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Answered Z Axis offset problem?

Discussion in 'Troubleshooting' started by Bruce Fyfe, Mar 9, 2017.

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  1. Bruce Fyfe

    Bruce Fyfe New Member

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    When I start a print the printer goes through the auto bed leveling. Everything seems fine but when the printing starts the print head is too far above the print surface so the filament comes out in a string rather than being pressed to the hotbed. I have tried pausing the print job and manually lowering the printhead but I can seem to find a place it likes. Since I am new to 3d I am just guessing but could this be a z offset setting?
    A side note that may have relevance is that I recently removed a ReRap XXL LCD display/controller because my prints too close to the bed and consistently clogging. Seems like too much of a coincidence that after I removed it now I have almost the exact opposite problem. Any help appreciated. TIA
     
  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It is almost certainly the Z offset not getting applied.
    What do you have it set to in your startup GCode?
    Paste the startup gcode block here.
     
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  3. Bruce Fyfe

    Bruce Fyfe New Member

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    ; Generated with MatterSlice 1.0
    ; filamentDiameter = 1.75
    ; extrusionWidth = 0.4
    ; firstLayerExtrusionWidth = 0.4
    ; layerThickness = 0.2
    ; firstLayerThickness = 0.3
    ; automatic settings before start_gcode
    G21 ; set units to millimeters
    M107 ; fan off
    M190 S50 ; wait for bed temperature to be reached
    M104 T0 S210 ; start heating extruder 1
    T0 ; set the active extruder to 0
    ; settings from start_gcode
    G28 X0 Y0 Z0 ; home all axes
    G1 Z5 F5000 ; lift nozzle
    M109 S210 ; set the extruder temp and wait
    G28 X0 Y0 Z0 ; Home Z again in case there was filament on nozzle
    G29 ; probe the bed
    ; automatic settings after start_gcode
    T0 ; set the active extruder to 0
    G90 ; use absolute coordinates
    G92 E0 ; reset the expected extruder position
    M82 ; use absolute distance for extrusion
    ; Layer count: 20
    ; LAYER:0
    M107
    G0 F9000 X121.055 Y96.714 Z0.3
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    No M565 in there at all. Should be before the G29.

    Additionally. Start with -1 mm and adjust from there.

    M565 Z-1.0

    Sent from my BNTV450 using Tapatalk
     
  5. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    I would also eliminate the first G28 X0 Y0 Z0 line from the start up gcode and change the second one from
    Code:
    G28 X0 Y0 Z0 ; Home Z again in case there was filament on nozzle
    to
    Code:
    G28 ; Home all axes
     
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  6. Bruce Fyfe

    Bruce Fyfe New Member

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    Is this something I can do with a printer profile or something in MatterSlice?
     
  7. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    I don't use MatterControl and do not have it loaded but the start up gcode should be wherever you can configure your printer settings. Someone else will need to pipe up and help here.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  9. Bruce Fyfe

    Bruce Fyfe New Member

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    OK I have tried a couple of settings. I am stilling getting the print head too close to the bed. I'm getting really confused. Here is the current gcode settings:

    ; Generated with MatterSlice 1.0
    ; filamentDiameter = 1.75
    ; extrusionWidth = 0.4
    ; firstLayerExtrusionWidth = 0.4
    ; layerThickness = 0.2
    ; firstLayerThickness = 0.3
    ; automatic settings before start_gcode
    G21 ; set units to millimeters
    M107 ; fan off
    M190 S50 ; wait for bed temperature to be reached
    M104 T0 S210 ; start heating extruder 1
    T0 ; set the active extruder to 0
    ; settings from start_gcode
    G28 X0 Y0 Z0 ; home all axes
    G1 Z5 F5000 ; lift nozzle
    M109 S210 ; set the extruder temp and wait
    G28 X0 Y0 Z0 ; Home Z again in case there was filament on nozzle
    M565 Z0.9;
    M500

    G29 ; probe the bed
    ; automatic settings after start_gcode
    T0 ; set the active extruder to 0
    G90 ; use absolute coordinates
    G92 E0 ; reset the expected extruder position
    M82 ; use absolute distance for extrusion
     
  10. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    @Bruce Fyfe more negative is further away from the bed, yours is positive so driving the nozzle into the bed. Make sure you go to the terminal screen in MatterControl and issue a M502 followed by an M500 just in case EEPROM is enabled and has some odd setting in there.

    M565 is just not intuitive and that is why it is a negative number and not positive.
     
  11. Bruce Fyfe

    Bruce Fyfe New Member

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    Here is the terminal output from OctoPrint when it gets to this code:

    Send: N9 G28 X0 Y0 Z0*81
    Recv: ok
    Send: N10 G29*35
    Recv: Bed x: 15.00 y: 20.00 z: -1.05
    Recv: Bed x: 110.00 y: 20.00 z: -1.33
    Recv: Bed x: 205.00 y: 20.00 z: -1.22
    Recv: Bed x: 205.00 y: 125.00 z: -1.24
    Recv: Bed x: 110.00 y: 125.00 z: -1.35
    Recv: Bed x: 15.00 y: 125.00 z: -1.33
    Recv: Bed x: 15.00 y: 230.00 z: -1.33
    Recv: Bed x: 110.00 y: 230.00 z: -1.46
    Recv: Bed x: 205.00 y: 230.00 z: -1.29
    Recv: Eqn coefficients: a: -0.00 b: -0.00 d: -1.19
    Recv: planeNormal x: 0.00 y: 0.00 z: 1.00
    Recv: ok
    Send: N11 T0*10
    Recv: echo:endstops hit: Z:-1.29
     
  12. Bruce Fyfe

    Bruce Fyfe New Member

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    Here is what the M502 returned:
    Send: M205
    Recv: ok
    Send: M105
    Recv: ok T:209.9 /210.0 B:50.9 /50.0 T0:209.9 /210.0 @:55 B@:0

    the M500 said the settings were restored.
     
  13. Bruce Fyfe

    Bruce Fyfe New Member

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    OK I just thought of something. I had to replace the heated bed due to a chip in the glass. I bet that this might be the root source. How could I confirm and would I need to somehow recalibrate that board to recognize the "new" normal position?
     
  14. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Bed doesn't determine anything, it is the switches on both sides of the Z axis that tell the printer where Z0 is. There is no normal old or new, just where the switch is triggered.
     
  15. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    You see the M500 in your startup cgode, get rid of it, It doesn't belong there. I don't use MC so I can't tell you what section it;s in but it is in the startup gcode.

    And I already said your M565 line should be negative not positive
     
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  16. Bruce Fyfe

    Bruce Fyfe New Member

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    I have tried settings from -.1 up to -1.3 and still no luck. How far should I go? Thanks for the help so far, this is awesome!
     
  17. Bruce Fyfe

    Bruce Fyfe New Member

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    BTW, what do you use other than MC?
     
  18. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Cura, repetier host (those are both free) and a lot of folks use Simplify3D (not free).

    Either way.... (free or not) you need to make the M565 command negative :)

    In most others (I know simplify and repetier host) have a straight-up StartUp GCode block in the slicer and you pout in there what you want executed at the start of the print.

    This is mine (your Z offset will vary):

    G28 ; home all axes
    G1 Z5 F5000 ; lift Z by 5mm
    M565 Z-0.6 ; set the offset for auto-leveling mechanism
    G29 ; run auto-level
    M117 Waiting for extruder to stabilize
    M109 S[temperature] ; set the extruder temp and wait
    M104 S[extruder0_temperature] T0 ; tool 0 temp
    M117 Working on Print
     
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I am pretty sure if you just put it in the startup GCode you will need to remove it from where ever else MatterControl has it in the UI.
    It does have a place (somewhere) in the UI that you can specify it (as a positive number) that it (supposedly) then applies another way (not using the M565).
     
  20. Bruce Fyfe

    Bruce Fyfe New Member

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    So I tried a diffent program (Cura for Robo) to generate the gcode. The initial try with default setting didn't work. I tried a -1 and -2 Z offset. The 1 wasn't enough and 2 seemed too much. I have tried -1.3, -1.5 and -1.7 and can't get it going. Now I have a clog that cause the filament to break when I tried to remove. Here is the startup code from Cura:

    ;FLAVOR:RepRap
    ;TIME:6242
    ;Generated with Cura_SteamEngine 2.3.1
    M190 S60
    M104 S210
    M109 S210
    G21 ; set units to millimeters
    M107 ; fan off
    M190 S50 ; wait for bed to reach temp
    M104 T0 S210 ; wait for extruder to reach temp
    G28 ; home all axes
    M565 Z-2 ; set z offest up by 2mm
    G1 Z5 F5000 ; lift the nozzle by 5mm
    G29 ; probe the bed
     
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