Three Response Optimization of Spot-Welded Joint Using Taguchi Design and Response Surface Methodology Techniques

One of the main challenges in correlating welding parameters and weld quality is its complexity to include as many as possible factors. In this research, the effects of spot welding parameters on weld quality were investigated. The effects of weld time, weld current, and electrode force on the sizes of fusion zone and heat affected zone, and tensile-shear load were studied. These welding parameters and weld quality were analysed using the three response Taguchi L9 orthogonal array method in Minitab 17. Second-order regression models of fusion zone size, heat affected zone size and tensile-shear load were constructed by adapting Response Surface Method. The optimum weld time was 0.2 s, weld current of 10 kA and the required electrode force was 2.3 kN. These parameters were within 5% discrepancies with the experiment results. Weld current was the most important welding parameter that determines the weld quality, with the contribution of 69%. From our observation, the failure mode was the pullout type, a generally accepted failure for welded joint. The outcomes of this research contributed to the advancement in optimization technique for RSW joint, by increased the number of weld quality from two to three response.