To automatically change and set machining conditions suitable for a plate thickness even when machining paths of a rough machining step and an end surface finishing step are different in level difference machining in which the plate thickness changes during machining. In a wire electric discharge machining method and a wire electric discharge machining apparatus of the disclosure, an XY-plane of a workpiece stand is divided into small regions to form a plurality of divided regions, and a plate thickness of the workpiece is detected and stored in association with the divided regions. Thereafter, whether there is a level difference ahead of a traveling direction of a machining path is estimated according to plate thickness information associated with the divided regions and a plate thickness of the workpiece at a current machining position, and machining conditions are changed.

A narrow-hole electric discharge machine (100) is provided with: a pump (52) with a variable flow rate that supplies machining fluid to a pipe electrode (28); a flow rate sensor (56) provided in a pipe between the pump (52) and the pipe electrode (28), the flow rate sensor (56) being configured to detect the flow rate of the machining fluid flowing through the pipe; a storage unit (58b) that stores a set flow rate of a jet flow suitable for each cross-sectional size of a plurality of pipe electrodes (28) having different cross-sectional sizes; and a pump control unit (58a) that drives the pump (52) such that the value detected by the flow rate sensor (56) is kept at the set flow rate stored in the storage unit (58b) suitable for the cross-sectional size of the pipe electrode (28) currently attached to a main shaft (114).

A method and device for electrical discharge machining (EDM) a workpiece by means of a train of machining pulses. During the machining time the machining pulses are applied to the working gap between workpiece and electrode. An open voltage is first applied, and it is increased to a second open voltage level if a discharge does not occur within a waiting time d.sub.0, and further increased to a third open voltage level if a discharge does not occur within a second waiting time d.sub.1.

An average product of the actual open voltages times the partial ignition delays is computed and subtracted from the product of a reference open voltage times the total ignition delay, and the servo setpoint value is adjusted accordingly. The actual axes positions are sampled in real time and the discharge electrical parameters are adjusted accordingly. The discharge electrical parameters can be adjusted according to the duration of d0 and d1.

A method and device for electrical discharge machining (EDM) a workpiece by means of a train of machining pulses. During the machining time the machining pulses are applied to the working gap between workpiece and electrode. An open voltage is first applied, and it is increased to a second open voltage level if a discharge does not occur within a waiting time d.sub.0, and further increased to a third open voltage level if a discharge does not occur within a second waiting time d.sub.1.

An average product of the actual open voltages times the partial ignition delays is computed and subtracted from the product of a reference open voltage times the total ignition delay, and the servo setpoint value is adjusted accordingly. The actual axes positions are sampled in real time and the discharge electrical parameters are adjusted accordingly. The discharge electrical parameters can be adjusted according to the duration of d0 and d1.

A wire electrical discharge machine controls a second motor unit including motors for feeding a wire electrode in a wire running direction in which the wire electrode extends, so as to feed the wire electrode at a set feed rate during a machining period from a first time point at which the wire electrode moving relative to a workpiece in a direction intersecting the wire running direction is estimated to enter the workpiece, to a second time point at which the wire electrode is estimated to exit the workpiece. The second motor unit is controlled so as to feed the wire electrode at a feed rate lower than the set feed rate during at least one of a first non-machining period from a processing start time point to the first time point and a second non-machining period from the second time point to a processing end time point.

A wire electrical discharge machine controls a second motor unit including motors for feeding a wire electrode in a wire running direction in which the wire electrode extends, so as to feed the wire electrode at a set feed rate during a machining period from a first time point at which the wire electrode moving relative to a workpiece in a direction intersecting the wire running direction is estimated to enter the workpiece, to a second time point at which the wire electrode is estimated to exit the workpiece. The second motor unit is controlled so as to feed the wire electrode at a feed rate lower than the set feed rate during at least one of a first non-machining period from a processing start time point to the first time point and a second non-machining period from the second time point to a processing end time point.

An electrical discharge machining apparatus and an electrical discharge machining method with adjustable machining parameters comprise a carrier and an electrical discharge machining (EDM) unit. The carrier is used for placing a to-be-machined object defined with a machining target area. A discharge electrode of the electrical discharge machining (EDM) unit is used to cut the machining target area of the to-be-machined object along a first cutting direction with at least one machining parameter, the machining parameter is correspondingly adjusted when a specified parameter of the to-be-machined object changes to a first numerical value, thereby using the adjusted machining parameter to perform a second cutting step on the machining target area of the to-be-machined object. A segmented cutting technology for solving a problem that a cutting speed (mm.sup.2/min) is slowed down and a total cutting time is prolonged due to changes of the specified parameter of electrical discharge machining cutting.

An electrical discharge machining apparatus and an electrical discharge machining method with adjustable machining parameters comprise a carrier and an electrical discharge machining (EDM) unit. The carrier is used for placing a to-be-machined object defined with a machining target area. A discharge electrode of the electrical discharge machining (EDM) unit is used to cut the machining target area of the to-be-machined object along a first cutting direction with at least one machining parameter, the machining parameter is correspondingly adjusted when a specified parameter of the to-be-machined object changes to a first numerical value, thereby using the adjusted machining parameter to perform a second cutting step on the machining target area of the to-be-machined object. A segmented cutting technology for solving a problem that a cutting speed (mm.sup.2/min) is slowed down and a total cutting time is prolonged due to changes of the specified parameter of electrical discharge machining cutting.

A first modulation voltage is applied to a thin film. An amount of a change in the phase of a current carried through the thin film with respect to the phase of the first modulation voltage is compared with a threshold. Upon detecting that the amount of the change in the phase exceeds the threshold is detected, the application of the first modulation voltage is stopped. Thus, a nanopore is formed on the thin film at high speed.

A method for the monitoring of a wire electrical discharge machining (WEDM) process, the method comprising the steps of: setting a unit observation length for the signal acquisition, continuously acquiring at least one process signal which is representative of an amount of material removed by at least one discharge and the position (X;Y) of said at least one discharge, and determining, based on said at least one process signal and one or more properties of a current machining, a cumulated amount of material removed per unit observation length along a machining path, including amounts of material removed by travelling in a forward cutting direction and amounts of material removed by travelling in a reverse cutting direction.