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Unresolved Z-axis rods out of sync

Discussion in 'Troubleshooting' started by Buckwild, Jun 20, 2015.

  1. Buckwild

    Buckwild New Member

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    Somehow (maybe from tipping my Robo over to install the lcd controller) my two z-axis threaded rods became out of sync with each other so now the virtual plane connecting them is not parallel to the print bed. Anybody have a clever way to fix this?
     
    #1 Buckwild, Jun 20, 2015
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Just move the nuts up/down as needed with the power off?
    Pictures may help, not certain I get what the issue is.

    If you hold one rod and turn the other ...
     
    #2 mark tomlinson, Jun 20, 2015
  3. Buckwild

    Buckwild New Member

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    Yes but is there any way to ensure that the plane between the two is perfectly parallel to the build plate? Other than maybe measuring the difference in height with calipers. Is there any method of "zeroing" the two z rods in software? I hoped that having the limit switches would solve the issue, i.e. if the two rods were out of sync and I sent a home command that the limit switch that was at a higher position would continue to move down until it was "zeroed", however that doesn't seem to be the case. I have adjusted the threaded rods manually as best I can but I'm just wondering if there is a good way to know with confidence that the two are at the same height.
     
    #3 Buckwild, Jun 20, 2015
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    That is not how the limit switches work. If either switch triggers you are at the endstop. To the Robo, it doesn't matter which one or even know which one switched. They are wired in parallel. If you need it closer than what you have already done, then a machinists dial indicator and some sort of printed holder will likely be the best way. But this is really not necessary as the auto-tramming levels the print for you, not the bed itself, but the print will be level. We are not talking about a micron precise machine here, some times close enough is good enough.
     
    #4 WheresWaldo, Jun 20, 2015
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  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yea, terminology here.

    When we talk about 'level' we don't really mean level.
    We mean level with respect to the bed (level on a plane represented by the bed). In other words, the print head is positioned correctly and will move in a 'level' fashion across the bed.

    The 9 point probing is where the arduino code is measuring the bed and building a programmatic model of the bed so that it can then keep the head positioned 'level' across that plane. It makes small adjustments as the head moves around to the 'zero' offset of the head.
     
    #5 mark tomlinson, Jun 21, 2015
    Last edited: Jun 21, 2015
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  6. jtn7040

    jtn7040 Active Member

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    you can open up the terminal and then run G29 (auto level) and look at what is returned in the terminal in the Z coordinate rotate the z axis rods accordingly until you can get the numbers as close to 0 as possible. (I've only been able to get it to like .02 on all 3 areas) if it's negative then spin the other way


    EDIT: Make sure you run G28 first to hone your axis. if you don't the printer will be very angry.... trust me.
     
    #6 jtn7040, Jun 21, 2015
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  7. Mike Kelly

    Mike Kelly Volunteer

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    I'd bet the helical coupler is loose against the lead screw.

    Grab the screw and try spinning the aluminum spring looking thing against each other to see if one is loose
     
    #7 Mike Kelly, Jun 22, 2015

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