Friction Stir Welding (FSW) was adopted for the joining of fuel tanks on satellite launch vehicles in the late 1990s with spectacular results in terms of improved joint efficiency, strength, reduced rework and substantial cost savings. Its use in commercial aircraft manufacture has been slower to develop, but is starting to increase due to the weight and cost savings associated with its use.
Weight is one of the biggest challenges to aircraft manufacturers. Using FSW to join aluminium alloy stringers to skins for aircraft wings and fuselage structures will reduce weight by the removal of thousands of rivets, and any overlapping aluminium material. A leading aircraft manufacturer estimated that potential weight savings of around 1 kg per metre of FSW could be made.
TWI invented the FSW process and has over 20 years of experience of working on the joining of a wide variety of materials, thicknesses and joint configurations using this process. The continuing development of FSW tools and welding techniques keeps TWI at the leading edge of process development for its Industrial Membership base.
TWI issued an FSW licence, and provided technical assistance, to Eclipse Aviation for the manufacture of the Eclipse 500 business jet. Eclipse made 128m of friction stir welding per airframe, replacing approximately 7000 rivets. FSW is also used by Spirit Aero Systems in the production of nose barrier beams for the Boeing 747 freighter, with 14.4lbs of weight saved per set of 5 barrier beams. TWI is also assisting Embraer to introduce FSW into the manufacture of forward fuselage panels on the Legacy 450 and 500 aircraft (see quote below).
The main structure of the business jets will be built from Al alloy, with a substantial content of composite materials. In production there will be a considerable increase in the use of robots, and TWI friction stir welding technology will be used for the first time at Embraer in a production aircraft.
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