3D printing with metals has made many advances in recent years, but there are still limitations researchers are trying to improve to fine-tune the process and create more stable and complex objects. To that end, researchers at Carnegie Mellon University-collaborating with Argonne National Laboratory-have identified a key reason for an abnormality in metal 3D-printed products. Anthony Rollett, professor of materials science and engineering at CMU who led the research, said the work can lead to better quality control and better control of working with machines used in metal additive manufacturing. In this process, lasers are used to melt and fuse material metal powder together, scanning over each layer of material to fuse the metal where it’s needed. Defects typically form when pockets of gas become trapped into these layers, leading to imperfections that could mean a breakdown in the object down the road. Previously, manufacturers and researchers did not know much about how the laser drills into the metal to produced cavities called “Vapor depressions,” but they had some assumptions that blamed the depressions on the type of metal powder or strength of laser used in the process. “Most people think you shine a laser light on the surface of a metal powder, the light is absorbed by the material, and it melts the metal into a melt pool. In actuality, you’re really drilling a hole into the metal.” Faster 3D printing of metals also could be an effect of the research, Rollett said.
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