Optimization of Process Parameters for Friction Stir Welding of Aluminum and Copper Using the Taguchi Method

Producing joints of aluminum and copper by means of fusion welding is a challenging task. However, the results of various studies have proven the potential of friction stir welding (FSW) for manufacturing aluminum-copper joints. Despite the proven feasibility, there is currently no series application in automotive industry to produce aluminum-copper joints for electrical contacts by means of FSW. To make FSW as efficient as possible for large-scale production, maximized welding speed is desired. Taking this into account, this paper presents results of a parametric investigation, the objective of which was to increase the welding speed for FSW of aluminum and copper in comparison to welding speeds that are considered to be state of the art. Taguchi method was used to design an experimental plan and target figures of the investigations were the resultant tensile strengths and electrical resistances. Dependencies between input parameters and target figures were determined systematically. The optimal welding parameters, at which joints failed in the weaker aluminum material, included a welding speed of 700 mm/min. Consequently, it could be shown that joints with a performance similar to those of the base materials can be obtained using significantly higher welding speeds than reported in the relevant literature.