Entries in electronics (13)
by General Fabb
Harvard materials scientist Jennifer Lewis has produced a new liquid material that could be used to 3D print lithium-ion batteries.
The "ink" is intended to be 3D printed using the syringe approach that is frequently used for bioprinting or culinary experiments.
The process to produce the liquid material is quite interesting. Printing battery anodes requires deposition of metal, accomplished through very tiny nano-particles of lithium titanium oxide, mixed in an ethylene glycol / water solution. The problem is that the nano particles clump together.
The innovation here is the addition of small ceramic spheres to the solution. When the mixture is sufficiently agitated (apparently for 24+ hours), the balls gradually break apart the clumps leaving a "smooth" solution of metal nano particles suspended in the solution.
Then it's simply a matter of using the liquid material in a sufficiently small syringe mechanism to print battery circuits. The solution is such that it forms a liquid under pressure during extrusion and re-forms into solid form after printing.
The implications of this technology could be profound. Imagine adding another extruder to your 3D printer capable of printing this material. You could then print a physical object with embedded batteries and circuits.
It wouldn't be an iPhone, but it's a start.
Researchers Collin Ladd, Ju-Hee So, John Muth and Michael D. Dickey at NC State University have published a paper describing their experiment in 3D printing liquid metal - at room temperature.
The liquid metal used by the researchers is binary eutectic alloy of gallium and indium, which, in very small droplet form becomes relatively stable as you can see in the video below. They've been able to 3D print microstructures, wires and interconnects with this new approach.
The structures formed are soft and flexible, making the technique suitable for building microelectronics. Four extrusion techniques were successfully demonstrated:
- Extruded wire
- Stacked droplets to form arbitrary structures
- Molding within channels
- Jetting out a filament structure
The structures produce are electrically conductive and are capable of acting in electric circuits.
This is a major development. Previous attempts at printing electric circuits have proven difficult, particularly at micro-scale. This technology could theoretically be easily added to a conventional 3D printer enabling the production of objects with embedded electric circuits.
And then everything changes.
Fabbaloo recently caught up with Adafruit's Limor Fried to discuss her views on 3D printing. Here's the interview:
Fabbaloo: Adafruit recently partnered with MakerBot to produce a bundle of DIY electronics and the capability of 3D printing. Do you see further collaborations with 3D printer manufacturers or 3D print services?
Limor Fried: We'll see electronics makers working with 3D printing companies (hardware and services) to empower their communities, by that I mean we'll see electronics start to take on more interesting forms because the enclosures can be printed or sent off to be printed. For years we've just had the circuit boards on our desks, now they can look amazing with enclosures and functional parts, from cases to robotics parts.One members in our Adafruit community is making a Raspberry Pi powered robot snow blower that is completely 3D printed, all at home!
Fabbaloo: Has 3D printing enabled the development different types of electronic kits?
Limor Fried: 3D printing is allowing us to quickly test out a lot of ideas and directions, for our wearable line up we're interested on how electronics and 3D printing could be beautiful to build, print and wear.
Fabbaloo: Do you see a relationship between 3D printing and DIY electronics? How do you see this relationship developing in the future?
Limor Fried: I think companies that make electronics ultimately have some type of 3D printing offering, maybe it's the files to print the case to a phone like Nokia, or maybe it's like Adafruit and you get enclosure files when you get a kit or electronic component. We partnered with MakerBot to have a great out of the box experience, while you're soldering up a DIY watch kit you can be printing out the enclosure to wear it!
Fabbaloo: Do you own a 3D printer? What kind? What do you like to print?
Limor Fried: At Adafruit we have a growing collection of 3D printers, MakerBot replicator & Replicator 2, parts to a make a couple 3D printers and an UP! Printer. Most of the time we're printing out enclosure ideas for our products.
Fabbaloo: Aside from 3D Printing, how's the electronics business going lately?
Limor Fried: Adafruit tripled within the last year or so, we're working around the clock (sometimes making clocks!) to keep up with the demand. We have amazing customers and distributors that are building and sharing all their projects, this is a fantastic time to be a maker and an open-source hardware company!
Do you build electronics projects? Do you 3D print objects? Do you print 3D cases for your electronics projects? If you answered yes to any of those questions, especially the last one, you'll be interested in a fascinating collaborative offer from electronics kits distributor Adafruit and personal 3D printer manufacturer MakerBot.
The two companies have combined to offer a "Limited Edition MakerBot® Replicator® 2 Desktop 3D Printer" with three of Adafruit's most popular electronics kits. Included:
We suspect that anyone making these kits would enjoy not only building the electronics, but also being able to creatively design and produce a unique case. Twice the making fun!
The limited edition unit is available at a price of USD$2,295 at Adafruit.
Carbomorph is a new, experimental material for 3D printing that promises to add a whole new range of capabilities with its ability to embed sensors within 3D printed items.
Carbomorph was invented by researchers at the University of Warwick in the UK in their quest to develop a method of 3D printing electronic circuits. So far, they have "used the material to print objects with embedded flex sensors or with touch-sensitive buttons such as computer game controllers or a mug which can tell how full it is."
The team created a substance using Carbon Black filler combined with polycaprolactone (PCL) and successfully printed it using a BFB 3000 3D printer. They discovered that the new composite material would change electrical resistance when flexed, leading to the notion of 3D printing sensors.
If this is commercialized (and we suspect it might), those owning a personal 3D printer using plastic extrusion technology could actually print embedded sensors into their objects. We're wondering what kind of devices will be created when this capability is released.
It's not a 3D printer, but you could make one with it. It's the RA 3D printer controller, now showing on Kickstarter.
The project involves creation of a "cutting edge" 3D printer controller board. This is the electronics portion of your 3D printer, typically used in RepRap-style kit assemblies.
What makes this board special over more commonly available parts? The team, led by James Harder of Utah, wanted to pack in as many features as possible, yet retain a low cost solution. As you'll see on their Kickstarter page, there are dozens of features. The ones we found most interesting were:
- Lighting control - up to 64 RGD LEDs
- 2 - 12V MOSFET outputs for heated beds (10A per board fused) controlled by one pin
- 3 - 12V MOSFET outputs fused together at 10A for extruder cores
- Dedicated +3v3, +5v and +12v outputs fused at 5A per rail for additional components including light ring, fans, MP3 sound controller, lighting control kit, camera IR trigger and any custom uses you can think up.
As is customary on Kickstarter, there are numerous payment options. Essentially you can get a kit for this controller board for as low as USD$149 or an assembled version for USD$189. For higher levels you'll get various combinations of add-ons and packs of plastic filament.
Basically, it seems you could build a truly kick-ass 3D printer around this board. Of course, you'll need a lot more mechanical parts and some time to put it all together, but in the end you'll have a very capable machine.
We're reading about a group of researchers at Stanford who have concocted new gel-like substance that has some very interesting properties. We think the electrically conductive hydrogel created by Stanford Associate Professors Zhenan Bao and Yi Cui could potentially be used in 3D printers, or perhaps a modification of it. At least it's worth an experiment or two.
But what are the unique properties of this substance? It's initially a liquid that is "turned into a gel after it's already in place". It's flexible and electrically conductive. The substance can also store an electrical charge. To us this sounds like the characteristics of a new kind of material one could run through a 3D printer.
A material that could enable 3D printing of electrical circuit traces embedded within a 3D object. Or 3D printing an embedded battery that precisely fits an internal cavity. This could be quite important.
We don't know how to produce this substance, but evidently it is made from "commercially available ingredients thrown into a water solution". No doubt this discovery will be patented as it could be highly useful to not only 3D printing but also to a wide variety of 2D electrical applications.
The RepRap team continue to develop methods of printing electrical conductors. If they succeed, it would be possible for future 3D printers to print objects that include (at least at first) simple electronic circuits embedded directly in their shapes. One can imagine a wide variety of LED lamps or switchboxes emerging quickly once this tech is available, for example.
But is it available? Rhys Jones described RepRap's recent experiments in a long post detailing the steps they've taken. While the mechanics of 3D printing electronics would be mostly identical to printing in plastic or food, the extruder and material are what's really different.
They've been testing electrically conductive materials with these characteristics:
- Reasonable melting point, similar to the plastic currently used in 3D printers
- Significant viscosity to enable extrusion
- Low surface tension effect to ensure accurate deposition during printing
But problems emerged, mainly that their metal extruder (brass) slowly dissolved in the molten metal material and new approaches had to be developed. Eventually they used a hi-temp PTFE nozzle liner and a low-melt point alloy of 57.5% Tin, 41.3% Bismuth, 1.2% Indium that successfully achieved printing the conductive traces above.
This is by no means a ready-to-use technology; They're still working on it, and there is also the question of sourcing this peculiar mix of metals in printable filament. However, this is how all new technology appears, and if it works, we may see it on your desktop sometime in the future.
Researchers at the Frederick Seitz Materials Research Laboratory at Illinois have achieved something never before accomplished: printing an electronic antenna onto a curved surface. Why would you want to do this? According to electrical and computer engineering professor Jennifer T. Bernhard:
These antennas are electrically small relative to a wavelength (typically a twelfth of a wavelength or less) and exhibit performance metrics that are an order of magnitude better than those realized by monopole antenna designs.
Printing in this way is quite different than the layer-by-layer approach typically used in 3D printing. Instead the print head must scurry along the curved surface so precisely that it doesn't mess up the smooth and uniform deposition of the electrically conductive material. The very short video is quite interesting to watch.
However, this raises an interesting idea: does 3D printing really need to be done layer-by-layer? Or can print heads move up and down as necessary to permit more printable object geometries? Obviously, extremely precise motion is required, but the Illinois team's work demonstrates this is possible.
We just noticed this development that was posted last July: a RepRap 3D printer was used to print a circuit board. Well, not completely - the 3D printer actually printed the etch resist, which protected the conductive bits from the acid bath. The resulting board was then cleaned up and had components mounted on it.
The 3D printing process was actually 2D: a marker pen was guided by the RepRap over the virgin board to outline the electronic traces. Two passes were required to produce a sufficient amount of resist.
There are several approaches to electronic printing, but it's great to see another successful one.