NC post-processor for 5-axis milling machine of table-rotating/tilting type

The free surface machining with more than three axes motion needs CAD/CAM system for the cutter location and orientation data. Since these data are defined with respect to the coordinate system of workpiece, they need converting for machine control commands in machine coordinate system, through processing so called a NC post-processing. Most commercial CAD/CAM software vendors provide these post-processors for each type of 5-axis machines. However, they may cause some erroneous operation during phase reverse process that is due to unsymmetrical operation limits about rotating axes. In this work, efficient algorithms for NC post-processing have been presented for typical 5-axis milling machine of table-rotating/tilting type. The first algorithm is for avoiding the interference between a workpiece and the machine tool during the process of phase reverse. The second is for better strategy of machine path, which needs fewer number of phase reverse processes.