NC machine tool driven by NC programs is very useful to machine standardized products with high accuracy and productivity. However, conventional NC machine tools have no function to change cutting conditions during machining operations by themselves because NC programs instruct all cutting conditions before the operation. This is the biggest problem to realize an autonomous NC machine tool. To realize an autonomous NC machine tool, a new architecture is required to operate an NC machine tool without NC programs and to adapt cutting conditions in real time to maintain stable machining operation. This paper deals with implementation of a feedback machining control using digital copy milling system, which consists of function to generate tool paths in real time and machining strategy to adapt cutting conditions. The proposed digital copy milling system is verified to show its ability in cutting experiments.