Kudos to the team at North Carolina State University (and the National Science Foundation for sponsoring the research) for coming up with an interesting paper and an entertaining video on 3D printing with liquid metals.
The build up of the finished part is occurring through depositing of small drops of binary eutectic alloy of gallium and indium (EGaIn, 75% Ga 25% In by weight) which is conductive and liquid at room temperature (slightly below, actually ∼15.7°C) . The 3D printer is essentially a microscope positioning stage with a third axis attached, which is carrying a syringe with the liquid alloy. The alloy is being deposited through a needle approx 250um in diameter.
Each droplet is coalescing into a sphere due to surface tension and each is quickly forming a thin protective layer (only about 1nm ) of passivating skin composed of Gallium oxide.
Be sure to check out the video for the samples of the shapes that can be printed with this technique. This is an early development stage yet and I’m sure we’ll see more interesting results come out soon. Some of the improvements that are in works have to do with devising ways to prevent the spherical droplets from further coalescing into larger diameter spheres instead of staying where they’ve been deposited.
3D-printed microstructure build with liquid metal
No less intriguing are the 2D applications of the same technology – the droplets can be stretched into thin wires from 30 to 200um in diameter to build electronic circuits using CNC positioning of the depositing syringe.
Check out the 3D Printing of Free Standing Liquid Metal Microstructures paper for more details on the fascinating new technology.
On a personal note: I had no idea how affordable indium and gallium are (in quantities needed for a DIY lab, of course) – they are about $1 / gram each and eBay is full of offers. Definitely something within the reach of an adventurous DIY 3D printing enthusiast! 🙂
I don’t get the concern here. 3D printing files are essentially CNC files, they are not any kind of “special” files. In some 30 years of CNC use I haven’t seen a “Napster” for CNC files yet, have you? Despite some of them describing production operations of some expensive parts.
Additionally, it’s a bit too late to get your panties in a bunch over (illegal) 3D model sharing – 3D models as well as any kind of file imaginable are probably shared just as much as any other file type over peer-to-peer connections and have been for ages now (10 years easily). Perhaps not specifically for 3D printing but for 3D rendering.
There’s already a “Napster” or “Napsters” for legal 3D file sharing – Thingiverse obviously and Shapeways list of publicly shared models. What exactly should “illegal” 3D printer “Napster” do to justify the wrath of the “3D manufacturing lobby” – a comment made tongue in cheek, obviously because 3D manufacturing has not and will not have a clout strong enough and unified enough to create a lobby anywhere close to that MPAA was able to field. Besides, profits in 3D printing/manufacturing are nowhere near ones that provide (comfortable) livelihood for the army of MPAA lawyers. I don’t see 3D printing DRM materialize anywhere in the foreseen future.
So, I call the concept of 3D printing piracy a “manufactured controversy”
It’s a shame Mcor Technologies website is pretty much disabled at the moment – only shows “Join Us at the Inside 3D Printing Conference & Expo, April 22-23 in New York City!” and “Prepare to be wowed!”.
Well, consider myself pre-wowed! I did miss the conference but would very much like to find out more about the paper 3D printing technology. Having a sculptor in you family exposes one to all sorts of materials that end up in a 3D design (sculpted by hand as it is now) and so I have seen how paper clays and Papier-mâché performs (when dry) and I would say if Mcor can produce similar strength/weight ratios art paper clays do, I would absolutely want a printer like this! Especially if it includes full color printing on the surface of the 3D model if I got the idea about the way they create colored 3D models right.
Looking forward to learning more about the Mcor 3D printing with paper!