Bed Leveling 9 points

Discussion in 'Calibration, Help, and Troubleshooting' started by corey, Apr 22, 2016.

  1. corey

    corey Well-Known Member

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    Hi Guys

    Just finished building my bigbox.

    I raised the bed up to the nozzle, put the belt under the sensor and lowered it on to it. I then hit the auto home then selected bed leveling, it done the first 3 points along the front, then did another 3 through the center. but the last 3 points the print head went all the way to the back of the printer so the nozzle was over the dump bucket...

    How do i stop it going so far back on the y axis, its like it thinks my print bed is a lot bigger than it is...

    Any ideas ?
     
  2. Kick2box

    Kick2box Well-Known Member

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    Check this in configuration.h:

    #ifENABLED(MESH_BED_LEVELING)
    #defineMESH_MIN_X5
    #defineMESH_MAX_X(X_MAX_POS-MESH_MIN_X)
    #defineMESH_MAX_Y(200-MESH_MIN_Y)

    ...
     
  3. Greg Holloway

    Greg Holloway Administrator
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    Check you have the correct pulleys on the X & Y motors. You should have the 16T on Y and the 20T on X.
     
  4. corey

    corey Well-Known Member

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    Hi Greg

    How stupid do i feel, i had 20t on both, just found the 16t in the box, just changed over and all is fine :)

    On the plus side i have learnt to flash firmware because of this issue so not all bad...
     
  5. Greg Holloway

    Greg Holloway Administrator
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    it's all good!

    You're not the first get caught out with this either :)
     
  6. Steven Burns

    Steven Burns Well-Known Member

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    Like me!! I did exactly the same thing and Greg came to my rescue.
     
  7. Alexandre Beyls

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    I have the same issue so I'll stole this discussion to talk about it.
    The symptoms are the same: During the bed levelling, the print head try to mate (very technical description, but this is spring after all) with the top-back panel and I need to shut-down the big-box before it hurt itself in the process.

    I've checked the Pulley on the Y motor (the one at the back on the wall above the big 2) and it is the 16 toothed one.

    Is there anything that is supposed to stop it that I've missed ?

    Not sure if this is related, but when I do an auto home, the noozle doesn't stop on the 150/100 mark but 3 and a half row behind (but still centred left/right). I didn't find any remark about where it should stop, so this might not be an issue at all.
     
  8. Nicu Damse

    Nicu Damse Member

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    You only have endstops at the front and left of the printer. The rest is limited in the firmware. While homing to you hit the endstops ? Is the home position close to the 0,0 position on the bed ?
     
  9. Alexandre Beyls

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    Yes to both questions. Home is at the correct 0,0 mark (front left), and both the endstops are triggered when returning to 'home'.
     
  10. Nicu Damse

    Nicu Damse Member

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    Sounds to me like your steps/mm are wrong for the Y axis. Can you check in control -> motion -> Ysteps/mm. It should be at 180.
     
  11. Alexandre Beyls

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    They are at +180.00 so that's not it (But thanks for the suggestion).
     
  12. Alexandre Beyls

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    And I think I found where my problem is ... the motor on the Y axis is a 1.8deg/step one, instead of the 0.9deg/step as found in the plans.
    Now the question is, where the frack did I put the 0.9deg/step motor ? (because it also means that somewhere else there is another wrong motor).
     
  13. Nicu Damse

    Nicu Damse Member

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    1.8 should only be on the z axis
    so check the z axis or maybe the extruder(s)
     
    #13 Nicu Damse, Apr 30, 2016
    Last edited: Apr 30, 2016
  14. Alexandre Beyls

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    And that's it ... the extruder is one of the 1.8, and my two Z axis are the two remaining 0.9 ...
    How lucky I am that I only need to move four out of five motors (which me luck, if I'm not back in 24h, send an undertaker
    , and all my stuff belong to my daughters)

    Small suggestion : Add the information about the deg/step wherever there is a motor to mount. I mean an idiot-proof (and I totally include myself in this description) warning in big red letters.
     

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