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 solution because of this.
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”.
Im away 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.
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.
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.
ShutUpWesley@piefed.zip 3 weeks ago
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 3 weeks ago
That would be impossible to control. paper CMYK printers don’t even do it like that.
ShutUpWesley@piefed.zip 3 weeks ago
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 3 weeks ago
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 solution because of this.
klankin@piefed.ca 3 weeks ago
Some epoxy nozzles do a pretty good job of mixing, I could see a brass or stainless nozzle like that working
blue_morpho@lemmy.world@lemmy.world 2 weeks ago
There were projects from 10 years ago like mixtruder and kickstarter.com/…/the-quadfusion-print-head-makin…
From 7 years ago that never went anywhere.
Crozekiel@lemmy.zip 3 weeks ago
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 3 weeks ago
Im away 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 3 weeks ago
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 3 weeks ago
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.