Full Color 3D Printing With PolyDye And Existing Inkjet Cartridges

The PolyDye system installed on an Elegoo Neptune 2 printer. (Credit: Teaching Tech, YouTube)

Being able to 3D print FDM objects in more than one color is a feature that is rapidly rising in popularity, assisted by various multi-filament systems that allow the printer to swap between differently colored filaments on the fly. Naturally, this has the disadvantage of being limited in the number of colors, as well as wasting a lot of filament with a wipe tower and filament ‘poop’. What if you could print color on the object instead? That’s basically what the community-made PolyDye project does, which adds an inkjet cartridge to an existing FDM printer.

In the [Teaching Tech] video the PolyDye technology is demonstrated, which currently involves quite a few steps to get the colored 3D model from the 3D modelling program into both OrcaSlicer (with custom profile) and the inkjet printing instructions on the PolyDye SD card. After this the 3D object will be printed pretty much as normal, just with each layer getting a bit of an ink shower.

Although it could theoretically work with any FDM printer, currently it’s limited to Marlin-based firmware due to some prerequisites. The PolyDye hardware consists of a main board, daughter board, printed parts (including inkjet cartridge holder) and some wiring. A Beta Test unit is available for sale for $199, but you should be able to DIY it with the files that will be added to the GitHub project.

Even for a work-in-progress, the results are quite impressive, considering that it only uses off-the-shelf translucent filament and inkjet cartridges as consumables. With optimizations, it could give multi-filament printing a run for its money.

34 thoughts on “Full Color 3D Printing With PolyDye And Existing Inkjet Cartridges

  1. In injection molding we melt colored pellets in with uncolored pellets to get the various colors. Color changing on the fly is still an issue but the colors are pretty much unlimited.

    Two questions on the ink jet idea.

    Does it negative affect layer adhesion?
    Doesn’t this mean whatever plastic you use must be hydrophilic to accept the dye?

    1. It depends on the dye solvent.

      A quick search shows that plenty of inkjet dye is in a non-aqueous solvent.
      This seems like it would work well with a compatible material.

      Alternatively, there are uv cure inkjet dyes.

    1. You can buy this commercially from DaVinci. I remember reading all the attempts to do it DIY before the DaVinci came out. The uses for DIY versions beyond color printing are huge though as you can mix in all sorts of things for bioprinting applications etc.

      1. Unfortunately, XYZprinting (the makers of DaVinci) seems to have gone out of the 3D printer business this year. Kind of a pity, since their printers were pretty innovative. However, they never got to the level of quality that Bambu Labs has in order to be really successful.

          1. The cartridge chips were very easy to get around (you could reset them with an Arduino). Moreover, you could replace the printer firmware and avoid the issue altogether.

      1. How is that bambu’s problem? Plenty of people, hobbyists or not, download, print and sell models they shouldn’t. It isn’t a problem limited to non hobbyists and bambu printers.

        Also using open source ideas and projects in a closed source system isn’t stealing as long as the license allows it. Is it even really open source if you are telling people what they can and cannot do with it?

        Why do you people look for anything to blame on bambu?

  2. About effin time! (not tryin to be rude or to devalue the work done btw!)

    Commercial 3d printers were using inkjet cartridges for color prints decades ago, honestly surprised it took this long to reach “home 3d printing”, glad to see its here now!

    1. That was a different kind of printing, though. The inkjet heads sprayed something chemically similar to colored vodka into a bed of maltodextrin and plaster. They produce nice, sometimes very high res color prints – but the prints are suuuuuper fragile unless you put them in a vacuum pressure warming pot with superglue. Then they’re just fairly fragile.

  3. lawsuit from HP in 3…2…1…

    bambu labs tries to patent it in 3…2…1…

    seriously though i’ve been watching this progress and it really is awesome to see it gain some attention I just hope my previous joke does not come true

      1. That’s only because Bambu doesn’t have any original ideas to patent, they just steal other people’s. I kinda hope strarasys wins just to put Bambu out of business and watch all the Bambu turds try to print with their $ bricked printers.

        1. The patents that bambu is accused of breaching are the same ones used by pretty much every printer company, including Prusa. If stratasys wins against bambu then they could easily go after most 3D printing companies.

          How does bambu steal ideas? If they are open source then it isn’t stealing. Prusa and other companies use lots of open source ideas too so why aren’t you criticising them? They aren’t fully open source.

          Why do you hate bambu so much? Why do you think the printers would be bricked if bambu went out of business? They have no reason to do that, likely they would just stop the cloud services and they would then be local only machines.

          1. Open source designs used by 3D printer companies, must remain open source by the company that is using said design. To do otherwise, is a breach of the agreement that allows someone to use the open source design. Some companies take open source designs, modify the design to fit their requirements, then hide the modified design behind company proprietary.
            As far as I know, Prusa has not breached open source agreements, although they have add new components like the heated, magnetic printing platter.
            They have also added capabilities to their slicer which remains open source.

  4. I’ve been curious for a little while if we could solve multicolor 3D printing by either using CMYK fillament (mixing issues) or going further back and using raw pellets.

    I could see a double extrusion model sort of like the Pallete add-on but taken to the extreme. Raw plastic pellets are extruded like when it is made and a system precisely mixes in pigments CMYK style on the fly. Ideally any color change that isn’t super sharp could be made without a purge tower.

    1. Check out some software called Hueforge, it’s pretty awesome, not quite what you’re after but for what it is, it’s fantastic, the print quality from it is superb and seems to be making a good name for itself.

    2. I had this exact idea about two years ago as a potential senior project in college, but we went with building an app since hardware wasn’t any of our forte. I still want to experiment with on-the-fly color filament creation, as I really like the idea. I’m guessing that precisely melting and extruding filament will be very difficult and require some complicated fluid and thermodynamic equations, but I wonder if it’s still workable.

        1. That’s why I suggested the other option of adding the pigment to pellets in a pre-extrusion step.

          I don’t see the other guy mentioning which method he’d aim for but CMYK filament would definitely need some sort or mixing area before extrusion that would almost certainly be difficult to make and difficult to deal with clogs.

    1. It currently has some pretty odd requirements that likely come from it being early in development (like needing specific acceleration settings), once they sort some of those out there shouldn’t be any reason it couldn’t be done on klipper.

  5. “but you should be able to DIY it with the files that will be added to the GitHub project.” The files in the GitHub project appear to just be STLs for printing the plastic parts, which the $199 kit didn’t include anyway. No gerbers, no schematics, no kicad / eagle / altium / anything. No firmware in binary or source form. Essentially “heres some blurry photos of this thing we made, we don’t have any more of to sell, and haven’t released anything to make your own. But we’re clearly open source because we have a github!”

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