The source details a scientific breakthrough in 3D printing that creates metal structures up to twenty times stronger than conventional methods. Developed by scientists at EPFL, the technique addresses a weakness in vat photopolymerization (VP), which typically results in weak, porous metal parts prone to shrinkage. The new method, called "hydrogel infusion," involves first 3D printing a temporary, sacrificial hydrogel lattice which is then repeatedly soaked in metal salts to infuse it with metal nanoparticles. After multiple infusion steps, the hydrogel scaffold is removed via heating, leaving behind a dense, high-quality metallic structure. While currently time-consuming, the researchers believe this approach, where material selection occurs after printing, represents a new manufacturing paradigm and are working to automate the process for industrial use.