I'm interested in 3d printing rotors for cipher machines, like the Enigma machine rotor. These are cylindrical objects with a complicated internal wiring scheme that's very labor intensive to duplicate with manual construction techniques.

The obvious solution would be to print the rotor structure using non-conductive filament, and then use conductive filament to create the complex, twisting connections from the one side of the rotor to the other.

Can this be done? If so, how?

Since I don't have access to a dual-extruder machine, are there any commercial services which have this capability?

  • $\begingroup$ Should be relatively easy with a dual extruder printer. You could always retrofit your existing machine too. As for other approaches: How about printing just the isolator part of the rotor? Then, insert solid copper wire into the internal paths (maybe glue them in) and grind down what sticks out. $\endgroup$
    – towe
    Commented Dec 14, 2022 at 12:13
  • $\begingroup$ The design I have in mind involves fairly complicated 3-dimensional internal connections. Adding copper wire after the fact would defeat the elegance and reproducibility of the whole concept. I want to have something that I can open-source, then anyone can download and either print it themselves or send it to a commercial outfit for printing. That's also why I'd prefer to avoid retrofitting and/or printer modifications: they make it harder for others to experiment with and improve on the design. $\endgroup$
    – moblie
    Commented Dec 14, 2022 at 13:20
  • $\begingroup$ most conductive filaments have a very high resistance. $\endgroup$
    – Trish
    Commented Dec 15, 2022 at 14:26

1 Answer 1


Here is a video published by a Virginia Tech student in 2017, printing alternately with conductive and magnetic pastes (not filaments) to make planar and toroid inductors:

Disclaimer: This was done with Hyrel 3D equipment, and I work for Hyrel 3D.

  • $\begingroup$ This is great, but doesn't show how I can do it or (better yet) provide a reference to a commercial service where I can send designs and have it done. $\endgroup$
    – moblie
    Commented Apr 18, 2023 at 3:59
  • $\begingroup$ I believe it absolutely does show you how you can do it - or at least that others have already completed very similar projects. $\endgroup$
    – Davo
    Commented Apr 19, 2023 at 11:39

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