Rotoforge: an affordable open source multimaterial 3D printer, for printing metal, plastic and ceramics on the home desktop

Hello everyone, I am a graduate student developing a free and open source hardware/software 3D printer designed to use friction stir surfacing and high shear extrusion machining to print high quality metals, plastics and ceramics on the home desktop. We are still in early days, but we are having some success in printing aluminum and copper, onto themselves and onto various ceramics, as well as organics like FR4.

Links below for those interested.

send me an email at
or message me on discord if you care to chat. I am always happy to have new ideas and suggestions and meet new people!


Excited to watch this project grow, thanks for sharing!

@mtlynn I see your GitHub repository uses the GNU AGPLv3 license, cool! It’s one of my favorite licenses.

That said, for the hardware components may I suggest using a hardware-specific open source license? For example, the CERN OHL-S-2.0 is the equivalent of the GPL but for hardware designs. Here is an example GitHub project using it. You can still use the AGPLv3 for all software/firmware components.

For some background, check out this thread on the efforts of the GOSH community that successfully made the CERN OHLv2 family of open source hardware licenses available on GitHub!

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Having read the threads and license information you have provided, I think this is a great idea.
I had not previously, thoroughly considered the hardware licenses that were actually available.

I will act on this in short order. Thanks for the tip!


I very much like this idea @mtlynn. I am nearly done putting together an e-textbook on all aspects of maker education. Would you like this to be featured in the book?

For printing metals, you may want to try gallium-indium mixtures. They are pretty close to room temperature.

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If you would like to feature it, I would be honored.

I would also refer you to the recent literature on the technique.
I did not invent it, just scaled it down.

Regarding gallium and indium mixtures, I will keep this in mind. I have actually been trying softer alloys like Zamak, and lead tin solders as well, as gallium/indium are quite expensive. :slight_smile:

The melting point of the alloy is not the most critical element, its really how its viscosity evolves with shear and temperatures. In general, the more machinable the material, the more extrudable it is for rotoforge.


I had not previously, thoroughly considered the hardware licenses that were actually available.
I will act on this in short order. Thanks for the tip!

Splendid! Some practical steps for doing this would include stating which licenses apply to which components in the README file, and using the REUSE and Open Know-How standards to make your hardware design information machine readable and more easily reproducible by others.

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Hey @mtlynn,
cool project! I just wanted to chime in and throw yet another OSH resource at you :stuck_out_tongue:
Me, @jarancio and @vektor have developed a training program on best practices for open hardware development. This has been widely reviewed by this community and addresses a lot of interesting aspects on OSH (some of which @hpy has pointed out here, like licensing, findability, etc), including suggestions and materials to prepare your project for community engagement and support…

I thought I’d share it, since it hopefully would be useful…
the program content is here
and the landing page of the program with more details is here:


I will be sure to take a look!

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Posted a new video with some progress updates and some changes.
thought the folks here at GOSH might like to know about it. I plan to be in the chat answering questions this evening. :slight_smile:


I have uploaded a zenodo repository of all the friction surfacing data I have collected so far…
this is not rotoforge per se, but a much older simpler technique which is easier to analyze and which I hope will inform my future work by giving me useful starting parameters to evaluate and which may be of use to others in prototyping electronics or building metal printers of their own which use friction for heating and deposition…

as far as I am aware this is the largest and most complete dataset of its kind anywhere on this process, and particularly for pairings of various metals on various ceramics…

Also there is a youtube playlist I have created which contains date coded thermal videos, and individually uniquely tagged macro videos of each deposition made, that correlates with the data in the zenodo repository.

all of it released under CERN OHL V3 and AGPL V3. Enjoy if you find it interesting. :slight_smile:


The Rotoforge project has also been progressing somewhat, in that we have developed a new magnetic non contact thermometer for measuring temperature in the rapidly rotating deposition region cheaply and relatively directly. I talk about it, and some of our other developments in my blog post.

we have also opted to pursue some high temperature FDM direct metal extrusion approaches using EDM drilled glow plugs…and other configurations.

I have not been on these forums in a while. Figured I would post a few updates. :slight_smile:

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This is very interesting. I’m having trouble viewing the playlist though. The permissions seem to be off.

BTW is this project related to your PhD?

I have fixed the permission issue and cleaned up the zenodo a bit.
the rotoforge project is something I have been and continue to do on my own time and my own dime.
the recent release on zenodo and the playlist I have hosted on the channel are related a much simpler process found in the open literature called “friction surfacing”. I have been putting together a dataset and process-parameter properties relationships in the friction surfacing of metals onto ceramics for my PhD work.
So yes, and no.
its more like the PhD is related to the project.

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