I created a new profile for my custom printer with a chimera extruder. The second nozzle has an offset {18.1; 0.6}, which I entered in the appropriate field in the settings of the Cura. When I cut the model for printing with any of the nozzles separately, everything is fine, but when the model should be alternately printed with both extruders, then an incorrect generation of g-code occurs. The fact is that when switching to the second extruder, the following lines appear in the code:
;LAYER:1
M140 S60
M106 S63.8
M104 S195
G0 F3600 X0.00 Y0.00 Z0.45
G1 F1800 E67.02626
G92 E0
T1
G92 E0
M109 S200
M104 T0 S175
M106 S127.5
G0 F3600 X-18.1 Y-.6 Z0.45
G1 F1800 E45
G0 F3600 X-18.1 Y9.4
G0 X90.64 Y175.78
G0 X91.208 Y176.306
G0 X214.97 Y252.47
M104 S210
This code occurs every time you switch to a second extruder. It is not clear why here these two lines:
G0 F3600 X-18.1 Y-.6 Z0.45
...
G0 F3600 X-18.1 Y9.4
They both instruct the printer to move the extruder carriage beyond the print area, to negative coordinates. Naturally the printer can not do this, the carriage rests against the frame and the engine skips the steps. After that the carriage moves back to the print zone but it skips the steps and as a result a shift occurs. Of course you can delete these lines with the help of post processing but I would like to know why this is happening at all? This is similar to the code for wiping the nozzle, but how did the developers allow it to generate coordinates beyond the print area? How to fix this?