Is there any existing technology that takes a variety of filaments of different colors (say a CMYK blend), and then blends them in different ratios to achieve whatever color you want?
I had this thought the either day, and I figure it’s either stupid, already exists, or genius.
That would be impossible to control. paper CMYK printers don’t even do it like that. You’d need some sort of blending reservoir with active mixing to get a uniform color with that approach, and you can’t make it continuous (you’d lose control of color) so you’re basically making small individual batches of filament and flushing the mixing chamber between colors. you’ve now come full circle back to multicolor printing with one extruder like Bambu et.al. does now, but with more steps.
You may be right, but I may attempt of to build some POCs to explore the concept, because I think the challenges are manageable
I’d mostly worry about controlling color transitions, because you can’t really control the actual color properly when changing the mix for a different color. I think you’d end up needing some sort of purge between colors to avoid weird unwanted color transitions. I don’t think it would provide lower material use or a speed benefit to the existing MMU multicolor solutions because of this.
Some purge would definitely be required, I can’t think of any way around that. But a smart slicer may be able to do all/most during infill.
Purging to infill is also already a thing, so you wouldn’t need to solve that at least, but you need a very high infill percentage (and low color variance in a single layer) to have enough volume to only use that.
IDK, I’m just not sure what benefit this actually has over just having the individual colors of filament you need for a print. It seems to me it adds complexity without really doing a better job.
There were projects from 10 years ago like mixtruder and https://www.kickstarter.com/projects/m3d/the-quadfusion-print-head-making-color-3d-printing
From 7 years ago that never went anywhere.
Some epoxy nozzles do a pretty good job of mixing, I could see a brass or stainless nozzle like that working