Electric discharge machining is halted during machining program operation, and a position of the machining halt point is stored. A wire electrode is retreated from the machining halt point to an arbitrary position in which a short-circuit with a workpiece is removed (retreat position), by interrupt operation in which axis movement is performed manually. Then, a return is made from the retreat position to the machining halt point while electric discharge machining is performed, machining program operation is started from the machining halt point, and electric discharge machining is restarted.

An electrical discharge machine includes: a work tank to store the working fluid in order to perform electrical discharge machining; a sound collector to collect sound generated by electrical discharge machining and transmitted through the working fluid stored in the work tank; and a controller to perform a predetermined operation based on sound information collected by the sound collector.

An electrical discharge machine includes: a work tank to store the working fluid in order to perform electrical discharge machining; a sound collector to collect sound generated by electrical discharge machining and transmitted through the working fluid stored in the work tank; and a controller to perform a predetermined operation based on sound information collected by the sound collector.

A machining condition setter in a wire electrical discharge machine, sets up: as machining conditions, a first machining condition for enabling the core fixing function in a first section on the upstream side; a second machining condition for enabling formation of a slot in the workpiece in a second section on the downstream side; and a medial machining condition that is different from the first machining condition and the second machining condition in a medial section located between the first section and the second section.

A machining condition setter in a wire electrical discharge machine, sets up: as machining conditions, a first machining condition for enabling the core fixing function in a first section on the upstream side; a second machining condition for enabling formation of a slot in the workpiece in a second section on the downstream side; and a medial machining condition that is different from the first machining condition and the second machining condition in a medial section located between the first section and the second section.

In a wire electric discharge machine of the present invention, a control variable detection apparatus is an inter-pole voltage detection apparatus and detects an average inter-pole voltage as a control variable correlating with an inter-pole distance. The wire electric discharge machine comprises a machining feed speed calculation apparatus determining a machining feed speed on the basis of a deviation between target voltage set by a target value setting apparatus 7 and the average inter-pole voltage so as to eliminate the deviation. The wire electric discharge machine further comprises a feed speed distribution apparatus and a relative movement apparatus. The inter-pole distance can be kept constant by the relative movement of a wire electrode and a workpiece made on the basis of a command of thus determined machining feed speed.

A double resistor-capacitor discharge machining system comprises an electrode, a discharge circuit module and a control unit. The electrode is configured to process a workpiece. The discharge circuit module comprises a first discharge circuit and a second discharge circuit. The first discharge circuit comprises a first resistor, a first capacitor and a first transistor and configured to generate a first discharge current. The second discharge circuit is connected in parallel with the first discharge circuit and includes a second resistor, a second capacitor and a second transistor to generate a second discharge current. The capacitance value of the first capacitor is greater than that of the second capacitor. The control unit is configured to respectively control the first transistor and the second transistor, and control the discharge circuit module to alternatively output the first discharge current and the second discharge current to the electrode.

A double resistor-capacitor discharge machining system comprises an electrode, a discharge circuit module and a control unit. The electrode is configured to process a workpiece. The discharge circuit module comprises a first discharge circuit and a second discharge circuit. The first discharge circuit comprises a first resistor, a first capacitor and a first transistor and configured to generate a first discharge current. The second discharge circuit is connected in parallel with the first discharge circuit and includes a second resistor, a second capacitor and a second transistor to generate a second discharge current. The capacitance value of the first capacitor is greater than that of the second capacitor. The control unit is configured to respectively control the first transistor and the second transistor, and control the discharge circuit module to alternatively output the first discharge current and the second discharge current to the electrode.