| 摘要 |
PURPOSE:To machine the corner part of a work with precision on an apparatus on which the work and a wire electrode move relatively at a fixed speed by a method wherein in proportion to the reduction of machining quantity the tension of the wire electrode is increased to prevent corners of work from dulling. CONSTITUTION:At the straight part of the work W the relative feed speed of the work W to the wire electrode P is fixed, the average machining voltage is detected by a detector like an integrator INT etc. and the output is proportional to machining quantity per unit hour. At the corner part of the work W the machining quantity is smaller than the reference value. This decrease closes a relay switch ry1 through a comparator COM. The angle of the corner is computed by an NC apparatus NC just before machining the corner and when it is within a desired angle a relay switch ry2 is closed. When both switches ry1, ry2 are closed the output of the integrator INT is given to the base of a transistor Tr through amplifiers AMP1, AMP2, etc. the current of a brake shoe BS wound on the electrode P increases and the tension of the wire electrode P can be enlarged. |
