Not a first print problem: Linear Bearing is scoring metal rod
 
Notifications
Clear all

Not a first print problem: Linear Bearing is scoring metal rod  

  RSS
rob.w5
(@rob-w5)
Trusted Member
Not a first print problem: Linear Bearing is scoring metal rod

I've had my MK2.5s for a long time.  About a year and a half ago the right Y axis (the one closer to the user interface knob) got scored. I replaced the linear bearing with an LMU8 bearing as well as replacing the scored rod.  Well, guess what?  The very same rod is scored again!  Just feeling the score from front to back, it seems uniformly scored.  As in, it seems to be consistently off all the way from back to front.  And all three bearing columns are scoring.
When I run the calibration wizard I get high marks for alignment.  Is there some twist I can give the printer to stop this from happening?  Is this bad luck and I just happen to be putting defective bearings in the exact same place? Remember, the MK2 uses threaded rods instead of the extruded aluminum, so it would be easy to get this out of square.  I'm not sure what I can do to get this to stop happening.  It's not a serious problem, as I only use the MK2 when the MK3 is already busy.
A solution I have considered is to buy the extruded arms for the MK3 and see if I can modify the MK2 using them, getting rid of the threaded rods altogether.

Looking for ideas to try.

Posted : 11/06/2022 6:35 pm
cwbullet
(@cwbullet)
RE: Not a first print problem: Linear Bearing is scoring metal rod

Did you lubricate the bearings?

Posted by: @rob-w5

I've had my MK2.5s for a long time.  About a year and a half ago the right Y axis (the one closer to the user interface knob) got scored. I replaced the linear bearing with an LMU8 bearing as well as replacing the scored rod.  Well, guess what?  The very same rod is scored again!  Just feeling the score from front to back, it seems uniformly scored.  As in, it seems to be consistently off all the way from back to front.  And all three bearing columns are scoring.
When I run the calibration wizard I get high marks for alignment.  Is there some twist I can give the printer to stop this from happening?  Is this bad luck and I just happen to be putting defective bearings in the exact same place? Remember, the MK2 uses threaded rods instead of the extruded aluminum, so it would be easy to get this out of square.  I'm not sure what I can do to get this to stop happening.  It's not a serious problem, as I only use the MK2 when the MK3 is already busy.
A solution I have considered is to buy the extruded arms for the MK3 and see if I can modify the MK2 using them, getting rid of the threaded rods altogether.

Looking for ideas to try.

 

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

Posted : 11/06/2022 8:31 pm
rob.w5
(@rob-w5)
Trusted Member
Topic starter answered:
RE: Not a first print problem: Linear Bearing is scoring metal rod

Nope.  There are 10 sets of bearings in these printers.  I'm only having problems with the bearings in this one location.  I recall that when I replaced the bearing last time, tiny balls were all over the place.  I'll replace it again and this time will lube them.  May as well lube all 10 bearings.  20 if you count the other printer.

Posted : 11/06/2022 11:53 pm
Share: