Vacuum injection moulding for large structural applications

Resin Transfer Moulding (RTM) is a successful closed mould technology for small composite products in large series. For large products in smaller series (i.e. boat hulls or rotor blades) the Vacuum Assisted RTM is applied in order to save cost of moulds. Compared with RTM the VARTM technology is still not practised in many products today. The risk of failures in very large products is often considered too high. This paper describes ways to improve reliability and predictability of the VARTM technology in order to decrease development cost and to make the risk of failures during production as small as possible. First, appropriate methods to achieve void free processing of the composite material are described. Secondly, it is explained how the injection strategy can be optimised by using resin flow simulation software. Two examples of successful developments of large structural applications are described; a 20 m rotor blade and a 16 m long boat hull for a sailing yacht.