Abstract: The cathode includes a machining surface, at least a portion of which comprises alternate layers or lamina of conductive and non-conductive material whose spacing and thickness are selected to reduce over-cutting on the workpart surface.

Abstract: An apparatus and method are disclosed for electrochemically finishing or smoothing an irregular anode surface of a conductive metal part while removing a minimum of metal from the anode surface. The smoothing or finishing of irregular surfaces, such as burred surfaces, for example, is achieved by mounting the face of a cathode member adjacent the anode surface to be finished to define a minimum gap therebetween and moving the face relative to the anode surface while subjecting the face and anode surface to a flow of electrolyte fluid through the gap. An electrical power means is coupled to the face and anode surface for generating a current therebetween through the electrolyte for electrochemically finishing the burred anode surface with a minimum removal of metal therefrom.

Abstract: An automatic TW (traveling-wire) electroerosion machining system for machining a plurality of workpieces of different types required to acquire different contours includes a TW machine having a wire setting unit and located adjacent a predetermined path. A work dispensing unit successively dispenses the different workpieces onto the path from a store thereof located adjacent the path. This unit and a work handling and transfer unit operate under control commands from an NC unit and, in conjunction with the TW machine with the wire setting unit to carry out a plurality of work processing operations sequentially. In each operation, each individual workpiece selected from the store is transferred as it is carried on a pallet for loading onto and unloading from the TW machine. The electrode setting unit on the machine acts both to form a start hole and thread a wire-type electrode through the formed hole in the workpiece.

Abstract: A spark erosion machine having a machine table fixed to the machine upright and on which can be arranged a working container for the dielectric fluid by joining a vertically movable, cross-sectionally C-shaped component to an L-shaped component in longitudinal section. The L-shaped component comprises a fixed vertical wall element forming the rear wall of the working container and the machine table plate, which is detachably connected to the fixed wall element through a seal. The machine table plate is fixable in the reference plane of the machine table by means of rapid fastening and centering devices.

Abstract: Apparatus for the electrical discharge machining of a circumferential section from the wall of a bore in a metallic cylinder has a housing and a wire electrode guide disposed within the housing. A wire feeder continuously feeds a wire electrode to the wire electrode guide. The wire electrode guide also moves the wire electrode radially into and out of an axial groove extending between the circumferential grooves in the bore wall. The wire electrode guide further moves a wire electrode, when the wire electrode is disposed within the axial groove in the bore wall, between a first position in which the distance along the bore wall between the point where the wire electrode enters and leaves the axial groove is the same as the distance between the circumferential grooves, and a second position in which the distance along the wall of the bore between the point where the wire electrode enters and leaves the axial groove is greater than the distance between the circumferential grooves.

Abstract: An electrolyte chamber for an electrochemical machine tool includes oposed cathodes movable in respective directions toward one another and toward a workpart therebetween and in respective transverse directions and sealing pistons each movable in the electrolyte chamber in a respective transverse direction to sealingly engage the side of a respective one of the cathodes. An electrolyte inlet is disposed between the sealing pistons, and the sealing pistons direct electrolyte flow toward the workpart between the workpart and cathodes and prevent electrolyte from by-passing around the cathodes.

Abstract: The present invention relates to a method and an apparatus for the manufacture of dental prostheses by means of an electroerosion process by using two template electrodes for erosive excavation. The dental prosthesis to be inserted is made directly from solid material which has not been previously worked. The negative templates of the dental prosthesis contained in the template electrodes can also be made by the electroerosion method. The manufacture of the dental prosthesis can be accomplished by a simultaneous movement of the two template electrodes or by manufacture of the two form halves of the dental prosthesis at different times.

Abstract: An electric spark machining apparatus includes a cooling device which is arranged so that machining liquid pumped up from a reservoir and fed to an electric spark machine is controlled in temperature to minimize a temperature difference between machining liquid entering into the electric spark machine and the latter.

Abstract: An EDM method and apparatus in which a succession of machining voltage pulses of regular polarity is applied from a first pulse supply between a tool electrode and a workpiece to produce erosive discharges across the EDM gap in the presence of a water flushing medium. A second pulse supply is also provided to apply one or more voltage pulses of reverse polarity during a time interval between successive machining voltage pulses of regular polarity across the EDM gap. A sensing circuit is provided to respond to a gap open-circuit condition and to provide an output signal representative thereof. The output signal is used to act on the second pulse supply so as to selectively trigger such one or more reverse-polarity pulses, or to temporarily modify the parameters of the reverse-polarity pulse or pulses, upon occurrence of the gap open-circuit condition.

Abstract: The instantaneous flow state of the scavenging medium in the cutting plant work gap is determined and operating parameters of the spark-erosive cutting process are regulated and/or controlled as a function thereof. These operating parameters include the generator machining parameters such as pulse magnitude, pulse duration and pulse interval; the relative feed rate of the tool electrode; and the supply of the scavenging medium. For this purpose, the cutting plant includes a device for pressure and/or suction scavenging of the work gap and a control device for adaptively controlling the operating parameters, including at least one sensor for determining the instantaneous flow state of the scavenging medium in the work gap and at least one control element.

Abstract: An electrode arrangement for the electrochemical metal erosion process for producing a radial cylindrical tooth system is provided by the present invention. This arrangement has a metal plate forming the electrode which is provided with a ring of tongues, and an insulator ring which is arranged radially resiliently and presses against the crests of the produced teeth. Burn-free radial cylindrical tooth systems with improved precision are produced with the electrode arrangement according to the invention.

Abstract: A traveling-wire electroerosion machine with nozzle assemblies on each side of the workpiece, has at least one of these nozzle assemblies formed with a rotatable outlet member with a caster-like formation engaging the workpiece surface to orient an inclined machining liquid orifice against the back of the wire electrode and in the direction of the machining front at an inclination to the linear wire travel path through the workpiece.

Abstract: A method and apparatus for electrochemical rifling of gun barrels and the like is disclosed. In one embodiment of the apparatus, an elongate pressure chamber for receiving electrolyte fluid under pressure is mounted in alignment with an anode gun barrel and in fluid communication therewith. A cathode rod rifling assembly is mounted in the pressure chamber in axial alignment with the gun barrel. Drive means simultaneously rotates the rifling assembly and moves it relative to the barrel for passage of the rifling assembly through the barrel along with the electrolyte fluid. In another embodiment, the rifling asembly comprises first and second adjacent segments joined on a plane. Each segment has peripheral, radially outwardly extending, circumferentially spaced strips of insulation which are out of alignment with, and overlap, one another along the plane. The overlapped regions define the width of the unetched portions or lands on the barrel.

Abstract: An analyzer for acid-soluble aluminum in a steel sample precisely controls the etching charge by monitoring the etching current level and integrating the current with time. Once a predetermined charge is reached, the etching current is terminated. In a preferred embodiment, the etching cell is stacked above the mixing and developing chamber such that etching fluid flow is by gravity between these elements.

Abstract: A wire cutting type electrical discharge machining system includes a wire supply device, an upper and lower electrode guides, and a wire take-up device for feeding a wire electrode so as to carry out the discharge machining on an electrically conductive workpiece. An improved wire-disconnection detecting device attached to the system includes a first and second wire-slack detecting members of metallic tube through which the wire is passed with a small distance formed therebetween, a wire-disconnection detecting circuits connected between the detecting members and the wire, including a power supply, and a sensor for sensing a flow of current from the power supply through the detecting members and the wire upon contact of the two due to a slack of the wire. A disconnection of the wire is detected when the flow of current is sensed by the sensor.

Abstract: A drilling rate and depth monitor is provided for determining the rate in which apertures are formed in a workpiece using an electro-chemical machining process. The drilling rate and depth monitor is particularly useful where the rate of aperture formation is extremely slow, i.e., less than one-thousandths of an inch per second. The drilling rate includes a position sensor coupled between a workholder and a movable member supporting a plurality of cathodic drilling tubes which yields a depth signal proportional to the distance between the drilling tubes and the surface of the workpiece. Differentiation means are responsive to the depth signal for producing a drilling rate signal and display means are provided for both the drilling rate and drilling depth.

Abstract: In electrochemically machining individual oversize blades of an integral bladed gas turbine engine rotor, opposed cathodes are initially offset in an electrolyte chamber relative to a selected machining position with the rotor outside the chamber skewed at an angle relative to the final position of the cathodes in the electrolyte chamber. The rotor and electrolyte chamber are then relatively moved in a vertical direction to position an individual blade to be machined in a workpart machining position in the chamber and concurrently one cathode is moved in a direction toward one side of the blade and the other cathode is moved in two other different directions, one toward the blade from the opposite side of the blade and the other transverse thereto, to position the cathodes in aligned relation on opposite sides of the blade at the machining position with blades adjacent the individual blade to be machined received in pockets in the cathodes without contact.

Abstract: An electrically conductive arbor indexer shaft is coupled to an indexing D.C. motor by an insulator connector and the indexer shaft in an indexed position is tightly gripped by a resilient electrically conductive clamp connected to an electrically conductive support to which a buss is engaged for supplying electrical current to the arbor via the indexer shaft, clamp and support. During the ECM process, a workpart on the arbor is made an anode by current passing through the arbor indexer shaft, clamp, support and buss with the resilient clamp insuring sufficient electrical coupling of the arbor indexer shaft to the other upstream current carrying components.

Abstract: Optoelectronic devices are produced as integrated chips which include elements to control optical signals and electronic elements to control the optical elements. An integrated chip includes optical wave guides with tapered ends to facilitate exit and entry of optical signals. The tapered ends are produced by photo-electrolytic etch using illumination of graded intensity, e.g. the penumbra of a shadow.

Abstract: An EDM method and system in which a DC output is pulsed to produce a succession of discrete, time-spaced, essentially unidirectional current pulses of a short duration not in excess of 10 microseconds for finish-machining a workpiece with a tool electrode across a fluid-flooded EDM gap, each of the discrete current pulses having an essentially half-cycle sinusoidally rising and falling current time characteristic and a peak current in excess of a predetermined current level. According to the invention, a peak current portion of each of the current pulses beyond the predetermined level is clipped to produce a reformed gap current pulse which is substantially square- or trapezoid-edged and has the predetermined current level.

Abstract: The device includes an electrode in the form of a cylindrical tube, an arrangement for causing an electrical discharge between the electrode and the workpiece, a support fixed to the workpiece and disposed at least partly inside the electrode for guiding the electrode in a direction perpendicular to the workpiece and electromagnetic structure placed inside the electrode to cause the electrode to vibrate.

Abstract: A six axis ECM machine is provided for electrochemically machining the airfoil blades of an integrally bladed rotor of a gas turbine engine. The cathodes of the machine each move along two different sets of axes, a right X-axis and Y-axis and left X-axis and Y-axis, relative to a workpart machining position in the electrolyte chamber while the rotor is moved vertically along a Z-axis. The rotor is indexable about a sixth horizontal axis to present individual airfoil blades for machining at the workpart machining position. The rotor is fixtured on the Z-axis slide with its lateral center plane at an angle relative to the cathodes at the workpart machining position and the cathodes have recessed pockets to receive airfoil blades immediately adjacent the individual blade being machined as the individual blade is positioned at the workpart machining position.

Abstract: In a travelling wire EDM apparatus for effecting a cut by electrical discharges on a workpiece blank by an electrode wire, the workpiece blank is supported by two support members mounted on a rotary table, one support member being disposed in the interior of the perimeter of the cutting path and the other support member being disposed exteriorly to the perimeter of the cutting path such as to support the two portions of the workpiece blank severed from each other during the cutting operation. A partial cut is first effected through the workpiece blank and the workpiece blank is subsequently angularly oriented to a different position by rotating the rotary table such that collision between any one of the electrode wire support arms and the workpiece blank support member disposed within the perimeter of the cutting path is prevented.

Abstract: A capacitor-type power supply for electrical machining has a capacitor connected across a machining gap while a high-frequency power generator is disposed at a location remote from the machining gap and provides a high-frequency electric power. A feeder connects the power generator with the capacitor to permit the capacitor to be charged with pulses of the high-frequency electrical power. The system permits the high-frequency source to be located distally from the machining gap.

Abstract: An integral bladed rotor for a gas turbine engine is fixtured on an incrementally indexed arbor and enclosed by a shroud except for a portion of the rotor to be inserted into an electrolyte chamber for machining by opposed cathodes at a workpart machining position. The shroud and electrolyte chamber are in sealed relation when the portion of rotor is inserted for machining, and the shroud and electrolyte chamber include cooperative locating features to precisely position the rotor portion at the workpart machining position in the chamber. The shroud remains on the arbor during incremental indexing of the latter and is itself retained against substantial indexing movement while the rotor is indexed.

Abstract: A machine for electrochemically machining oversize airfoil blades of an integral bladed gas turbine engine rotor includes a yoke assembly on which the rotor is fixtured and which is pivotable to place the lateral center plane of the rotor at an angle or skew relative to the center plane of the machine and opposed cathodes in an electrolyte chamber at a workpart machining position in the chamber. The cathodes have pockets to receive airfoil blades adjacent the individual blade to be machined without contact with the adjacent blades as the cathodes and workpart are moved relative to the workpart machining position during workpart positioning in the chamber and also during advancement of the cathodes from a cathode start machining position toward the workpart during machining. The yoke assembly includes a pivot pin and locking mechanism for releasably locking the angular position of the yoke assembly.

Abstract: In the electroerosive machining of workpieces with the aid of a tool electrode, a pulse-like d.c. voltage is applied between the workpiece and electrode, the applied voltage being in the form of pulse groups where the pulse groups are formed of individual pulses having current amplitudes of selected magnitudes. Preferably, the individual current pulses belonging to the pulse group have successively rising amplitudes. Several individually controllable power switching circuits are connected in parallel to the work gap. The primary side of a pulse transformer connected to each power switching circuit is driven by a control device for the time shaping of the pulse groups. At least one controlled switch belonging to each power switching circuit is connected to a second control device for shaping the current pulse amplitudes.

Abstract: A rotating electrode tool made of polycrystalline synthetic diamonds in a metal foundation is used in the electro-erosive machining and mechanical grinding of a metal bonded, electrically non-conductive hard material such as synthetic diamonds or boron nitrides in an electrically conductive metal matrix. The tool is first used to electro-erosively machine the workpiece. When a signal is obtained from the machining current or voltage indicating that no further electroerosive removal is possible, the tool automatically mechanically grinds the workpiece to remove nonconductive particles not removed by spark erosion.

Abstract: A stream confinement apparatus which contains an EDM cooling stream in the work zone region includes a grooved element which is releasably clamped to the workpiece. The groove and workpiece form a fluid conduit which confines the stream of coolant to the work zone engulfing the EDM electrode minimizing electrode failure due to electrode overheating.

Abstract: Thin-layered conductive or semi-conductive electric circuits are made on a thin conductive or semi-conductive layer that was previously deposited on an electric insulating substrate. The electric circuits are produced by attacking with an electro-erosion tool the thin layer so as to form insulated paths thereon.

Abstract: An electrical discharge machine with automatically replaceable electrodes. The machine includes an electrode holder with a clamp operable to alternately receive and release an electrode, an electrode cartridge containing a plurality of stacked electrodes and a shuttle movable toward and away from the electrode holder. When the shuttle is moved toward the electrode holder, it removes an electrode from the cartridge and moves it into alignment with the electrode holder.

Abstract: A gap energizing system for TW electroerosion, in which a fluid delivery assembly has an elongate internal fluid passage longitudinally traversed by a straight-line path for a traveling wire electrode traversing a workpiece while defining a machining gap therewith. The passage is supplied with a machining fluid from an external fluid source and has at its end a nozzle outlet for discharging the supplied fluid as an envelop flow surrounding the electrode towards the workpiece and into the machining gap. Disposed in the internal passage are a precision guide member and an electrode contact means.

Abstract: An automatic TW (traveling-wire) electroerosion machining system for machining a plurality of workpieces of different types required to acquire different contours includes a TW machine having a wire setting unit and located adjacent a predetermined path. A work dispensing unit successively dispenses the different workpieces onto the path from a store thereof located adjacent the path. This unit and a work handling and transfer unit operate under control commands from an NC unit and, in conjunction with the TW machine, with the wire setting unit to carry out a plurality of work processing operations sequentially. In each operation, each individual workpiece selected from the store is transferred as it is carried on a pallet for loading onto and unloading from the TW machine. The tank of the TW machine has a movable front wall to facilitate this operation. The electrode setting unit on the machine acts both to form a start hole and thread a wire-type electrode through the formed hole in the workpiece.

Abstract: An electrical discharge machine is provided with at least one weight measuring apparatus for detecting the weight of one or both of an electrode and a workpiece, and a control unit for selecting or controlling the working conditions in response to the output of the weight measuring apparatus. The weights of the electrode and the workpiece are measured after the working operation has been interrupted temporarily, or while continuing the working operation. Well-known various accurate balances or force measuring apparatuses may be used as the weight measuring apparatus. A microcomputer including a numerical control unit may be used as the control unit.

Abstract: The invention relates to a process and an apparatus for the electrochemical etching of grooves of very small width, in particular smaller than 1.0 mm, into a workpiece. Etching is performed with a wire electrode or a rod electrode extending across the etching direction. In order that the electrolyte liquid introduced into the work gap does not flow away uncontrolled, but fills out the work gap over the entire working length of the electrode, a baffle acting behind the rear of the electrode is provided. This ensures that the flow of the electrolyte takes place essentially in the work gap and in the longitudinal direction.

Abstract: A traveling-wire (TW) electroerosion apparatus in which at least one of wire guides which are disposed at opposite sides of the cutting zone has a plurality of guide elements with respective circular wire-receptive guide openings each of which is of a diameter substantially larger than a nominal diameter of the electrode wire and which are arranged to be mutually eccentric to make up a composite guide opening such that the diameter of an imaginary cylinder which can be inscribed therein is substantially equal to the nominal wire diameter. Preferably, the guide elements are arranged to be displaceable relative to one another and in their respective planes to change the eccentricity of these guide openings and thus to change the diameter of the imaginary cylinder.

Abstract: Method and apparatus for combined electrolytic-abrasive polishing: providing a tool electrode rotatable by means of a rotational drive and having a liquid-permeable visco-elastic polishing member attached to the surface of a conductive disk-like tool base; contacting the visco-elastic polishing member with a free curved surface of a workpiece, with the rotational axis of the tool electrode in tilted state relative to a plane averaging undulations on the free curved surface, to contact only peripheral portions of the visco-elastic polishing member retaining abrasive grains with the workpiece; supplying an electrolyte to polishing portions between the visco-elastic polishing member and workpiece; and conducting current for electrolysis across the visco-elastic polishing member and workpiece. The apparatus can perform the combined electrolytic-abrasive polishing automatically along free curved surface of a work by the use of an automatic two-dimensional feed mechanism.

Abstract: A traveling-electrode electroerosion apparatus using a pair of wheeled carriages which accommodate axial electrode drives and machining feed drives. The wheeled carriages also carry a pair of guide members for establishing a straight-line path for the electrode to travel through the workpiece. The axial drives used to maintain the electrode in traveling alignment with the straight-line path serve in this improvement to generate a tension force acting on the traveling electrode to force one of the wheeled carriages against one of two parallel surfaces and the other of the wheeled carriages to the other of the surfaces, thereby intensifying their respective frictional engagement with these surfaces, e.g. the upper and lower surfaces of the workpiece which may be massive.

Abstract: Portable and flexible electrolytic machining apparatus is characterized by ease of stylus replacement and individual stylii configured to optimize the particular machining operation to be performed. The stylus, through which the electrolyte is discharged onto the workpiece, is resiliently captured in a handle and may be rotated relative thereto. In some embodiments of the invention the electrolyte discharge port in the stylus has an annular shape and is defined by inner and outer conductive members which have a common connection to the power supply of the apparatus.

Abstract: A workpiece cutting method and apparatus in which an elongated wire or band tool spans a pair of guides and is continuously advanced relative to the workpiece by a first drive system but is reciprocated in the region of the workpiece by a second drive system at higher speed than the rate of continuous advance. This is permitted by storage devices between each guide and the first drive. The tool can carry out electrical machining and/or abrasive cutting using an abrasive bonded to the tool or in a machining fluid introduced into the cutting region.

Abstract: An electronic flame off (EFO) electrode used to form balls on bonding wire builds up layers of aluminum oxide during use. The aluminum oxide is removed by moving the EFO electrode next to a cleaning electrode, and causing a glow discharge to pass across the gap between them. The EFO electrode is charged negative with respect to the cleaning electrode, and a noble gas, such as argon, fills the region around the gap.

Abstract: An inner movable nozzle and an outer movable nozzle are slidably supported by a hollow base member having a first and a second internal fluid passage flooded with a pressurized machining liquid medium in a first and a second inlet flow, respectively. The inner nozzle is constituted by a first hollow body surrounding a traveling electrode and ending with an outlet portion forming a first annular face adjacent the workpiece and defining a principal nozzle orifice for discharging the liquid medium of the first flow about the electrode. The hollow body is movably supported by the base member so as to be thrusted outwards thereof to urge the outlet portion towards engagement with the workpiece against pressure in constituted fluid passages created outside the principal nozzle orifice and defined with the workpiece.

Abstract: Efficient, high-precision machining of ceramic materials is achieved by supplying onto a workpiece of a ceramic material a liquid electrolyte having components at least one of which is normally inert to but becomes chemically reactive with the ceramic material at an elevated temperature, and applying to a limited zone of interface between the liquid electrolyte and the workpiece, localized energy of a magnitude sufficient to heat the liquid electrolyte and the ceramic material there to the elevated temperature and to remove from the workpiece the locally heated ceramic material in a form at least partially chemically degenerated with that electrolytic component. The limited zone acquiring the localized energy is displaced in a scanning manner from one region to another on the workpiece along numerically programmed path to consecutively remove the ceramic material along the path from the workpiece.

Abstract: In electrochemical machining, arcing across workpiece and forming electrode can result in both being scrapped. Efforts have been made to detect the electrical signals which develop on occurrence of the spark which normally terminates in an arc. Ordinary electrical noise however, tends to have similar amplitude to that of the spark and so make it difficult for the detection device to differentiate between that noise and spark noise. Consequently the machine tool was disabled though no spark had occurred. The invention enables differentiation between the two noise sources by virtue of detecting the term over which noise occurs. This is achieved by dividing the noise pulses into two trains and passing one train via a pulse delay device 32 to a gate 34 and passing the other train directly to the gate 34. If pulses from both trains arrive at the gate 34 this is indicative of the generation of a spark and the gate 34 emits a signal which is utilized to disable the machine.

Abstract: This is an electrochemical machining process for removing high spots from the surface of reactive metal workpieces. The process utilizes measuring of the workpiece to locate high spots (imperfections), then positioning a wedge-shaped, zero-angle electrochemical machining tool with its center line aligned with the center of the high spot, and then moving the tool parallel to the workpiece surface across the high spot at a product of current times inverse of speed essentially proportional to the amount of material to be removed. Preferably, the speed of tool movement is maintained essentially constant and the current is varied proportionally to the amount of material along the center line of the high spot which is to be removed.

Abstract: A grinding wheel having a circumferential rim and a plurality of electrically conductive zones and non-grinding zones therebetween the rim. A method of using such a grindstone as disclosed. Further, certain alternative methods of making such a grindstone are disclosed.

Abstract: An apparatus for the electrolytic drilling of precision holes into a work piece surface which extends at an acute angle to the drilling direction, has one tubular electrode for each hole to be drilled. Each electrode directs an electrolyte stream in the desired direction. In order to assure a proper drilling and to protect the work piece outside the holes to be drilled, a covering body is located to cover the work piece surface through which the holes are to be drilled. The covering body has a surface which closely hugs or forms an interface with the work piece surface, and another surface which extends perpendicularly to the drilling direction so that the drilling begins through the covering body which then forms a guide for the electrode and for the return flow.

Abstract: Electrochemical machining of ceramic particulate and metal matrix surfaces, and of other uneven or discontinuous surfaces, is conducted using an electrode which has a porous metal working face. Relatively low electrolyte pressures of the order of 5 kPa and low flow rates of the order of 6 ml/s/cm.sup.2 of electrode surface are used. Preferably the electrode face is made of sintered powder. Facing the electrode upward and the workpiece surface downward enables machining of workpieces without unwanted flow of electrolyte onto areas away from the machined surface.

Abstract: Systems and methods for detecting and eliminating short circuit current paths through photovoltaic devices of the type including at least one semiconductor region overlying a substrate and a layer of conductive light transmissive material overlying the at least one semiconductor region are disclosed. The short circuit current paths which are eliminated extend through the at least one semiconductor region from the substrate to the layer of conductive light transmissive material. The resistivity of the short circuit current path is increased substantially at the interface between the conductive light transmissive material and the semiconductor region by isolating electrically the conductive light transmissive material from the short circuit current path.The isolation can be provided by removing the transparent conductive material from electrical contact or connection with the short circuit current path.

Abstract: An improved machining method and electrode for use in the traveling-wire EDM process utilizing an aqueous machining fluid medium which is decomposed by erosive electrical discharges into gaseous oxygen and hydrogen. Breakage of the traveling-wire electrode is reduced or eliminated through the use of an improved electrode element comprising a continuous electrode wire substrate and a layer of a polymeric substance having a temperature of thermal decomposition of 100.degree. to 500.degree. C. attached thereto in a distributed manner such as to partially cover the surface of the substrate.