Distortion Control in Laser Beam Welding using Taguchi ANOVA Analysis

Industrial process control is essential as the customer demand for quality, cost, performance; safety and reliability are ever-increasing. To obtaining a process that will give minimum distortion after laser welding using orthogonal array experimentation a fractional factorial method. Nine controlled randomized experiments of laser welding were done using three parameters; Laser power, welding speed and Argon flow rate. Each of these factors had three degrees of freedom and the fractional factorial experimentation was analyzed to find the best combination of levels in control parameters of the output, lower the better, LB, distortion. Simple inspection methods, No-way ANOVA, Linear Figures, ANOVA and Pooled ANOVA, were used, and two parameters were identified to be critical, welding speed at 31% and Argon Flow rate at 68% contribution with a statistical confidence of about 90% to 95%. The third factor of power was set to minimum cost level as it was found to be an insignificant factor for distortion control. Various aspects of the Taguchi method [15] were used to make the analysis useful for designers and engineers to use the results. Confirmation interval, process capability and tolerance design were calculated.