Abstract
In this project the drift was improved using six sigma tools. The project was performed through four steps such as M(measure), A(analyze), I(improve) and C(control). The main factors were measured in M step. The critical problems were analyzed through the process capability and run chart in A step. The influences of the main factors on the drift were analyzed using the DOE(design of experiments) to find out the CTQ(critical to quality) in I step. The tire conicity and toe angle difference were proved to be the CTQ. The process improvement of the CTQ were performed. The respective toe angle tolerance for the adjustment process was obtained using the monte carlo simulation. The improved results were validated by the hypothesis test and continued to be statistically controlled in C step.