr say, or rather good bearings turned bad due to lack of lubrication. Not your fault, Prusa says not to pack with grease the bearings during the assembly. There’ re long and controversial threads in the forum regarding this matter.

When I had the problem I decided to disassemble the X axis and found that the 2 bearings of the upper rod were leaving black residues. Some balls were stuck and wouldn’t rotate. The rod itself was already a bit scratched. So I replaced these two bearings and the lower one too (it looked fine but, just in case..). Before installing the new Misumi units I packed them well with grease. Buttery smooth X axis since then.

Lubricating the rods is no good  because the shields on the sides of the bearing prevents thick grease to pass inside. Light oil for sewing machines does enter and helps for a while but it doesn’t lasts. In the end you’ll have to disassemble the X axis. Check the  condition of the bearings, Maybe they’re not  damaged yet and properly packing them with grease will fix the issue. If they’re visibly worn, Prusa should honor the warranty and send you new ones.

In case one plastic part of the X axis break in the disassembly, you better have spares at hand or, if Prusa sends you new bearings, ask them to include also a ‘X-end-motor’ and ‘X-end-idler’. Beware, the ‘x-end-motor’ for the MK3S and MK3S+ are different. Tell them clearly yours is a MK3S+.  

Posted : 04/09/2022 12:31 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: x-axis creaking and cracking. Bad bearings?

An interesting article on the Linear Bearings used by Prusa:

In addition to precise mounting, good preparation (cleaning and lubrication) of the bearings is important.

wbr,

Karl

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 : 04/09/2022 12:37 pm
sammythesquibb
(@sammythesquibb)
Active Member
Topic starter answered:
RE: x-axis creaking and cracking. Bad bearings?

Thanks for the info Artur5. I definitely noticed that the grease was just pushed to the end of the rods by the bearing casing when lubricating. 

What were your bearings leaving a black residue on, the rods?

I'll definitely be sure to ask for spare plastic parts. How did you get the x-end-idler off the rods? That's going to be a nightmare.

Posted : 04/09/2022 5:33 pm
sammythesquibb
(@sammythesquibb)
Active Member
Topic starter answered:
RE: x-axis creaking and cracking. Bad bearings?

Thanks, karl-herbert. I'll be following the recommendations in the video for sure.

Posted : 04/09/2022 5:35 pm
sammythesquibb
(@sammythesquibb)
Active Member
Topic starter answered:
RE: x-axis creaking and cracking. Bad bearings?

Just to conclude the thread here, a scratch a few inches long had developed along the steel rod from the unlubricated bearings.

Strangely, when given replacements under warranty there were still no instructions to lubricate the bearings before reassembly. I don't understand why Prusa fails to acknowledge this issue and amend the assembly instructions accordingly. I followed a youtube video using superlube and all is well again.

Posted : 18/12/2022 11:08 am
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