Process Encyclopaedia

Composite shaping (generic)

Overview

The unique structure of reinforced plastics requires special processes to shape them into useful products. Although some of the polymer forming processes can be used (when the fibres are chopped and mixed in a polymer), there are special processes which are specific to composites containing long, continuous fibres (such as CFRP) – it is these that are discussed here. Many of the polymer resins used can give off toxic fumes, so precautions have to be taken to protect operators from the adverse effects. Design issues include:

Avoiding sharp changes in section
Orienting fibres where possible to improve mechanical properties
Forming as close as possible to finished shape; drilling holes can dramatically reduce strength

A few years ago, fibreglass Formula 1 car bodies needed to be replaced after every race. New carbon fibre and precision forming techniques mean that these bodies can now last all season.