Robotic refill friction stir spot welding for aerospace applications
The consumption of high-strength aluminum alloys in aerospace industries is increasing and refill friction stir spot welding is found to be a suitable joining technology for aerospace aluminum alloys. Currently, aerospace industries use riveting to assemble aircraft components as it bears well-established standards and specifications. Refill Friction stir Spot Welding (RFSSW) that can replace riveting is an emerging solid-state spot-welding technology that thermo-mechanically produces a molecular level bond between workpieces. RFSSW does not require any filler or foreign materials and hence no additional weight is added to the assembly. There is no major lack of fusion or material deterioration exhibited by RFSSW as it does not involve phase transitions during the welding process in general. Unlike the conventional friction stir spot welding, RFSSW produces a spot joint with a flush surface finish that is free from a key or exit hole. Kawasaki Heavy Industries (KHI) has developed a robotic system with an RFSSW end effector. The aim of this study is to evaluate the mechanical properties of refill friction stir spot welds produced by the robotic RFSSW system with an emphasis on aerospace applications. As the aerospace applications require rigorous standards and specification, this study also explores potential methodologies for developing standards and specifications for RFSSW Keywords: Refill Friction Stir Spot Welding; Refill Friction Stir Spot Joining; Aerospace Aluminum Alloy; Robotic Spot Welding; Aerospace Manufacturing
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