Help C axis is not homing properly

Discussion in 'Motion System' started by Amr, Aug 13, 2019.

  1. Amr

    Amr Well-Known Member

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    C-axis (Coupler) is not homing properly and I cant get it to grab any tool. It dose move when I ask it to but I dont understand why it is not homing properly, Lock and unlock macros are not working too.

    My Guess is that when homing it, the rotation stop is not in the correct position but i can not figure out why, any help is appreciated.

    ps: it did work once when I was building the system. I only had one tool setup then.
     
  2. Amr

    Amr Well-Known Member

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    I Think it was the I2C error from the Duex5 I updated the firmware and it is back alive, so Probably to save your self the headache update the firmware to 2.03 (2019-06-13b2).;)
     
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  3. Amr

    Amr Well-Known Member

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    I Guess that was not it. I am having weird behavior here. Some times the tool is picked up and dropped just fine, and some times it picks up the tool and then dropping it results in the tool being dragged off the dock and and some times picking up just dose not hold the tool firmly on the changer.

    My guess is the C axis is not rotating as expected but I cant put my hands on why. Any help or Ideas Ideas are appreciated.
     
  4. Greg Holloway

    Greg Holloway Administrator
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    Hi,

    Have you tuned the dock positions? Is the pin and contacts lubricated? Have you done a manual lock and unlock?
     
  5. Amr

    Amr Well-Known Member

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    Done all the above the problem is that it is in consistent some time it works and some time it dosent
     
  6. Amr

    Amr Well-Known Member

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    I checked on the grab bar and when this issue happens it is not horizontal in the unlocked position which I understand is not the correct state it should be horizontal in the unlocked position right?
     
  7. Greg Holloway

    Greg Holloway Administrator
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    double check the tool, dock and pickup alignment. run through the process again.
     
  8. Amr

    Amr Well-Known Member

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    I re-did all the steps again ran the calibration gcode and test gcode and all was good, after changing the offsets and when runing the calibration gcode it fails to pickup the second tool again, I am going crazy here cant figure this one out.
    photo_2019-08-16_03-10-39.jpg

    image of the first calibration run
     
    #8 Amr, Aug 15, 2019
    Last edited: Aug 16, 2019
  9. Greg Holloway

    Greg Holloway Administrator
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    in the homec.g script change

    M913 C5 ; XY MOTORS TO 5% CURRENT

    to

    M913 C40 ; C MOTOR TO 40% CURRENT

    Have you done any repeatability testing on tool pick up and drop off and watched it as it runs?

    You can make a g-code script with the following

    T0
    T-1
    T0
    T-1
    T0
    T-1
    T0
    T-1
    T0
    T-1
    T0
    T-1

    Repeat as much as you want for each tool replacing T0 with T1 etc.

    Also check the cables that face the electronics panel, make sure they are not hitting the acrylic or moving the tool off of position.
     
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  10. Amr

    Amr Well-Known Member

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    I did run the Tool Changer Test GCODE file a couple of times before running the calibration and it worked with no issues, I will check the cables and report back, and should I go all the way to 40% of the bat, should I instead increase gradually until the issues is resolved if that is the reason. One thing I was thinking about not sure if it may be the reason I used 3 in 1 Machine lubricating oil for the lubrication instead of the one you refer to in the guides. 3 in 1 = Lubricating, Penetrates Rust, and Cleans. at least that is what is writen on the bottle.

    Thanks for the help I will report back once I check and try the above.
    Cheers
     
  11. Amr

    Amr Well-Known Member

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    You know bringing up the current value for the C axis just made me remember the it dose not detect crash on homing it actually takes a while faintly clicking at its limit before going to home position that might be it. I will try that ASAP.
     
  12. Greg Holloway

    Greg Holloway Administrator
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    yup, i couldnt get stall detect to work. so it crashes.
     
  13. Greg Holloway

    Greg Holloway Administrator
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    needs grease, 3 in 1 is no good!
     
  14. Amr

    Amr Well-Known Member

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    Ok The 40% current did the trick. Fingers crossed it stays this way. I will order some grease for lubrication but for now the 3 in 1 will have to do for now.

    Thank You Greg your help is appreciated.
     
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  15. Andy Cohen

    Andy Cohen Well-Known Member

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    Ekk! Please DON'T use 3in1!! Seems to me if you really need to use oil the best is the stuff made for sewing machines, but me, my preference is suspended PTFE aka Superlube.
     
  16. Spoon Unit

    Spoon Unit Well-Known Member

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    I used this stuff where grease was needed. Good enough?

    [​IMG]
     
  17. Greg Holloway

    Greg Holloway Administrator
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    we use magnalube
     
  18. Andy Cohen

    Andy Cohen Well-Known Member

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    The HTG stuff looks good. I'd like to see if I can find some. Superlube is not high temp. For sure though 3in1 is not a choice.
     
  19. Nibbels

    Nibbels Well-Known Member

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    I see
    within the current config.g. So this is still not working today?
     
  20. Amr

    Amr Well-Known Member

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    That is what I have working for me, try playing around with the current value for the coupler stepper I recall I had to increase it in the homec.g file check thread above for the details.
     

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