Vacuum consolidation technique as a cost effective manufacturing technology for continuous fibre reinforced thermoplastics

Kurzfassung

The application of composites in aircraft structures is based traditionally on fibre reinforced thermosets, rather than thermoplastics, since it is believed that thermoset matrix composites are more cost effective through both lower materials and processing costs. This view is challenged in the paper which demonstrates a low cost fabrication technology for large aircraft structures based on vacuum forming fibre reinforced thermoplastics. Successful forming of thermoplastic aircraft structures using press technology and tape laying was first presented for the first time by the DLR at ICAS (London, 1986). The cost reduction was achieved here by developing an improved vacuum consolidation process, in which both forming and welding are integrated. The new vacuum consolidation process developed has considerably lower investment costs, requiring a heated vacuum table rather than a hydraulic press, and it may be easily adapted to large components. By design and fabrication of a generic tail rudder for a fighter aircraft in 2000, it is demonstrated that thermoplastic composite structures based on carbon fibre/PEEK prepreg have a potential cost saving of about 30% compared to the use of traditional carbon fibre/epoxy materials. The demonstrator tail structure was based on load cases and laminate construction for an existing certified composite structure, and was developed in a co-operative programme between EADS and the DLR Institute of Structures and Design in Stuttgart.