Investigation of fast curing epoxy resins regarding process induced distortions of fibre reinforced composites

Unavoidable deformations occur during part production due to the non-isotropic nature of carbon fibre reinforced plastics (CFRP). These deformations often lead to dissatisfaction of tolerances or result in cost and time intensive rework of the tooling. In a cost driven production environment, similar to the automotive industry, it is essential to predict the deformations early on in the part development process in order to compensate toolings accordingly. In future applications, Fast Curing Epoxy Resins (FCER), with curing times of less than 20 min, will play a key role in high rate CFRP-production at low cost. The present paper reports on a comprehensive experimental study on different FCER systems. It includes the thermo-chemical characterization of neat resin samples as well as the quantification of spring-in deformations of L-profiles. Essential part and processing parameters, as the lay-up, the curing temperature, the cooling rate and the fibre volume fraction are varied and their effect on process induced deformations is quantified. Results for FCER system are compared to slower curing systems to assess differences.