CRC-ACS develops new technology to attach composites

COmposite Fitting Attachment (COFA) technology is a method of rapidly welding “non-structural” brackets to composite structures. It was invented by CRC-ACS and is under development as part of a current CRC-ACS project. Several patents related to the technology are granted or pending.

COFA technology is of great interest to Airbus because of the robust joints produced and potential assembly cost savings, and is being assessed for a number of different uses in future Airbus aircraft.

The initial target application is the attachment of small brackets called insulation pins which are found throughout the internal fuselage structure. Airbus is very closely involved in the development of the technology, and a number of their engineers are part of the project team and help guide development in their application.

The most recent activities in COFA development have included confirming the strength and durability of COFA joints in the target environments: showing that the brackets can be easily replaced if necessary; demonstrating quality assurance methods; and demonstrating the installation process in production environment.

In demonstrations at an Airbus site in Stade, Germany, it was shown that brackets can be welded using COFA technology in a matter of seconds using a hand-operated welding device. These devices are relatively simple to operate and can include integrated quality assurance capability.

Airbus uses their own Technology Readiness Level (TRL) system to validate and track the development of new technologies. Technologies are ranked on a scale from TRL1 (just invented) through to TRL9 (ready for entry into service).

The TRL assessment is thorough and extensive, and involves examination of a wide range of Technology Readiness aspects including performance readiness, engineering readiness, manufacturing readiness, and operational readiness, as well as the value of the technology and any risks.

As a result of the demonstrations, development and testing work, COFA technology has now passed TRL4 with the exception of some issues related to the specification and supply chain for the preferred thermoplastic surfacing media. Airbus is seeking to resolve these remaining issues and find opportunities to include COFA technology in future aircraft programs.

Keen interest in COFA technology is also emerging in other sectors, where the rapid cycle time, robust joint produced, and suitability for automation are of great interest. CRC-ACS, and the COFA team in particular, is very pleased with the progress of the COFA technology and proud of this significant technology readiness milestone. The achievement of this milestone marks the completion of development work on COFA within CRC-ACS, with further Airbus development work now to continue external to the CRC-ACS program.

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