Aspects of Material and Process Optimisation for Automotive Composite Production Using Resin Transfer Moulding

Within this project, investigations have been made into the materials and processes involved in resin transfer moulding (RTM), the process used to produce McLaren Automotive’s mono-cell, used as the monocoque in its various models. Following an assessment of the literature surrounding RTM and an analysis of the state-of-the-art technology on the market, fundamental material property data was obtained for multiple components used in the production of the mono-cell. These materials include matrix resin, carbon fibre, preform binder, assembly adhesive, structural foams, primer and aluminium. A framework for process-related resin selection and optimisation was produced to increase prospective matrix system assessment and reduce the cost of doing so through an efficient regime of investigations into cycle time, including filling time against gel time, micro-infiltration time and demould time. Reaction kinetics modelling using differential scanning calorimetry (DSC) and characterisation of viscosity, storage- and viscous-shear moduli by dynamic mechanical analysis (DMA) in a rheometer were used in the initial down selection while further investigations were performed using capillary pressure measurements of curing resin impregnating a fibre yarn. Investigations were carried out into the optimised usage of binder and adhesive additives in conjunction with fibre reinforcements in the RTM process. Their effect on the processability and final product quality was assessed through the use of mechanical testing and microscopy. Structural foams and metallic inserts were investigated as comoulded assemblies for their processability and in-service performance through the use of mechanical and contact angle testing, microscopy and DSC measurements. The data obtained from the investigations into each material and their interactions with each other and the high-pressure RTM (HP-RTM) process as well as the methodologies of investigation have been adopted to optimise McLaren Automotive’s mono-cell production process through the timely and cost-effective production of data transferrable to large scale composite component manufacture