X-core is a novel foam core material developed by Donkervoort Automobielen, it enables a unique one-shot process for seamless composite sandwich structures with mould-defined features all-around. The foam is co-cured to carbon fibre/epoxy prepregs, in this form the process is currently used to make car components for the Donkervoort D8 GTO RS. One of the main challenges that is faced in the manufacture of these ‘bare carbon’ components is the visible presence of surface defects. In this research a variety of process variables are primarily correlated to the surface porosity content of the laminate. Processing guidelines pertaining to the cure cycle, core material composition, moulding and type of prepreg are formulated based on these relations. The main causes for surface porosity are identified and it is found that the process is especially sensitive to the laminate composition: Variations in stacking sequence and fibre aerial weight.

Besides building ultra-lightweight sportscars, Donkervoort Automobielen B.V. is developing a novel core material to be applied in complex shaped composite sandwich structures. This material goes by the name of X-Core and has the unique capability of generating the pressure required for facesheet consolidation, enabling a one-shot manufacturing process for the first time. The present research has focused on the phenomena present during the manufacturing process of the foam. In-situ temperature measurements have been carried out to gain a deeper understanding of the thermal behaviour of the material. A numerical model, based on a transient finite difference method, was then constructed to predict the temperature distribution in the material during its cure under different processing conditions, material compositions and cure cycles. The proposed model can now be applied in fine-tuning cure-cycles required to attain certain desirable X-Core properties.