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Solved Print Head Crashing when Parking after completion

Discussion in 'Troubleshooting' started by Perry Genovese, Dec 13, 2016.

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  1. Perry Genovese

    Perry Genovese Member

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    Hey guys....been lurking for a long time and never needed to ask a question I couldn't find an answer to but I have one now.

    On taller prints it appears I have something in my firmware overriding the ending script but can't figure it out.

    When the print is complete it runs the ending script but then seems to run something else and crashes my print as it moves to a completely different parking location.

    Its the ROBO 3D r2 and I use simplify3D.

    I dumped the G-code and here's the last couple lines and the ending script. After this the head appears to want to park lower and goes through the print getting there. I believe the code below is fine. Attaching pics to showing what I find when its done. I have not witnessed it yet as its finished when I'm not in the room :) Thoughts?

    G1 X160.940 Y94.336 F2132
    G1 X164.475 Y97.871 F3200
    ; layer end
    M104 S0 ; turn off extruder
    M140 S0 ; turn off bed
    G1 Z20 X10 Y200 ; park position
    M84 ; disable motors
     

    Attached Files:

    #1 Perry Genovese, Dec 13, 2016
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Are those relative or absolute positions?
    Really I mean which did you intend because those are going to be absolute positions since you did not toggle relative in the GCode.
    When you enter absolute positions like that you run the very real risk of crashing into your completed model since the printer will take the most direct path ... You should use relative positions and add some though about how to dodge what may be printed.

    example:

    M104 S0 ;extruder heater off
    M140 S0 ;heated bed heater off (if you have it)
    G91 ;relative positioning
    G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
    G1 Z+0.5 E-5 X-20 Y-20 F9000 ;move Z up a bit and retract filament even more
    G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
    G1 Y150 F5000 ;move completed part out
    M84 ;steppers off
    G90 ;absolute positioning
    .
     
    #2 mark tomlinson, Dec 13, 2016
  3. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    As you may note you want to go back to absolute positioning after your script is done...
     
    #3 mark tomlinson, Dec 13, 2016
  4. Perry Genovese

    Perry Genovese Member

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    Thanks for the super fast response Mark ... Actually that ending script is the default Simplify 3D script. I only changed the Z from 10 to 20. I understand exactly what you are saying and will copy your code gladly. My understanding and apparently incorrect was that those values were from the last position and if not then why is the print head almost 3" off the table and 2" below where the print ended? Thats whats most bizarre is where it parked
     
    #4 Perry Genovese, Dec 13, 2016
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You might think

    "but the printer knows what it just printed and will dodge around it"

    Nope, sadly it is not that smart :) It only does what the slicer tells it to do

    and by default the slicers leave the printer in ABSOLUTE mode, not relative.
    So it will go to Z20 X10 Y200 (20mm off the bed, 10 mm from X home position, 200 mm from Y home position) in a very direct line.
     
    #5 mark tomlinson, Dec 13, 2016
  6. Perry Genovese

    Perry Genovese Member

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    lol....no I hear ya. but look at the pic....its not 20mm off the bed its more like 100mm. But I didn't withness it and now that you made clear relative vs absolute I'll change it and run it again.

    Thanks for the help!
     
    #6 Perry Genovese, Dec 13, 2016
  7. Perry Genovese

    Perry Genovese Member

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    Worked like a charm Mark :) Thanks again for the quick help!
     
    #7 Perry Genovese, Dec 13, 2016
    mark tomlinson likes this.
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