A controller for a wire electrical discharge machine that machines a workpiece along a machining path by relatively moving the workpiece and a wire electrode to each other while generating electric discharge across an electrode gap between the workpiece and the wire electrode, includes: a machining surface state acquisition unit configured to acquire the state of a machining surface of the workpiece; and a machining path setting unit configured to specify an excessively machined portion of the workpiece based on the acquired state of the machining surface and set an approach point at which the wire electrode is made to approach the machining surface from a machining start point, so as to avoid the excessively machined portion.

A controller for a wire electrical discharge machine that machines a workpiece along a machining path by relatively moving the workpiece and a wire electrode to each other while generating electric discharge across an electrode gap between the workpiece and the wire electrode, includes: a machining surface state acquisition unit configured to acquire the state of a machining surface of the workpiece; and a machining path setting unit configured to specify an excessively machined portion of the workpiece based on the acquired state of the machining surface and set an approach point at which the wire electrode is made to approach the machining surface from a machining start point, so as to avoid the excessively machined portion.

A guide unit that stretches a wire electrode and guides the wire electrode to a machinable range section where a workpiece is placed includes: a first wire guide and a second wire guide; a first support element disposed spaced apart between the first and second wire guides and disposed spaced apart from the first wire guide, which determines a passage location of the wire electrode; and a second support element disposed spaced apart from the second wire guide, which determines a passage location of the wire electrode. The first support element has a variable direction relative to the first wire guide, the machinable range section of the wire electrode is formed of a portion stretched between the first and second support elements, and the wire electrode can tilt with respect to the wire electrode supplied from the supply unit.

A guide unit that stretches a wire electrode and guides the wire electrode to a machinable range section where a workpiece is placed includes: a first wire guide and a second wire guide; a first support element disposed spaced apart between the first and second wire guides and disposed spaced apart from the first wire guide, which determines a passage location of the wire electrode; and a second support element disposed spaced apart from the second wire guide, which determines a passage location of the wire electrode. The first support element has a variable direction relative to the first wire guide, the machinable range section of the wire electrode is formed of a portion stretched between the first and second support elements, and the wire electrode can tilt with respect to the wire electrode supplied from the supply unit.

An electric discharge machine includes an electrode, a shaft-feed driving unit that, a voltage/current applying unit, a shaft-feed control unit that causes the shaft-feed driving unit to perform a jump operation, and a machining-condition setting and changing unit that sets a voltage applied between the electrode and a workpiece and an electric current flowing between the electrode and the workpiece. The machining-condition setting and changing unit determines whether the electric discharge between the electrode and the workpiece stabilizes after the jump operation ends and, in at least a part of a period before determining that the electric discharge stabilizes, sets at least one of the voltage and the electric current to a condition in which electric discharge more easily occurs than in the condition in applying the electric discharge machining.

An electric discharge machine includes an electrode, a shaft-feed driving unit that, a voltage/current applying unit, a shaft-feed control unit that causes the shaft-feed driving unit to perform a jump operation, and a machining-condition setting and changing unit that sets a voltage applied between the electrode and a workpiece and an electric current flowing between the electrode and the workpiece. The machining-condition setting and changing unit determines whether the electric discharge between the electrode and the workpiece stabilizes after the jump operation ends and, in at least a part of a period before determining that the electric discharge stabilizes, sets at least one of the voltage and the electric current to a condition in which electric discharge more easily occurs than in the condition in applying the electric discharge machining.

A control device includes a speed setting unit configured to set a relative movement speed of a wire electrode with respect to a workpiece depending on the average of gap voltage per unit time, i.e., average gap voltage, and set the relative movement speed so as to move the wire electrode backward when the average gap voltage is less than a threshold, and a map compensation unit configured to change the threshold from a first threshold that is set when the amount of change in the average gap voltage is lower than a predetermined variation, to a second threshold that is greater than the first threshold, when the average gap voltage has changed in a decreasing direction and the amount of change in the average gap voltage becomes equal to or greater than the predetermined variation.

A control device includes a speed setting unit configured to set a relative movement speed of a wire electrode with respect to a workpiece depending on the average of gap voltage per unit time, i.e., average gap voltage, and set the relative movement speed so as to move the wire electrode backward when the average gap voltage is less than a threshold, and a map compensation unit configured to change the threshold from a first threshold that is set when the amount of change in the average gap voltage is lower than a predetermined variation, to a second threshold that is greater than the first threshold, when the average gap voltage has changed in a decreasing direction and the amount of change in the average gap voltage becomes equal to or greater than the predetermined variation.

This wire electric discharge machine comprises: an average interelectrode voltage calculation unit which calculates an average interelectrode voltage between electrodes; a correction unit which determines a corrected average interelectrode voltage in accordance with the speed of machining performed on a workpiece by a wire electrode; and a motor control unit which keeps constant the magnitude of the distance between electrodes during machining, by controlling an X-axis motor and a Y-axis motor on the basis of the corrected average interelectrode voltage. The correction unit determines a corrected average interelectrode voltage according to a formula in which the average interelectrode voltage is expressed as a numerator and a value, obtained by using a coefficient as a base and the machining speed as an exponent, is expressed as a denominator.

This wire electric discharge machine comprises: an average interelectrode voltage calculation unit which calculates an average interelectrode voltage between electrodes; a correction unit which determines a corrected average interelectrode voltage in accordance with the speed of machining performed on a workpiece by a wire electrode; and a motor control unit which keeps constant the magnitude of the distance between electrodes during machining, by controlling an X-axis motor and a Y-axis motor on the basis of the corrected average interelectrode voltage. The correction unit determines a corrected average interelectrode voltage according to a formula in which the average interelectrode voltage is expressed as a numerator and a value, obtained by using a coefficient as a base and the machining speed as an exponent, is expressed as a denominator.