Tips for replacing bearings?

Discussion in 'Calibration, Help, and Troubleshooting' started by wfredette, May 30, 2016.

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  1. wfredette

    wfredette Well-Known Member

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    I have 8 Misumi bearings ready to go. I saw a thread that said the Z axis bearings can be replaced without disassembly, but I can't find it now. Any leads on that thread, or other tips? Not looking forward to the process, but I think it's necessary. Thanks in advance.
     
  2. R Design

    R Design Well-Known Member

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    My suggestion:

    Send bed nearly to the bottom of Z (such that can still loosen coupler/leadscrew connection) with LCD and power down.

    Loosen couper/leadscrew bolts.

    Take off the caps on the lead screws and the rods.

    Remove lead screws (so that can properly commission rods by moving bed freely up and down).

    loosen bolts around one of the bearings (only a minimum amount so that nuts don't drop off!)

    Slide up bearing.

    Lift up rod just enough to remove bearing and insert new one.

    Adjust new bearing to correct height and retighten bolts.

    Move to next bearing and repeat.

    When all done then follow relevant commisioning steps for tightening the rod-caps, then adding screws, adjusting couplers, tramming bed.

    Bingo!

    (All quite quick and no terrible uncertainties.)

    ps am leaving the (less urgent) XY bearing changes until an eventual titan / x carriage upgrade or some other world event.
     
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  3. Old_Tafr

    Old_Tafr Well-Known Member

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    Maybe add some grease to the inside of the bearing before assembly. The original bearings have a seal and a wiper, to prevent lubrication escaping and dust getting inside, however grease seems to get sucked inside if you grease the rods. The more expensive may not be so lenient.
     
  4. Alex9779

    Alex9779 Moderator
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  5. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    Thanks, I have read it before but good to read it again. I need to get some Lithium soap based grease.

    Cut from the Misumi lube recommendation:
     
  6. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    When we are talking bearings. What can I use to de-grease them? And what should I not use?

    I have some break cleaner and carburetor/EGR valve cleaner which is as strong as it gets. Could this stuff eat up the liner on the bearings?

    Another cut from the Misumi recommendations:
     
  7. Old_Tafr

    Old_Tafr Well-Known Member

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    Hmmmmm The main thing is........

    "Before usage, apply grease to the ball rows within the Linear bushings, then
    periodically apply grease during the use"

    I suspect using some types of de-greasing agents will do more harm than good. I can't as yet see what the seals are made of but the de-greaser could make a mess of them, need to look at other info on failure modes.
     
  8. Dr Jeep

    Dr Jeep Well-Known Member

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    Heh maybe it's time to build some X,Y and Z movement totalisers into octoprint, so you can see how close you are getting to that 1000km linear movement service interval :D
     
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  9. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    Nitrile rubber seals are what Misumi uses. Finding stuff Nitrile doesn't like is easy. Finding what doesn't degrade it was a bit more difficult. Don't know if Ammonium Chloride (Salmiakk cleaning agent in Norwegian) will dissolve the oils in the bearings but according to this list it will not eat Nitrile::http://mykin.com/rubber-chemical-resistance-chart
     
  10. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    @wfredette, I hope you don't mind me talking about grease and degreasing bearings in your thread? But I find it on topic because it would be the perfect time to do this when replacing bearings :D
     
  11. wfredette

    wfredette Well-Known Member

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    Thanks, everyone, for the good suggestions.
     
  12. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    I got an answer from Misumi today. To degrease the anti rust oil before greasing they recommend ultrasonic cleaning or kerosene.
     
  13. Old_Tafr

    Old_Tafr Well-Known Member

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    You could always put kerosene in your ultrasonic cleaner ! :eek:

    I did notice that the original e3d bearings didn't have much lubrication as supplied, they were just loose in a box, the new ones I have each in its own little plastic bag are swimming in it.
     
  14. Alex9779

    Alex9779 Moderator
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    @ R Design ha I knew it :p
     
  15. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    Hehe, watch out and it will dissolve your hand!

    I got 4 replacement bearings from E3D after complaining but they were not much better. But they came in plastic bags and some oil.

    I'll get me some kerosene so I'm ready whenever I will disassemble the motion system next. A while ago I looked for ultrasonic cleaners but never bought any.
     
  16. Henry feldman

    Henry feldman Well-Known Member

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    Is there a difference between ultrasonic cleaner fluid? I have one at the hospital I can use, but not sure what that has in it?
     
  17. Old_Tafr

    Old_Tafr Well-Known Member

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    For other cleaning jobs in my ultrasonic cleaner I just used water, or water plus detergent, but joking apart, the recognised approach seems to be water or solvent.
     
  18. Bluemalu

    Bluemalu Well-Known Member

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    I'm afraid there are plenty of different solutions available for ultrasonic cleaners. Most common is water with a surfactant (washing up liquid) to reduce surface tension.

    Other flavours are fancy non conductive liquids for cleaning electronics (in particular mobile phones) that remove the salts on the PCB hopefully fixing the phone (sorry to those phones where you can't remove the battery).

    Last flavour are the degreasing solvents kerosene / alcohol based.

    Reading through the Misumi info you can wipe the bearings down and grease them with the lithium lube. I've got a set of their rods to change at the same time as the Titan upgrade.
     
  19. Stian Indal Haugseth

    Stian Indal Haugseth Well-Known Member

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    I have tried isopropyl but it is not enough. Kerosene should work better. Misumi actually recommends to degrease before greasing the bearings.

    I also got some rods from Misumi but they were about the same as the stock BB rods. Except the Z-rods E3D did an extra grind on to make them slightly thinner to lessen the chance of Z sticking.
     
  20. Alex9779

    Alex9779 Moderator
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    That's because it is an oil used for conservation and not for greasing...
     

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