NC programless machining which is realized by the virtual copy milling system have been demonstrated. In the virtual copy milling system which is developed in this study, a stylus and a master model in copy miling are defined as geometrical surface models, the stylus motion corresponding to the tool motion is simulated by applying copy milling principle. This method is simple enough to generate the tool motion in real time, because it detects only the collision between the stylus and the master model which are defined. Experimental cutting have been succeeded to show that the virtual copy milling system is able to perform NC programless milling of sculptured surface. The real time tool path generation accomplished by this system aims to be used for the adaptation of cutting conditions such as depth of cut and feed speed to maintain stable machining. The adaptation of cutting conditions is an important function to realize an autonomous NC machine tool towards 21st century.
