Reduction of Rework in Bearing End Plate Using Six Sigma Methodology: A Case Study

Six Sigma is a structured and systematic approach to performance and quality improvement. Six Sigma is a rigorous methodology consists of five major phases, namely definition, measure, analysis, improvement, and control for problem solving. A lot of case studies have been published and many large organizations have reported financial benefits by the application of Six Sigma methodology. This paper is a case study on reducing the bearing end plate reworks in a machining process through the application of Six Sigma methodology. The study focuses on reducing the rework due to thickness and diameter variation. From the list of identified potential causes, two causes, namely tool type and coolant pH are shortlisted as root causes. The optimum values of tool type and coolant pH, which would simultaneously optimize the diameter and thickness, are identified using the design of experiments and Taguchi's loss function approach. The implementation of optimum settings shows that the capability of the machining process to meet the customer requirements on thickness and diameter has substantially improved and rework has reduced.