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.
23 Comments
ExcessShiv@lemmy.dbzer0.com · 8 pts · 2d
It's already a thing in orca and prusaslicer at least
ShutUpWesley@piefed.zip · 4 pts · 2d
Are you referring to Full-Spectrum? Because that's not really what I'm talking about.
ExcessShiv@lemmy.dbzer0.com · 5 pts · 2d
No, I'm talking about this
ShutUpWesley@piefed.zip · 6 pts · 2d
That was an awesome read, but it does seem to be an evolution of the dithering in FullSpectrum.
What I'm talking about is a print-head that would combine multiple melted filaments into blending hotend, so the extruded plastic would be a blend
ExcessShiv@lemmy.dbzer0.com · 9 pts · 2d
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.
ShutUpWesley@piefed.zip · 1 pts · 2d
You may be right, but I may attempt of to build some POCs to explore the concept, because I think the challenges are manageable
ExcessShiv@lemmy.dbzer0.com · 4 pts · 2d
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.
ShutUpWesley@piefed.zip · 0 pts · 2d
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.
klankin@piefed.ca · 1 pts · 2d
Some epoxy nozzles do a pretty good job of mixing, I could see a brass or stainless nozzle like that working
Crozekiel@lemmy.zip · 2 pts · 2d
Filament won't mix in the nozzle, it is laminar flow. That's why the multi-color filaments still print multi-color instead of becoming a mix.
Also, as someone else pointed out, color printers do not mix ink, they put tiny dots on the page - like pixels on a monitor. In fact, basically everything you look at today with color is using tiny dots of color and dithering to make it look like a different color. So, it sounds more like your problem here is that FDM printing does not have the resolution needed to make the dithering effect indistinguishable at the distance you would like. Which may be fair, but it is more likely that someone invent a way to significantly increase the resolution of FDM prints than it is that they would find a way to mix any color you want from CMYK filament "on the fly".
ShutUpWesley@piefed.zip · 1 pts · 2d
Im aware that ink printers don't mix ink, but it's the resolution issue with FDM that makes me think filament blending is the way to go
I've been contemplating how to blend the liquid (or near liquid) filament without introducing chaotic flow, which fortunately I have some experience with from previous projects, and in effect I believe that the filament stream could be twisted, it wouldn't bleed strictly laminar but can be done in a way that can avoid turbidity. It wouldn't be perfectly "blended", but with some uneducated guesses I estimate it could get the color resolution down to about 0.08mm.
Crozekiel@lemmy.zip · 1 pts · 1d
Welp, I gotta eat my words on this one. Not only is it definitely doable, apparently it's already a thing. I stumbled across this by coincidence just now.
https://reprap.org/wiki/Diamond_Hotend
Crozekiel@lemmy.zip · 1 pts · 2d
I think the process is prohibitively complicated for filament FDM printers. From what I understand, mixing fluids that are in laminar flow would require a large working area which you don't have in a 3d printer. On the fly, from the printer, is SO MUCH more than what a 3d printer is already doing. It would basically be a color mixing chamber, at melting temperature, and then extruding back into a new filament at the correct diameter to run through the rest of the printer - may as well do that separately from the print process.
However, I think this would work so much better without starting at filament and using pellets instead. There are pellet hopper FDM 3d printers out there, though not nearly as common as filament printers. But you could have a system of 4 hoppers of pellets that let out measured ratios into a primary hopper that agitates and mixes the pellets (while still solid) and then feeds them through print head like normal. Although, the normal size of pellets might be a bit big to get a good mix that isn't just a splotchy mess, once the hoppers and mixing is figured out you should be able to find a path to smaller pellets.
That said, I do also like the idea someone else had of using a neutral color filament and then having a process of adding pigment somewhere along the way to the nozzle.
seang96@spgrn.com · 1 pts · 2d
Prusa just announced a bundle for this feature using 4 tool changers or 7. https://blog.prusa3d.com/prusament-pla-colormix-print-45-color-shades-using-just-five-filament-spools-and-more_137835/
Thorry@feddit.org · 3 pts · 2d
I think Roetz 4.0 has done some experiments with this iirc. It worked fine, but it was more like one of those multi-color filaments as there is no way to control the color coming out of the nozzle. He tried with 2 different colors I think, but his setup had 4 wires of filament being pushed through.
There is actually a relative long time between filament being pushed into the nozzle and coming out at the bottom. In between is a reservoir of molted and partially molted plastic, which is essentially a chaotic system. When extruding or retracting the filament, this is actually controlling the pressure inside that reservoir. This makes it extremely hard to get any kind of controlled mix.
You also have the issue of the number of filaments required. Remember CMYK only works when printing on white paper, the white is an important component to the end result. And those don't actually mix those inkts. They just print little dots close enough together for our eyes to lack sufficient resolution and thus see them as one mixed color. For a lighter result less dots are printed, for a darker result more dots are printed and black dots added to go even darker.
So you would need to have 5 filaments being pushed into a single reservoir, which is a challenge. Then you'd never get perfect mixing, even if you machine the combination inside perfectly (look at how nice the machining on Roetz his nozzle was). The pressure inside would vary leading to some filament being pushed less that others, it's a very unstable situation which makes it very hard to perfectly predict or control. And being it's mixing inside that reservoir, there is very little control of how the color comes out. It wouldn't be the same color from all angles due to imperfect mixing and the changing of colors would be a slower gradual thing, not instant. And the way the color presents is also dependent on the direction the nozzle is moving.
The amount of material being pushed in would vary a lot, where we'd want mostly the same continuous pressure on the nozzle side. And when moving reduce that pressure to prevent stringing. Controlling this with 5 filaments would be borderline impossible and would require a high flow large diameter nozzle. So only very large high speed printers would work. Or the filament would need to be thinner, so less material is pushed in, but then you run into compression strength issues in the filament.
I think for practical results, people either just paint it after the fact. Use a multicolor filament for cool colored results. Or use a different technique that offers prints in precise colors.
There is this super cool 3D printing technique from HP that is abandoned now, but does kinda work like you say with CYMK and a white material. It uses inktjet heads to eject a ceramic powder to 3D print. It can make high resolution 3D prints in full color and when baked the ceramic is very hard, so the objects can be practical to use. The big issue with this technology is the powder clogs up the nozzles on the inktjet heads. Just like with printers when the ink dries and the head clogs, it's a nightmare. So those machines need constant cleaning and supervision. When they work they produce amazing results, but the technology is such a pain in the ass, they stopped making the machines. I think they still make the material and heads tho, for people who are already using the machines. I think they are often used in medical settings where they paid a lot for the machine and keep using them.
ExperiencedWinter@lemmy.world · 3 pts · 2d
No idea if if ever took off, but e3d had a hotend that could mix 2 filaments. I've never seen one in person, but messed around with the chimera a bit when it was first launched.
https://www.filastruder.com/products/chimera-cyclops?variant=1035850192
BigTrout75@lemmy.world · 2 pts · 2d
It's not here yet that I know of. But I feel like it's going to get figured out in a couple of years. I daydream I had was not to blend but to have a filament that would change color with different temperatures.
TheGPT@sh.itjust.works · 2 pts · 2d
Binder jet printing is an older 3D printing technology in which adhesive is sprayed on layers of powder to build an object. A mix of ink can be included in the spray to produce detailed color combinations.
https://en.wikipedia.org/wiki/Powder_bed_and_inkjet_head_3D_printing
MxRemy@piefed.social · 2 pts · 2d
I feel like I definitellyyy saw a CMYK printer in a VOD of some printing convention a couple years ago? It was presented by some company and looked huge and expensive, wish I could remember who they were.
TootSweet@lemmy.world · 1 pts · 2d
What I'd love to see even more than that is some kind of pigment cartridge system. You'd use natural, unpigmented filament and the printer would inject pigment in different mixtures as it prints. Just seems... I dunno. More efficient?
I remember seeing a YouTube video (that I might search for and find again if I remember) where some company had developed (and probably patented) an approach that involved inkjet-coloring as it printed. I remember the colors looked pretty pale and washed-out looking. Not vibrant the way I would have hoped. But the approach might be one that could be improved on. 🤷
evidences@lemmy.world · 2 pts · 2d
This is HP and their Multi Jet Fusion or MJF line.
BigDanishGuy@sh.itjust.works · 1 pts · 14m
It kinda depends on what your goal is. Is it making a custom filament? or are you thinking of blending colors on the go? And are you looking for commercially available solutions?
If you're looking for commercial solutions, then your guess is as good as mine. I know you can get filament recycling systems, where you crush failed prints and supports before then extruding usable filament. But I think that's not what you're looking for.
Going the tinker route instead, I think it was CNC kitchen that experimented with extruding their own filament by printing spiral of thick filament and then running it through a 1.75mm nozzle. They even got their logo embedded, and it was detectable in the finished prints layers.
But if you're looking to blend on the go then maybe some manual g-code manipulation and custom hotends could work. But given that I asked about experiences with dual input hotend like the one below, and all the answers were along the lines of "don't even bother", I guess that you having to do a triple or quad input hotend won't make it more likely to succeed.