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alidaf
(@alidaf)
Eminent Member
Scratched top x smooth rod

Since building this in November last year I've had a relatively trouble free experience with fairly light usage until recently. I decided to service it and have noticed scratches on the top x smooth rod and traversing the hot-end assembly feels quite rough but gets worse towards the right hand side where it is more difficult to push. The scratches are spaced apart and seem to coincide with the spacing between the 2 bearings. I'm a bit perplexed as to what caused this and how to go about fixing it. The printer has been installed in a cabinet.

Posted : 08/02/2022 2:13 pm
ARU
 ARU
(@aru)
Active Member
RE: Scratched top x smooth rod

I had the same issue 1 year ago after ~1500 run hours. The issue was causing layer shifts.

I suspect that the root cause is the combination of poor quality bearings, poor lubrication in the bearing (not outside) and the fact print mostly at the center of X axis.

I guess you will not avoid replacing the 2 rods (or swapping them on short term) and the bearings.

Posted : 08/02/2022 5:54 pm
Brad
 Brad
(@brad-2)
Trusted Member
RE: Scratched top x smooth rod

My top X rod is the same and in my case it was caused by defective bearings. I need to replace the top rod and both top bearings.

Posted : 09/02/2022 11:46 pm
Diem
 Diem
(@diem)
Famed Member

A frequent cause is insufficient attention to steps 8 & 9 of:

https://help.prusa3d.com/en/guide/3-x-axis-assembly_167854

and steps 49 & 50 of:

https://help.prusa3d.com/en/guide/5-e-axis-assembly_169235

Check these.  You may be lucky if the damage isn't too bad and you get the positions right and rotate the scratched rod to offer a smooth surface.  A bit of polishing might help.

The other contributary cause is lack of lubrication.  Some users advocate packing the bearings with grease but I never have, instead I clean and lubricate the smooth rods monthly.

Also check your Y axis, it may be out of sight but it is liable to the same issue if neglected.

Cheerio,

Posted : 10/02/2022 1:24 am
alidaf
(@alidaf)
Eminent Member
Topic starter answered:
RE: Scratched top x smooth rod

Thank you for that information. I was very diligent in building the printer and believe it to be a failed bearing since it happened within a few months of light printing. Prusa are sending replacement parts.

Posted : 10/02/2022 2:41 pm
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