A wire electrical discharge machine includes an upper wire guide and a lower wire guide supporting a wire electrode, a probe provided on an upper guide block having the upper wire guide, an offset storage unit for storing an offset amount from the upper wire guide to the probe, a position shift drive unit for changing the relative position between the table, and the upper and lower wire guides, a drive controller for controlling the position shift drive unit, a contact position calculator for calculating a contact position that is a position of the probe when it comes in contact, and a machining start position calculator for calculating a machining start position of the wire electrode, based on at least two contact positions and the offset amount. The drive controller controls the position shift drive unit so that the position of the wire electrode becomes the machining start position.

A wire electrical discharge machine includes an upper wire guide and a lower wire guide supporting a wire electrode, a probe provided on an upper guide block having the upper wire guide, an offset storage unit for storing an offset amount from the upper wire guide to the probe, a position shift drive unit for changing the relative position between the table, and the upper and lower wire guides, a drive controller for controlling the position shift drive unit, a contact position calculator for calculating a contact position that is a position of the probe when it comes in contact, and a machining start position calculator for calculating a machining start position of the wire electrode, based on at least two contact positions and the offset amount. The drive controller controls the position shift drive unit so that the position of the wire electrode becomes the machining start position.

A wire electrical discharge machine determines the position of an endface of a workpiece by relatively moving a wire electrode toward the workpiece. The wire electrical discharge machine includes: a voltage application control unit configured to continuously apply voltage pulses between the wire electrode and the workpiece; a voltage detection unit configured to detect a voltage between the wire electrode and the workpiece; a pulse occurrence ratio calculation unit configured to calculate a pulse occurrence ratio that is a ratio of the number of the voltage pulses detected by the voltage detection unit to the number of the voltage pulses applied per a predetermined time by the voltage application control unit; and an endface position determination unit configured to determine the position of the endface of the workpiece based on the pulse occurrence ratio.

A wire electrical discharge machine determines the position of an endface of a workpiece by relatively moving a wire electrode toward the workpiece. The wire electrical discharge machine includes: a voltage application control unit configured to continuously apply voltage pulses between the wire electrode and the workpiece; a voltage detection unit configured to detect a voltage between the wire electrode and the workpiece; a pulse occurrence ratio calculation unit configured to calculate a pulse occurrence ratio that is a ratio of the number of the voltage pulses detected by the voltage detection unit to the number of the voltage pulses applied per a predetermined time by the voltage application control unit; and an endface position determination unit configured to determine the position of the endface of the workpiece based on the pulse occurrence ratio.

A wire electrical discharge machine for machining a workpiece by generating electric discharge at a discharge gap between the workpiece and a wire electrode includes: a machining current setting unit for setting the magnitude of a normal machining current depending on the discharge gap state at application of a discharge induction voltage at the previous time or previous times; and a machining current control unit configured to control a main discharge circuit so as to supply the normal machining current to the discharge gap when the present discharge gap state is the normal state, control the main discharge circuit so as to supply a short-circuit machining current smaller than a predetermined current to the gap when the discharge gap state is the short-circuited state, and control the main discharge circuit so as not to supply any machining current to the gap when the discharge gap state is the open state.

A wire electrical discharge machining apparatus includes a servo controller that controls the relative speed of a wire electrode in relation to a workpiece, in accordance with a machining parameter; a machining electrical current control unit that controls the electrical discharge energy produced between poles; an electrical discharge determination unit that determines whether electrical discharge has occurred between the poles within a unit time; and a machining parameter setting unit that sets a machining parameter, which is for during the approach to a machining end surface, to a first parameter, and sets the machining parameter to a second parameter when the number of times that electrical discharge has been determined to have occurred has reached a prescribed number of times.

A wire electrical discharge machining apparatus includes a servo controller that controls the relative speed of a wire electrode in relation to a workpiece, in accordance with a machining parameter; a machining electrical current control unit that controls the electrical discharge energy produced between poles; an electrical discharge determination unit that determines whether electrical discharge has occurred between the poles within a unit time; and a machining parameter setting unit that sets a machining parameter, which is for during the approach to a machining end surface, to a first parameter, and sets the machining parameter to a second parameter when the number of times that electrical discharge has been determined to have occurred has reached a prescribed number of times.

This wire elective discharge machine includes: a relative movement control unit that performs an end surface detection operation a predetermined number of times; a storage control unit that stores, in a storage unit, a relative location of a wire electrode to a workpiece table when it is determined that a wire electrode is in contact with a workpiece in each end surface detection operation; and a data extraction unit that extracts, as effective data, a plurality of relative locations located in the order of a predetermined range in a middle when the plurality of relative locations are arranged in ascending order; and an end surface location determination unit that determines the location of an end surface of the workpiece on the basis of the effective data.

This wire elective discharge machine includes: a relative movement control unit that performs an end surface detection operation a predetermined number of times; a storage control unit that stores, in a storage unit, a relative location of a wire electrode to a workpiece table when it is determined that a wire electrode is in contact with a workpiece in each end surface detection operation; and a data extraction unit that extracts, as effective data, a plurality of relative locations located in the order of a predetermined range in a middle when the plurality of relative locations are arranged in ascending order; and an end surface location determination unit that determines the location of an end surface of the workpiece on the basis of the effective data.

An electrical discharge machining system includes a semiconductor workpiece, a voltage source, an EDM tool, and an illumination system. The illumination system is configured to illuminate the semiconductor workpiece in order to increase the conductivity of the semiconductor workpiece. The voltage source establishes an electric potential difference between the workpiece and the EDM tool while the illumination system illuminates the semiconductor workpiece. The electric potential difference is such that an electrical discharge occurs between the workpiece and the EDM tool, thereby removing material from the workpiece.