The Application of DMAIC to Improve Hardness in Low Speed Shaft Manufacturing Process

Inconsistent quality of low speed shaft has been an ongoing problem for Company S. The fracture of the low speed shaft has caused scrapped products and failure product with serious production consequences to both Company S and its clients. Define-Measure-Analyse-Improve-Control (DMAIC) framework of Six Sigma management methodology was adopted in this case study. During different stages, the problems and critical factors were identified to improve the low performance of low speed shaft hardness. The results provided solid evidence that how Six Sigma can be successfully applied in practice. The low speed shaft failure was caused by the defect of raw materials. Control plans for continuous improvements were suggested and implemented.