Lightweight materials and the techniques used to process them are constantly changing. One technique is to use composite materials in a sandwich structure in which an especially light core is combined with ‘skins’ of fiber reinforced plastic on both sides. As part of the “MAI Sandwich” research project, sponsored by the Federal Ministry of Education and Research of Germany, a consortium consisting of various renowned partners has spent the past two and a half years performing fundamental research in this area, developing an innovative, integrated sandwich structure concept for components made of composites in the aviation and automotive industries. The concept applies cutting edge thermoplastic material design with recycled carbon fibers combined with an exceptionally efficient production technique.
At the recent JEC World in Paris, the world’s largest industry trade fair for composites, the partners were rewarded with a JEC Innovation Award in the category Aerospace Process for this development. The project was coordinated by the Chair for Carbon Composites at the Technical University of Munich. Additional partners of the project were Airbus, BASF SE, BMW, SGL Group, Foldcore, Neenah Gessner, Neue Materialien Bayreuth and Hofmann – Ihr Impulsgeber (Werkzeugbau Siegfried Hofmann).
Today, producing sandwich structures take a great deal of time, making it expensive. In traditional processes, producing a standard generic component could take a cycle time of up to one day. This project has revealed that these long cycle times can be reduced drastically to 5 minutes for a comparable component in the aerospace industry and to 2.5 minutes for a similar component in the automotive sector. Optimal integration of the different components, including fusion bonded thermoplastic materials between the core and skins, makes this result possible. . Furthermore, the partners developed an innovative, fine-tuned production sequence using the three techniques of thermoforming, injection molding and fusion bonding in a primarily automated working facility. The process was realized and demonstrated on Neue Materialien Bayreuth`s 2,500 t compression and injection molding machine using a novel tool concept by Hofmann – Ihr Impulsgeber.
Components with a sandwich structure enable especially lightweight and sturdy designs. These properties make them ideal for secondary structures such as floor paneling or interior lining of aircraft or underbody or seat back panels in automobiles.