What just happened? Traditional printed circuit boards are pretty much stuck being flat and 2D. But a team of researchers from the National University of Singapore has leveled up circuit printing into the third dimension with a smart new technique called CHARM3D. And it’s not just 3D – these printed circuits can actually heal themselves, too.
By going vertical instead of staying flat, components can be stacked up, meaning much smaller footprints for our electronics – and we all want our devices smaller and sleeker these days. But achieving that 3D circuitry is a challenge with existing methods like direct ink writing (DIW). Those techniques use special composite inks that need support materials and are pretty viscous and slow.
CHARM3D takes a totally different approach by exploiting some clever material properties. It uses a metal alloy called Field’s metal made from indium, bismuth, and tin. This alloy has a very low melting point around 62°C, flows smoothly, and rapidly self-solidifies.
The unique combination of properties helps CHARM3D print super smooth, uniform 3D metal microstructures from 100-300 microns wide – about as thin as a few human hairs. These structures can also include cubic frameworks, vertical letters, and scalable helixes.
Such printed structures can also self-heal from damage. If you scratch or deform the circuit, you can simply heat them up past the low melting point and they’ll re-solidify back into their original shape. It makes the circuits much more durable and even recyclable.
The possibilities here are huge. As the researchers mention, the high resolution, speedy printing (up to 100 millimeters per second), and the ability to create complex 3D shapes make it viable for all sorts of cool stuff.
Perhaps the biggest application noted by the researchers is healthcare. Imagine wearing smart clothes with 3D-printed sensors that monitor your vitals without ever touching your skin. It could also lead to more accurate medical imaging, like using microwaves to detect breast cancer tumors earlier. The team has already used the tech to make a wearable battery-free temperature sensor, antennas for wireless vital sign monitoring, and metamaterials for manipulating electromagnetic waves.
“By offering a faster and simpler approach to 3D metal printing as a solution for advanced electronic circuit manufacturing, CHARM3D holds immense promise for the industrial-scale production and widespread adoption of intricate 3D electronic circuits,” said Benjamin Tee, an associate professor at the university who led the research.
Of course, there’s still work ahead for the researchers. They hope to apply CHARM3D to various other metals and structural applications. The team is also exploring commercialization pathways to bring the technique to wider industrial adoption. You can find the full research in the paper published on Nature.
