FLEX: Flexible, resin transfer moulding (RTM) tool with automated distortion correction
Resin transfer moulding (RTM) is a closed moulding process for producing high-quality, fibre-reinforced plastic composites with two finished surfaces. Despite its wide utility, it faces challenges due to the geometric changes that can occur to parts when released from the forming tool; so-called spring-back changes. To address this, the FLEX project developed an innovative RTM tooling system that actively and automatically changes the mould shape, thereby compensating for distortion. In addition, advanced quality monitoring ensures that parts are suitable for demanding applications including production of European aircraft components.
The project objectives were to:
- Design an RTM tooling system with: novel distortion compensation capability in order to reach the final mould lines (shapes) quickly with minimum design / rework iterations; curing process optimisation; and automation at every stage of the manufacturing process, creating the ability to handle increased productivity of up to 200 parts per month.
- Demonstrate the capabilities of the developed technologies in a small-scale mould representative of the real scale tool, and use this to conduct trade-off and validation studies, with the final design of the real scale mould being ready on mould clamp (M)16 after a Critical Design Review.
- Study and realise process automation concepts for the manufacture of the demonstrator (flaperon – a hinged surface on the trailing edge of an aircraft wing, used to control both roll about the longitudinal axis and lift), entailing investigation of the preform/fibre placement, the resin injection process and mould cleaning. Include these automation steps in the initial tool concept but finalised on M12, and incorporate into the final mould design, validated on the small-scale tool in M24.
- Fabricate a real-scale, functional tool that incorporates the developed technologies, and use to build the relevant demonstrator, with the final tool being ready in M20.
The FLEX tooling concept has brought a number of benefits to the production of composite flaperon or similar aerospace components. The primary one is that it removes the trial-and-error aspects of initial part manufacturing trials, thereby reducing the development costs and lead time associated with RTM tooling of composite components. The automatic compensation system removes the need to rework the tooling to compensate for part distortion, saving significantly on time and material cost. It also allows the tooling to compensate for ply misalignment during manufacture, which reduces scrap and rework costs on components, ensuring that manufacturing process yields can be increased. In addition, the integral heating within the tool requires no ovens, reducing the infrastructure needed to support high production rates, and the tool’s lower thermal mass reduces cycle times.
Visit the FLEX website to find out more about the project.
Partners: SAAB, also Topic Manager, Loiretech, Engineering Technology Solutions (ETS), Cranfield University and Brunel Composites Centre (BCC).
FLEX received funding from the Clean Sky 2 Joint Undertaking under the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 821488.