Design of a new composite forming process using a formal design methodology

Composites are becoming more common in manufacturing today, but the high cost of materials and production are still deterrents for many applications. Currently one of the most cost effective processes is Resin Transfer Moulding (RTM). To improve the cost effectiveness of composite manufacturing using RTM, a new process, Flexible Resin Transfer Moulding (FRTM®), is being developed. FRTM® lowers lay–up and tooling costs by injecting resin into fabric placed between two flat flexible diaphragms. A formal design methodology has been used to develop a process to deform the injected fabric into its desired shape. This design methodology utilizes tools normally used to improve existing products and processes (evolutionary design) and applies them to development of a new generic technology (revolutionary design). A cost analysis using Taguchi methods applied to analytical cost models indicates that FRTM® would be cost effective in all markets examined. It has also identified the FRTM® injection cost as the dominant factor in determining its cost effectiveness. A prototype machine for deforming the fabric has been developed as part of the FRTM® process. The machine consists of a sequenced actuator array which forms impregnated fabric into a three dimensional shape. The effects of varying different process parameters were examined to determine their influence on the deformation process. Results indicate that lubrication of the mould did not have a significant effect and that matched moulds could not form complex parts as well as moulds where individual sections of the mould could be actuated independently. The development tools used in the formal design methodology included House of Quality, Pugh Concept Selection, and Taguchi analysis. The adaptation of these tools for use in the development of a revolutionary technology is discussed.