A Tooling and Production Strategy for a Fully Integral, Hig Production Rate NLF Upper Wing Skin

Kurzfassung

Abstract: A Tooling and Production Strategy for a Fully Integral, High Production Rate NLF Upper Wing Skin. Producing large integral composite components at a high production rate is a major challenge because the required level of process maturity is extremely high. Further more only a highly streamlined and optimised production approach can provide the required competitiveness. For a typical single aisle aircraft wing skin a length of up to 20m and typical laminate thicknesses of up to 25mm can be expected. In addition only secondary bonding or fully integral design approaches can provide the surface smoothness required for Natural Laminar Flow capabilities. In the framework of the LUFOIV Project LaWiPro it was decided to go for a fully integral design approach with integrated stringers and integrated rib caps following the tradition of the first Airbus CFRP VTP. In order to optimise the production sequence priority was given to minimised set-up and processing times. The so called “Shoe Box” solution that is currently investigated is based on a manufacturing optimised wing skin design without undercuts and interleaved Stringer, Rib Cap and Wing Skin plies. The production sequence starts with the wrapping of Hollow Tooling Modules that are afterwards combined to a row. Several rows of wrapped Tooling Modules are than placed on the referencing tooling base plate and covered with additional wing skin plies. After the set-up phase the tool is closed and placed in an autoclave or convection oven. To reduce the cycle time the Hollow Tooling Modules are connected to the process environment and there is a controlled airflow through the Tooling Modules. In the end the geometrical precision of the aerodynamic surfaces and also the joining areas is investigated with a contact-free high precision GOM-ATOS measuring equipment. Even though the first trials are based on prepreg it is an option to combine the prepreg wing skin laminate (e.g. ATL, AFP) with infused stringers and rib caps (Combined Prepreg Infusion (CPI)) or to chose a complete Infusion based approach. To evaluate the competitiveness of the “Shoe Box” solution all activities are accompanied by a related cost assessment that indicates areas that need to be improved from a maturity point of view or where automation concepts could be successfully applied to further reduce production costs.