Application of the polyurethane spraying process on the large scale production of fibre-reinforced structural components with sandwich elements for IT-transportation systems

• Applicant: Professor Dr.-Ing. Christian Hopmann
• Subject Area: Plastics Engineering
• Term: from 2014 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 248182243

High performance parts made from composites with a polyurethane (PU) matrix have proven their economic potential in many industrial applications. Therefore, the fast cross-linking kinetics of the PU have played a decisive part in the success of the material. However, the disadvantages of the produced parts are the low fibre volume content and the use of foamed PU. The developments in the field of PU-spray impregnation of continuous fibre textiles (Resin Spray Prepregging (RSP)) in combination with an optimised forming and curing process within the scope of the joint research project knowledge (FOR860) allow to produce automated high performance parts in short cycle times with high fibre volume contents (> 50 %). Up to now, the production techniques have only been analysed for simple geometries. Therefore, the aim of the applied project is the transfer of the FOR860 knowledge to produce high performance composite parts in short cycle times to the production of highly stressed sandwich structures. For an implementation of specific products, further scientific investigations are necessary. Because of the complexity, these investigations are only feasible by interdisciplinary cooperation between industrial companies and research institutes. Within the scope of the FOR860, the results have shown that the production of highly stressed top layers for sandwich parts in short cycle times with an adjusted process technology and an industrial manufacturing equipment is possible. To ensure an acceptance of the process in the industry, highly stressed continuous fibre reinforced top layers should be initially combined with commonly used cost-effective paper honeycomb or foam cores produced in the process. Therefore, the system technology should be modified based on the findings of the FOR860, so that the sandwich structures can be produced in one step and the process can be adapted according to the resin reactivity and the foam reaction. Taking into account the parameters of the process, the characteristics of the produced parts should be analysed afterwards, e. g. surface quality, acoustic properties and mechanical values. Subsequent to fundamental investigations on planar parts, the knowledge should be transferred to the production of a lightweight IT transportation case (figure). The selected geometry of the demonstration part for the investigations allows a transfer of the results to large-area parts (e. g. in commercial vehicles or trains) as well as to applications in the field of other consumer goods.

• DFG Programme: Research Grants (Transfer Project)
• Participating Institution: Greiner Perfoam GmbH; Krauss Maffei Technologies GmbH; Parat Beteiligungs GmbH; Rühl Puromer GmbH