The disclosure provides an electric discharge machining apparatus. The apparatus includes: temperature sensors respectively attached to an upper portion, a middle portion, and a lower portion of the electric discharge machining apparatus and measuring temperatures of the electric discharge machining apparatus at predetermined time intervals; a control device calculating values of temperature environment diagnostic indexes, which are indexes for determining machining accuracy of the workpiece obtained when electric discharge machining is performed in a current temperature environment, from measurement results of the temperature sensors, comparing the values of the temperature environment diagnostic indexes with reference values of the temperature environment diagnostic indexes recommended for achieving desired machining accuracy, and outputting determination results indicating a degree of whether the current temperature environment around the electric discharge machining apparatus is appropriate for achieving the desired machining accuracy according to differences; and a storage part storing the reference values and the determination results.

A wire electrical discharge machine includes: a gap voltage detector for detecting a voltage across an electrode gap; a first voltage control unit for applying a first voltage to the electrode gap; a discharge determiner for determining whether or not the electrode gap is in a discharging state during application of the first voltage; and a second voltage control unit for supplying a machining current through the electrode gap when the electrode gap is in a discharging state. After a supply of the machining current to the electrode gap, even when a discharge is induced by the next application of the first voltage to the electrode gap, the second voltage control unit prohibits application of a second voltage to the electrode gap.

A wire electrical discharge machine includes: a gap voltage detector for detecting a voltage across an electrode gap; a first voltage control unit for applying a first voltage to the electrode gap; a discharge determiner for determining whether or not the electrode gap is in a discharging state during application of the first voltage; and a second voltage control unit for supplying a machining current through the electrode gap when the electrode gap is in a discharging state. After a supply of the machining current to the electrode gap, even when a discharge is induced by the next application of the first voltage to the electrode gap, the second voltage control unit prohibits application of a second voltage to the electrode gap.

A core moving device is provided, including a core adsorption holding part for adsorbing and moving a core cut out of a workpiece with a magnetic force of a magnet. The core adsorption holding part includes: a rod member, a distal end portion of which is constituted of the magnet; a bottomed cylindrical member which has a bottom surface on a distal end portion side and into which the rod member is inserted from a base end portion side; and a cylindrical member drive part which moves the bottomed cylindrical member forward, wherein the bottomed cylindrical member, on one hand, moves backward to adsorb the core to the magnet and, on the other hand, moves forward to remove the core adsorbed to the magnet.

A core moving device is provided, including a core adsorption holding part for adsorbing and moving a core cut out of a workpiece with a magnetic force of a magnet. The core adsorption holding part includes: a rod member, a distal end portion of which is constituted of the magnet; a bottomed cylindrical member which has a bottom surface on a distal end portion side and into which the rod member is inserted from a base end portion side; and a cylindrical member drive part which moves the bottomed cylindrical member forward, wherein the bottomed cylindrical member, on one hand, moves backward to adsorb the core to the magnet and, on the other hand, moves forward to remove the core adsorbed to the magnet.

To provide an electrode wire for electrical discharge machining including -brass and -brass arranged on an outer peripheral surface of a core and a method of manufacturing the electrode wire, capable of enhancing wire connection performance and cutting down manufacturing cost while trying to increase a processing speed. The electrode wire for electrical discharge machining according to this invention comprises: an external layer including -brass and -brass; and a core having an undulating shape formed at a boundary surface with the external layer. The -brass and the -brass are arranged densely and sparsely at the boundary surface of the undulating shape. The method of manufacturing an electrode wire for electrical discharge machining according to this invention comprises: a thermal processing step of executing thermal process on a base material under a predetermined thermal processing condition, the base material having a core with a zinc-coated surface; and a wire drawing step of drawing a base wire under a predetermined wire drawing condition provided with -brass and -brass formed at the surface of the core by the thermal process to make the -brass reach the core, thereby forming a boundary surface of the core with an external layer into an undulating shape.

To provide an electrode wire for electrical discharge machining including -brass and -brass arranged on an outer peripheral surface of a core and a method of manufacturing the electrode wire, capable of enhancing wire connection performance and cutting down manufacturing cost while trying to increase a processing speed. The electrode wire for electrical discharge machining according to this invention comprises: an external layer including -brass and -brass; and a core having an undulating shape formed at a boundary surface with the external layer. The -brass and the -brass are arranged densely and sparsely at the boundary surface of the undulating shape. The method of manufacturing an electrode wire for electrical discharge machining according to this invention comprises: a thermal processing step of executing thermal process on a base material under a predetermined thermal processing condition, the base material having a core with a zinc-coated surface; and a wire drawing step of drawing a base wire under a predetermined wire drawing condition provided with -brass and -brass formed at the surface of the core by the thermal process to make the -brass reach the core, thereby forming a boundary surface of the core with an external layer into an undulating shape.

The invention relates to a wire electrode (10) for the spark-erosive cutting of articles, comprising and electrically conductive core (2) and a jacket (5) surrounding the core (2), which jacket comprises at least on +-cover layer (6) that contains -brass and/or -brass. In order to provide a wire electrode that has improved cutting efficiency, according to the invention, the +-cover layer (6) forms a homogenous phase (7) of -brass and/or -brass in +-brass grains (8) having an +-phase and/or a +-phase are embedded.

An apparatus for an electrical discharge machine for milling a shaped cavity in a workpiece includes a hollow electrode having a metallic inner shell with at least one passage for receiving dielectric fluid. A layer including at least one brass alloy is provided over the inner sheel and exhibits a zinc content greater than a zinc content of the inner shell.

An apparatus for an electrical discharge machine for milling a shaped cavity in a workpiece includes a hollow electrode having a metallic inner shell with at least one passage for receiving dielectric fluid. A layer including at least one brass alloy is provided over the inner sheel and exhibits a zinc content greater than a zinc content of the inner shell.