3.3.0-BETA Why does the slicer retract 6.5 then 16mm at the start of layer 0?
I'm using the Vertex K8400 dual profile and disabled extruder 1 in Cura to print using extruder 2 (which is a really useful feature!!)
When I slice, just before layer 0, the extruder retracts 22.5mm!
This is the code created when extruder 1 is disabled to print using extruder 2
;FLAVOR:Marlin
;TIME:678
;Filament used: 0m
;Layer height: 0.2
;Generated with Cura_SteamEngine 3.3.0-BETA
T1
M190 S55
M104 T1 S200
M109 T1 S200
M82 ;absolute extrusion mode
; Cura Startup Script v1.0
G21 ; metric values
G90 ; absolute positioning
M82 ; set extruder to absolute mode
M107 ; start with the fan off
G92 E0 ; zero the extruded length
M117 Home all axis...
G28 ; home all axes
M117 Level bed...
G29 ; level bed
M106 P1 S64 ; Start Extruder Fan
M117 Prime Extruder!
G1 F8000
G1 X210 Y190 Z0.5 ; move off edge of bed
G1 E15 F500 ; extrude 15mm
M400 ; wait for extrusion
G1 Z0 X200 Y180 E20 F1000 ; Wipe and extrude 5mm
G92 E0 ;zero the extruded length again
G1 F9000
;Put printing message on LCD screen
M117 Printing....
;end of script
G92 E0
G1 F1500 E-6.5 ; Why do this?
;LAYER_COUNT:57
;LAYER:0
G1 F1200 E-16 ; Why do this too?
G92 E0
T1
G92 E0
M109 S200
M107
G0 F3600 X89.192 Y89.558 Z0.3
;TYPE:SKIRT
However, if you disable extruder 2, to print with extruder 1 the line G1 F1500 E0 is added which compensates for the earlier retraction.
It seems this line is missing when you print with extruder 2.
;end of script
G92 E0
G1 F1500 E-3
;LAYER_COUNT:32
;LAYER:0
M107
G0 F3600 X77.85 Y115.65 Z0.3
;TYPE:WALL-INNER
G1 F1500 E0
G1 F1800 X77.85 Y111.85 E0.16115
G1 X80.35 Y111.85 E0.26716
G1 X80.35 Y111.626 E0.27666