The diploma thesis presents the elimination of starting vibrations of an axial fan with the introduction of the DMAIC methodology. Vibrations are a big problem due to numerous customer complaints and unnecessary finishing touches in the assembly process. In the theoretical part, the basics of the considered axial fan are presented. The DMAIC methodology and some of the tools used in each phase are described in details. In the practical part, the entire course of the project of eliminating the starting vibrations of the axial fan is presented. The main part is the hypothesis tests, which allow us to define the root causes of the resulting vibrations. Based on the hypothesis tests, the most appropriate improvements in the process and on the product itself are defined and introduced. In the conclusion, a comparison of the old and the new process is shown with the help of control charts and process capability. A comparison between the initial, target and actual status of customer complaints and the cost of additional hours is shown.