Today I started to google the idea of multimaterial printing. I checked out prusa multimaterial upgrade and while it looks nice, it is expensive and will not probably work with my non-prusa printer.

I discovered there is Diamond hotend, which allows for 3 (or even more) colors at the same time. But everywhere I checked, one extruder motor was used for each color. Since my MKS Gen L motor connections are already all used, I was thinking if it would be possible to handle all of the filaments with single extruder motor.

Basically the motor would have long shaft which will cover all filaments, and I would add some servo that would push a pulley against the selected filament.

I think I would slice it as a multiple hotend setup and then postprocess the gcode in a way, that when tool is changed I would add custom command that would push the pulley against appropriate filament.

I would either need a servo for each of the filemants, or maybe with some clever mechanics one servo in different positions could do all of them.

I am just curious if you think this would be possible to do, since I did not find anyone discussing this idea. Probably because it will require adding custom commands to the firmware.

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    $\begingroup$ Sounds a lot like the MMU concept - which is available online for you to build yourself. As for the diamond hotend and your board, it might be easier to have a look at the Klipper firmware and just use two boards. $\endgroup$
    – towe
    Dec 12, 2019 at 7:17
  • $\begingroup$ I did not find any information about how to make the MMU, just $300 to buy it. $\endgroup$ Dec 12, 2019 at 9:11
  • $\begingroup$ what you describe is a variant of the Prusa MMU2 but with triple the bowden tubes and a hotend about 2-4 times as heavy. $\endgroup$
    – Trish
    Dec 12, 2019 at 15:34

1 Answer 1


You might save yourself a lot of engineering by copying the Prusa MMU2. Here is a github project for someone doing exactly that: https://github.com/cskozlowski/mmu2

If you look on Prusa's web site, you can find printable parts for the MMU2.

  • $\begingroup$ I also noticed that new version of Marlin includes the support for the prusa MMU2, so maybe this is the way to go... except I still have to solve how to control the additional motors.... $\endgroup$ Dec 17, 2019 at 13:58

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