Professor Kim Miso and her research team at Korea Advanced Institute of Science and Technology (KAIST) develop a technique to improve the durability of photopolymerization 3D printing, which uses light to solidify liquid materials into structures. The research paper is published online in the materials journal Advanced Materials in July and is selected as this month's cover article. /Courtesy of Advanced Materials

A domestic research team has developed a new technology that overcomes weaknesses in 3D printing used in dental treatment and precision machinery fabrication. Conventional 3D printing is fast and precise but has the limitation of being brittle and easily broken under impact. This study is expected to solve those problems and open the way to make everything from medical implants to precision machine parts stronger and more expense-efficient.

Korea Advanced Institute of Science and Technology (KAIST) said on the 29th that a research team led by Mechanical Engineering Professor Kim Miso developed a technology that boosts the durability of "photocuring 3D printing," which hardens liquid materials into structures using light. The findings were published online in the international materials journal "Advanced Materials" in Jul., and were selected as the cover paper this month.

Photocuring 3D printing uses light such as ultraviolet to harden liquid "resin" into precise structures. In particular, the digital light processing (DLP) method cures the resin layer by layer at once by projecting light, enabling fast production and high precision. However, existing methods lacked strength and were vulnerable to shocks and vibrations.

To address this, Kim Miso's team developed two core technologies. The first is a new material called "dynamic-bond polyurethane acrylate (PUA)," which can absorb shocks and vibrations while allowing strength to be tuned. This material has both elasticity and viscosity, so it absorbs impact and excels at rapidly dissipating vibrational energy.

The second is "grayscale digital light processing (Grayscale DLP)." This technology adjusts light intensity to create different strengths in different parts of a structure during printing. It is similar to how bones and cartilage in the human body harmonize with different strengths.

On top of that, the team added a machine-learning-based design technique that automatically designs the optimal strength distribution tailored to the structure and load conditions. This allows material development and structural design to be consolidated naturally and enables customized fabrication.

Conceptual diagram of a high-durability photopolymerization 3D printing technique using light-controlled gradient structures. This technology, which increases durability through stiffness-controllable PUA materials, AI design, and grayscale DLP techniques, can be applied to various industries. /Courtesy of KAIST

It is also economical. Previously, creating diverse material properties required expensive "multi-material printing," but the new technology achieves the same effect with a single material and a single process. As a result, equipment and material management expense are reduced, and development and design time is shortened through artificial intelligence (AI) design.

Kim said, "This technology simultaneously increases the degrees of freedom in materials and design," adding, "Custom implants become stronger and more comfortable, and precision parts can be manufactured more robustly." Kim continued, "It is meaningful that various strengths can be achieved with a single material and process while enabling expense savings," and added, "It will be used in various fields, including biomedical, aerospace, and robotics."

(front) Nam Jisoo, doctoral candidate; (back row, from left) Boxin Chen, doctoral candidate; Professor Kim Miso. /Courtesy of KAIST

References

Advanced Materials (2025), DOI: https://doi.org/10.1002/adma.202504075

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