Design Chain – Advantage foam in the automotive world

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The use of foam in car exterior and interior trim parts can lead to significant weight reduction.

Mecaplast, a Monaco-based supplier of plastic automotive components, says it can cut the weight of interior and exterior trim parts by at least 30%, using a new injection moulding process.

It has just begun working on a project called Plume, sponsored by the French government, which uses moving cores - and a blowing agent - to reduce the density of moulded polypropylene (PP) components.

And the targets are very tough, especially in Europe: current CO2 emission levels of 165g per km driven must be reduced to 130g/km by 2015 - and down to 95g/km by 2020.

On average, every 100kg of weight reduction brings a 10g reduction in CO2 emissions. Simple maths shows the magnitude of the task in hand.

"Lightweighting is one of the primary factors that can help to achieve this reduction," he says, though says it will achieved alongside other factors such as greater engine efficiency and reduced rolling resistance of tyres.

Plastics have already consigned many metal parts to history: air intake manifolds are just one example. But the changing nature of modern cars - whose engines often run at higher temperatures - means that materials must be more robust than before.

An example here is engines that use exhaust gas recirculation, or EGR, which helps to reduce emissions of NOx gases. These gases are produced at very high temperatures,

"An air duct that was once a simple part must now withstand a much harsher environment," he says. "It's this kind of thing that drove us to develop our Zytel Plus range."

Zytel Plus is a family of PA66 resins that have higher heat stability and temperature resistance. The materials were developed in direct response to the needs of OEMs.

Replacing a large metal part with plastics is the surest way to start reducing car weight, and make progress towards the new emission targets. But plastics will continue to make an incremental difference as well, helping designers to shave off small amounts of weight here and there - which may end up being just as important.

"At the end of the day, every gramme counts," says Cazuk. "Any saving, at gramme level, is worth it."

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