Hollow-Profile Hybrid Technology Elaborate tooling technology superfluous?
Materials company Lanxess is launching a hollow-profile hybrid technology. With this new lightweight design technology, metallic hollow profiles can be functionalised on conventional injection moulding machines with plastic compounds.
With the new hollow-profile hybrid technology from Lanxess it is possible to produce plastic-metal composite components with greater torsional stiffness and strength than with other technologies, the company announced. “Hollow-profile hybrid technology has now progressed to such an advanced level that we have embarked on a variety of development projects with customers and have already reached the prototype stage with some of them,” says Dr. Matthias Theunissen, an expert in lightweight design at Lanxess. The potential applications in the automotive industry include cross car beams, coupling rods, stabilizers and seat elements. In addition, the new lightweight technology could be used to produce skiing and hiking poles and components for furniture and the construction industry, for example.
The hollow-profile hybrid technology is a further development of the “traditional” plastic-metal composite technology (hybrid technology) using sheet metal. According to the company, the general advantage of the new technology is that processors can manufacture with short cycle times, as is typical for injection moulding in high-volume production. There is no need for auxiliary units or tooling technology, which keeps investment costs low, Lanxess adds. The fact that reasonably priced hollow profiles with relatively large dimensional variations could be used, would make the process cost-effective, too, explains Theunissen. “With the aid of innovative tolerance management, we can prevent profiles of that type from damaging the mould or stop leaks occurring in the injection moulding cavity.” When the thin-walled hollow profiles are overmoulded with the molten plastic, high pressures often exceeding 400 to 500 bar occur in the cavity. As a result, there is a high risk of the profiles deforming or collapsing. “We have optimised the process such that the profiles withstand the pressures that occur and do not need to be supported from inside,” says Theunissen.
Weight saving of 30 percent for automotive cross car beams
For the hollow-profile hybrid technology, the company offers highly reinforced polyamide 6 types such as the easy-flowing Durethan BKV60H2.0EF DUS060, which has a short glass fiber content of 60 percent by weight. With their high strength and stiffness, these compounds further enhance the performance of the corresponding components. In a simulation study, Lanxess examined how using the compounds pays off in the design of an automotive cross car beam. “The component can be designed with around 30 percent less weight than an all-steel structure while offering better mechanical performance in some respects,” says Theunissen. Typical load cases and component properties were calculated, such as vibration behavior and the stiffness of the steering wheel in the direction of gravitational forces. “The component also underlines the huge potential of the technology in implementing cost-saving functional integration. For example, connections for the A-pillar as well as mountings for the steering column, dashboard, climate control units and airbags were directly injected.
Simulations with a high level of forecast quality
The company has developed new calculation models for the hollow-profile hybrid technology based on simulation tools that have proven successful for years in conjunction with the “traditional” hybrid technology. These allow precise prediction of the production process and the quality of the connection between the metal and plastic, Lanxess states. “With these tools, we can, for example, accurately predict the maximum stresses hollow-profile hybrids will withstand and at what point they will fail. We apply this expertise in working with our customers,” explains Theunissen. A newly developed test specimen was used to validate the simulation. Extensive component testing for static and dynamic load cases underpinning the simulation results was carried out on real components.