This has been a lot of fun exploring over the past few days. Let me know if you have suggestions/questions about this kind of hybrid approach using 3D printers.
Anything else you'd like to see printed with multiple materials?
1) Thank you for writing this! Some of the techniques you've outlined here, I have thought of so many times... but deemed them too dangerous. Your post has given me the courage to try some of this out on my own. To begin with, I will print some artsy statue with ... uhm, a low infill (like say, 10%?) and routinely fill it with some heavy sand or viscous liquid. I think it'll work well... it'll save me material, but on the other hand it makes 3d printing very hands on huh! I suppose I should pause and fill every other 30 minutes or so.
2) > this approach is ultra powerful, and it's the same thing you see on some of the high-end maker printers (like in the TAZ production docs that describe how to use strong/precise steel parts combined together with 3D printed parts).
Sorry man, what do you mean here? Can you maybe please specifically link to what you are referring to here?
If you inspect most of the FDM (maker-style, RepRap, etc.) printers, you'll notice that they themselves are constructed of 3D printed parts. But the way they use the parts is a lot different than most end-users (a single purpose item that works stand-alone; like a statue, cup, wall hook, etc.).
Instead, the way the 3D printed parts on the printer are used (in general) is by combining the strengths/attributes of multiple materials. All fasteners are standard metal parts, with mating metal nuts (often embedded or even hot-inserted into the back of a printed part). Precision bushings are press-fit into printed parts to use along steel guide rails.
The TAZ assembly docs show a lot of that thinking, so I thought I'd link over to it in the write-up.
In short, it's the kind of thing that I'd love to see more of because it leverages the best properties of multiple materials instead of being all one or the other. :)
It would be interesting to print a cancer tumor with one material the and the surrounding tissue with another. Some data here:
http://www.cancerimagingarchive.net
> It would be interesting to print a cancer tumor with one material the and the surrounding tissue with another. Some data here: http://www.cancerimagingarchive.net
Wow, that's like the first cool reason I have stumbled upon for a dual-extruder printer. :) (a lot of people think they need a printer with dual-extruders -- they don't, and actually the biggest reason they don't need it is 3d printing suddenly gets twice as difficult when you're doing it with dual-extruders)
In this case, you extrude motor 1 and print. Then to switch, you retract until you're before the Y, and extrude with filament 2. Use a wipe-tower to get a consistent flow, and you have 2 colors (of the same material) with 1 hotend.
It is very easy to jam one of the colours, you have to be very careful about retraction distances because if you retract to far the other colour can leak into the cold end part and solidify and then you only have one colour working.
Great post! You should post it to this 3DP facebook group[0] for feedback on slicer settings that could help with this. I think for liquids you might want to use additional perimeters, increase the infill density, and maybe even slightly overextrude to avoid gaps. I know /r/3dprinting would love this post too!
Anything else you'd like to see printed with multiple materials?