Numerically controlled curved surface machining unit

A numerically controlled curved surface machining unit equipped with three linear axes and, at least, one rotary axis, including a simultaneous multiple-axis control NC machine, which is numerically controlled by a numerical control unit (NC controller) with a numerical control NURBS (non-uniform rational B-spline) interpolation function;

• provided with
• a means for reading a NURBS curve of three linear axes and a rotary axis calculated on a machine coordinate system;
• a means for reading cutter location (CL) data calculated on a workpiece coordinate system;
• a means for calculating a NURBS curve from the tool control point center position vector of the CL data;
• a means for calculating a NURBS curve from the tool axis vector of the CL data;
• a means for calculating each sequence-of-point data to a specified machining accuracy from the NURBS curve of three linear axes and a rotary axis on a machine coordinate system;
• a means for converting the sequence-of-point data on a machine coordinate system into CL data on a workpiece coordinate system;
• and
• a means for calculating each error between the CL data converted into a workpiece coordinate system and a NURBS curve of the tool control point vector and also a NURBS curve of the tool axis vector calculated on a workpiece coordinate system.

A numerically controlled curved surface machining unit equipped with three linear axes and, at least, one rotary axis, including a simultaneous multiple-axis control NC machine, which is numerically controlled by a numerical control unit (NC controller) with a numerical control free curve interpolation function, and a means for calculating NC data for controlling the spindle feed rate;

• provided with
• a means for reading the tool control point vector data and tool axis vector data, calculated along the tool path on a workpiece coordinate system with defined curved shape by a host computer, and the feed rate on a workpiece coordinate system as cutter location (CL) data and converting the CL data into a position vector of the three linear axes and a rotation angle on a machine coordinate system so as to operate the simultaneous multiple-axis control NC machine in accordance with the machine configuration of the NC machine;
• a feed rate determining means, which, in generating the NC data wherein the position vector and rotation angle on a machine coordinate system are interpolated by a NURBS (non-uniform rational B-spline) curve, determines the feed rate on a machine coordinate system by NURBS curve interpolation, using the knot vector of the NURBS curve;
• a means for converting the feed rate on the workpiece coordinate system into the feed rate per minute or feed rate per inverse time on the machine coordinate system;
• and
• a means for transmitting the obtained NC data to the NC controller.