In today's era of technical digitization and global competition, the manufacturing industry must be economical, the only way to do this is to process variables optimization. Manufacturing engineers and production team utilize computer numerical control machine tools to rapidly and efficiently set up industrial technique for new items. Before starting the milling operation, it is important to precisely choose an input variable and select its range, resulting in a systematic experiment plan. To obtain the best results, the appropriate input variables must be selected, and their range must be fixed. Thus, it reduces the number of experiment trials that must be carried out on the machine. For further investigation, the following parameter ranges were selectedcutting speed range from 120 to 140 m/min, Feed rate from 300 to 350 mm/min, and depth of cut from 0.45 to 0.55 mm. Then with these results, main experiments are performed.