In this paper, an interpolation method with spline curves is proposed to smooth cutter location source data called CLS data. 3 rd -order and 5 th -order spline curves are easily implemented for interpolation. Then, a post processor is designed for an industrial robot FANUC R2000iC to produce FANUC robotic program called LS format. The post processor works as a straightforward and cooperative interface between CAD/CAM systems and the industrial robot, so that a desirable teaching-less operation environment is realized. The validity and usefulness of the proposed methods are evaluated through a simulation on FANUC RoboGuide and an actual machining experiment with the robot. The FANUC RoboGuide is a robotic simulation environment that can execute both the robot's motion and application, largely reducing the setup time and risk in using an actual robot.