US scientists develop 3D printing method that could reshape body armor

Researchers at The University of Texas at Austin and Sandia National Laboratories have developed a novel 3D printing technique called Crystallinity Regulation in Additive Fabrication of Thermoplastics (CRAFT). This method enables the creation of 3D objects with varying mechanical and optical properties—such as hardness and transparency—at the pixel level using a single, inexpensive material, cyclooctene resin. By precisely controlling light intensity during printing, the team can manipulate the molecular order of the material as it solidifies, allowing different parts of an object to have distinct textures and properties within a single piece. For example, they successfully printed a realistic human hand model that mimics the textures of skin, ligaments, tendons, and bone, offering a superior alternative to cadavers for medical training. CRAFT’s ability to produce seamless transitions between hard and soft regions addresses a common limitation in existing multi-material 3D printing, which often suffers from weak bonding at joints. Beyond medical applications, the technique