Impact & improvement of tool deviation in friction stir welding

The present study proposes the use of an industrial serial robot to reduce the investment cost and to increase the process flexibility of Friction Stir Welding (FSW). The first part of the study characterizes the impact of pin axis position on FS Weld (FSWed) quality. The second part shows a method to compensate the lateral pin deviation in real-time during Robotic Friction Stir Welding (RFSW). This paper shows that a robot with an embedded real-time algorithm for the compensation of the lateral tool deviation can reproduce the same FSWed quality as a gantry-type CNC system. The elastostatic model of an industrial robot is carried out by the classical identification technique and this is embedded in the robot controller. Based on force measurements along the welding process, the corrected path is calculated in real-time. We use the compensation algorithm in order to do a lot of industrial project on real parts (confidential parts).The algorithm which is presented in the paper increase the precision of the robot.The algorithm which is presented could be used for other process like incremental sheet forming or deburring.