CHARM3D

What it does

CHARM3D enables rapid printing of complex, free-standing metal structures from digital designs without hazardous post-processing. Safe for research and home use, it creates conductive circuits and devices via direct ink writing, using an AI chat interface.

Your inspiration

With the rise of AI and rapid prototyping, we imagined a future where anyone, including students and inventors, could create advanced metal circuits/structures as easily chatting with the printer. Most metal 3D printers require extreme heat or tedious post-processing, limiting its use to industry. We wanted to change that. After countless iterations over 5 years, we refined CHARM3D for speed, safety, and quality. Early iterations faced problems with discontinuous extrusion, but with a unique discovery, we achieved smooth, reliable prints. Our experiments showed that CHARM3D could print unprecedented 3D metal designs and self-healing circuits.

How it works

CHARM3D uses an innovative direct ink writing process to 3D print metal parts safely and efficiently. A low-melting-point, non-toxic metal alloy is gently heated in a controlled syringe and extruded through a fine nozzle by a 4-axis robotic arm, precisely forming complex, free-standing metallic structures directly from digital designs. As the molten metal is deposited, it rapidly cools in air, creating a stabilizing oxide shell that gives strength and electrical conductivity to the structure. The entire system is managed through an intuitive AI chat interface, enabling users with minimal experience to operate the printer safely and effectively. With no need for high-temperature sintering, soldering, or hazardous chemicals, CHARM3D is ideally suited for schools, makerspaces, and designer labs. This efficient process minimizes material waste and completely eliminates post-processing, allowing users to rapidly transition from design to functional metal prototype.

Design process

Our development process for CHARM3D followed a rigorous, iterative approach to ensure technical robustness, manufacturability, and user safety. Building on years of university research in direct ink writing, our multidisciplinary team systematically evaluated a range of low-melting-point alloys and experimented extensively with print parameters to optimize for structural integrity and electrical conductivity. A key challenge emerged when applying pressure to the heated nozzle, which caused the metal to form droplets instead of the continuous filaments required for high-quality prints. To resolve this, we conducted over a hundred trials, varying process conditions and hardware components. Our breakthrough came when we adopted atmospheric pressure at the nozzle and precisely controlled the nozzle’s movement speed, achieving stable, continuous extrusion without relying on a pressure-feed mechanism. This resulted in reliable, free-standing metal prints suitable for real-world applications. The solution enabled us to create a safe, easy-to-operate, compact system that minimizes material waste and is manufacturable using standard components, ensuring safety, feasibility and user accessibility.

How it is different

CHARM3D stands out through a combination of original engineering, accessibility, and robust performance. Unlike traditional metal 3D printers that require high temperatures and complex post-processing, CHARM3D uses a safe, low-melting-point alloy and a unique pressure-free direct ink writing process. By precisely controlling nozzle movement at atmospheric pressure, we achieved continuous, free-standing metal filaments without the need for a pressure-feed system. This breakthrough emerged after more than 100 iterations and extensive material testing. The result is a patent pending user-friendly 3D printer that delivers reliable, conductive metal structures in minutes, with no hazardous chemicals, minimal waste, and no post-processing required. Its intuitive interface, built-in safety features, and scalable design make advanced metal printing accessible to innovators, students and home users.

Future plans

Our goal is to make microscale 3D metal printing accessible, enabling anyone to prototype functional 3D devices. One of the most promising areas of applications is healthcare, where we’ve already demonstrated a highly miniaturized antenna (more than 30x size reduction) capable of monitoring vital signs. Moving forward, we’re also collaborating with motion robotics specialists to refine the prototype, with plans to miniaturize the system and expand the range of compatible materials. These advancements will push the boundaries of what's possible, unlocking new frontiers in robotics, wearable devices and other smart medical technologies.

Awards