The effect of preforming and infusing bindered and unbindered carbon non-crimp-fabrics on the final quality of composites parts

Abstract

Vacuum infusion (VI) is a liquid moulding process used to manufacture fibre-reinforced polymer composite parts. The VI process for non-crimp fabric (NCF) preforms is one of the most promising processes for improving the quality and cost efficiency of traditional processes using prepregs and autoclave curing. An understanding of the preform thickness behaviour in the compaction, wetting, and curing stages is necessary to optimise the overall process and obtain high-performance composite parts. In this study, the influence of the material, preforming, and infusion parameters on the thickness of four different carbon NCF laminates were investigated. The preforming behaviour includes the influence of the NCF composition, such as the presence of an organic binder or the number of compaction steps. Infusion was characterised using dielectric analysis (DEA). The properties of the resulting composites were analysed in terms of the fibre volume fraction (FVF) and porosity, as measured using X-ray computed tomography (CT). The main consequence of the outcome of the present study is that, from a manufacturing point of view, downward through-thickness resin infusion offers benefits in terms of thickness, FVF, and porosity tolerance. In addition, the acquired results allow for the identification of the main settings for an optimised consolidation strategy, which could be used for manufacturing NCF composite parts.