Investment casting research has been carried out by the University of Birmingham, sponsored by E.P.S.R.C. and a consortium of industrial companies. The programme was aimed at developing an in-depth understanding of all aspects of the process, with a view to routinely producing sound, net shape castings. The investment technique itself has tremendous advantages in the production of quality components and key benefits of accuracy, versatility and integrity. As a result the process is one of the most economic methods of forming a wide range of metal components. Environmental and economic pressures have, however, resulted in a need for the industry to improve current casting quality, reduce manufacturing costs and explore new markets for the process. Drying and strength development is the most significant rate-limiting factor in reduction of lead times and production costs for the industry. Therefore, scientific development within the industry is fuelled by the need towards reduction in production times without compromising the primary requirement of the mould to cast metallic shapes. Optimisation of the mechanical and physical properties of the ceramic shell, whilst reducing process/material costs, will be fundamental to achieving these aims. The use of organic fibre reinforcements to produce improved composite ceramic materials is a proven technique in standard pre-formed component technology. This technique is currently being introduced into shell technology as a method to tailor shell properties and decrease production times and costs. This paper shows the results of experimentation to determine the effect of fibre length (determining the aspect ratio of the reinforcement) upon the mechanical and physical properties of a standard aluminium casting shell system.
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