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Unresolved Z-Axis not raising mid-print

Discussion in 'Troubleshooting' started by Chris Sweeney, Sep 10, 2019.

  1. Chris Sweeney

    Chris Sweeney Member

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    After my latest maintenance on my R1 (with auto leveling), all of my larger prints stop raising in the Z after the first layer or so. I can successfully print any part that fits in a 1" square, but nothing larger.

    What I am using:
    Robo 3d R1
    MatterControl
    PLA
    A raft (for adhesion)

    Fixes i have tried thus far:
    Different files/parts (downloaded/made my own)
    Different versions of MC
    Tried Cura
    Changed infill/supports
    Raft versus no raft
    Reflashing the firmware

    There are no issues with auto leveling, or manual jog on the Z-axis. I raise it 10 mm, it goes 10mm. The first layer always prints fine, with or without a raft. No changes to the parts or programs were made.

    Would this be a software or mechanical issue? Could this have happened from swapping out some bearings?
     
    #1 Chris Sweeney, Sep 10, 2019
    Last edited: Sep 10, 2019
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    So, to be clear, if you send a command for Z + 10mm it moves 1mm?

    Sounds like the Z steps are misconfigured. Did you at some point reflash the firmware? If so which one did you use and EXACTLY which printer do you have (R1beta, R1, R1+...)
     
  3. Chris Sweeney

    Chris Sweeney Member

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    My apologies, it moves 10mm per 10mm command. I have the 5/16 threaded rods and flashed the appropriate firmware.I also have the R1
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Hmm, then I would check the terminal to see if you are getting any errors back during the print.
    If not then double check everything mechanically by manually raising it 200mm or so in one shot (or two 100mm movements).
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    With 5/16 rods you have the beta because the R1 had 8mm...
    I have some of all of them (beta, R1, R1+)
     
  6. Chris Sweeney

    Chris Sweeney Member

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    Ok it seems that i have a couple issues. I remeasured and reflashed with the 8mm firmware and i am now at the correct raise ratio. 10mm wasn't enough to see the difference, 100mm was.

    However, my nozzle is still digging into my parts in some areas, and is too far above in other areas like it was before i originally reflashed. I also looked through the terminal and didn't see any errors during or after the print.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well that sounds more like a leveling issue or (more evil) a weak stepper or stepper driver.
    If the Z is going up the correct amount on command then the Z steps are right.

    If could also be over-extrusion if you are seeing more of the crashing into layers than you are of it being too high.
    Calibrate the extruder and see where that gets you.

     
  8. Chris Sweeney

    Chris Sweeney Member

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    I went through the calibration procedure and it turns out my printer was always under-extruding (good to know thank you). But i am still getting crashing on the upper layers of the print.
     
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Well if it is not over extruding (putting down too much filament and then crashing into it) then you are not getting the right Z steps.
    That could be because the firmware is incorrect (which I think you have checked) or because the Z stepper driver is weak. With two Z steppers it is unlikely one of those is weak or the Z axis would tilt. However the R1 (and the previous R1-beta) both use a single Z stepper driver for both steppers. If it gets weak it will not drive sufficient current for the steppers to stay on target and they will skip steps.

    Either replace the Z stepper driver or swap it for another one to see if that affects it. Here is a layout of the RAMPS board so you can see which driver is the Z...

    RAMPS.png


    this is the actual top of the board:

    RAMPS_top.jpg

    So the stepper driver card on the bottom right is the one to swap. They look like this and are plugged into those sockets:
    Stepper drivers.jpg
     
  10. Chris Sweeney

    Chris Sweeney Member

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    Thank you for the help thus far. I reflashed with the 8mm again for good measure (calipers>ruler) and ran it again with no improvements. I will be picking up more stepper drivers to see if that helps.
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If it mostly is Z stepping correctly (like when you tested it) and not when you are running the model for printing it is probably the stepper driver overheating and dropping current which causes steps to drop. They are CHEAP. A couple of bucks a pop ... get some spares :)
     

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