Tension-Driving Fluid Drawing System Delivers Fine, Flexible, 3D-Printed Circuits
New approach "challenges the status quo in flexible circuit manufacturing," claims co-corresponding author Dazhi Wang.
Researchers from the Dalian University of Technology have come up with a new approach to 3D-printing, based on tension-driven fluid drawing — with which, they've proven, it's possible to make functional flexible circuits.
"This work challenges the status quo in flexible circuit manufacturing," claims co-corresponding author Dazhi Wang of the team's creation. "By drawing the ink rather than extruding it, we gain unprecedented control over structure, speed, and size — all from a single needle. It's not just a printing method — it's a rethinking of how we build circuits in three dimensions. The implications for wearable tech and soft robotics are profound."
Where traditional liquid-based 3D printing involves pushing ink through a nozzle, the team's approach instead draws it through like a thread — using a combination of air pressure, the specific viscosity of the ink, and thermal evaporation. The ink: a silver nanoparticle suspension that is heated to form a bridge between the needle and the substrate and then stretched by lifting the needle to create 3D structures as thin as 4μm — thinner, in fact, than the needle itself.
The conductive traces printed using the ink are flexible, the researchers found, withstanding 200 bending cycles without losing conductivity. To prove the flexibility of the new approach to printing, the team built a series of demonstration circuits including addressable LED arrays, heatable "displays" that show up on thermal imaging cameras, and a flexible self-oscillating multivibrator circuit, all of which performed as-expected.
The researchers suggest that the new manufacturing method could be used for circuit design in fields including wearable medical sensors that conform to the shape of the human body, stretchable display, and ultra-compact Internet of Things (IoT) devices. The lack of need for multiple layers of circuits and the drilling of vias could speed up production, the team adds.
The scientists' work is published in the journal Microsystems & Nanoengineering under open-access terms.