Bridge tooling through layered sintering of powder

Thesis (M. Tech.) - Central University of Technology, Free State, 2007
Faster mould production methods will undeniably impact positively on the product development community. Rapid Tooling (RT) concepts, in context with the product development process and related product development theories, were analysed. Conventional tooling techniques used such as epoxy plastic tooling and machined injection moulding techniques were used as point of departure for the research work, which focused on Laser Sintering of powder materials. The new generation RT materials that are available at the Central University of Technology, Free State, are a vast improvement on the old materials. RT materials are constantly being developed and the project aims were to stay abreast with the latest developments. The thesis gives a complete overview of all related technologies, and also an in-depth discussion of both the Selective Laser Sintering (SLS) and Laser Sintering (LS) processes. Mould size limitations, as well as general tooling design issues, polishing and finishing techniques were all taken into account. Data has been collected to compare mould inserts grown with RP machines with that of conventionally machined tools. Aspects such as tool life, part quality, lead times and cost were used as parameters to determine the differences and make recommendations. Through analysis of several experiments and industrial case studies, RT through sintered materials was proven as a capable technology, giving the option of an intermediate (bridge tooling) or even a final step of tooling. Recommendations for future use were made in terms of insert size and geometry, accuracy, durability and shrinkages, to ensure the feasibility of the RT process in SA.