J. Cesarano III, Sandia National Laboratories, Albuquerque, NM
Robocasting is a freeform fabrication technique that uses computer controlled layer-wise extrusion of colloidal pastes to fabricate components from fine powders. Complicated and unique components may be manufactured without the use of molds or containers. The process is relatively rapid and does not require waxes, thermosetting polymers, or polymerization reactions to build parts. Instead, robocasted parts ”cure” when highly concentrated pastes transition from a yield-pseudoplastic rheology to a dilatant, solid-like state upon minimal drying. Processing particulate pastes in this semi-plastic state requires careful control of rheology and is accomplished with polyvalent cation complexation of the polyelectrolyte dispersants. This presentation will focus on: 1) the fundamentals of manipulating inter-particle forces in concentrated colloidal suspensions for the explicit use in robocasting; 2) the versatility of robocasting for catalytic, filtration, bio-medical, electronic, and composite applications; 3) properties of unique structures fabricated via robocasting; 4) potential for automated manufacturing and 5) limitations of the technology. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.
Summary: Robocasting is a freeform fabrication technique that uses computer controlled layer-wise extrusion of colloidal pastes to fabricate components from fine powders. Complicated and unique components may be manufactured without the use of molds or containers. The process is relatively rapid and does not require waxes, thermosetting polymers, or polymerization reactions to build parts. Instead, robocasted parts ”cure” when highly concentrated pastes transition from a yield-pseudoplastic rheology to a dilatant, solid-like state upon minimal drying. Processing particulate pastes in this semi-plastic state requires careful control of rheology and is accomplished with polyvalent cation complexation of the polyelectrolyte dispersants. This presentation will focus on: 1) the fundamentals of manipulating inter-particle forces in concentrated colloidal suspensions for the explicit use in robocasting; 2) the versatility of robocasting for catalytic, filtration, bio-medical, electronic, and composite applications; 3) properties of unique structures fabricated via robocasting; 4) potential for automated manufacturing and 5) limitations of the technology.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under Contract DE-AC04-94AL85000.
