This work utilizes the application of the DFSS (Design for Six Sigma) methodology, employing requirement identification to uncover customer needs, transforming these needs into design metrics through QFD (Quality Function Deployment), screening the optimal solution using the PUGH matrix, validating through simulation with 3DCS, finding the relationship between gaps and tolerances through DOE (Design of Experiments), and finally, setting targets and finding the optimal combination of tolerances through response optimization. Through simulation and assembly validation, the gap target is achieved. The application of new tools and methods to solve problems provides guidance.