Composites Applications for the Aston Martin DB9

Composites provide a wide range of advantages over conventional metal forming processes used in automotive manufacture. These include weight reduction, styling flexibility, lower tooling investment, part consolidation and customer satisfaction. Composite components can be found in structural and semi-structral applications, under-the-hood components, and exterior (Class-A) body panels. The vast majority of the components used at Ford are exterior body panels produced using the SMC process and include : hood, GOR and front fenders (Lincoln Navigator); tailgate (Volvo V70); hood, decklid, front fenders, package tray and removeable hard top (Ford Thunderbird); rear fenders (Ford F150 Flareside); and GOR, pickup box inner/outer and tonneau cover (Ford Explorer Sport Trac). Data from the Automotive Composites Alliance has shown that SMC useage in North America has almost doubled from just over 100,000 tonnes in 1998 to almost 200,000 tonnes in 2004, with the growth trend almost certain to continue. The same study showed that Ford had a 45% share of this market

SMC Usage at Ford
In contrast to the scale of SMC useage in North America, several composites applications at Aston Martin demonstrate that the technologies have uses over a wide range of volumes. The design challenges and investment constraints on the Aston Martin V12 Vanquish, a completely new vehicle from the ground up with no carry-over body parts, were such that 24 composite components were specified, all being manufactured by the RTM process. In addition to the noteable and novel use of triaxial braiding to produce safety-critical, structural carbon fibre A-Pillar reinforcements and a structural carbon fibre Strut Brace, the Vanquish was used to pioneer the Ford Programmable Preforming Process (F3P). The application of F3P-RTM in the manufacture of the Vanquish Bodysides demonstrated the capability of the process to produce Class-A panels. This success has recently been expanded upon with the introduction of 8 further Class A F3P-RTM panels on the DB9.

F3P is a progression of the P4 process in which glass fibre rovings are chopped and are deposited along with a binder onto a component screen using a robotic system. The fibres are held in place on the screen by air flow until the compaction phase where hot air is used to melt the binder. Cold air then freezes the binder which holds the fibres and sets the preform before it is de-moulded.

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