Recycling-orientated thermoplastic composite lightweight structures for automotive engineering

This research presents innovative developments in lightweight vehicle structures using the FuPro design method, which synergistically combines thermoplastic fibre-reinforced polymer (FRP) hollow profiles, organosheets, and injection moulding to address the environmental challenges of resource-intensive aluminium and magnesium structures. The study focuses on three key technological advances: energy-efficient hollow profile manufacturing, laser structuring for durable and adhesive-free hybrid connections, and integration of recyclates for sustainable production. A novel tool tempering concept utilizing thin-walled electrically heated shells significantly reduces thermal mass compared to conventional variothermal oil systems. Laser structuring investigations demonstrated that varying surface modification intensities combined with controlled compression enable high bonding strengths between hot organosheets and cold hollow profiles, eliminating the need for additional adhesion promoters and preserving recyclability. The recyclate integration strategy achieved a 20% recyclate quota through fibre direct compounding (FDC), where virgin-recyclate material blends matched or exceeded the mechanical properties of reference PP-GF30 virgin materials. A prototype cockpit cross-car beam was successfully manufactured using an automated production cell, replacing the original aluminium structure with a continuous glass fibre-reinforced polypropylene hollow profile featuring laser-structured metal inserts and overmoulded organosheet supports. This integrated approach demonstrates significant potential for reducing environmental impacts while maintaining structural performance in automotive applications.