Economic and environmental assessment of alternative production methods for composite aircraft components

The use of carbon fibre reinforced plastics is steadily increasing in the aerospace industry as rising fuel costs and concerns over the environment push airframe manufacturers to improve aircraft efficiency. The high costs associated with manufacturing carbon fibre reinforced components in autoclaves have prompted interest in alternative out-of-autoclave processing methods. In this study a combined cost modelling and life-cycle assessment approach is applied to selected out-of-autoclave production scenarios. Out-of-autoclave specific “prepregs” and resin infused fabrics are cured in thermal and microwave ovens of comparable volume and assessed against a benchmark autoclave scenario. Results showed that materials, in particular carbon fibres, contributed most significantly to component cost and environmental impacts. Resin infusion processes were effective at reducing costs, as reinforcement fabrics and resin were less expensive. Due to the small contribution of energy to total cost, reductions in energy use did not lead to significant savings, although they did improve the environmental performance of the manufacturing process. Out-of-autoclave specific prepregs did not perform as well due to their higher costs, longer associated cycle times and the need for lengthy de-bulking operations. Microwave oven curing offered little in terms of cost reduction and environmental improvement as investment costs were comparable to those of an autoclave, and energy consumption was relatively high compared with traditional thermal oven use. Opportunities for improvement exist if investment costs can be reduced and additional work carried out to promote more efficient transfer of energy. Improvement of the carbon fibre production process would be the most effective approach for reducing impacts and costs from carbon fibre components.