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LM8UU free Alternative ?

Discussion in 'Mods and Upgrades' started by tonycstech, Nov 8, 2014.

  1. tonycstech

    tonycstech Active Member

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    I came across this link
    http://www.igus.com/wpck/3665/drylin_r_rjm_01
    Then i came across this link
    http://www.thingiverse.com/thing:24990

    Makes me wonder, why do we need to buy bearings again ?
    All one would have to figure out is what to lubricate it with.
    As for printing in PLA, i dont see a problem. There is simply not enough friction to create any temperatures that would ruin the bearing.
    Even if melt point is reached (say printing cylinder 10x10x200) at very high speed(who does that anyway) you can still print another one.

    PLUS people say its quieter too.
    Now am not sure what the noise complain all about, but i think its because LM8UU's ware out or ride on none precision rods.
    What ever the case may be, i think these little slippy sliders are great.
    You can print 1 two times long so you wont have to have 2 inserted into each end like we all do when we change them.

    Any thoughts on that ?
    Has anyone tried these ?

    I will 100% try these on Z since i run brand new X rods and bearings and my bed printable upgrade is only couple of months old.
    drylin_r_rjm_01_1.jpg LM10UU_preview_featured.jpg
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Interesting. Whether or not they will be quite as good as linear bearings... no clue. Worth experimenting with if you have the motivation.
    The linear bearings probably do a little better jobs of avoiding any lash in the drive, but I am not really sure how much there is to avoid.
    The movements do tend to get a bit abrupt at times...<shrug> try it. Friction wise I doubt there is a real issue, but there is more to a bearing than friction.

    edit: I made mine a lot quieter by simply replacing the ones they provided with some decent quality linear bearings.
     
  3. tonycstech

    tonycstech Active Member

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    I agree with the replacement trick, but there are so many on the market that have no particular brand name so its a gamble purchase hoping to get that one thats better then the rest.
    I think everything is crap that becomes popular no matter how much you pay for it. Every Chinese sweatshop starts to make cheap replicas and sell for less or for more claiming quality etc, but in reality even buying it from a reputable store does not mean they wont sell you junk.

    Might as well make them your self :p
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I would be interested in the results of someone trying this. Even if they wear faster--no problem.
    Again, my only concern is for stress (other than friction) along the axis of travel AND (more importantly) stresses perpendicular to that*.
    The bearing would counter these, this slider may not.

    *it may be that these are trivial and can be ignored.
     
  5. tonycstech

    tonycstech Active Member

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    Plenty of people using silicone lube say great things.
    I have grease but not spray as they all suggest.
     
  6. tonycstech

    tonycstech Active Member

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  7. Magic-Goat

    Magic-Goat Member

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    Thanks for the video! Is this still running ok? I was wondering if printing in nylon would make the bearings last any longer?
     
  8. tonycstech

    tonycstech Active Member

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    I dont know. Printable bearings are for those who can't buy proper smooth rods.
    I have no need to even try
     
  9. tonycstech

    tonycstech Active Member

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    Scratch that, my bearings were never lubricated so they got ruined started to scratch the rod so i had to replace them before its too late (probably is already)
    So i designed and printed few that would work best on exact 8mm smooth rods (original robo's comes with smaller diameter) to make sure they fit and bam, printer is back in business.
    DSC00005.JPG
    This is the code i used to print. Code will not HOME X and Y, it will start printing right from where nozzle is so make sure its not all the way on the right :)
    My Own LM8UU.gcode
     

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  10. tonycstech

    tonycstech Active Member

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    I am currently trying ABS version of the bearing.
    PLA worked good and all but i found it shrinking when its cold so i printed and replaced them with ABS once hoping that it would give better temperature stability.
    Very smooth so far.
     
  11. tonycstech

    tonycstech Active Member

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    UPDATE:
    ABS bearing worked much better. Its no longer shrinking on a cold winder morning as much as PLA did, so i can start printing without giving it a second thought.

    Original attempt to use that was forced upon me by failed bearing that scratched the smooth rods surface making it useless, but the printed one didnt care so much about surface perfection and it prints and it prints and it prints like Duracell battery rabbit goes and goes.

    If you have smooth rod scraped or scratched or rusted, use printed bearing to save money and time replacing them.
     
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  12. Ben R

    Ben R Active Member

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    Im curious if u saw any improvement in print quality. I have shadows... Obviously a vibration/lash issue somewhere... I cant find where it is though... Is it in these bearings?
     
  13. tonycstech

    tonycstech Active Member

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    Print quality has little to do with the bearings.
    If bearings are loose, they are either worn out or rods are cheap and smaller. You can tell it by moving extruder by hand. See if there is any (any) motion or knocking sound coming from bearings. That would indicate they are loose.

    When i got my robo, i instantly had rattling noise every time when extruder would go the oposite direction, almost like a whiplash effect.
    I measured the rod and it was less then 8mm. It has to be exactly 8mm to work as intended but it wasnt.

    I later replaced rods with exactly 8mm once hardened and polished etc from ebay and replaced all bearings with brand new, but in less then a month 1 bearing went out and it started to scrape the rod. When rod is scraped its not gonna work well anymore and will damage any lm8uu bearing that rides on it.
    That was perfect opportunity for me to try plastic, and when i did i was happy because not only it works, but also i dont have to replace the rod even the damaged one.

    I printed the bearing and it did not fit the rod as i expected, so i took this tool DSC00076.JPG which happened to be slightly less then 8mm and ran it thru the bearing once or twise before trying it on the rod.
    Once i got the perfect fit, i installed the bearings (2 in the front at this point) into the extruder and i am printing and printing and printing.
    They are tight against the rod (thanks to lubricant silicon grease) and also quiet.
    No whiplash no loose motion at all.
     
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  14. Magic-Goat

    Magic-Goat Member

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    If there's no noise or looseness issues then aren't they better than the LM8UU's?
     
  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Decent LM8UU bearings are going to last the life of the printer.
    These are simply cheaper alternatives. Not for me, thanks, but an alternative.
     
  16. tonycstech

    tonycstech Active Member

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    What is "decent lm8uu" stand for ?
    I had brand new rod and brand new bearings. They failed in a month damaging the rod.
    The $5 lm8uu each is exactly the same as 10 for $5 from china. Absolutely no difference.

    They are so cheap and there are so many of them made by so many replicating companies in china that its impossible to tell which one is which.
    In my case i know that my bearing is made by Tonycstech LLC lol
    At least i know what quality of my own product.

    Plus, his question answers by its self.
    Quiet+tight+cheap=cha ching !!!!! VS metal with potential to fail.
    There is no failure in printed bearing. It has no parts to fail.

    If i could print one from polymer or some nylon, it would last for life
     
  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The bearings that Robo provided with the bed upgrade were cheap. Junk really.
    I replaced them with better quality ones. Smooth as silk and no noise.

    Not putting these down as an alternative, but as cheap as the good quality bearings were I don't see a lot of motivation to use these except as a temporary fix (or semi-permanent temporary fix) if you had one fail.
     
  18. tonycstech

    tonycstech Active Member

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    Really ?
    What i had was the rods that Robo provided were not 8mm but 7.9 or something like that.
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The rods were perfect, but the bearings were total crap. Noisy, cheap... just junk really.
    Those type pf bearings should be lube-free and quiet and smooth. They were not.
    The annoyance factor for me is that decent bearings were not really that expensive.

    The ones in the X carriage have not been an issue yet so it was really just the ones for the bed upgrade.

    This is an interesting approach, perfect for a 3D printer since the more of it that is self-replicating, the better.
     
  20. tonycstech

    tonycstech Active Member

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    Then i guess your release had better rods but bad bearings. Mine came with good bearings but bad rods.
     

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