Having already gone through the build-up to the mould-making process (see previous feature), Renault F1's new car, the R24, is well on the way to seeing its first monocoque come to life.

Indeed, the first monocoque will soon be ready, as patterns have already been completed and the mould production next stage is about to begin. But this is a high-precision job that comes in three stages...

By the time the process reaches the stage of taking moulds, the team possesses a chassis pattern accurate to 0.05mm. This is produced from epoxy resin after several stages of machining on computer-controlled Jobs machines.

"These parts are then spray painted with a black finish, and polished to a high-gloss finish," explains composites manager Colin Watts, "The following stage is much more complicated as we need to decide how the moulds will be produced - some large components, or those with very complex surfaces, for example, require more than one section mould."

A monocoque, for example, requires six different sections to produce the two moulds, four for the upper and two for the lower.

Once the pattern has been finished, painted and covered with a mould release agent, the Renault engineers cover each surface with sheets of paper cut to produce templates. These will then serve as patterns for the composites department in order that identical sheets of carbon can be cut.

To the uninitiated, the raw carbon fibre might look to have the same sort of consistency as liquorice, but the reality is quite different.

"The material we use is a type of carbon fibre that is produced in big sheets," Watts continues, "They are stored frozen, at a temperature of -18?C. The material includes a lot of resin to ensure that the surfaces of the moulds are completely smooth."

These cut pieces of carbon are then placed carefully on the resin pattern, and the whole 'structure' is then put into a plastic bag, from which the air is subsequently extracted. This assembly is then taken to the 'autoclave' oven, where it is 'cured' under high pressure, often around 100psi.

Nuts and bolts are inserted into each side of the mould, in order to ensure they can be adjusted to perfection during the subsequent stages of the process.

"After they have cooled, the moulds are carefully removed from the patterns," Watts concludes, "The resin pattern now has no function, and is destroyed. As for the moulds, they are machined to sand off the sharp exterior edges, and are subsequently used throughout the season to produce new chassis."

To improve reaction times, Enstone produces two sets of moulds for each monocoque, allowing the team to produce multiple chassis in parallel.

But that is another story entirely....

 

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