Voron purge blob.gcode

# In order to use this you need to increase max_extrude_cross_section in your extruder config or klipper will complain. I set mine to 30
[gcode_macro PURGE_BLOB]
gcode:
    # This is for a 300mm bed. If you have a diferent bed size you may want to adjust the line below
    {% set rand_pos = (105 + ( printer.system_stats.cputime * 1000 ) % 60) %}           ; Generate pseudo random start pos so we dont wear out that one spot on the bed. 
    M117 Purging at X{ rand_pos }                                                       
    
    # The start pos will be within the "handle" of the flex plate where there is some extra Y space available so we can go all the way to Y0
    # If your setup does not have this extra space then just increase the y valie in the line "G1 X{ rand_pos } Y0 Z1 F18000"
    G92 E0                          ; zero the extruder
    G90                             ; absolute positioning
    G1 X{ rand_pos } Y0 Z1 F18000   ; Go to start pos for perge line
    G1 Z0.4 F600                    ; Lower to purge height
    G91                             ; relative positioning
    G1 X5 E40 F40                   ; Extrude blob of filament on the bed
    M106 P0                         ; Enable Cooling Fan
    G1 X20 Z5 F100                  ; Slow drag away from the blob with fans helping cool and break strings. Also raiz z zo the blob clears the fan duct
    G1 X5  Z-5.1 F9000              ; Now that the blob has cleared the duct we go back down for a short 0.3mm height extrusion
    G1 X5 E2 F180                   ; Slow 5mm extrude move to help with stringing
    G1 X30 E-1 F6000                ; Fast move and retract to break strings and reduce ooze
    G1 Z1 F100                      ; Lift
    M106 P0 S0                      ; Disable Cooling Fan
    G92 E0                          ; zero the extruder
    G90                             ; absolute positioning

Worked like a charm! 😊 Thank you, it replaces the traditional, less effective line... 😉

Here's some adjustments that will make it work with various bed sizes automatically, and easier to adapt to different sizes of flexplate handles. It also changes the direction of travel based on where it starts the purge relative to the center of the handle:

[gcode_macro PURGE_BLOB]
gcode:
    SAVE_GCODE_STATE NAME=PRIME_NOZZLE_STATE
    # FROM: https://gist.github.com/brandon3055/f5297f191fa576d2228e700ac6857abc
    # In order to use this you need to increase max_extrude_cross_section in your extruder config or klipper will complain. I set mine to 30
    {% set BEDWIDTH = printer.toolhead.axis_maximum.x|int %}

    # Set the width of your flexplate handle here
    {% set FLEXPLATE_HANDLE_WIDTH = 80|int %}
    # And if your flexplate is not centered, you can adjust that here
    {% set FLEXPLATE_HANDLE_LEFT_X = 0.5 * BEDWIDTH - 0.5 * FLEXPLATE_HANDLE_WIDTH %}

    {% set FLEXPLATE_HANDLE_CENTER_X = FLEXPLATE_HANDLE_LEFT_X + 0.5 * FLEXPLATE_HANDLE_WIDTH%}
    {% set PURGE_X_LOC = (FLEXPLATE_HANDLE_LEFT_X + ( printer.system_stats.cputime * 1000 ) % FLEXPLATE_HANDLE_WIDTH) %}           ; Generate pseudo random start pos so we dont wear out that one spot on the bed. 
    {% set PURGE_TRAVEL_DIR = (1 if PURGE_X_LOC < FLEXPLATE_HANDLE_CENTER_X else -1) %}

    RESPOND TYPE=echo MSG="Bed width        W={BEDWIDTH}mm"
    RESPOND TYPE=echo MSG="FlexPlate handle W={FLEXPLATE_HANDLE_WIDTH}mm starting @X={FLEXPLATE_HANDLE_LEFT_X}mm"
    RESPOND TYPE=echo MSG="Using purge loc  X={PURGE_X_LOC}mm, Traveling { 'LEFT' if PURGE_TRAVEL_DIR > 0 else 'RIGHT' }"

    M117 Purging at X{ PURGE_X_LOC }                                                       
    
    # The start pos will be within the "handle" of the flex plate where there is some extra Y space available so we can go all the way to Y0
    # If your setup does not have this extra space then just increase the y valie in the line "G1 X{ PURGE_X_LOC } Y0 Z1 F18000"
    G92 E0                          ; zero the extruder
    G90                             ; absolute positioning
    G1 X{ PURGE_X_LOC } Y0 Z1 F18000   ; Go to start pos for perge line
    G1 Z0.4 F600                    ; Lower to purge height
    G91                             ; relative positioning
    G1 X5 E40 F40                   ; Extrude blob of filament on the bed
    M106 P0                         ; Enable Cooling Fan
    G1 X20 Z5 F100                  ; Slow drag away from the blob with fans helping cool and break strings. Also raiz z zo the blob clears the fan duct
    G1 X{ 5*PURGE_TRAVEL_DIR }  Z-5.1 F9000              ; Now that the blob has cleared the duct we go back down for a short 0.3mm height extrusion
    G1 X{ 5*PURGE_TRAVEL_DIR } E2 F180                   ; Slow 5mm extrude move to help with stringing
    G1 X{ 30*PURGE_TRAVEL_DIR} E-1 F6000                ; Fast move and retract to break strings and reduce ooze
    G1 Z1 F100                      ; Lift
    M106 P0 S0                      ; Disable Cooling Fan
    G92 E0                          ; zero the extruder
    G90                             ; absolute positioning

    RESTORE_GCODE_STATE NAME=PRIME_NOZZLE_STATE

I recently encountered Y-layer shifts, because of the printhead colliding with the blob..