| 摘要 |
A numerical-control (NC) method and system for machining a desired three-dimensional contour in a workpiece with an axial tool, e.g. a rotary milling cutter or electroerosion electrode, formed at its axial end with an active machining surface which is spherical about a center intersected by the axis of the tool. According to the invention, numerical coordinate values for the positions of this center of the tool to be displaced relative to the workpiece need not to be preprogrammed and stored on a record medium. Rather, the numerical coordinate values for a series of prescribed points on the desired contour, together with the angular values defining an imaginary line normal to the contour at each of these points are simply programmed and stored on such an NC tape or like medium, and a numerical datum for a constant value substantially equal to the radius of the sphere is keyed in into a computing device arranged between a tape reader and drive units for computing from the data reproduced from the NC tape and the keyed-in datum, for each of the prescribed points, the three-dimensional coordinate values of the position of the center of the sphere. The computing device is associated with a drive control unit for producing from the computed numerical coordinate values, command signals to operate the drive units so that the workpiece and the tool are relatively displaced to allow the desired contour to be progressively developed in the workpiece. |
