Effect of preform fibre distribution on the surface finish of composite panels

Achievement of high class surface finish is important to the high volume automotive industry when using the Resin Transfer Molding (RTM) process for exterior body panels. In this work, the effect of the fibre distribution in F3P preforms on the surface quality of RTM moulded panels was investigated. Taguchi experimental design techniques were employed to design test matrices and an optimization analysis was performed on the fibre preform architecture. The F3P preform fibre distribution was measured by carrying out image analysis of the light intensity transmitted through dry preforms. Test panels were manufactured using a flat plate steel mould mounted on a press. The panel surface quality was measured using the ONDULO non-contact surface measurement system. Fibre density distribution was compared to the measured surface roughness. Predicted surface quality is presented and compared to measured values from the manufactured parts. The results obtained indicate that small variations in preform fibre volume fraction and top veil thickness have no effect on the surface finish of 'Class A' composites parts.