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.

Electrodes for and methods of electrical discharge machining are provided. For example, a method for forming a feature in a ceramic matrix composite (CMC) component comprises repeatedly advancing an electrode into and retracting the electrode from the CMC component until a desired depth is reached, where the electrode has a head end, a tip end, and a shaft extending from the head end to the tip end. The shaft has a first side and a second side each recessed inward such that the head end and the tip end are wider than the shaft. A method for forming a feature in a CMC component also may include feeding a dielectric fluid into the feature utilizing the recessed sides. In some embodiments, electrodes may include a shaft extending from a head end to a tip end and a central plane, where the shaft is recessed widthwise toward the central plane.

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 simulated current generation unit is connected in series to a power supply device for an electric discharge machine in a state in which a contact and a contact are in contact with each other and generates a simulated current (I.sub.sim) for simulating current caused by dielectric breakdown of a discharge gap constituted by a workpiece and a pipe electrode, which face each other with a predetermined gap in order to perform electrical discharge machining of the workpiece by a narrow-hole electric discharge machine, based on an applied voltage of the power supply device for an electric discharge machine. An NC device judges the presence or absence of an abnormality of the power supply device for an electric discharge machine based on the simulated current (I.sub.sim) detected by a current detection unit.

An ECM method involves the use of a thin hollow electrode assembly that carries the electrolyte within and that is advanced relatively to the workpiece. The small profile of the electrode results in a minimal removal of metal in forming the desired rotor or stator shape. The electrode profile allows significant power consumption reduction or increased machining speed for a given rate of power input. The electrode can be a unitary ring shape or can be made of segments that are placed adjacent each other so that a continuous shape is cut. Not all the lobes of the stator or rotor have to be cut in the same pass. Electrode segments can be used to sequentially provide the desired lobe count in separate passes. The lobe shapes in the electrode can be slanted to get the desired rotor or stator pitch or they can be aligned with the workpiece axis.

The present invention relates to a method for introducing a recess (3) into a workpiece (1), wherein the recess (3) is introduced with a processing cathode (2) by electrochemical ablation, wherein a flank (1.3) delimiting the recess (3) is exposed with the ablation, which flank extends from a first surface (1.1) of the workpiece (1) in the direction of an opposite second surface (1.2) of the workpiece (1), wherein a protective anode (7.1, 7.2) is arranged on at least one of the surfaces (1.1, 1.2) during removal, which protective anode is associated with the flank (1.3) and bears against the at least one surface (1.1, 1.2) in electrical contact with the workpiece (1), and wherein the protective anode (7.1, 7.2) is offset outwards relative to the flank (1.3), i.e. away from the recess (3).

Electrodes for and methods of electrical discharge machining are provided. For example, a method for forming a feature in a ceramic matrix composite (CMC) component comprises repeatedly advancing an electrode into and retracting the electrode from the CMC component until a desired depth is reached, where the electrode has a head end, a tip end, and a shaft extending from the head end to the tip end. The shaft has a first side and a second side each recessed inward such that the head end and the tip end are wider than the shaft. A method for forming a feature in a CMC component also may include feeding a dielectric fluid into the feature utilizing the recessed sides. In some embodiments, electrodes may include a shaft extending from a head end to a tip end and a central plane, where the shaft is recessed widthwise toward the central plane.

An electric discharge machining method for machining a core pin for a resin die using an electric discharge machine including a secondary electrode for molding of a round-bar shaped machining electrode. The electric discharge machining method includes a step of executing generating electric discharge machining for cutting out a schematic shape of the core pin from a work with the machining electrode, a step of transferring a shape element of the secondary electrode to the machining electrode and molding the machining electrode for diesinking electric discharge machining, and a step of applying the diesinking electric discharge machining to the work cut out in the schematic shape of the core pin using the machining electrode molded for the diesinking electric discharge machining.

A tool-electrode for machining an imprint in a conductive part by sinking-die type electrical-discharge machining. It includes a conductive body having lower and upper opposite surfaces, two opposite main lateral surfaces, lower and upper areas superposed according to a die-sinking direction of the tool-electrode, the lower area comprising the lower surface and a portion of the main lateral surfaces, the upper area including the upper surface and the other portion of the main lateral surfaces. The body is provided, at least in the lower area, with a plurality of openings selected from among channels or slots; a channel is an opening which opens onto at least one of the upper and lower surfaces; a slot is an opening which opens onto the lower surface and onto the two main lateral surfaces.

An electric discharge machining method for machining a core pin for a resin die using an electric discharge machine including a secondary electrode for molding of a round-bar shaped machining electrode. The electric discharge machining method includes a step of executing generating electric discharge machining for cutting out a schematic shape of the core pin from a work with the machining electrode, a step of transferring a shape element of the secondary electrode to the machining electrode and molding the machining electrode for diesinking electric discharge machining, and a step of applying the diesinking electric discharge machining to the work cut out in the schematic shape of the core pin using the machining electrode molded for the diesinking electric discharge machining.