Investment casting is a time-consuming, labour intensive process, which produces complex, high value-added components for a variety of specialised industries. Drying and strength-development of each coat in the shell mould production is the most significant rate-limiting factor in the reduction of lead times and production costs for the industry. As such, improvements which reduce cost and cycle times, open up new opportunities for product development. This will be a significant advantage to a casting industry competing with large labour cost reductions from overseas foundries.

A new shell build technique using a super absorbent polymer additive has been developed for mould production such that moisture removal is not required to cause binder gellation and the drying stage is dramatically reduced. All investment coats can be carried out using the same novel additive thus leading to a large cumulative saving in processing time. This technology should allow the industry to successfully compete for the first time with other high volume forming methods such as forging, machining and welding. This paper introduces the technique, details shell development and results and follows the process through various iterations to the complete patented concept. Finally, examples of casting trials using the rapid shell will be presented and discussed.