COJOCARU Radu National R & D ISIM

Possibilities of Monitoring the Friction Stir Welding Process by Real-Time Control of Energy Consumption

Friction stir welding (FSW) is a relatively new and attractive technique for the scientific community, which has lately generated high interest among industrial applicators, especially in fields such marine, aviation/aerospace and land transportations. There are many applications that require long and continuous welded joints. For this reason, real-time monitoring of FSW process is extremely useful. Complex monitoring systems that control the forces developed during the welding process started to be applied worldwide. Recent research has shown that infrared thermography technique can represent a viable solution for monitoring automated welding processes. This paper presents studies and results obtained by the authors during experimental programs regarding the analysis and practical fundamentals of real-time monitoring of the FSW process, by measuring the total current consumed by the FSW equipment, respectively its modules, fitted with electric motors. Experiments have shown that, by measuring and controlling the current consumption, when using selected or optimized welding parameters, a real-time monitoring of the FSW process can be achieved. Good results can be obtained by monitoring the behavior of the motor for rotating the welding tool. The monitoring had also the purpose of information and data acquisition regarding the current consumption in the main sequences of the FSW process: rotation start - contact between tool pin and welding materials - contact between tool shoulder and welding materials - effective welding process - completion of the process and removal of the welding tool from the welded joint.