This paper deals with the real-time cutter path modification in radial cam profile milling, by which the shape error due to the workpiece thermal deformation could be reduced. A cam profile is determined by the computer using the parameters indicated by a designer. And then, the temperature rise and the thermal deformation of the workpiece, during the cutting process, are roughly predicted by the finite element method previously. During actual machining process, the workpiece temperature rise, which is concerned with the variance of cutting conditions, is monitored by the minicomputer. By comparing the measured workpiece temperature with the previously predicted value, the actual thermal deformation of the workpiece is estimated. Since the minicomputer is directly connected to the numerical control unit, it generates the modified cutter path instructions and sends these instructions to the NC unit. These instructions are based on the original cam profile and the thermal deformation. It is certified through some experiments that this method improves the machining accuracy without some cooling systems. Furthermore, the minicomputer is connected to the large scale time sharing system via telephone line. Using this two level hierarchical system, computational load is shared effectively between the large scale computer and the minicomputer.
