Bug Dual Extrusion: wrong extruder assignment

Hello guys,

I started up to install a 2nd Bowden Extruder to my Geeetech Prusa I3. All mechanical parts are correct connected and work fine.

But I still have a mistake by starting my dual extrusion. Repetierhost seems to switch the extruders randomly after slicing.
The print preview shows the 2 objects of the calibration square I want to print out.
In my options green is Extruder 1 (E0 in G-Codes) and black is Extruder 2 (E1 in G-Code).

I started the programm and everythink was working like wished. Due to the extruder offset I had to stop the print and took some adjustments. I didn't change anything else, sliced the objects again and suddenly the green square on the picture was printed with extruder 2 in black.
For the slicing I used Cura 2.5 with the 3 latest Versions of repetierhost but I had no improvement.
I get the same problems when I use Slic3r.

Even if I want to print a single object with extruder 2 (black) it's shown as black in the printpreviwe but switches to green (extruder 1) after slicing.

Does somebody knows how to handle this problem?

Best regards



  • Make sure you have not changed the extruder in object placement. Especially with curaEngine you can only use extruder 2 if Extruder 1 is also used or it will always fall back to extruder 1. With slic3r this does not happen.
  • Thanks for the fast answer.
    So Cura can only support Extruder 1 for single print. Okay, I understood this point.

    So if I have a normal "dual extrusion" I can only adjust the extruder in object placement once?
    And when I have a crash or want to change something than I need to restart the programm?

  • No in object placement you can modify it all the time in position, composition and extruder assignment. Just needs to reslice to take effect. And as said use both extruders for dual extrusion or use slic3r.
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