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Adrian Wilson

Editor's Viewpoint

26th July 2017, UK

Hidden gains for automotive composites

The new Audi A8, BMW 7 Series and Porsche Panamera all employ highly aerodynamic composite underbody shields developed by Röchling Automotive.

Some of the most significant gains that automotive manufacturers are making with composites are pretty well hidden and this is certainly one of them. Underbody shields, which have historically been designed using plastic and metal, are now being replaced by much lighter composite designs for considerably increased performance.

The new Audi A8, BMW 7 Series and Porsche Panamera all employ highly aerodynamic underbodies developed by Röchling Automotive. © Röchling Automotive

The Röchling Group, headquartered in Mannenheim, Germany, specialises in parts for aerodynamics and engine encapsulation, as well as powertrain components and the development of solutions for new mobility. The group achieved sales of €1.55 billion across its three divisions – Automotive Industrial and Medical – in 2016, and is anticipating sales of €1.8 billion in 2017 following considerable expansion in the past few years.

Röchling Automotive’s 2016 sales were €855.9 million and in March operations began at its new production hall in Peine, Germany, where some 27 million parts are produced annually. This is in addition to new technical centres in Worms also in Germany, Laives, Italy and Troy, Michigan in the USA which have all opened recently. Further manufacturing expansions have taken place in Wackersdorf, Germany, Duncan in South Carolina, Ostrava in Czech Republic, and a new plant in Silao, Mexico. New facilities are currently being built in Spain, China and Romania.

Engine encapsulation

In improving the aerodynamics of a vehicle, Röchling notes, automotive OEMs are focusing on intelligent air flap systems for the engine that enable high cooling capacity through maximum air flow when they are in an open position. In a closed position, they reduce drag and the time necessary to bring the battery up to operating temperature. The fuel savings impact, however can be further increased by fully encapsulating the engine thermo-acoustically.

Röchling Automotive employs a broad spectrum of technologies for lightweight engine undershields and underbody panels, such as injection and compression moulding technology, glass mat-reinforced thermoplastics (GMT), direct long-fibre-reinforced thermoplastics (D-LFT), and low-weight reinforced thermoplastics (LWRT).

Röchling Automotive has recently opened new technical centres in Germany, Italy and the USA. © Röchling Automotive

In terms of both aerodynamics and acoustics, its Softlofting LWRT technology – with its ability to provide variable acoustic performances in materials engineered in different thicknesses – offers numerous advantages over GMT or D-LFT technology.

BMW origins

The first GMT composite underbody components replacing hard plastic parts appeared over 30 years ago on the BMW 3 Series and amounted to about 0.7 square metres per vehicle, but larger parts have subsequently been introduced with much lower weight for the same performance.

The BMW GMT parts weighed around 2,000 gsm and the subsequent introduction of LWRT has reduced this to nearing 1,000gsm.

Röchling’s standard product, Seeberlite 2, is a 1,400 gsm LWRT product in a three-layer sandwich structure, with different glass fibre content in the skin and in the core.

Seeberlite forms the basis for the Röchling’s award-winning new central acoustic air manifold. © Röchling Automotive

A big advantage of Seeberlite 2 compared to a compact injection moulded or GMT material is that it can be engineered in different thicknesses for variable acoustic performance.

Seeberlight 4, produced for the Mercedes S class, is a four-layer 1,100 gsm underbody part which is employed under the vehicle in pairs, so 2,200gsm of composite per vehicle.

Air manifold

Seeberlite also forms the basis for Röchling’s new central acoustic air manifold which was a finalist in the 2017 Automotive News PACE Awards

The part is said to collectively meet the leakage standards, acoustic performance and stiffness level requirements of OEMs for central air manifolds, while providing material and process cost optimisation.

Röchling’s central acoustic air manifold reduces noise considerably in the vehicle cabin by drastically improving the technical aspects of traditional automotive climate ducts. The lightweight manifold, which is integrated into the vehicle’s central console, allows the air noise at maximum air flow to be improved by 6dB(A), and up to 10dB in certain frequency ranges.

The air distribution device is constructed with two sound-absorbing LWRT shells welded onto an injection moulded carrier. As such, the Seeberlite material creates a component that integrates stiffness and acoustic requirements through the use of a single material and represents another win for composites in automotive.

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  • Dell Toki 5th September 2017 10:30AM

    Australian company First Graphite Ltd is producing graphene @ 99.99% purity. Vein graphite mined in Sri Lanka is used to produce this product, which is suitable for composites and polymers and various other applications. May be an optimal cost effective solution for future automotive development.


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