A product of Evonik, the structural foam for sandwich components of fibre composites was selected by the jury to receive the second award in one of the three categories, Products and Applications, for the new development ‘ROHACELL Triple F – Production-Ready Foam Cores for Sandwich Components.’ The ‘PulPress Process for Large-Scale Production of Complex fibre Composite Parts,’ for which ROHACELL is used as a foam core, is also among the winners in the Innovative Processes and Systems category.
According to Evonik, its ‘ROHACELL Triple F’ sandwich cores for fibre composite parts are currently designed primarily as flat structures. It says that, now, an innovative manufacturing process (particle foams, in-mould foaming IMF), is enabling production of complex, three-dimensional structural cores for industrial-scale CFK sandwich components that, thanks to their extreme strength and temperature resistance, can also be used in efficient curing processes such as high-pressure RTM or wet impregnation.
For ROHACELL Triple F, PMI granules in the desired density are foamed into a finished foam core in a mould. Evonik explains that, metallic parts such as threaded inserts can be directly integrated during the foaming process. It says that the innovative IMF technology can significantly lower the cost per part by reducing waste, manual work and cycle times, and produce up to 50,000 complex 3D sandwich structures per year fast and efficiently. Customer-specific foam cores are produced by LiteCon, a joint venture between Evonik and Secar Technologie. Renowned European car manufacturers are already using them in series production. Potential applications include car bodies, chassis, and add-on parts. Another potential field of application is aircraft construction, which could benefit from cost-efficient production of large quantities of common parts. Not least, lightweight sandwich cores for sports articles are an increasingly attractive possibility.
The PulPress process is designed for the highly automated, continuous and cost-effective series production of fibre-composite profiles with complex part geometries. Developed by the Composites Project House of Evonik Creavis together with Secar Technologie, it innovatively combines the pultrusion and compression methods, as well as the fibre composite materials and ROHACELL rigid foam structural core used in the process. Because of its thermomechanical properties, Evonik says that the process is fast and stable in serial production and enables moulding of highly complex parts. It explains that the process ensures extremely narrow component tolerances and outstanding component properties. Conventional resin systems allow production of over 30 profiles per hour, with a length of approximately 0.5 m. With fast-curing systems, that quantity increases. The PulPress process, therefore, is particularly well-suited to the serial production of cars. Production is about 30-60 percent more cost-effective than with conventional FRP processes (e.g. RTM).