Effect of tool geometry and material flow on fsw tool wear: insights into wear processes

Previous studies have shown that the wear of FSW tools is influenced by process parameters as well as the relation between tool material and workpiece material. However, the effect of tool geometry and the associated material flow on geometrically induced tool wear has not yet been addressed in the existing literature. Against this background, the study systematically investigates the wear behaviour of various shoulder (cylindrical, scroll) and probe geometries (cylindrical, conical, threaded, threaded with flats) as a function of material flow during friction stir welding of the aluminium alloy AA-6060 T66 with a thickness of 5 mm. The wear behaviour was investigated over weld lengths of up to 500 m at a rotational speed of 2000 rpm, a welding speed of 0.5 m/min, and an axial force of 5.5 kN. The study revealed that both horizontal and vertical material flow contribute to wear in the transition zone between the shoulder and the probe. Furthermore, the results showed that reducing tool complexity can significantly reduce tool wear. The experiments were carried out using a force-controlled robotic welding system from Grenzebach Maschinenbau GmbH.