The effect of a rapid curing process on the surface finish of a carbon fibre epoxy composite

This work investigated the effect of a rapid curing process, Quickstep™, in conjunction with different fibre architectures (unidirectional and 2 × 2 twill) and surfacing film (SynSkin®), on the surface finish of a carbon fibre G83C epoxy composite. Different magnitudes of pressure, heating and cooling rate were used to cure the composite laminates and the surface finish was studied using surface profilometry. It was found that the surface roughness was the most sensitive to the heating rate, which increased in roughness with high heating rates as a result of surface porosity entrapment. The high heating rates increased the rate of molecular cross-linking prior to gelation, which reduced the processing window and the removal of surface porosity via resin transport. The surfaces cured using fast heating rates were also found to have low fibre volume fraction and high resin content, which also supported the hypothesis that the resin flow is restricted prior to gelation.