after homing X axis thinks its at -38

Discussion in 'BigBox General Chat' started by Geedor, Dec 3, 2016.

  1. Geedor

    Geedor Member

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    I just got my printer back up and running after upgrading from big box dual to dual hybrid with titan. I did all the things I was supposed to in the manual and it was working fine. The next morning I turn the printer on and and now my printer thinks x axis is at -38 after homing the x axis. Does anyone have an idea of what is happening because nothing I try is working
     
  2. Stefan

    Stefan Well-Known Member

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    maybe you have start/end g-code problem, like the wrong extruder is selected before homing
    I have this in my start g-code
    Code:
    T0 ; select extruder 0
    G28 ;home
    Only question is T0 your left extruder?
     
  3. Syko_Symatic

    Syko_Symatic Well-Known Member

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    Might be using a non-mirrored firmware with a mirrored setup or vice-versa. That's what I think @Stefan is alluding to.
     
  4. Greg Holloway

    Greg Holloway Administrator
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    On the hybrid dual the home position for T0 is correct at -38

    You need to position the right extruder (T1) to be at 0,0 on the bed when the system is homed. The left extruder (T0) should hang off the edge of the bed. You will need to swap the x-axis endstop screw for a 10mm socket cap screw.
     
  5. Spoon Unit

    Spoon Unit Well-Known Member

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    Doesn't this depend on where the z-stop is? My home position puts the z-stop, currently still mounted on x-carriage, over 5,5, essentially meaning that my home position is at 66,5. Actually, that explains why it's currently not directly over 5,5 as I must have not reset that when I moved to RC8. Still, I think 0,0 is only the right home position if you've got your z-stop on the bed rather than on the x-carriage?
     
  6. Greg Holloway

    Greg Holloway Administrator
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    Quite possibly, I forget that people still have the sensor on the x-carriage!
     
  7. Spoon Unit

    Spoon Unit Well-Known Member

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    I know. I should really move it. It would certainly remove once source of inconsistency )in my case the thickness of the tape used to ensure the sensor triggers.
     
  8. Syko_Symatic

    Syko_Symatic Well-Known Member

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    Touch sensor is the way to go! I installed the BLTouch recently and it's fantastic. Auto bed levelling is magic.
     
  9. Spoon Unit

    Spoon Unit Well-Known Member

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    Not mesh levelling? Is the BL on the bed or the carriage? Photos?
     
  10. Syko_Symatic

    Syko_Symatic Well-Known Member

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    It is on the carriage. I will get some pics and maybe a video online in about an hour, got to put the boys to bed! just finishing the prints of your hinges, i have done the ones for the electronics cover and am currently doing the ones for the side panels.
     
  11. Syko_Symatic

    Syko_Symatic Well-Known Member

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    Stefan and Spoon Unit like this.
  12. Spoon Unit

    Spoon Unit Well-Known Member

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    Looks good. And that'll be MBL with nine points. Definitely looks like a good solution as it can automate all measured points.
     
  13. Syko_Symatic

    Syko_Symatic Well-Known Member

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    Easily adjustable too. If you want more points for higher accuracy. Though if your bed is that warped you probably shouldn't be using it!
     
  14. Stefan

    Stefan Well-Known Member

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    damn it now I need a BLTouch too :( but too expensive yet

    About auto leveling... when you have a Z min end stop on the bed like Greg's design and a probe on the x carriage, how do they mechanically work together? Like bed moves to z home, it hits the end stop and cannot go higher than this point since we do not want to crash the nozzle in the bed.
    How can the probe then auto level?
    It cannot go z negative sind the end stop blocks it.
     
  15. Spoon Unit

    Spoon Unit Well-Known Member

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    I don't think they do work together. You either use the z-stop optical sensor to get a single point, and then every measure is a manual offset from that using either paper or eyeballs .... OR .... you use the BL touch where every measure is made automatically at all 9 points so you can throw away the piece of paper (but recommend keeping the eyeballs).
     
    mike01hu and Syko_Symatic like this.
  16. mike01hu

    mike01hu Well-Known Member

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    . . . at all times! :D
     
  17. Syko_Symatic

    Syko_Symatic Well-Known Member

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    For calibration purposes you actually may need the bed to move beyond zero (by commenting a line in the firmware).
     
  18. Stefan

    Stefan Well-Known Member

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    OK so in this case a microswitch cannot be used for a z-end stop because it would mechanical block z negative or the mount it is a way that it is not blocking...
    thx
     
  19. Syko_Symatic

    Syko_Symatic Well-Known Member

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    In theory yes. But I don't know if there would be a need for the microswitch at all.
     

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