Optimization of RTM processing parameters for Class A surface finish

Resin transfer moulding (RTM) has the potential to become an efficient and economical process for manufacturing large automotive composite parts. For body panels, the material and processing parameters must be optimized in order to achieve a Class A surface finish. In this work, the Taguchi method was used to investigate the effect of low profile additives, injection pressure, temperature gradient, filler content, styrene content and gel time on the surface finish of glass fibre polyester composite panels. The low profile additives (LPA) concentration, mixed in with the resin to compensate for its chemical shrinkage, was found to be the most influential parameter affecting surface roughness and waviness. More samples were subsequently moulded under the corresponding optimum processing conditions for validation and variability assessment.