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overextrusion during pre-print sequence

Discussion in 'Troubleshooting' started by DavidR, Jan 6, 2018.

  1. DavidR

    DavidR Member

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    During the pre-print sequence (I'm not sure what this is actually called-- the sequence of movements where the bed and extruder go up and down and almost touch at different points on the bed that is identical before each print) the extruder will sometimes release filament, often so much that it will bunch up and stick to the side of the extruder and screw up the print process down the line. This happens around 30% of prints. I was hoping someone can point me in the right direction in terms of identifying the cause and resolving this issue.
     
    #1 DavidR, Jan 6, 2018
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    That is oozing and generally will happen to everyone. I think many long time users have gotten to the point where they are extruding as cold as many filaments will allow and that helps minimize the ooze. Other C2 / R2 users have removed the pre heating commands from the Web interface scripts. The part where they print the single line in the front of the printer. That also will help minimize the oozing.
     
    #2 WheresWaldo, Jan 6, 2018
    mark tomlinson likes this.
  3. DavidR

    DavidR Member

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    @WheresWaldo Thank you for your reply! I take it your are referring to the following section. I'm assuming I can put a semicolon in front to comment it out (so I can re-add them if I decide I want them)? which of the following are normally removed?:

    ; set to millimeters
    G21
    ; set to absolute mode
    G90
    ; zero extruder
    G92 E0
    ; turn off fans
    M107
    ;non blocking heatup of extruder and bed
    M104 S230
    M140 S60
    ; home all axis
    G28
    ; probe for bed autolevel plane
    G29
    ; pause for 2 seconds
    G4 S2
    ; move bed down 15mm
    G1 Z15 F300
    ; move to front left corner
    G1 X1 Y1 F7200
    ; heat to priming line temp
    M109 S230
    M140 S60
    ; move bed to printing position
    G1 Z0.3
    ; print 190mm priming line
    G1 X190 E15.0 F500
    ; move bed down
    G1 Z15 F300
    ; zero extruder
    G92 E0
    ; set movement speed
    G1 F7200
     
    #3 DavidR, Jan 6, 2018
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Here is how I would set it up:
    Code:
    ; set to millimeters
G21
; set to absolute mode
G90
; zero extruder
;G92 E0
; turn off fans
M107
;non blocking heatup of extruder and bed
;M104 S230
;M140 S60
; home all axis
;G28
; probe for bed autolevel plane
;G29
; pause for 2 seconds
;G4 S2
; move bed down 15mm
;G1 Z15 F300
; move to front left corner
;G1 X1 Y1 F7200
; heat to priming line temp
;M109 S230
;M140 S60
; move bed to printing position
;G1 Z0.3
; print 190mm priming line
;G1 X190 E15.0 F500
; move bed down
;G1 Z15 F300
; zero extruder
G92 E0
; set movement speed
G1 F7200
    My script has an extra line since I modded to printer to add G-code controlled lighting, otherwise it is almost identical. @mark tomlinson sets his up very differently as he sets as many printer specific things in these scripts as opposed to the slicer. I tend to set everything up in the slicer.
     
    #4 WheresWaldo, Jan 6, 2018

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