An NC program simulator has been developed for evaluating productivity in NC lathe turning. Machining information about cutting parameters, tool paths and operating time are retrieved from an NC program by the simulator. These information are very useful in order to evaluate productivity in NC lathe turning. A total of 193 NC programs from 29 manufacturing companies are investigated their productivity by comparing the percentage of jog feeding time during turning operation. The result of the investigation shows that the jog feeding time occupies about 80% of total operation time on an average of 193 examples. The simulation of the revised NC programs using the touch and cut method which eliminates an air-cut travel during jog feeding shows that the operation time of the NC program can be reduced about 6% on an average. The cutting test for estimating tool life proved that the touch and cut method does not reduce the tool lifetime under the experimental cutting condition.
