Simple work flow for using duplicate mode

I am having trouble getting to grips with the duplicate mode on J1S with Luban. It should be simple enough, but can’t get it to work.
I have mode selected as duplicate. I load a very simple model that doesn’t require supports. I right click the model and select auto arrange and the model moves to the left side of the platform. The generate gcode is greyed out. I right click and select duplicate, the new model goes to the right side and is coloured red. Still the generate gcode is greyed out. I have made sure that both extruders have the same filament selected with the same settings, but still no generate gcode button enabled. I have looked on the internet widely for tutorials, but nobody seems to have anything except time lapses of it working! anybody here got a workflow to get this working?

Many thanks,


TLDR: it is not issue of Luban or other slicer, it is some bug directly in the firmware.
I don’t use Luban but Simplify3D and the printer is connected via USB to Raspberry Pi with Octoprint and have same issue - the duplication doesn’t work (only mirroring, see Can't use copy mode M605 S2 via back USB port - #7 by Viktor).
At the moment, the only working FW is 2.3.5 (but I am afraid is no more available for download) or you can compile the open source version from github. Last working commit is 1c21bcdcb12aa0223da74d55c7e59e52cbf6f4f0 (Pref: pause temp set timeout set to 2 miniute).
I have reported this issue both here and in the Github but no reaction from Snapmaker yet.

Thanks Viktor,

I found that this actually works in Luban! Not intuitively, but very simple in the end. The process is to select “Duplicate” as the mode. Load the model. Right click and select “Auto arrange” the part will move to the left section. Select the pull down by the little paint brush in the objects list and select L to allocate the model to the left extruder. At this point the generate gcode button becomes active. note there is no model showing on the right hand side. Nor does it show at all in the workspace environment. But, it does create the gcode for duplicate printing and all is good. If you want more pieces, simple duplicate the original model as many times as will fit on the left side of the printing plate before going through the extruder allocation and auto arrange as above. Then it will duplicate all the left models to the right side when you send the gcode to the printer.

Hope this can help.


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Hi David,

thank you. But, I prefer different slicer (Simplify3D) and connection via Octoprint (which allows the camera as well).


Ok, perhaps it can help somebody else using Luban. At least it works!



OK, thank you.
I can use duplication mode from Simplify3D now. Actual FW 2.7.1 of Snapmaker J1/J1s has incorrectly adopted the M605 command but it can be corrected with startup script from slicer. Full M605 command (M605 S2 X162 R0) must be used, not only the short version (M605 S2).