(Georgia Institute of Technology, 2007)
Rosen, David W.; Williams, Christopher Bryant
Cellular materials, metallic bodies with gaseous voids, are a promising class of materials that offer high strength accompanied by a relatively low mass. Unfortunately, existing manufacturing techniques constrain a designer to a predetermined part mesostructure, material type, and macrostructure. In this paper, the authors document their design rationale for the selection of the Three-Dimensional Printing (3DP) additive manufacturing process as a means to fabricate metallic cellular materials. This is achieved by selectively printing a solvent into a bed of spray-dried metal oxide ceramic powder. The resulting green part undergoes reduction and sintering post-production processes in order to chemically convert it to metal.
(Georgia Institute of Technology, 2005)
Mistree, Farrokh; Rosen, David W.; Williams, Christopher Bryant
Low-density cellular materials, metallic bodies with gaseous voids, are a unique class of materials that have high strength, good energy absorption characteristics, good thermal and acoustic insulation properties, accompanied by an extremely low mass. Unfortunately, current cellular material manufacturing processes severely limit a designer's ability to control the part mesostructure, the material composition, and the part macrostructure. As such, the authors look towards the use of layer-based additive manufacturing (AM) as a means of providing the design freedom that is currently absent from cellular material manufacturing processes. Since current metal-based AM techniques do not offer an adequate means of satisfying the unique requirements of cellular materials, the
authors carry out the conceptual design of a new AM process that is dedicated to the manufacture of cellular materials. Specifically, the authors look to the layer-based additive fabrication of metal oxide powders followed by post-processing in a reducing atmosphere as a means of fabricating three-dimensional, low-density cellular metal parts with designed mesostructure. In this paper, the authors detail this conceptual design process and select working principles that are worthy of further investigation. Insights gained as a result of designing an AM process for a specific class of geometry (e.g. considerations for small wall thickness, high quality surface finish, internal voids, and support material) and investigating the use of AM for production-scale manufacturing are also detailed.