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 method for preprocessing data related to a tool electrode, which is applied in an EDM machine to manufacture a part comprises: generating an electrode model for the tool electrode based on the geometry of the part; generating the cavity shape model (volume of the part to erode), combining the electrode and cavity shape model, dividing the resulting model into a plurality of slices in a plurality of parallel planes, wherein at least one slice is composed of at least two sections, which are topologically disconnected; and generating for each slice a slice-geometry data, and generating an electrode-geometry data including the slice-geometry data.

A method for preprocessing data related to a tool electrode, which is applied in an EDM machine to manufacture a part comprises: generating an electrode model for the tool electrode based on the geometry of the part; generating the cavity shape model (volume of the part to erode), combining the electrode and cavity shape model, dividing the resulting model into a plurality of slices in a plurality of parallel planes, wherein at least one slice is composed of at least two sections, which are topologically disconnected; and generating for each slice a slice-geometry data, and generating an electrode-geometry data including the slice-geometry data.

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.

This small-hole electric discharge machining machine for electric discharge machining of a workpiece by use of a rod-like or pipe-like electrode is equipped with: a first support part for supporting the base side of the electrode; a second support part for supporting the tip side of the electrode; and an intermediate guide device that is disposed between the first support part and the second support part, and guides the electrode. The intermediate guide device is equipped with: a guide part that has an open form and a closed form, and guides the electrode when in the closed form; a driving means for causing the guide part to transition between the open form and the closed form; and a biasing means for biasing the guide part in the closing direction when the guide part is in the closed form.

In a wire electric discharge machine, time from application of a voltage to a machining gap between a workpiece and a wire electrode until occurrence of electric discharge is measured as a discharge delay time, and the measured discharge delay time is integrated over a predetermined measurement period to calculate a discharge delay integrated time. Further, the number of times of the voltage application in the measurement period is counted. An average discharge delay time per voltage application in the measurement period is calculated from the discharge delay integrated time and the number of times of voltage application. The movement of the wire electrode with respect to the workpiece is controlled on the basis of the average discharge delay time.

In a wire electric discharge machine, time from application of a voltage to a machining gap between a workpiece and a wire electrode until occurrence of electric discharge is measured as a discharge delay time, and the measured discharge delay time is integrated over a predetermined measurement period to calculate a discharge delay integrated time. Further, the number of times of the voltage application in the measurement period is counted. An average discharge delay time per voltage application in the measurement period is calculated from the discharge delay integrated time and the number of times of voltage application. The movement of the wire electrode with respect to the workpiece is controlled on the basis of the average discharge delay time.

The object of the present invention is to make it possible to maintain a stable electric discharge and to achieve a stable quality and machining performance even when a work having a non-uniform composition is machined. A wire electric discharge machining device performs electric discharge machining on a work while controlling an inter-electrode distance between a wire and the work based on an inter-electrode voltage between the wire and the work so as to match a set target voltage. The wire electric discharge machining device includes an inter-electrode voltage measuring unit that measures the inter-electrode voltage, an actual amplitude calculating unit that calculates an amplitude of the measured inter-electrode voltage, and a target voltage correcting unit that corrects the target voltage in such a way that the calculated amplitude approaches the target amplitude that is set to a value larger than zero.

The object of the present invention is to make it possible to maintain a stable electric discharge and to achieve a stable quality and machining performance even when a work having a non-uniform composition is machined. A wire electric discharge machining device performs electric discharge machining on a work while controlling an inter-electrode distance between a wire and the work based on an inter-electrode voltage between the wire and the work so as to match a set target voltage. The wire electric discharge machining device includes an inter-electrode voltage measuring unit that measures the inter-electrode voltage, an actual amplitude calculating unit that calculates an amplitude of the measured inter-electrode voltage, and a target voltage correcting unit that corrects the target voltage in such a way that the calculated amplitude approaches the target amplitude that is set to a value larger than zero.