An EDM machine includes a machine head, a wire guide, a machining wire extending from the wire guide to the machine head, a rotary table mounted to a first surface and a fixed table mounted to the rotary table, and a fixture mounted to the fixed table. The fixture includes a mounting portion substantially circumscribing the fixture. The mounting portion further includes a mounting surface. The mounting surface is closer to a first surface than an upper surface of the fixed table.

A wire electrode is hung from an upper die guide of a wire electric discharge machine toward a workpiece, a distance from a position where the wire electrode on the top surface of the workpiece is hung down to a top end position of a machined groove formed by the electric discharge machining is calculated based on a commanded taper angle and the distance from the top surface of the workpiece to an upper die guide fulcrum position of the upper die guide, and automatic wire connection is performed by moving an upper nozzle by the calculated distance. In this way, a wire connecting operation can be performed in the vicinity of the tapered groove.

A wire electrode is hung from an upper die guide of a wire electric discharge machine toward a workpiece, a distance from a position where the wire electrode on the top surface of the workpiece is hung down to a top end position of a machined groove formed by the electric discharge machining is calculated based on a commanded taper angle and the distance from the top surface of the workpiece to an upper die guide fulcrum position of the upper die guide, and automatic wire connection is performed by moving an upper nozzle by the calculated distance. In this way, a wire connecting operation can be performed in the vicinity of the tapered groove.

A wire electrical discharge machining apparatus capable of improving the shape precision of a continuous corner part includes a corner speed coefficient calculation device calculating a machining speed ratio between a middle corner section and a straight part from a machining volume ratio between the straight part and the middle corner section in which machining volume becomes a constant value. A corner speed coefficient interpolation device interpolates a speed coefficient calculated by the corner speed coefficient calculation device in a pre-corner section and a post-corner section. A speed reference calculation device calculates a machining speed reference based on a representative speed and the corner speed coefficient, and a drive control device controls a drive device. A continuous corner detection device determines whether continuous corner sections overlap each other when the length of the straight part connecting two corner parts is shorter than the length of the pre-corner section.

It is a purpose of the present invention to provide a wire electrical discharge machining system allowing a wire electrical discharge machining device and a robot to operate in conjunction with each other with high efficiency. A wire electrical discharge machining system 1 includes wire electrical discharge machining devices 7, 11, and 15, and a robot unit 17 that mounts a workpiece on the wire electrical discharge machining device. The wire electrical discharge machining devices 7, 11, and 15 may each perform either rough machining with supported cores or finishing machining after the cores are removed. Subsequently, core processing may be performed by means of a corresponding dedicated apparatus. Also, the core processing may be performed by means of a single common apparatus. The robot unit 17 mounts and collects the workpiece so as to allow these wire electrical discharge machining apparatuses to effectively operate, thereby providing wire electrical discharge machining with improved efficiency for the overall system.

A wire electrical discharge machining system includes: an electrode motion control unit for moving a wire electrode while keeping the wire electrode parallel to Z.sub.1-axis and bring the wire electrode into contact with a reference piece, and moving the wire electrode while keeping the wire electrode inclined with respect to the Z.sub.1-axis and bring the wire electrode into contact with the reference piece; an electrode position acquiring unit for acquiring a position of the wire electrode in an X.sub.1Y.sub.1Z.sub.1 orthogonal coordinate system when the wire electrode touches the reference piece; a piece position acquiring unit for acquiring a piece position of the reference piece in an X.sub.2Y.sub.2Z.sub.2 orthogonal coordinate system when the wire electrode touches the reference piece; and a relative positional relationship calculator for calculating a coordinate system relative positional relationship, based on the acquired positions.

A machining path creating device for wire electric discharge machines creates a machining path for machining a keyway in a side surface of a round hole. The machining path creating unit compares a keyway depth and a diameter of the round hole input by an operator. The machining path creating device determines that the input keyway depth is a cut depth when the input keyway depth is smaller than the diameter of the round hole and that a value obtained by subtracting the diameter of the round hole from the input keyway depth is the cut depth when the input keyway depth is larger than the diameter of the round hole.

A machining path creating device for wire electric discharge machines creates a machining path for machining a keyway in a side surface of a round hole. The machining path creating unit compares a keyway depth and a diameter of the round hole input by an operator. The machining path creating device determines that the input keyway depth is a cut depth when the input keyway depth is smaller than the diameter of the round hole and that a value obtained by subtracting the diameter of the round hole from the input keyway depth is the cut depth when the input keyway depth is larger than the diameter of the round hole.

A wire electrical discharge machine includes: a wire electrode cumulative moving time calculator for calculating a value correlated to a wire electrode cumulative moving time as a cumulative value of time for which a wire electrode has moved in each of multiple wire electrode moving regions which are defined by dividing a movable range of the wire electrode moving relative to a worktable; and a display control unit for displaying on a display unit the information on values correlated to the wire electrode cumulative moving time for respective wire electrode moving regions.

A wire electrical discharge machine for performing electrical discharge machining on a workpiece by applying voltage across an electrode gap between a wire electrode stretched between an upper nozzle and a lower nozzle and the workpiece to generate electrical discharges, includes a lifting mechanism configured to move the workpiece in the travelling direction of the wire electrode.