From the outset, the programme of work was underpinned by a commercialisation plan in order to provide a strong market and customer focus for the research and development activity. This plan encompassed a broad range of aspects including market intelligence, the supply chain, sales and marketing strategies and distribution/logistics. It had a significant ongoing input into the development of both the PFA prepreg materials and their method of manufacturing.
Based on the findings of the commercialisation plan, a range of PFA resin formulations was tested and refined with a view to meeting customers’ requirements for processability (tack [stickiness] of the material, resin flow, working life) and process cycle times (prepreg line speed, part cure time). By the end of the project, a preferred resin formulation had been identified and has now been standardised within Composites Evolution’s own internal New Product Development procedure.
Investigations also took place into the most-effective means of bringing together the PFA resins with the carbon and glass reinforcement fabrics. Different methods of applying the resins were explored, as was the interface between the resin and the reinforcement, to achieve the required impregnation (resin weight %), final product performance (e.g. interlaminar shear strength), surface finish and process consistency.
Having optimised the resin formulation and its method of impregnation, the next step was to implement a modified up-scaled process for producing PFA prepregs of the required specification, quality and volumes. Each aspect of the production process was examined and refined. This included improved approaches to material handling, control of resin content, resin impregnation strategy, in-line quality control and product presentation/packaging.
Finally, in order to demonstrate and validate the performance of the improved PFA prepregs, two demonstrator parts were manufactured by Bercella - a train seat component and a helicopter roof. These parts were extensively evaluated by Element in terms of their mechanical and fire performance. For the vast majority of the application requirements, the refined, up-scaled prepregs were found to perform exceptionally well. Furthermore, a robust prepreg costing model developed by Composites Evolution has demonstrated that the PFA prepregs are cost-competitive with phenolics.
