This is a belt-reduced non-bowden dual extruder, with care taken to allow flexible filament use. It has a tight 17mm nozzle interval, can probably be ...made under 500g. This was designed first around the Ord Hadron X carriage, and adapted to MendelMax 2 X carriage. Other mounts are possible.
I tried my best to minimize the weight penalty over many non-bowden single extruders. I believe I can have a working unit under 500g. The first working prototype is 600g, including hot ends and motors. Many direct drive single extruders are in this weight range, making the weight penalty of a second direct drive extruder negligible.
Care has been taken to allow for flexible filament use, a straight path with minimum seams & joints, and no room to buckle.
Filament idler pressure is easily adjustable, and there is a "bird nose" quick release to allow visible access to the hobbed pulley or to quickly switch materials.
I designed around an Ord Hadron carriage, but with a simple mount plate, it will also mount to a MendelMax 2 carriage using a different groove mount plate, see my other designs in my account.
This is a work in progress, but I have had about 40 hours of successful operation. The photos represent my first prototype, the drawings represent improvements based on use.
On an Ord Hadron, it requires no modification to the carriage, and only a little adjustment to the X limit endstop. It still allows 196mm of full dual extrusion X working width. Mount plates for other machines should be coming soon.
3d model print parameters
See the BOM spreadsheet in the documents section....