Additive Manufacturing: A Renaissance for Powder Metallurgy Research

Abstract
Additive manufacturing is an umbrella term that encompasses the various methods of producing bulk material and three dimensional parts by adding one layer of materials at a time. The best known of these processes, Fused Deposition Modelling (FDM) which involves 3D printing with thermoplastic filament, has reached commercial status for the consumer. Affordable 3D printers that can connect to desktop PC’s have turned anyone with a few thousand dollars and some CAD software into a “rapid prototyper.” While the technology has been around for decades, the recent mainstream acceptance of additive manufacturing has pushed the additive manufacturing methodology to the forefront of advanced manufacturing. It has long been known in the Ceramic and Powder Metallurgical community that that ability to tailor the microstructure of a material can be controlled trough the proper selection of precursor powders, particle sizing, sintering methods and attention to process parameters like atmosphere, mechanical pressure and temperature. In many ways, ceramics and powder metallurgy are the root technologies of all solid state additive manufacturing processes. With the technology of affordable and industrial scalable printing combined with material deposition and fusion methods, powder metallurgy is poised for a renaissance.Why a “renaissance?” The dark ages that preceded the Italian Renaissance were marked by centuries of reliance on proven methods, and lacked innovation. Certainly the timeframe is compressed, but for decades powder metallurgy as an industrial fabrication process has benefited from relatively few leaps of innovation. Limited to traditional powder compaction and densification methods, applications of powder metallurgy were limited by part geometry and design loading conditions, and the sequential nature of compaction, densification/sintering and finishing. With the advent of additive manufacturing in the last decade, the fusion process is coincident with the powder layup, eliminating the need for separate compaction and sintering. Heat sources such as lasers and electron beams provide the energy for fusion by sintering or melting in an extremely localized fashion.