The Lanxess group has a wide-ranging product portfolio of specialty, basic and fine chemicals together with polymers. Its focus is on the development, production and marketing of high-quality chemicals, rubber and plastics. For some time, the group has been involved in developing hybrid technologies for some of the major automakers. Last month, Matthew Beecham talked to Ulrich Dajek, specialist in hybrid technology at Lanxess, about the group's front-end module applications.
 

just-auto: What stage of development are Lanxess' hybrid technologies for front-end modules?

Ulrich Dajek: The first injection-moulded plastic/metal hybrid front-ends entered the market in 1997 in the Audi A6 and Ford Focus. Since then, Lanxess has supplied its plastic/metal hybrid technologies for front-end modules for 55 different car models. We can provide high reinforced Durethan material, which is up to 60% glass fibre and capable of flowing as a standard 30% reinforced polyamide 6. In this way, front-end structures become lighter with the same stiffness. On the other hand, there is also a special 30% reinforced Durethan Easyflow available, which allows us to achieve extended flow distance and thinner wall thickness in the injection mould.


just-auto: What are the forces that have driven this development?

Ulrich Dajek: In the 1990s, modularisation was identified as a useful way for simplifying the automotive production especially for the OEMs. The responsibility for such a complex module was transferred to tier-one suppliers which offered the whole module. This supplier has to organise and manage the production of such a module, if necessary together with tier-two suppliers. Following this, the front-end module carrier became more complex consisting of a number of metal profiles welded together. Simultaneously, closer tolerances, high loadability - due to augmented crash requirements - and a lot of other parts were required. Sheet-moulding compound [SMC] front-end carriers with separate assembled sheet metal reinforcements could fulfil this but were not as economic to produce as hybrid front-end carriers, due to the cost-intensive post treatment of SMC parts like trimming, assembling, etc.


just-auto: What are the benefits of this technology compared to the traditional front-end modules, which are usually made from a combination of sheet metal and glass-reinforced plastic components?

Ulrich Dajek: Compared to traditional front-end modules, there is a considerable amount of cost saving. In plastic/metal hybrid technology, the plastic portion is used for supporting the sheet metal structure as well as functional plastic elements. Therefore, thin-walled sheet metal profiles can be used without the need to carry out further processing to assemble the metal structure with functional or supporting plastic elements.


just-auto:  How are your hybrid technologies for front-end modules manufactured?

Ulrich Dajek: The plastic portion is injection-moulded to the sheet metal profiles, which are positioned inside the injection mould. The plastic is fastened to the sheet steel by forming plastic rivets through perforations in the sheet metal profiles. Neither preheating of the sheet metal insert nor bonding agents are required.


just-auto: The first phase of the European Union's stringent pedestrian protection rules took effect in October 2005. How do your front-end module designs comply with these regulations?

Ulrich Dajek: According to the [current Phase 1] European pedestrian regulations, the lower leg and child head are possibly affected by the front-end structure. The lower leg requirements are generally fulfilled with an additional pure plastic beam in the lower area of the front-end carrier. This can be integrated in the front-end design and injection-moulded together with the plastic ribs and plastic functional elements. Depending of the front design of the vehicle, the upper beam of the front-end can also influence the pedestrian regulation limits for the head impact, especially if a child head impact happens close to the hood lock. Thus, all involved parts have to be modified in order to restrict the impact. A suitable plastic rib structure at the upper hybrid beam helps to regulate the energy absorption behaviour.


just-auto:  Can you see more use of hybrid solutions for structural applications to help meet the EU pedestrian protection rules? If so, how do you see this evolving?

Ulrich Dajek: Plastic has a very good energy absorption capability. Together with a tightly connected sheet metal profile, it can also absorb high energy impacts in a controlled manner. In our experience, a pure plastic structure can also be sufficient if only a human person clashes with the front side of a car. So we think about hood structures, motor covers, fender adapters, and headlamp adapters.


just-auto:  What are the factors inhibiting the use of hybrid parts in front-end modules?

Ulrich Dajek: First of all, it has to be an economic number of cars with the same front-end. Then, this front-end should have several fastening positions (in order to hang parts) and other functional elements which can be realised in pure plastic. In addition, the front-end structure has to fulfil certain mechanical requirements. In compliance with these requirements, the hybrid front-end module becomes the most economic solution. Otherwise, pure plastic design or conventional welded sheet steel assembly becomes more economic.


just-auto:  Could you compare and contrast the use of hybrid parts in front-end modules in Europe, North America and Japan?

Ulrich Dajek: Hybrid front-ends are generally used as a module carrier, which has to fulfil both static and dynamic requirements. The degree of integration of functional elements in plastic is part of the philosophy of the OEM and depends on the number of cars which are produced. Although this design philosophy does not relate to certain regions, most of the hybrid front-ends with a high degree of integration or functionality are developed in Europe.

Matthew Beecham

See also: RESEARCH ANALYSIS: A review of the front-end module market