JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010 - 47

Thermoplastics
available fibre placement equipment uses different heating systems, such as hot gas and laser. In 2008, Fokker Aerostructures started to look for suitable fibre placement equipment. Unfortunately, a chicken-and-egg situation arose in which serious investment was needed upfront whereas the production volume was still some time away for customers. In this context, ultrasonics appeared to be a good option for the heating source at a relatively low-cost. Fokker Aerostructures has a long history of ultrasonic spot welding experience, such as welding injection moulded parts to thermoplastic plate components. Moreover, the layup of A380 fixed wing leading edge skins is done by ultrasonic spot welding (Fig. 10). Ultrasonic welding is a wellestablished, low-cost welding process.
Fig. 9: Skin panel with integral butt joined T-stringers

Dutch companies and institutes. They joined forces with Airbus and launched a 4-year project called TAPAS: Thermoplastic Affordable Primary Aircraft Structure. The goal of the TAPAS project is to create the thermoplastic composite technology necessary to produce large primary structures for future aircraft programmes. Materials, manufacturing processes, design concepts and tools must be developed to a technology-readiness level (TRL) 6. Full-scale demonstrator products are being developed as part of this effort. The technological challenges include: development and qualification of suitable materials, the butt joint, and manufacturing technologies such as fibre welding, press forming and fibre placement. Partners in the TAPAS project are Airbus, Fokker Aerostructures, Ten Cate Advanced Composites, Airborne Technology Center, KVE Composites Group, DTC, Technobis Fibre Technologies, Technical University Delft and the University of Twente. The Dutch National Aerospace Laboratory carries out related research projects and testing programmes in parallel.

Fig. 10: Ultrasonic welding, A380 J-nose skin

Ultrasonic fibre placement
Fibre placement is the lay-up technology of choice for large surface area products with a double curvature. The currently

Although continuous ultrasonic welding of plates onto plates had proved difficult in the past, it seemed feasible to ultrasonically weld a thin carbon/UD tape onto a stack of UD tapes. To this end, ultrasonic welding units were integrated into a fibre placement head mounted on a robot (Fig. 11). The initial trials – welding 10-mm-wide carbon/PEKK UD strips by hand – were successful. The next step was to weld on a linear rail. By mid-2009, a 2x1x1 metre 3D R&D fibre

More information
Fokker Aerostructures designs, develops and produces lightweight aerostructures for the aerospace and defence industry. Customers include Airbus, Boeing, Lockheed Martin, Gulfstream, Dassault, Pratt & Whitney and Dutch Space. With their cost efficiency and environmental advantages, thermoplastic composites are a key technology for Fokker. The company’s participation and co-operation in innovation networks together with customers, knowledge institutes and suppliers contributes to the continuous development of these materials.

Fig. 11: Ultrasonic fibre placement head

No58 June - July 2010 / jec composites magazine

JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #58 - June - July 2010