What Setting In Cura Determines The Value Of "G1 E-{switch_extruder_retraction_amount}" At The Beginning Of A Print?

Question

I am trying to print the Chep calibration cube sliced in Cura on my new Sovol SV04 Dual Extrusion printer. When I print the model the extruder prints the wipe line on the left of the bed, moves to the centre of the bed to begin the print and does a huge retraction (enough that it's almost the amount needed to change filaments), enough so that there is no filament in the nozzle and nothing comes out, I had to manually feed the filament back down in order to get it printing again.

The beginning of the G-code that Cura produces is as follows:

;FLAVOR:Marlin
;TIME:2593
;Filament used: 1.41417m
;Layer height: 0.1
;MINX:133.2
;MINY:133.2
;MINZ:0.2
;MAXX:168.8
;MAXY:168.8
;MAXZ:21
;Generated with Cura_SteamEngine 4.12.1
M82 ;absolute extrusion mode
;Single 01 start
M140 S60.0;
M104 T0 S210.0;
M280 P0 S160;
G4 P100;
G28;
T0
M190 S60.0;
M109 T0 S210.0;
G92 E0;
G1 X10.1 Y20 Z0.28 F5000.0;
G1 X10.1 Y200.0 Z0.28 F1500.0 E15;
G1 X10.4 Y200.0 Z0.28 F5000.0;
G1 X10.4 Y20 Z0.28 F1500.0 E30;
G92 E0 ;Reset Extruder
G1 Z2.0 F3000;
G92 E0
G92 E0
G1 Z{retraction_hop_height_after_extruder_switch} F12000
G1 E-16
G92 E0
G92 E0
G1 F2400 E-3
;LAYER_COUNT:199
;LAYER:0

The problem seems to be caused by the line G1 E-16 which I think comes from the extruder start G-code, however, I cannot seem to find what causes the retraction to be so large. The Start G-code for my printer is:

;Single 01 start
M140 S{material_bed_temperature};
M104 T0 S{material_print_temperature};
M280 P0 S160;
G4 P100;
G28;
T0
M190 S{material_bed_temperature};
M109 T0 S{material_print_temperature};
G92 E0;
G1 X10.1 Y20 Z0.28 F5000.0;
G1 X10.1 Y200.0 Z0.28 F1500.0 E15;
G1 X10.4 Y200.0 Z0.28 F5000.0;
G1 X10.4 Y20 Z0.28 F1500.0 E30;
G92 E0 ;Reset Extruder
G1 Z2.0 F3000;

And the Start Gcode for the extruder is :

G92 E0
G1 Z{retraction_hop_height_after_extruder_switch} F12000
G1 E-{switch_extruder_retraction_amount}
G92 E0

All of the settings that I have for the printer in Cura are copied over directly from Sovol's own version of Cura as I wanted to try and use one programme for all of my printers. When I slice the model in the Sovol Cura it does not seem to produce the same problem with the G-code for the model as follows:

;FLAVOR:Marlin
;TIME:2394
;Filament used: 1.43625m
;Layer height: 0.15
;MINX:136.5
;MINY:136.5
;MINZ:0.2
;MAXX:165.5
;MAXY:165.5
;MAXZ:20.3
;Generated with Sovol Slicer 1.3.0
M82 ;absolute extrusion mode
;Single 01 start
M140 S60;
M104 T0 S190;
M280 P0 S160;
G4 P100;
G28;
T0
M190 S60;
M109 T0 S190;
G92 E0;
G1 X10.1 Y20 Z0.28 F5000.0;
G1 X10.1 Y200.0 Z0.28 F1500.0 E15;
G1 X10.4 Y200.0 Z0.28 F5000.0;
G1 X10.4 Y20 Z0.28 F1500.0 E30;
G92 E0 ;Reset Extruder
G1 Z2.0 F3000;
G92 E0
G92 E0
G1 Z{retraction_hop_height_after_extruder_switch} F12000
G1 E-3
G92 E0
G92 E0
G1 F2100 E-3
;LAYER_COUNT:133
;LAYER:0

The G1 command is set to -3 instead of -16 and I cannot determine why.

Any help that you can give will be greatly appreciated.

Answer 1

The -16 is an option in Cura, please filter on switch, to make it visible:

The search for the "switch" option shows a default value of 16 for the Nozzle Switch Retraction Distance.

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Your interpreted G-code contains the line G1 Z{retraction_hop_height_after_extruder_switch} F12000 which is not expanded/translated. This is defined in your extruder change start script. Please check if the Z Hop After Extruder Switch is enabled.