
[youtube]http://www.youtube.com/watch?v=jXFp2pQvG9A[/youtube]
Interesting that you say that. I'm an insulin dependent diabetic and I use an insulin pump. It has 200 unit cartridges (that's one fifth of a CC) and tubing that connects to a very fine needle at the end. I've thought about trying to make an injection nozzle for dyeing Taulman 618/645. Would obviously require SW changes and some way to specify the coloring(I don't believe STLs support color -- couldbewrongaboutthat, though). Anyway, it's on my "todo someday" list. I still haven't finished setting up my E3D hot-end so I can print with the a Taulman 618.626Pilot wrote:Give me a dye injection nozzle instead.
I was thinking of treating the dye injection as a second (or second, third, fourth and fifth) extruder. So you'd lay down a layer of filament and then pass over it again with the coloring. I see two benefits with that method: 1) No need to modify existing extruders and 2) More precise -- you put the dye exactly where it's supposed to be.626Pilot wrote:If you need a mount for that, look me up on Thingiverse.
I think that for dye injection we'd need a needle valve or maybe a fuel injector. Fuel injectors are pretty great because they run on PWM, so they can be controlled with a cheap Arduino. If you figure out a way to mount four of them, you could get CMYK colors. I think you can get by with just three. STLs don't support colors so I think the scheme is to have multiple STLs, one for each color. Obviously, something way better than that is necessary. For the time being, it would be enough to drive color injection from a separate Arduino controller. It would be smart enough to set any desired color, and to fade between colors in a sequence, so it would emulate the effects of dying different lengths of the filament in different colors. It might need a few transistors, but I don't think it would be too difficult.
I can handle the electronics and coding, but I don't have the facilities to modify a hot end to accept fuel inectors and channel the dye to where the filament is. It would have to go right into the input side of the nozzle, or even inside the nozzle so as to avoid jamming the filament before it reaches the melt zone. Significant machining would be necessary. Extrusion volume would fluxuate with the volume of dye injected, and that could throw some things off.