A drive circuit configured to drive a load. The drive circuit comprises a transformer. The transformer comprises a transformer primary comprising one or more primary windings connected to arms that pass through a magnetic material. The transformer also comprises a transformer secondary comprising secondary windings connected to planar secondary conductors which pass through the inside of the arms. The drive circuit also comprises a voltage source configured to apply a voltage across the transformer primary.

A spark erosion machine includes a frame with a space for spark erosion of a workpiece, a wire for cutting by spark erosion, and a wire guide head for guiding the wire across the workpiece, so as to detach an offcut from it; an offcut support mounted movably relative to the guide head, the support being configured to move at least between a retention position under the spark erosion space, where it can collect the offcut, and a retracted position; and an offcut extractor.

A spark erosion machine includes a frame with a space for spark erosion of a workpiece, a wire for cutting by spark erosion, and a wire guide head for guiding the wire across the workpiece, so as to detach an offcut from it; an offcut support mounted movably relative to the guide head, the support being configured to move at least between a retention position under the spark erosion space, where it can collect the offcut, and a retracted position; and an offcut extractor.

The disclosure provides a wire electric discharge machine which has a simple configuration and can make a wire electrode fed to a machining position rotate around an axis. The wire electric discharge machine for machining a workpiece includes an upper wire guide and a lower wire guide, which stretch a wire electrode therebetween, and a rotator. A position of the rotator is changed, whereby the wire electrode is rotated around an axis.

A method for the machining of workpieces (11) and inspection of the processed workpiece surface in a machine tool (1), preferably a die sinking electrical discharge machine. The method uses at least one machining process interruption during which the processed surface of the workpiece (11) is inspected. Within said machining process interruption, at least one image of the processed workpiece surface is captured on the machine tool (1) by means of a digital camera (12). The images are processed by one or two pattern recognition algorithm (PRA D, PRA S), which were previously trained to determine the surface characteristics such as roughness parameters, functional surface features and/or characteristic defects of the processed workpiece surface captured on that at least one image. The determined surface characteristics are used to resume the processing of the workpiece surface with or without adjusting the processing parameters.

A method for the machining of workpieces (11) and inspection of the processed workpiece surface in a machine tool (1), preferably a die sinking electrical discharge machine. The method uses at least one machining process interruption during which the processed surface of the workpiece (11) is inspected. Within said machining process interruption, at least one image of the processed workpiece surface is captured on the machine tool (1) by means of a digital camera (12). The images are processed by one or two pattern recognition algorithm (PRA D, PRA S), which were previously trained to determine the surface characteristics such as roughness parameters, functional surface features and/or characteristic defects of the processed workpiece surface captured on that at least one image. The determined surface characteristics are used to resume the processing of the workpiece surface with or without adjusting the processing parameters.

Circuitry for driving a variable capacitive load comprising: a variable capacitive load; a digital control circuit configured to generate a digital drive signal; and a drive circuit configured to convert the digital drive signal into an analogue drive signal, the analogue drive signal forming a drive waveform for charging the variable capacitive load, the drive circuit comprising a slewing circuit configured to drive a time dependent voltage component of the drive waveform; wherein the digital control circuit is configured to modify the digital drive signal for each charging cycle so as to match the time dependent voltage component of the drive waveform to the variable capacitive load.

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.

A wire electrical discharge machine includes: a travelling route formed of multiple divisional regions, through which a wire electrode is fed by an auto wire feeding mechanism; and a memory storing failure evaluation reference data on the auto wire feeding for every divisional region. The wire electrical discharge machine detects failure of the auto wire feeding and locate the tip position of the wire electrode at the time of failure and causes a controller to determine whether to perform or stop retry of the auto wire feeding based on the located tip position and the failure evaluation reference data for every divisional region.

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.