Multi Response Optimization of Spot Welding Process Parameters by Taguchi Method

Abstract

Electrode deterioration by deformation and chemical reaction during resistance spot welding of steel sheets confirming to AISI1020 is an issue for class II electrode. In view of this, the present study carried out the impacts of squeeze, weld, current and pressure on the nugget diameter, height, force and waviness of welding joint in electrical resistance spot welding of 0.8mm and 1.5 mm thickness of steel sheets with class II electrode to achieve the benefits of cost saving and quality products. A timer and current controlled electrical resistance spot welding machine having 120 kVA capacities were used. During welding process, current periods of 5, 10, 15, 20 and 25 were selected and it was adjusted by increasing from 8 to 10 kA. The optimum welding parameter for multi objectives was obtained using multi signal to noise ratio and the significant level of the welding parameters was further analysed by analysis of variance for all responses. Based on the confirmation test results, it is found out that the developed model can be effectively used to predict the size of weld zone which can improve the welding quality and performance in GRA. The details of welded joint generated by class II electrode were measured and results were analysed in detail.