Apparatus and method of machining article of eccentric configuration

Abstract

An eccentric-shape machining apparatus as well as an eccentric-shape machining method are provided which can efficiently and accurately bore, contour or thread a workpiece about any position other than the rotational center of the workpiece. The workpiece is rotatably driven while controlling the rotational phase of the workpiece. A rotating tool spindle adapted to mount a cutting tool is rotatably driven while controlling the rotational phase of the rotating tool spindle. The rotating tool spindle is mounted on a cutting head which is controllably fed and positioned in Z-axis extending parallel to X-axis perpendicular to the axis of the rotating tool spindle. During one complete revolution of the workpiece, the rotational phases of the main spindle and rotating tool spindle and the movement of the cutting head in the X-axis direction are simultaneously controlled such that the cutting tool is brought into contact with the inner and outer peripheries of the workpiece by a given depth of cut. At the same time, the movement of the cutting head in the Z-axis direction is controlled. As well as the work rotation mode described above, the work oscillation mode can be carried out.