alt Hacker NewsHmm, I am not in the 3D printer space anymore, but I am surprised they went with alternating layer per layer, as that severely limits resolution. It's probably the simplest way to achieve reproducible results, but I can think of a few other ways:
* the simplest is just mixing filaments, like one mixes paint. The article doesn't spell out the reason it doesn't work, I am curious as to why.
* together with alternating layers, colors could be alternated in the same layer. Some purging may be necessary, but I think you could either: accept some mixing (compute its impact to compensate) / take into account the volume in the nozzle (extrusion "latency") / discard the unwanted part in the infill (at the cost of less smooth edges)
Of course, the hard work with any approach, including their current work, is calibration, as the article highlights. I wonder if off-the-shelf monitor calibration sensors could help with measuring the filament you have at hand.
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the simplest is just mixing filaments, like one mixes paint.
That is actually the hardest way to do it, because that's not at all how 3d printing works. 3d printers take strands of plastic (aka "filament"), soften them up to being melty but not melted, and then "extrude" them, like cake frosting onto a surface. As with cake frosting, in order to mix colors, you have to do so before the extrusion step, so you would have to make your own (filament), and the machinery to do so is not cheap.
The thing about first order thinking is that it is very rarely useful, because the actual experts in the field have almost certainly thought of all the things that first order thinkers come up with, and deemed those ideas unworkable for various reasons.
>the simplest is just mixing filaments, like one mixes paint. The article doesn't spell out the reason it doesn't work, I am curious as to why.
This requires you to control both filaments independently directly at the extruder. Dual direct drive for a single nozzle sounds like an engineering nightmare. The extruder head is going to be huge.
There is also the obvious problem of how to stirr the filament. Printing temperatures aren't hot enough to turn the plastic liquid, they just make it soft enough to drip out the nozzle. This means you can't just feed the filaments at continuos rates, you will have to use a PWM scheme where you extrude the first filament and then the second filament in extremely small discrete increments. That switching will give you the necessary agitation without building a throwaway nozzle that can't be cleaned after a clog.
All of this sounds like it would take at least a year for a well equipped research department to figure out. It's definitely not the simplest solution.
EDIT: https://www.reddit.com/r/ender3v2/comments/ssuw3i/my_crazy_p...
Just the hot end of this extruder costs $70 alone. This is definitely not going to be cheap to do.
> the simplest is just mixing filaments, like one mixes paint. The article doesn't spell out the reason it doesn't work, I am curious as to why.
Plastic flow is laminar, where colour mixing requires turbulence. If you make a turbulent nozzle, it's basically impossible to print reliably with it (the pressure used to push filament out of the nozzle is mostly absorbed/redirect into turbulence).
This is a software solution designed to work with existing multi colour printers, so you can’t “just mix” them as this would need additional hardware