Friction stir welding (FSW) is a solid-state welding process that is used for fabricating high-quality
aluminum weldments. In this study, FSW is used to weld aluminum alloy AA6063 plates. Different combinations of
FSW conditions were used, and the generated welds were tested for surface quality. Factorial design of experiment
approach was used to investigate the significance of the FSW factors on the surface roughness of the joints.
Moreover, response surface methodology (RSM) was used to optimize the surface roughness response and the
optimal FSW conditions were determined. The results revealed that both tool rotational and traverse speeds have a
great influence on the surface quality. The interaction of tool rotational and traverse speeds exhibited the most
significant influence on the surface roughness of the FSW specimens. However, the rotational speed exhibited a
higher significant effect on the surface roughness than the traverse speed.