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Uneven Z-Banding

Discussion in 'Troubleshooting' started by adikted2astro, Nov 5, 2017.

  1. adikted2astro

    adikted2astro Active Member

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    After I performed MESH bed leveling, my first print looks like this:

    IMG_0567.JPG

    After what Mark said in a previous post, this is a slip in the axis drive. Anyone know how I can correct this? The bands protrude on one side and on the other are either even, or recessed. 0.2 mm layer thickness, 100% infill.
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You need to nail down which axis is slipping (only you know how it was mounted on the bed) and then check for anything loose.

    On the gantry style you need to examine the entire gantry on that axis (x or y) and make sure nothing is out of place causing binding or slippage.
     
  3. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Double check all the set screws, Robo does not use any thread locker so vibrations can work them loose. If you decide to use thread locker Blue or Green is as strong as you will ever need.
     
  4. adikted2astro

    adikted2astro Active Member

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    I checked all of the set screws that I could find on the X and Y axes. None were loose. The only thing loose is that x-axis belt I talked about in previous threads. I'm printing another part now, so I'll see what happens with it. However, it is nowhere near as tall as the previous print.
     
  5. adikted2astro

    adikted2astro Active Member

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    This new print is good, but like I said, it isn't nearly as tall as the last one. IMG_0569.JPG
     
  6. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You can dial back the acceleration and jerk numbers which will help avoid the slip, but to cure it you are going to need to find the slipping component. I agree with @WheresWaldo that it is most likely a set screw not 'set' well.
     
  7. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    On the R2 you can go to Utilities >> Options >> EEPROM. Scroll down to Accelerations and make sure they are something like this
    Code:
    P: 500.0
    R: 1000.0
    T: 1000.0
    Unfortunately you cannot set Jerk settings from the Robo LCD screen. But you can set it via G-Code.
    Code:
    M205 X7.0
    This single parameter will set both X and Y Jerk to 7.0 (the setting I use).
     
  8. adikted2astro

    adikted2astro Active Member

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    I'll double-check the set screws after the current print is done. Thanks for the acceleration and jerk numbers. My LCD screen is currently unresponsive for some reason, so I'll check those numbers when the print is over. However, the EEPROM settings in Octoprint show maximum XY accelerations are both at 1000, max Z accel. is 100, and XY jerk is at 7.00.
     
  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Not maximum just acceleration.
     
  10. jwmueller

    jwmueller Active Member

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    Check for play on the extruder gantry itself, and check for Z-axis wobble from the lead screw. It does not fully look like Z-wobble as the pattern is regular, I would make sure your build is not moving around. Mine has some minor play and even that is enough to drive me nuts, but on another machine the Z axis bearing was loose and the print head could move the plate if it caught some friction during the print. The results look much closer to what I see in your picture.

    Extruder gantry sloop would look more like micro layer shifting, while your picture looks more like the build plate slipping. Anyway, just some ideas to look at since you already checked some other things.
     

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