Author(s): M. Shanmugaraja, C. Vasanthakumar, K.S.Yokesh

Abstract: In recent days, Six Sigma programme is the subject of a lot of discussion papers, case studies and papers on application issues. Among the published literatures, only few have discussed about Taguchi’s experimental design strategy to improve sigma quality level in six sigma arena. This paper illustrates the application of Taguchi design of experiments in DMAIC cycle. This new approach is proposed to reduce defect level in aluminium die casting industry. Process capability of oil pump body casting is assessed before and after the case application in terms of sigma quality level. The results of the study show that the casting defect is reduced by 12.42% and process capability is improved from 2.51s to 3.18s. Application of robust optimization in six sigma arena has resulted in development of industrial statistic based quality improvement strategy for improving quality and productivity simultaneously.