Y-axis play after following the new instructions post v3.14 manual
 

Y-axis play after following the new instructions post v3.14 manual  

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Fred
 Fred
(@fred-2)
Active Member

My Y-axis started making some kind of metallic grinding noise recently. I decided to proceed to the maintenance of the Y-Axis assembly on my MK3s where I discovered these new instructions for the assembly.

I re-greased the bearings and change their orientation as shown in the picture but since then I feel there's even more play on the X-axis (left and right) for the Y-axis assembly. This play also increases the resonance of the metal grinding noise when the heatbed is moving. Is it a sign of damaged bearings or wear on the rods? I did a visual inspection and I don't see any wear or grooves in the rods.

Is replacing the rods and the bearings could help? Also, what's the difference between the LM8UU offered on the Prusa Store at $1.89 USD while on the MiSumi store the same bearing model is $12.60 USD?

P.S Before you ask, I did not overtighten, the U-bolts 

 

This topic was modified 5 months ago by Fred
Posted : 11/11/2020 4:16 pm
karl-herbert
(@karl-herbert)
Illustrious Member
Posted by: @fred-bouchard

My Y-axis started making some kind of metallic grinding noise recently. I decided to proceed to the maintenance of the Y-Axis assembly on my MK3s where I discovered these new instructions for the assembly.

I re-greased the bearings and change their orientation as shown in the picture but since then I feel there's even more play on the X-axis (left and right) for the Y-axis assembly. This play also increases the resonance of the metal grinding noise when the heatbed is moving. Is it a sign of damaged bearings or wear on the rods? I did a visual inspection and I don't see any wear or grooves in the rods.

Is replacing the rods and the bearings could help? Also, what's the difference between the LM8UU offered on the Prusa Store at $1.89 USD while on the MiSumi store the same bearing model is $12.60 USD?

P.S Before you ask, I did not overtighten, the U-bolts 

 

The LM8UU are cheap noname products of lower quality and the LMU8 Misumi are higher quality linear bearings and cost accordingly more.
Let everyone decide for himself what he wants to use.
I myself prefer the original Misumi, housed in a custom made bearing housing (as usual) instead of the U-bolts.

(picture: example with brass bearings)

Advantage: More precision, smooth running. The bearings are glued in (Floating and fixed bearing principle) and therefore cannot be stressed with overtightened screws.

The mechanics of the printer also affects the quality of the print results.

 
This post was modified 5 months ago by karl-herbert
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 : 11/11/2020 6:23 pm
Fred liked
Fred
 Fred
(@fred-2)
Active Member

@karl-herbert

Thank you Karl, very interesting that housing for the bearing. Do you know where I can find the STL for the i3? Also what is the model number of those brass bearings?

Posted : 12/11/2020 3:50 am
karl-herbert
(@karl-herbert)
Illustrious Member

@fred-bouchard

i have published this in prusaprints: https://www.prusaprinters.org/prints/45941-gehause-fur-linear-oder-gleitlager-15x8x24-lmu8-od

the brass bearings I bought here: brass/graphite bearings

 

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 : 12/11/2020 2:34 pm
karl-herbert
(@karl-herbert)
Illustrious Member

In general, the printer tends to print the holes smaller. For this reason I have added step data so that the hole diameters can be modified with any CAD software.
If somebody wants to use brass bearings, I would recommend to use a few drops of oil or grease in addition to the graphite fixed lubrication. I myself use an oil/PTFE based lubricant.

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 : 12/11/2020 2:44 pm
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