CHARM3D Creates Free-standing 3D Structures, Sans Supports
A research team from the National University of Singapore (NUS) has developed a cutting-edge technique called tension-driven CHARM3D to fabricate three-dimensional (3D), self-healing electronic circuits. This new technique enables the 3D printing of free-standing metallic structures without requiring support materials and external pressure.
CREDIT: National University of Singapore
Unlike traditional printed circuit boards, which are flat, 3D circuitry allows components to be stacked vertically, significantly reducing the footprint required for electronic devices. The new CHARM3D technique uses Field’s metal, a eutectic alloy of indium, bismuth, and tin, known for its low melting point of 62 degrees Celsius, high electrical conductivity, and low toxicity. These properties make Field’s metal an ideal material for 3D printing, allowing it to solidify rapidly and eliminate the need for support structures during the printing process.
CHARM3D leverages the tension between molten metal in a nozzle and the leading edge of the printed part, resulting in smooth, uniform microwire structures with adjustable widths ranging from 100 to 300 microns. This method avoids common issues in direct ink writing (DIW), such as beading and uneven surfaces. Additionally, CHARM3D offers faster printing speeds of up to 100 millimeters per second and higher resolutions, enabling the fabrication of complex 3D structures like vertical letters, cubic frameworks, and scalable helixes.
CREDIT: National University of Singapore
These structures exhibit self-healing capability, which allows the circuits to recover from mechanical damage. This also makes them recyclable.
The NUS team successfully demonstrated the technique by printing a 3D circuit for wearable, battery-free temperature sensors, wireless vital sign monitoring antennas, and metamaterials for electromagnetic wave manipulation.
The CHARM3D method can facilitate the development of contactless sensors integrated into smart clothing that provides continuous, accurate health monitoring without the discomfort or infection risks associated with traditional skin-contact sensors like electrocardiograms and pulse oximeters. Moreover, 3D antennas and electromagnetic metamaterial sensors fabricated using CHARM3D can optimize signal sensing and processing, improving signal-to-noise ratios and bandwidths.
The research team is exploring the potential for extending the CHARM3D technique to other metals and structural applications. They are also seeking opportunities to commercialize this innovative approach to metal printing, which promises to revolutionize the manufacturing of advanced electronic circuits.
The team published their findings in Nature Electronics on July 25, 2024.
