A numerically controlled machining unit for curved surfaces

摘要

To provide a numerically controlled curved surface machining unit, and a method or program thereof, which, by moving a tool smoothly along a NURBS (non-uniform rational B-spline) curve, enables not only to improve the machining surface roughness and machining surface accuracy but to achieve high-speed machining so as to be able to eliminate hand finishing and reduce machining steps drastically. Performing NURBS (non-uniform rational B-spline) interpolation machining by a machine equipped with a means for reading cutter location (CL) data consisting of a tool control point vector and a tool axis vector on a workpiece coordinate system, a means for converting the CL data into a position vector of three linear axes and a rotation angle on a machine coordinate system in accordance with the machine configuration of a simultaneous multiple-axis NC machine, a means for calculating knot vectors of a NURBS curve with the most suitable chord length on the basis of a position vector of the three linear axes and a rotation angle, a means for calculating NURBS curve of the three linear axes and one rotary axis using the knot vectors, a means for converting the NURBS curve into NURBS interpolation NC data, a means for converting the feed rate on a workpiece coordinate system into the feed rate per minute on a machine coordinate system, and a means for transmitting NC data to a NC machine.