Close



Results 1 to 7 of 7
  1. #1
    Technician
    Join Date
    Feb 2015
    Posts
    70

    Marlin 1.1.0-RC5 Odd Behavior on second hot end

    I set up an Itty Bitty Double Flex extruder today. The first hot end works just fine. When ever I try to print with the second hot end things are very screwy.

    Problem #1:
    I'm using ABL (G28 followed by G29) and trying to print with only my second hot end, T1. In this case when Marlin gets to the first move command (G1) the printer tries to move the hot end off the bed. The G29 leaves the hot end in the printer's far left corner. Then when the first move happens the hot end *should* move back into the center of the bed but instead it tries to run right off far left corner. It seems to me like we are in relative positioning mode when we should be in absolute positioning mode. If I run the same print with hot end 1 (T0) this problem does not happen. If I remove the G29 from my startup script then this problem does not happen.

    Gcode:
    G90
    M82
    M106 S0
    M140 S0
    M104 S0 T0
    M104 S205 T1
    M109 S205 T1
    G28 ; home all axes
    G29 ; Abl Routine
    G92 E0
    G1 E-1.0000 F1800
    G1 Z0.345 F120
    ; layer 1, Z = 0.345
    T1
    ; tool H0.345 W0.576
    ; skirt
    G1 X102.047 Y105.629 F3600

    Problem #2:
    I'm trying to print with only my second hot end, T1, just like above. But this time no ABL because it causes problem #1. Now the print starts normally and appears to be working fine until the end of layer 1. When attempting to raise the z-axis to print layer 2 the z-axis actually LOWERS itself and causes a head crash . No clue what is going on here. If I use hot end 1 (T0) this problem does not happen.

    Gcode:
    G90
    M82
    M106 S0
    M140 S0
    M104 S0 T0
    M104 S205 T1
    M109 S205 T1
    G28 ; home all axes
    ; G29 ; Abl Routine
    G92 E0
    G1 E-1.0000 F1800
    G1 Z0.345 F120
    ; layer 1, Z = 0.345
    T1
    ; tool H0.345 W0.576
    ; skirt
    G1 X102.047 Y105.629 F3600
    ....
    G1 X143.820 Y143.578 E28.1793
    G92 E0
    G1 E-1.0000 F1800
    ; layer 2, Z = 0.645
    ; tool H0.300 W0.480
    ; inner perimeter
    G1 X144.550 Y144.550 F3600
    G1 Z0.645 F120
    ...

    Does anyone have a clue what is wrong here? Thanks for looking.

  2. #2
    Engineer-in-Training beerdart's Avatar
    Join Date
    Feb 2014
    Location
    CT
    Posts
    345
    Sounds like your offsets are screwy

  3. #3
    Technician
    Join Date
    Feb 2015
    Posts
    70
    Quote Originally Posted by beerdart View Post
    Sounds like your offsets are screwy
    That would explain problem #1. I double checked my offsets and they look sane:
    #define EXTRUDER_OFFSET_X {0.0, 27.00} // (in mm) for each extruder, offset of the hotend on the X axis
    #define EXTRUDER_OFFSET_Y {0.0, 0.00} // (in mm) for each extruder, offset of the hotend on the Y axis

    I followed this up with an M502 then M500 to make sure I was using the firmware coded values.

  4. #4
    Engineer-in-Training beerdart's Avatar
    Join Date
    Feb 2014
    Location
    CT
    Posts
    345
    How about the Z probe offset?

  5. #5
    Technician
    Join Date
    Feb 2015
    Posts
    70
    Quote Originally Posted by beerdart View Post
    How about the Z probe offset?
    Here are the relevant config values.

    #define X_PROBE_OFFSET_FROM_EXTRUDER 52 // X offset: -left [of the nozzle] +right
    #define Y_PROBE_OFFSET_FROM_EXTRUDER 6 // Y offset: -front [of the nozzle] +behind
    #define Z_PROBE_OFFSET_FROM_EXTRUDER -1.70 // Z offset: -below [the nozzle] (always negative!)

    I set them based on my own measurements. Everything works great when using the 1st hotend. Things only go pear shaped when using the 2nd hot end.

    At this point, I suspect a Marlin bug. But I have not experimented enough to know for sure. Certainly getting farther by turning off ABL is a sign

  6. #6
    Engineer-in-Training beerdart's Avatar
    Join Date
    Feb 2014
    Location
    CT
    Posts
    345
    Im using RC3 without any issues. Perhaps it is a bug.

  7. #7
    Technician
    Join Date
    Feb 2015
    Posts
    70
    It was a bug. It is fixed in the Marlin RCBugFix branch (as of at least yesterday) on Github. Things are working fine now that I've upgraded.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •