Optimization processes are becoming increasingly important and widely used because the main goal of any type of technological processing is to produce a high quality product in the shortest possible time at the lowest possible cost. Material removal processing is, along with casting, welding and deformation, one of the most common technologies within the manufacturing industry. This Master Thesis is organized into 10 chapters. In the first, introductory chapter, the subject, purpose and goal of the research are presented. In the second, theoretical considerations on three-axis milling and the main parameters influencing this machining are given. CAD/CAM systems are explained in the third chapter, where the CAD/CAM software CATIA V5 used in this paper is explained in detail. The fourth chapter explains the types of processing that were used to make the specific example. The fifth chapter describes a specific example that was designed in CATIA V5 software. The task of the thesis is to find the method that will determine the optimal parameters of machining, so the sixth chapter explains the methods which were used - Taguchi method and Gray relational analysis. In the seventh chapter, experimental plans are made and thus the optimal parameters of machining are determined. After obtaining the optimal parameters, a machining program was created in CATIA V5 software, which is explained in the eighth chapter. The ninth chapter explains the last step of this work, which is the machining on the three-axis machining center VC 560 SPINNER. The tenth, last chapter, contains the conclusion of this Master Thesis.