Heating carbon/thermoplastic fibre hybrid nonwovens using microwaves to produce organo sheets

Carbon fibre reinforced composites have become a technical necessity in large sectors of the industry. Especially the aviation and the renewable energy sector are in need of carbon fibre reinforced composites. In addition the automotive industry is increasingly using composites in order to reduce the weight of their vehicles. An alternative to classical thermoset composites are thermoplastic matrix systems. The viscosity of molten thermoplastic material is distinctly higher than the viscosity of duroplastic material. Therefore reinforcing fibres are being mixed with thermoplastic matrix fibres using textile processes to reduce the melt flow paths. These fibre mixtures are then processed into textiles. To produce a composite part out of these textiles, also called prepregs, they have to be heated and consolidated. The cycle time of this process is determined by the heating and cooling of the material. The advantage of microwave heating is the volumetric heating of the material, where the energy of the electromagnetic radiation is converted into thermal energy inside the material. By using microwave ovens the process times can be shortened and the use of energy and therefore the production costs of composites can be decreased.