CNC milling machines are machines controlled by computers. They are used for processing flat surfaces. There are single-spindle and multi-spindle milling machines. Nowadays, CNC milling machines are programmed using specialized computers, all activities are performed within a specific coordinate system. However, the position of the milling machine and its cutters is controlled by sensors. The use of CNC milling machines allows for a significant reduction in production costs, time savings and improves the accuracy of manufactured elements.