Introduction
FITCoW (Full-scale Innovative integrated Tooling for Composite material Wing-box) is an ambitious project aiming at the development of an integrated tooling system capable of manufacturing large composite structures and parts. It targets at introducing new technology in the unconventional area of composite materials by improving the efficiency of the manufacturing method. FITCoW focuses on developing an innovative manufacturing method for a 7m CFRP (Carbon Fiber Reinforced Polymer) wing box in a one-shot process.
Five individual carbon fibre tools work together into forming an individual, primary structural component
The novel tooling system allows for an increased volume of work at a decreased cost, with less time and energy spent during the manufacturing process as well as minimal material waste. This translates into having a direct impact on the carbon emissions footprint, as well as an improvement in economic terms.
The designed tooling system proves itself to be versatile, as is capable of producing composite structures by pre-preg and LRI methods. Therefore, the beneficiary isn’t constrained by the tooling to a single manufacturing method. Regarding the fiber lay-up process, the tooling is compatible with automated lay-up methods such as AFP or ATL, besides the traditional manual lay-ups.
The project is characterized through two major milestones:
- The development of the 1.2 meter Small-scale Demonstrator (SSD)
- The development of the 7 meter Full-scale Demonstrator (FSD)
The design phase’s main objective is to develop a scalable version of the tooling system: from the 1.2 meter demonstrator to the 7 meters full size assembly. During this stage, the tooling system underwent through three versions, all of which were closely related. The upgrades implemented throughout these versions had a positive impact on the overall stability and functionality of the system.
Another vital aspect that had to be covered was the CTE-caused effects and how they can be managed. While the tools are manufactured out of composite laminates (therefore perfectly matching the materials used to manufacture parts), the whole assembly features some additional metallic items. In order to assure that the CTE mismatch between the metallic and composite parts doesn’t alter the quality of the manufactured products, clever technical solutions had to be implemented.
Challenges
- Develop a tooling assembly that is suitable for a one-shot manufacturing procedure
- Allow manufacturing through prepreg and Liquid Resin Infusion
- Eliminate CTE-caused mismatches
- Maintain mechanical properties at very high temperatures
- Provide accurate and reliable locating & fixture solutions
- Ensure process repeatability
- Develop a scalable tooling concept
Results
Small-scale Demonstrator - Critical Design Review
The proof-of-concept Small-scale Demonstrator reached its final design solution and is currently under manufacturing. The deployed philosophy revolves around scalability in order to ensure a smooth transition into the final phase of the project – the manufacturing of the Full-scale Demonstrator. A considerable amount of design iterations were necessary in order to reach the final solution.
Designing such composite-made tooling is often challenging. The most critical issues are the extraction of the tools during the final phase of manufacturing and ensuring accuracy during the assembly of the five individual components.
Rendered image of the Small-scale Demonstrator in its final configuration