Print head crashing against prints

Discussion in 'Calibration, Help, and Troubleshooting' started by Jaysen DAYDREAMn, Jan 18, 2017.

  1. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    After setting up the BigBox to do dual print. I thought I had a horrible alignment issue or something else wrong when my print head was bashing into the print. This would happened at seemingly random Layer heights.

    I gave up and went back to single nozzle. I removed the left nozzle and still had this issue during layer 15 of a print.

    I rebooted everything and tried again after checking z frame movement and the print competed successfully.

    Last night this happened again, This time on about layer 80.

    I was reading another thread and saw Greg mention something about bad gcode causing the print head to crash against prints.

    Is this happening with new version of Octoprint sending wrong gcode to the printer? Is anyone else experiencing this?
     
  2. Greg Holloway

    Greg Holloway Administrator
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    Hi,

    Octoprint doesn't inject code. It acts in exactly the same way that a desktop pc does and sends the code from a file line by line to the Rumba. The ONLY exception to this are the G-Code scrips used at the start, pause, cancel, resume and end of a print. These scripts are editable in the setting section of OctoPrint.

    Can you explain a little about the problem you are having? The issue mentioned on the other thread relates to the start of a print and is caused by incorrect g-code in the file being sent to the print. It has the incorrect position of the printhead for the priming/purge sequence. This error is generated by the scripts in S3D and is simple enough to correct.

    You mention the head is bashing into the print, which nozzle?

    What do you mean by bashing?
     
  3. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Greg,

    It seems at some seemingly random interval the BigBox stops advancing the Z.

    After the last mishap I did the following as a test.

    (I did not reboot the printer)
    Clean the nozzle.
    Check that it is extruding.
    Home.
    Load a new print file.
    Print.
    The printer stopped advancing on the Z after the first layer
    drags the right nozzle against the printed piece as it continues to extrudes. ( this seems to happen randomly meaning, different print files. at diferent layer height. )

    Currently....
    Shutdown BigBox
    Powered up
    PreHeat
    Home
    Level bed
    Save
    Home
    Load new print file
    Print

    Printer is currently on layer 8 and printing as expected.
     
  4. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Print failed at layer 9.
     

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  5. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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  6. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Another test different model. Looks like Z failed around layer 15 or so but continued printing....
     

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  7. Alex9779

    Alex9779 Moderator
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    Could be a too low setting of the Z motor current. When working a being under current the motors get warm which has an influence on their resistance. So even if the setting is fine when you test cold it could just not be enough when they are warm. I would slightly increase the current of the Z motors...
     
  8. Greg Holloway

    Greg Holloway Administrator
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    Also check the wiring is good. Turn off Z-Hop (vertical retraction lift) if you have that set up and try again.
     
  9. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Alex,

    When i test the voltage is at 5.9 what would you suggest?
     
  10. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Where do I find Z lift in Simplify3d?

    I will double check the wiring again. I did and all seem connected and secure.
     
  11. Greg Holloway

    Greg Holloway Administrator
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    printhead extruder toolhead (the first page of the process settings)... its labelled as retraction vertical lift.
     
  12. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    Setting is currently at 0.

    Do you think this could be sensor related? Sensor was moved tot he Z frame but has been recommissioned. I have had successful prints since moving the sensor.
     
  13. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    I pulled apart the z and re trammed it. Nothing was binding. everything was nice and smooth. The z frame is mechanically level to the base.

    The prints make it seem like it is skipping or stopping on certain layers and printing right one top of the previous layer without moving z.

    This is an example...
     

    Attached Files:

  14. Greg Holloway

    Greg Holloway Administrator
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    Have you changed or checked the wiring or adjusted the z-axis stepper driver? That is the likely cause. Symptoms are mechanical, fault is electrical.
     
  15. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    stepper driver is at 6. i have checked wiring. Should i try to increase or decrease the stepper voltage?
     
  16. Ephemeris

    Ephemeris Well-Known Member

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    Are you saying that Vref on the stepper driver boardis 0.6 volts?
     
  17. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    yes it is .59 - .6 someone suggested i try .5

    I have checked all the wiring.
     
  18. Greg Holloway

    Greg Holloway Administrator
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    .6 is fine.

    Try taking the stepper driver out and putting it back in again. Could be an iffy contact.

    When you checked the wiring did you take it out of the rumba for a visual inspection? Which Z-Axis cable(s) do you have?
     
  19. Jaysen DAYDREAMn

    Jaysen DAYDREAMn Well-Known Member

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    @Greg Holloway Yes, I did take the cables out and give them a once over. and the connectors on the stepper motor side seem to be fitting snug and making good contact. The Z cables are from the first batch I believe.

    I tried (on someone else recommendation) turning the stepper driver voltage down to .5 and it seems to have corrected the issue thus far.
    Is this a bad idea?

    Should i Still try taking the stepper driver out and resetting it and then go back to the .6v?
     
  20. Greg Holloway

    Greg Holloway Administrator
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    If it works it's not a bad idea!
     

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