Multi-colour Printing with One Extruder

  • Mosaic Manufacturing
    (Thanks for Mads Rugaard’s sharing in the Kickstarter comments.)


A very nice idea. The filament has to have the same thermal characteristics i guess so dual extruders are not challenged completely. But still very very cool. I wonder what the price range is for one of these bad boys.


Another company came up with a solution for colour printing and looks very good


Thanks for the post noreflexness! Really interesting. I’ve also thought about multi color printing because I find the powder method really cool and realistic. Even thoe the color looks faded. Just like the people in your post did, I also thought about a clear fillment that while being melting or being place on the hotbed dye ink similar to a reg. Priner would be “dropped” onto the fillment. I guess the fillment would need to be obsorbment while melted or hot. And the ink not dry.

Just a thought I had. Seems like this company is doing it.


Very cool idea from Mosaic Manufacturing! Thanks for the link to Mads Rugaard. I have a slightly different idea for a multi-colour extruder, and would love to get feedback from others reading this post. I was imagining a single extruder with 3 bowden tubes as filament inputs, one for red, one for blue and one for green. By controlling the material flow separately, one could mix the 3 filaments together according to the colour one needs while they are hot and in a melted state. For example say you need the colour turquoise (Turquoise on Wikipedia), that is specified in the sRGB colour space as [R,G,B] = [64, 224, 208]. This can be written in % as [64/255, 224/255, 208/255] = [25.09%, 87.84%, 81.56%]. Thus to get you Turquoise, you would need about 25% Red, 87% Green and 81% Blue. The individual extruder motors for each filament would then have to turn just enough that the right amount of filament as calculated above for each layer is fed into the extruder. Of course the underlying assumption here is that the colors will properly mix inside the extruder :smile:


Judging by how much filament i need to run through my machine when changing colours, i think there will be too much residual colour to get nice, clean colour changes. Multiple extruders seem like the best option, but way more expensive…so i hope somebody can figure out a way to mix colours effectively.


Something like this would work i would like to think. If the colored fillment is melted and mixed with the right amount then in theory it should create the color. The only thing is how after it has made a certain color how can you avoid your next color being mixed with the previous. Not sure if I’m explaining myself right. Which is why I thought a clear fillment would work best. With dye falling on top of the print before it drys?


@missing_link, Phatnugget: I also thought about the issue with residual filament in the extruder. To that end, I expect that by first retracting the 3 filaments, then pumping an acetone solution through another tube into the extruder would dissolve any residual PLA. After that, the next colour could be extruded from the nozzle as I described, and any residual acetone in the nozzle would be used up if that colour is extruded until it runs smoothly. This procedure would of course require a software solution and have to be done far away from the print :smile:


Right now i just pause the job, raise the nozzle, put some paper over the print to keep ooze off, replace the filament and run a bunch through to clear most of it out, lower nozzle and continue printing. It doesn’t really take long and i get decent results without too much mixing.


I guess the type of colored printing we are talking about is more like the powdered form. Similar to shape way not spot color. Well at least I am.


i cant take credit for this one, I Only commented on it :slight_smile:


Yes, that’s definitely an easy way to get multi-colour prints, but colour-mixing would allow one to create any colour in the RGB colour space, since filament makers currently only produce a limited set of colours.


RGB is good for light but not for printing in real life , full color printing should base on CMYK. There is a custom extruder which has 4 hot end for reprap, however it is not a cmyk extruder but maybe someone can change it since it is a open source design.


I personally love the spectrom’s solution, it is nice for replacing the filament splicer in Gerhard’s design.


This is what I am waiting for.


Nice post Missing link. Perhaps the flux creators can contact him since he is always from Taiwan.


Interesting for sure. Will be following this.


It has been attempted by Diamond Hot End. I’ve used it and mixing is nothing more than an illusion when using translucent filament (no actual mixing occurs)


I’ve seen some neat things on
Some folks are already talking about doing one that’s got 5 inlets for CMYK and White filament.

It’s electronics heavy, though, you’d have to run a Duet board with the expansion module or something like that to even have enough stepper outputs.


Are you doing this on a FLUX? If I ever pause a job, and then change filaments, that ends the job and goes to abort or idle. Would love to change colors for some jobs.