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Z Axis Artifacts - Known Issues and Fixes

Discussion in 'Mods and Upgrades' started by Ziggy, Jun 1, 2014.

  1. tesseract

    tesseract Moderator
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    I think Fix 4 from above worked the best for me and it was a simple fix
     
  2. SteveC

    SteveC Well-Known Member

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    I second that - fix #4 is the biggest bang for your buck. Do it before bothering with metric threads.
     
  3. AxisLab

    AxisLab Well-Known Member

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    I'm living this craziness all over again.
    With a new R1 now.
    This ribbing is driving me MAD!

    I went through all the same fixes from my first Robo. Nothing is affecting this machine.

    I have adjusted, set/un-set, ball bearinged, swore at, and begged this maching to give smooth prints.

    My only thoughts is it just HAS to be one of the couplers. If I replace them and it is still there... I will be at a total loss.

    I don't want to cheap out on them, does anyone have any suggestions for nice replacement couplers?
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Just throwing this out there, but check your extrusion. I had one .4 nozzle that extruded 20% over. When I adjusted for that the ribbing pretty much went buh-bye.
     
  5. AxisLab

    AxisLab Well-Known Member

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    I'll check it again, I did the 100mm calibration early on, It was a month ago or so. But worth double checking.
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I only found it by accident. I had a .6 that was perfect and swapped in a .4 -- rib-city.
    That led me to checking everything again.
     
  7. Ziggy

    Ziggy Moderator
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    Hi @AxisLab

    Can you post a pic or two of the ribbing please.

    Could be extrusion issue (as Mark has found once). Can you also check the extruder carriage to make sure there is no slop in X/Y and the extruder itself is not wobbling in its mount.

    And maybe, just maybe, one of the ball bearings is not seated properly on the motor shaft in the coupler. If that happens you will get ribbing big time.
     
  8. AxisLab

    AxisLab Well-Known Member

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    Picture for reference here.
    [​IMG]

    I thought the same about one of the bearings being off, I have checked them multiple times, and even removed them at one point to start from scratch.

    I've played with these damn couplers so much one of the screws is now stripped too, so one more thing to play with.

    I just did the 100mm extruder calibration, off by about 2mm. I adjusted the values, tested again, then printed.
    Same ribbing.

    One very odd thing I don't know how I missed, my carriage is only on the smooth X rods with 3 bearings!!!
    [​IMG]
    [​IMG]
     
  9. Mike Kelly

    Mike Kelly Volunteer

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    What the what o_O
     
  10. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yea, that is weird.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I suspect those are the LM8UU, but I have never taken that apart.
     
  12. Mike Kelly

    Mike Kelly Volunteer

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    Yup they're LM8UU's
     
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  13. SteveC

    SteveC Well-Known Member

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    Yeah, what the what the whato_O
     
  14. Mike Kelly

    Mike Kelly Volunteer

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    Gotta love China made stuff man...
     
  15. Ziggy

    Ziggy Moderator
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    Really nice to have a bearing missing on a new printer. Must have been missed in the very thorough quality check.

    No LM8UU will be letting the extruder carriage wobble in an X/Y eliptical pattern. The missing bearing is right under where they X belt connects too - in the worst possible spot.

    Have a close look at the ribbing pattern in your prints. But TBH the ribbing in your pics is so bad it's hard to believe the missing bearing is the only reason.

    Either way, obviously the LM8UU needs to be replaced before any further Z ribbing troubleshooting.
     
    #55 Ziggy, Nov 25, 2014
    Last edited by a moderator: Nov 25, 2014
  16. scotta

    scotta Active Member

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    I realise the metric rods were likely to have a negligible impact, but considering I had it all apart....
    I hate anything imperial. A real pain.
     
  17. AxisLab

    AxisLab Well-Known Member

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    Did I read, that the new R1's are now using metric rods?
    If so, or if not, what are the specs of the threaded rods in the r1's?
     
  18. Mike Kelly

    Mike Kelly Volunteer

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    R1's with a bottom cover have M8-1.25 threaded rods and 8mm smooth rods.
     
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  19. AxisLab

    AxisLab Well-Known Member

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    Welp, swapped both couplers, tried with bearing, without, rods seated and unseated.

    No change in ribbing. I think I can rule those out.

    I managed to find a local lm8uu bearing last night, so that will be the next project.

    But that is for later. It's a holiday here, I'm taking the day off :)
     
  20. Kristian von Bengtson

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    are you all telling me I bought a product that does not really work unless I replace and change stuff?
     

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