Powder Metallurgy Speeds Mold-Making

By combining rapid prototyping with powder metallurgy, researchers at Pennsylvania State University, University Park, have developed a faster, cheaper way to make molds. In the Penn State process, a part or mold can go from concept to a finished production-ready mold in a day and a half vs up to 26 weeks using standard machining techniques, says Prof. Randall German, a specialist in powdered metal technology. The process begins by using rapid prototyping to produce a plastic model of the part the mold will make. Then the mold for that part is created by pouring a slurry of powdered metal around the plastic prototype. With thermal processing, the powdered metal hardens while the prototype escapes by melting --leaving an exact imprint of the desired shape. He says the best-performing metal powders result from a mixture of cemented carbides and steel.