Diamond single-nozzle multiple extruder

[jsc]

Just came across this, thought it vaguely interesting: http://reprap.me/diamond-hotend

It's a multi-filament extruder with a single nozzle. Solves the dripping issue, but less flexible for printing non-similar filaments, I would think. I don't care about multi-color prints, but perhaps it would interest someone here.

[Jules]

You could put a couple of those on the dual and bump it up to 6 color printing.

[Tim]

I take issue with its "multi-material" statement. I don't see how it can run three filaments with different temperature requirements. It appears to have only one heater. I guess you could adjust the heat for whichever filament is active, but "instant jam" comes to mind.

It's a hotend that is appropriate for a Bowden drive (see their Prusa model with the Diamond hotend); a direct-drive model would be difficult to impossible and it would weigh a ton. You'd have to completely reconfigure the M2 as a Bowden drive machine if you wanted to mount this hot-end on it. That's been done before, but it's a lot of work, and I think the direct-drive configuration is one of the M2's strengths.

Also, full-color printing with three colors only works when laying down color on a white substrate, like ink-jet printing on paper. To get a full color spectrum with filament, you'd need an additional white filament, and probably black as well. I only see one photo on their website that appears to use color mixing, which is the rainbow of colors in the keyhanger, but the mixing does appear to work very well there.

Finally---the basic principle behind this design has been done before, with the E3D Cyclops, although that had support for two rather than three filaments. There was a short discussion of the Cyclops on this forum, basically bringing up the same issue that it probably would only work with two of the same kind of filament.

I've always thought that the proper solution should be to use a single white filament and inject colorants into it at the nozzle. I expect something like that setup is what's used by the expensive machines Shapeways has to do full-color prints.

[ednisley]

the expensive machines Shapeways has to do full-color prints

IIRC, those spray glue on layers of powder to produce something like sandstone: they "just" use colored glue to produce full-color sandstone. That's easy to say and hard to do, but the results certainly look pretty if you need colorful sandstone figurines.

Or maybe I'm remembering something completely different...

[Tim]

IIRC, those spray glue on layers of powder to produce something like sandstone: they "just" use colored glue to produce full-color sandstone. That's easy to say and hard to do, but the results certainly look pretty if you need colorful sandstone figurines.

Or maybe I'm remembering something completely different...

Yes, that was what I was thinking of, from examples I saw at the Shapeways display at Maker Faire. Could it really be that that's the only full-color 3D printing technique in existence? Poking around on Google, I come up with the 3D-systems ProJet, which claims to be the only full color 3D printer. Is that the machine that Shapeways is using? It's hard to tell from the 3D Systems' website exactly what is the material it's printing.

[ednisley]

the only full-color 3D printing technique in existence?

Other than smearing Sharpies on white filament just over the hot end, yup, I think so. [grin]

It'll be a while until colored sandstone reaches the DIY level; I can't imagine what the ink/glue cartridges cost...

[innkeeper]

R G B colored filament, you can the mix any color you like lol... sure it wouldn't actually work like that but... interesting thought.

[Tim]

R G B colored filament, you can the mix any color you like lol... sure it wouldn't actually work like that but... interesting thought.

It "doesn't work like that" for the same reason that ink jet printers don't use R, G, B ink. It's an additive color process, so you'd want C, M, Y, K. Unfortunately, you're not putting this on a white substrate like paper; the filament is the substrate. So you need C, M, Y, K, W. A five-filament-combining nozzle would be an impractical beast. The solution is to go the same way that Home Depot, Lowe's, etc., do paint: take a white substrate (white filament in this case) and add colorant (C, M, Y, K) at the nozzle where it's melted. Will it mix properly? Who knows, but the picture of the rainbow-colored keychain from the Diamond nozzle, just combining two color filaments, suggests that it will. It's not exactly a high-detail photo, but it looks like the orange and green colors are pretty well blended. I have no idea what they do to the firmware for the Diamond nozzle, though. You'd have to rewrite all the dual-extruder code, because blending colors means you have to divide up the total amount of extruded filament between the three extruder motors. You'd have to come up with additional g-code to represent color, and the slicer would have to know about it.

Now that I wrote that, I have to wonder how they got a slicer to produce the keychain. My suspicion is that the keychain isn't a color blend, that it's just layered colors. A layer of yellow on top of blue makes green. I assert that the statement "The Diamond Hotend is capable of mixing filaments of different colors directly in the hotend" is theory rather than practice. But wouldn't it be nice if you could just design things in color, have the slicer insert a "color change" code at the appropriate points, and let the firmware deal with it, rather than doing multi-color printing by generating X number of non-intersecting models and mucking around with having a different process for each model and coercing the processes to work with each other without screwing up?

[innkeeper]

ah.. yes ... that would makes sense.
Though it would take jamming to a whole new level
and yea, each model would need a color map. though, i have seen some processes that add jet ink coloring for each layer. so someone has already done it.

as a practical point, i wonder if the color would actually mix right in the hotend though.

[MagicEngineer]

I think This shows a little more promise. http://www.mosaicmanufacturing.com/