3D Printing with liquid metals

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

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! 🙂


Lithophane with 3D Printer

3D printing is an ultimate enabling technology! Once you have a way of creating physical objects from computer models and master material’s limitations, there’s no telling what you’ll be able to do! We’ve seen 3D-printed phonograph records, 3D printed bikini, not to mention the much hyped-up 3D printed gun, and now G.P. Le Sage Blog brings us 3D printed lithophane (a picture formed by light that passes through different thickness of semi-translucent material) .
Check out the results and of course the great step-by-step tutorial on the 3D lithophane process posted by G.P. Le Sage.

I have to add a personal note (and this is in no way to belittle results of GPLS’s work) but to me personally the lithophane pictures have a distinct Paranormal Activity flavor and may be in great demand around Halloween time 🙂 – that leaves us just enough time to master the technique and be ready to come up with ghostly images of loved ones before October 31st!

G. P. Le Sage Blog


I created a lithophane using my home-made 3D printer. By using BMP2IGES, a freely available program, I converted a grey scale image to a mesh, with white being thinnest and black being thickest. I printed white ABS filament, and experimented with overall thickness to make a clearly visible image with the light from a $2 night light from a dollar store.

I was following the example provided by Joe.

Here is the original image, and the conversion to grey scale. I added blackouts to protect the privacy of my friends.

JulieIan Eyes BlockedJulieIanBWCrop Eyes Blocked

I first experimented with the lithophane using Blender. I defined an emitting surface, and made the lithophane out of material that partially transmitted light. By rendering the lithophane with the light source behind, I could test the appearance.

Blender Render


Next I printed the actual object with my 3D printer. The first one was too thick, and required a very…

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Turning a phone into a media center remote

Now, here is a strange but interesting in a true hacking (phracking even) way remote control device. I was totally expecting there to be the need to pick up the receiver first in order to dial the commands (and hear DTMFs as you do) but that functionality was left out.

It’s surprising that an entire Raspberry Pi had to be used only for servicing a 12 button keyboard but I think the author was not satisfied with XBMC performance on Raspberry Pi and so the board was available for other uses.

It would be cool, however, to have the Raspverry Pi inside the phone set’s body with an HDMI on the back, hooked up to a TV. Would make for a pretty funky retro-looking multimedia player!



[Kees] wanted a remote for an XBMC audio system. He had a classic T65 Dutch telephone in one of his project boxes and thought this phone with the addition of a Raspberry Pi he could have a functional media remote with classic lines and 70s styling.

Each of the digits on the phone were wired up to a small solderless breadboard. With a handful of resistors, [Kees] set up a simple pull up/pull down circuit feeding in to his Raspi’s GPIO input.

With a short Python script, [Kees] managed to map the buttons to XMBC’s play/pause, volume up/down, next, and previous commands. There were a few buttons left over, so those were mapped to online radio stations, playlists, and a strange setting known only as ‘moo’. We’re not sure what that button does, but you can see the other functions of this XMBC phone remote in action in the video…

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Self-Folding, Printable Inchworm Robot

Interesting concept of self-folding device. I would not go as far as to call it a “robot” per se because its movement function which is enabled by the motor and the battery, all added after the fact manually, are secondary (IMHO) to the ability to fold, which is what’s cool about it. From the soundtrack to the video, the shape memory polymers are bent into final position by temperature created with appox 2A current though what looks like a graphite infused part of the polymer sheet.
I don’t know how useful the technique would be specifically in robotics but this may actually be useful for electronic devices that require an enclosure. The shape memory polymer could be made to become both the PCB for the electronics as well as the enclosure, in which the components would be mounted on the inside. A pick-n-place robot can populate the SMD parts on the inner side of the device, then, while the device is in the reflow oven, the sides will fold around to form an enclosure. Interesting… Gotta read up more on the shape memory polymers, much depends on the temperatures required for the shape recall.

Napster For Pirated 3D Printing Templates?

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”

CNC Control Box done and working

If you ever wanted to see one darn fine looking CNC control box, check out Downing’s project here. He poured all his PC modding talent into the box, and it shows! Not only does the box contain the PC (couldn’t figure out what it’s running but willing to bet it’s LinuxCNC) but the CNC controller as well as the *second* monitor and what looks like a second numerical keyboard. That is pretty dandy considering most of the inputs during a CNC run are numerical. That second keyboard is a great idea, I think I’m going to steal it. Not sure what the second monitor is for but hey, there’s a space there, why not?
There are also some feature buttons (proly the PC reset and power) but perhaps an op-stop (M1) button is also hooked up. And of course, the mandatory hard-to-miss red kill-all mushroom button.

What a lovely sight and professional look! As I’m getting parts together for my own CNC enclosure project (looking to put a small router about the size of Downing’s INSIDE an enclosure to capture dust and chips thrown about) , I think I’ll draw an idea or two from his Control Box.

Downing's Basement

So after suffering from some of the biggest headaches I’ve had to deal with in a long time, the control box for my router is completed. I wanna thank my friend [Dave Russo] for coming over and not only help solve the issue with CNC (which of course was only a single wire connected incorrectly) but also for helping me fix my main PC and upgrading to a Solid State Drive. Much thanks my friend.

So back to the CNC, the general premise of the project was to make up some space that my old PC tower and the CNC control box itself was taking up. Granted now a lot more space on top is taken up, everything is now in one location and even has a nifty little PSOne screen acting as a second monitor for the PC!

Though this isn’t perfect, it does the job. I will be…

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Using eclipse AVR application development plug in

Using eclipse AVR application development plug in

Here is a detailed and well-illustrated overview of using Eclipse IDE as an AVR development platform by Sulaiman Salim Marhoun Al Habsi:

Using eclipse AVR application development plug in.  at sulimanhabsi blog.

It is a second post about Eclipse on his blog and it shows a different approach to how many,  if not most, DIY electronics and robotics hobbyists come to program Atmel chips –  start with ATmega168 or ATmega328 in the form of an Arduino board and use Arduino IDE and Wiring version of C programming language as a starting point. Arduino IDE can be adapted for using it with other Atmel chips, such as ATMega8 which   Sulaiman used as an example, and many if not most other Atmel MCU. The only ones missing Arduino IDE support (to the best of my knowledge) are the smallest  of the AVRs  – ATtiny12 ,  ATtiny10, 9, 5 and ATtiny4. I am wondering if Eclipse plugin for AVR is better it terms of the chips supported.

Anyway, if you program other things in C (or Java or whatever else for that matter that also has an Eclipse plugin) and have a need to program AVR chips, you may want to check out his blog for some useful pointers on setting Eclipse up for AVR and then using it to program the chips.