Assessing the Success of Six Sigma: An Empirical Study

Abstract

In response to the ever increasing demand of customer and prompt changing economic conditions, various industrial engineering and quality management strategies such as ISO 9000, total quality management (TQM), lean manufacturing, manufacturing recourse planning, modular design, reengineering, flexible manufacturing system (FMS), etc., are adopted by the corporations to compete in the current competitive market. However, from the last three decades a new paradigm, known as “Six Sigma”, has made its prime
impact in the area of manufacturing strategies to solve the problems related to the quality and productivity. In this paper, a case of Indian foundry unit has been presented to explore the effectiveness of six sigma methodology. The DMAIC (Define- Measure-Analyze-Improve-Control) approach of six sigma has been followed here to reduce percentage of defects in green sand casting process. In addition, Taguchi method of parameter design is used to set the optimal process parameters in the ‘Improve phase’. Analysis of variance (ANOVA) is then performed to find the optimal parameter levels and to identify the statistical significance and contribution of each factor on the casting defects. Finally, a confirmation test is performed using the optimal parameter setting, which shows that the casting defects can be minimized, effectively. The results show  that after successful deployment of six sigma, the percentage of casting defects is reduced by 25.44%.

Keywords

green sand casting, six sigma, casting defects,Taguchi technique, design of experiment (DOE), orthogonal array (OA), signal-to-noise ratio, analysis of variance (ANOVA).

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