French company Plastic Omnium Auto Exterior produced over 1 million tailgates in 2013; more than five million vehicles have been equipped with Plastic Omnium tailgates to date. Tailgates incorporating its Higate composite and thermoplastic designs were first seen on the Peugeot 508 SW and are now to be found on the Range Rover Evoque, Jaguar XF, the latest edition of the Range Rover and Range Rover Sport and on the latest Citroën C4 Picasso. Its first composite tailgate in China is now in production for the Roewe E50 electric vehicle.
The technology on these vehicles features an inner panel made of thermoset sheet moulding compound (SMC) in a clam-shell design with a polypropylene (PP) thermoplastic outer panel, which is said to provide a Class-A surface finish and to offer designers improved styling freedom. In the case of the C4 Picasso such a design would be difficult to realise in steel or aluminium technology.
Also in 2013, Plastic Omnium introduced hybrid thermoplastic, which uses glass-filled thermoplastic olefin for the tailgate structure (PP LGF). As fitted in the new Peugeot 308 tailgate, it weighs less than 12kg – 25% lighter than its steel equivalent – and can integrate rear lighting, antennae and motorisation at low cost, as well as meeting low speed crash requirements.
Next generation materials and designs
A prototype tailgate presented at the IAA Show 2013 features a large inner panel in carbon SMC material. Lighting functions are integrated either in exterior panels or in the composite structure, and aerodynamic spoilers and side deflectors reduce the drag coefficient. The combination of new materials and appropriate design are claimed to deliver weights savings of 10% over all-aluminium equivalents. Plastic Omnium says that the new generation of high performance composites will offer improved mechanical properties and could be applied directly to the vehicle structure, holding out the possibility of weight savings of over 100kg.
The current range includes products that can be assembled either directly on the vehicle assembly line (on-line), before painting (examples include fender carrier, front-end carrier, trunk floor, inner hood; or after painting (off-line), with modules that can be pre-assembled such as tailgates. A prototype main floor using new-generation high performance composites has been designed to achieve a 50% weight saving using chopped and continuous fibres (glass and carbon) in an advanced SMC process. The floor is compliant with crash requirements and can replace a complex, multi-piece steel design with a single component.
On the road with Mercedes
The latest member of the Mercedes-Benz A-Class family on the MFA platform is the new CLA, which features front-end modules that are more than 20% lighter than the previous model. The special design of the assembly carrier as a structural front-end member enables a high degree of rigidity. Other technologies can be used to cut assembly time of the front-end module by around 30%.
An installation and attachment technique developed by Plastic Omnium sees the module installed from the side, via the wheel housing. Precise alignment and adjustment of the headlamps is achieved by orienting the units using specific reference surfaces, which has helped to reduce investment in what would otherwise have been expensive alignment and adjustment technology. The design philosophy is to treat the module as an integral whole, which enabled the full synergy effects and advantages to be recognised and implemented.