Analyzing the Force and Current Profiles using Pneumatic and Servo Based Electrode Actuation System for Resistance Spot Welding

Electrode actuation system plays important role on the resistance spot welding as it finalizes the force profiles before, during and after the welding process takes place. Basically the force profile influences the characteristic of weld growth as it varies the process resistance. In this experiment we have welded 1mm mild steels using pneumatic based and servo based electrode actuation system. It was a Japanese made 75kVA of spot welder which was used to accomplish the entire weld process. During the entire welding process; the process parameters such as electrode terminal voltage, secondary current and electrode pressing force are measured. Based on measured signals, the dynamic resistance, heat distribution, electrode tip contact area, and current density are calculated for both systems. Changing the electrode actuation system improvises the weld nuggets; reduces the forging forces; reduces the failure rates and extend electrode life.