Issues in fabricating manufacturing tooling using powder-based additive freeform fabrication

Recent interest has emerged for the development of ''tool-less'' processes capable of producing freeform geometries of metal and ceramic. One important application of such processes would be the rapid acquisition of manufacturing tooling including molds and dies. The basis of this paper is the review of additive freeform fabrication (AFF) processes that utilize particulate materials in processing freeform geometries. Current commercial AFF techniques include stereolithography, solid ground curing, selective laser sintering, fused deposition modeling, and laminated object manufacturing. Different approaches to direct metal or ceramic AFF using these processes have yielded a variety of results. The intent of the paper is to describe the various AFF techniques, summarize the powder processing capabilities of each, and identify some of the issues involved with applying these capabilities to manufacturing tooling. Equipment capabilities evaluated include speed, dimensional accuracy, surface roughness, material properties, work envelope, and cost.