Avoid implicit G-Codes after Start G-Code

[SusisStrolch 0]

Cura creates implicit G-Codes after the Start G-Code and before the sliced object.

;Generated with Cura_SteamEngine mb-master-20210516
M82 ;absolute extrusion mode
; >>> Printer Start G-code
; allow preheat in fluiid/mainsail
;M109 S235.0 
;M190 S75 
;M106 S0 
; start gcode is handled by Klipper
START_PRINT T_TOOL=235.0 T_BED=75 FAN_SPEED=0
; <<< exit Start G-code
G92 E0
; >>> Extruder Start G-code
; <<< Extruder Start G-code
G92 E0
G1 F1800 E-2
;LAYER_COUNT:32
;LAYER:0

How can I convince CURA not to insert this implicit retract before Layer 0?

 

[gr5 1,734]

I don't think you can.  It's usually a good thing - it prevents the nozzle from leaking while it moves to the start of the skirt or brim.  Then it does an E0 which undoes that retraction and then it starts printing the skirt or brim.

 

If you take out the E-2 it will leak a bit and there will be less filament for when it starts printing the skirt/brim.

 

[GregValiant 473]

@gr5 and @SusisStrolch,

When I was tweaking my start gcode I was having trouble getting the head to "pick up here, move over there, start to extrude".  It turned out to be that line that was the issue.  My fix (not a great one) was to use the Search And Replace plugin and search for G1 F1800 E-2 and replace it with G92 E-1.5.  Since there was no longer a retraction, the filament was right at the nozzle and the later G1 F1800 E0 that precedes the start of printing ends up being a good prime.  Now my skirt (or whatever) starts right up.

The downside to using the Search and Replace is that if I change retraction speed or retraction distance, the search criteria has to change as well.  The second downside is that if the same line was to appear later in the gcode (which is exceedingly unlikely), it would be changed as well.