Challenges and state of the art in industrial FSW - pushing the limits by high speed welding of complex 3D contours

Abstract

Over the last 25 years, Friction Stir Welding (FSW) has been gradually moving from research over first applications into mass production. Today, requirements for consistently high-quality welds occur in parallel with a demand for high throughput as well as production flexibility. This paper gives an insight to the state of the art of industrial FSW mass production, current trends, challenges and market demands as well as the potential of high speed complex contour welding on modern multi-axis FSW machinery with respect to process parameters, material properties, machinery requirements and control algorithms, and methods. The design strategy of complex 3D contours as a chance to maximize efficiency is introduced; challenges of its implementation with respect to the state of the art in FSW are described. This includes the importance of advanced force control methods, fixture design, clamping forces and methodology for sustaining high-quality welds as well as the management of distortions and residual stresses by thermal management and optimization of process parameters. Examples of successful weld performance are described. Steps to be taken that result in high-quality welds, as well as situations to be avoided, are discussed. The publication was written based on results of the DFG project RO 651/16-1 that was carried out at the University of Stuttgart.