Abstract: A method of and apparatus for electroerosively machining a 3D cavity in workpiece, in which a coil is wound on a tool electrode and energized by a current source to produce a magnetic field therein. The magnetic field of flux density in excess of 100 Gauss and preferably not less than 300 Gauss is passed through the ferromagnetic electrode body and applied to the machining gap formed between the tool electrode and the workpiece which are relatively displaced multiaxially under commands of a NC unit to cause the frontal end portion of the tool electrode to sweep in a scanning manner over the workpiece while following a prescribed 3D path to progressively develop the desired cavity electroerosively machined with a succession of electrical discharges affected by the magnetic field.

Abstract: The disclosure relates to a process and apparatus for the treatment of sodium-nitrate-containing electrolytes during the electrochemical machining of the surfaces of iron-containing workpieces. By adding an oxidizing agent, more particularly ozone, increased production of nitrite in the electrolyte is prevented and, thereby, premature passivation of the surface of the workpiece during the electrochemical metal removal. An apparatus for the oxidation of the electrolyte is comprised of a processing station inserted into the electrolyte circuit, an ozone generator, and a reactor.

Abstract: A wire-cut electroerosion machining method and apparatus in which the rate of axial travel of the electrode wire is temporarily increased immediately upon a change by the electrode wire of its course at a corner in a prescribed cutting path. The axial travel rate is preferably increased as a function of the angle of intersection defining the corner. Also, the time period in which the wire axial travel rate is increased should advantageously be varied as a function of, e.g. in inverse proportion to, the angle of intersection defining the corner.

Abstract: In combining electrical discharge machining (EDM) and electrochemical machining (ECM) the use of a strong electrolyte has, in the invention, been found possible. In one embodiment a pulse generator applies an intermittent voltage between an electrode and a workpiece causing both EDM and ECM to take place when a strong electrolyte is interposed in the gap between the electrode and the workpiece. At the onset of arcing a discharge monitor removes the voltage. A wire-cutting machine and method combining EDM and ECM are also described.

Abstract: An apparatus and means for removing slivers and burrs from machined laminated components utilizes a salt solution, such as sodium nitrate, as the electrolyte which flows between a cathode and the laminated member which is connected to the positive terminal of an electrical power supply. The electrolyte is pumped into the gap between the cathode and laminated component and an electrical current flows between the laminated member and the cathode, removing metal which is deplated or released into the stream of electrolyte. The use of a salt solution, as opposed to an acidic solution, for the electrolyte fluid reduces the need for cleaning and neutralizing the acid remaining on the workpiece and, furthermore, reduces the potential hazards normally associated with the use of acids.

Abstract: The invention relates to a method and an apparatus for the treatment of surfaces of a workpiece of carbon-containing cast iron, and in particular of blind holes in gray iron cast workpieces, by electrochemical stock removal and mechanical reaming-and-plating. Electrochemical stock removal and mechanical reaming and plating are carried out in separate steps whose operating parameters are independently adjustable, the mechanical stock removal being essentially confined to a reaming-and-plating of the surface which does not entail a closing of graphite flakes. A cylinder bore produced by the method of the invention with desired roughness will have a dark, lustrous surface.

Abstract: Methods and apparatus for electrochemically deburring perforate metallic clad dielectric laminates such, for example, as laminated printed circuit boards (PCBs) or printed wiring boards (PWBs) and similar machined and fabricated laminated dielectric parts; and, more specifically, methods and apparatus for removing burrs formed during drilling, punching and similar machining operations for forming holes in a workpiece and wherein the conductive path for current flow during the electrochemical deburring process extends through the thru-hole perforations formed in the workpiece being deburred so as to concentrate current densities and preferential electrochemical attack in the regions of the clad at the peripheral edges of the thru-hole perforations in the clad dielectric laminate.

Abstract: Apparatus for supplying a working fluid and a wire electrode to a wire region of a wire-cut electrical discharge machine comprising a housing supported by a support member and having opposed aligned openings through which a wire electrode is passed into operation association with a workpiece at the work region to be operated on by the electrode. A working fluid is supplied under pressure into the housing and the working fluid passes through a nozzle supported in the housing against the workpiece. The nozzle is positioned in the housing to surround the wire electrode which travels therethrough and it projects from the housing to discharge the working fluid against the workpiece at a gap formed therewith. A guide die is supported in the housing to guide the wire electrode through the housing and the nozzle.

Abstract: To correct the volume of a recess, for example to form the portion of the combustion chamber in the cylinder head of an internal combustion (IC) engine, a tool electrode (11) is introduced into the recess, the tool electrode having the shape of the desired recess. The tool electrode is spaced from the recess by a gap (12), which is filled with an electrolyte, such as a solution of NaNO.sub.3. The extent of removal of volume of material from the workpiece is determined by controlling the current-time integral.

Abstract: A multi-strand wire electroerosion machining method and apparatus are disclosed wherein a plurality of wires dispensed from respective wire sources are fed separately into a wire travel path and are assembled via wire guides into a bundle thereof. The bundle of the wires traversing a fluid-flushed cutting zone defined between machining electrode guides constitutes a single traveling electrode for electroerosively machining a workpiece. The wires from the cutting zone are taken up into a collection site while they are held sufficiently taut between the electrode guides. The workpiece is displaced relative to the bundle of traveling wires transversely to the axis thereof to machine a desired contour in the workpiece. Preferably, the wires in the bundle are twisted. Also disclosed is a rotary die for shaping the wires in their travel path to provide the bundle with a predetermined cross-sectional contour spaced from the wall of the workpiece across the machining gap.

Abstract: A method of forming a cavity of a desired three-dimensional contour in a workpiece utilizes two steps of machining operation. In the first step (a), a multiplicity of holes are mechanically drilled in the workpiece substantially all over but within a three-dimensional region which is destined to constitute the cavity and which is bounded by a programmed outline corresponding to the desired three-dimensional contour whereby only a minimum of stock is left unmachined in the workpiece within the region.

Abstract: An apparatus is provided which machines a generally cylindrical shaft in such a way so as to improve its roundness. A bracket is shaped to be slidably associated with the shaft in a two point contact. The bracket has a measuring means attached to it which measures the distance between a portion of the shaft's surface and a chordal line drawn between the two points of contact between the bracket and the shaft. Also provided is a means for electrochemically removing material from the surface of the shaft in response to a signal received from the measuring means which is amplified prior to being transmitted to a cathode portion of the electrochemical machining apparatus. Variations of the roundness machining apparatus incorporate placements of the cathode at various arcuate distances from the measuring means.

Abstract: An improved electrode and method for electroerosion machining both of traveling-wire type wherein an elongate element having a thickness of 0.05 to 0.5 mm is axially displaced to form a traveling-wire machining electrode therefrom. The traveling-wire machining electrode is juxtaposed with a workpiece across a machining gap flooded with a machining liquid issuing from a jet and a machining current from a source is passed between the electrode and the workpiece to electroerosively machine the latter. Gaseous bubbles formed by the electrical decomposition of the machining liquid tend to be adherent on the machining surface of the electrode and thus act as a thermal insulator between the electrode and the coolant machining liquid. The elongated element is formed with a rugged peripheral surface along a length thereof to facilitate the detachment of the gaseous bubbles from the machining surface of the electrode. Various ways of producing the rugged peripheral surface are described, e.g.

Abstract: A workpiece to be treated, for example, an engine cylinder, is held vertically with a liquid-tight seal in a treatment device including a head which is fixed in the working plane of a work bench, and a counterhead supported from the work bench by a bracket which can be raised hydraulically. The device is selectively connectible, through control valves and circulation pumps, to reservoirs containing different treatment liquids. The liquids enter the cylinder in an ascending flow through the head in such a way as to avoid swirling movements. Preferably, several treatment devices are arranged to work in synchronism.

Abstract: An apparatus for and method of electroerosively drilling a thin hole, e.g. of 1 mm diameter, of a high depth-to-diameter ratio, e.g. 5 or more, in a workpiece with a tubular electrode of corresponding high slenderness. The system utilizes a novel liquid-delivery mechanism which comprises a cylindrical reservoir communicating through an outlet opening thereof with the internal bore of the tubular electrode and hence with the machining gap and a plunger member for operative reception in the reservoir to be movable therein. Prior to a drilling operation, the reservoir is charged via a check valve with a given amount of the machining liquid from a source thereof. During the drilling operation, a motor advances the plunger member to move it within the chamber at a controlled rate. The charged machining liquid in the reservoir chamber is thus pressurized by the plunger member and discharged from and delivered through the internal bore of the tubular electrode into the machining gap at a regulated rate of flow.

Abstract: A current-conductor assembly for conducting a machining current to a wire electrode in a wire-cutting electroerosion machine comprises a pair of coplanar wheels rotatable about their respective shafts and having their respective peripheries for receiving the wire electrode between them. The wheels are urged towards one another to press the wire electrode between the peripheries and a brush connectable electrically to a source of the machining current and adapted to be urged under pressure into electrical contact with a flank of one of the wheels which is electrically conductive for conducting the current to the wire electrode. The brush is an electrically conductive body preferably composed of copper, graphite or a copper/graphits composite material containing a solid-state lubricating material, e.g. MoS.sub.2 or WS.sub.2. The pressing wheel urged towards the conducting wheel is, at least along its peripheral region, composed of an elastomeric material.

Abstract: A novel electroerosion machining method and apparatus makes use of an elongate, open-ended tubular casing of a heat-resistant material retaining therein discrete metallic bodies (e.g. granular particles, flakes, fine powdery particles or broken wires) in a packed state. The casing is axially juxtaposed with a workpiece to define a machining site in the region of the latter proximate to the open-end portion of the casing and traversed by a machining liquid. A conventional electroerosion power supply furnishes a machining current between the workpiece and the discrete metallic bodies in the casing successively fed into the machining site to electroerosively remove material from the region of the workpiece against the discrete metallic bodies functioning as continuously consumed eletroerosion electrodes in the machining liquid medium.

Abstract: Method of separating a semiconductor crystal, in particular a rod-like semiconductor crystal, into wafers by first providing it with a masking layer of non-conducting material interrupted by stripes. The semiconductor crystal is biased as an anode and is immersed in an electrolyte which is provided with an electrode serving as the cathode. The oxide layers produced in the regions of the semiconductor crystal which are not masked, are removed mechanically.

Abstract: A method of manufacture of hollow turbine blades for gas turbine engines comprises forming them in two parts and brazing the parts together. This requires very accurate machining of the two faces of the parts which are to be joined prior to the brazing process. The invention provides a method of machining two confronting faces of parts of an article which are to be joined together. The method includes the step of passing an electrolyte linishing belt (2) FIG. 4 between the confronting surfaces of the two parts (10,11) and in contact with both faces simultaneously while passing an electric current between the parts. Thus one or both faces of the parts are machined using one as the former for the other.

Abstract: An electrochemical apparatus with a table formed by three slabs on which the workpiece rests. The table is mounted for rotation about a vertical axis and rests on a fixed support. A plurality of rollers in recesses of the fixed support engage the undersurface of the lower slab, and can be raised by servomotors to rotate the table. A clamping arrangement also engages the lower slab and fixed support for clamping the table in any desired orientation.

Abstract: A method and system for continuously grinding tubing to finished cannulae, where the tubing is loaded in a carrier and the carrier is continuously guided past stations which cut the primary bevel, finish the butt end, clean the cut ends, and then make lancelet cuts on the primary bevel. The system further includes a cannula carrier and guide system which permits the cannulae to be unclamped, rotated and reclamped prior to each lancelet cutting station.

Abstract: A workpiece cutting 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: A method of and apparatus for electrolytically forming relatively narrow grooves which may extend either part way or entirely through a workpiece, in which excessive groove width is avoided by reducing electrical current density between major sides of the electrode disk and side surfaces of the groove as the groove is being formed. To reduce the density of electrical current between the side surfaces of the groove and the major sides of the electrode disk, the electrode disk is provided with openings which extend between the major sides of the disk, and are positioned radially inwardly from the periphery of the disk. The openings reduce the side surface area of the disk available for the establishment of current flow to thereby tend to minimize the extent to which the sides of the groove are electrolytically eroded during formation of the groove.

Abstract: Method of and apparatus for producing shaped surfaces on workpieces by electroerosion at a machining zone. A continuous wire electrode having a first, initial cross-section is fed toward the machining zone, and while it is thus fed the electrode is deformed to a second, desired cross-section before it reaches the machining zone, the second cross-section being complementary to the shape of the surface to be machined into the workpiece.

Abstract: The workpiece is partially immersed in a first electroerosion-machining liquid so that the surface of the liquid is positioned at a predetermined height from the lower surface of the workpiece. A wire electrode is passed vertically through the workpiece to define a machining gap therebetween which extends across the entire thickness of the workpiece including an upper portion and a lower portion divided from each other by the liquid surface of the first electroerosion-machining liquid. A second electroerosion-machining liquid having a specific resistivity greater than that of the first is supplied from above the workpiece into the machining gap along the upper portion and then allowed to diffuse into the machining gap along the lower portion. Electroerosive material removal from the workpiece occurs along the upper portion uniformly at a first rate and along the lower portion at a varying second rate which is not less than the first rate and which increases as the distance from the liquid level is increased.

Abstract: A guide body for constituting at least one of a pair of guide members for a continuous wire electrode in a wire-cutting electroerosion machine comprises a first segment formed with a continuous and elongated wire-receiving groove having a first portion which is rectilinear and proximate to the wire-cutting zone and a second portion which is arcuate and remote from the wire-cutting zone, the groove being V-shaped in cross-section continuously over the first rectilinear and second arcuate portions and thereby defining a pair of continuous and elongated wire-bearing surfaces joining with an angle to form the V-shape in cross-section; and a second segment coupled to the first segment for holding the wire electrode traveling in the first portion of the groove in a bearing contact with the said surfaces in the first segment.

Abstract: A workpiece of a non-planar, curved or intricate surface contour carried on a horizontal table is wire-machined with a vertical swivel head for traveling-wire tool by sensing an imaginary plane which is tangent to the surface contour at any point thereon to be successively substantially intersected by the axis of the traveling-wire tool; and tilting the head to cause the axis of the traveling-wire tool transversing the workpiece to be oriented at a predetermined angle, preferably 90.degree., relative to the said plane substantially at the said point so as to maintain substantially the predetermined orientation of the traveling-wire tool relative to the surface contour, irrespective of change in the inclination of the tangential plane relative to the horizontal plane from point to point, throughout a substantial portion of the entire machining operation.

Abstract: A method of and apparatus for electroerosively machining a desired contour in a workpiece with a wire electrode transported from a supply to a takeup and, in a path therebetween, supported by a pair of wire guide heads to tightly stretch the axially advancing wire electrode across the workpiece. On at least one side of the two opposite surfaces of the workpiece traversed by the wire electrode there is disposed a template blank secured to the workpiece and having a contour shaped to correspond to the desired contour to be machined in the workpiece for holding the axially advancing wire electrode on the surface of the template contour between the wire guide heads across the workpiece. At least one of the wire guide heads is movable and displaced to cause the machining wire electrode to move transversely to the axis thereof along the contour of the template block so that with the transverse movement of the wire electrode, the desired contour is progressively formed in the workpiece by electroerosion.

Abstract: A method and apparatus for electrolytic processing of a metallic workpiece in which short circuits in the operating gap which produce an arc are detected and extinguished by an auxiliary d.c. current of limited duration and counter to the direction of flow of the operating current without withdrawing the electrode or cutting off the operating current.

Abstract: In a method of mirror-finishing a cylindrical workpiece, according to which, with an abrasive matter and an electrolyte disposed at and supplied to each of the gaps between a cylindrical workpiece connected to the anode of a power supply and working electrodes connected to the cathode of the power supply and disposed oppositely to the outer surface or the inner surface of said cylindrical workpiece, an anodic liquation operation by electrolysis performed onto metal in the surface to be treated of the cylindrical workpiece is assisted with an abrasive operation by which anodic passive films generated on the surface to be treated are mechanically abrased by the abrasive matters, whereby the projected portions of the surface to be treated are electrolytically liquated and abrased preferentially, said method is characterized in that an electrolyte in a passive state is used, an electrolytic voltage to be used is in the range from a few V to about 15 V, the density of an electrolytic current to be used is about 10

Abstract: An apparatus for electrolytically plating, cleaning, or otherwise treating a surface of revolution of a metallic workpiece. The treatment is carried out by a pair of electrodes each having a conductive portion and a porous dielectric cover that engages the surface to be treated. The electrodes are resiliently supported by an arm that is mounted on a shaft that is coaxial with the surface of revolution to be treated. The arm has portions extending radially outwardly from the shaft, each portion being provided with a resilient member to which an electrode is secured so that when the shaft is rotated the electrodes are moved in a circular path and are resiliently urged into engagement with the surface to be treated. Means are provided for supplying electrolyte to the electrodes and for supplying electric current to the workpiece and the electrodes to carry out the electrolytic treatment.

Abstract: An apparatus and method for selectively electrochemically etching a surface is described. The use of the apparatus and the related method allows the establishment of etched planar surface which may be inclined with respect to the original surface.The apparatus has a cathode and multiple connectors which attach to the workpiece whose surface is to be etched. When the apparatus is operated the potential of the connectors are set so that the cathode is at least as negative as the lowest potential of the connectors.

Abstract: Means for and method of electro-polishing generally planar upright surfaces of relatively large areas on machine parts of various shapes and sizes. The means and method constitute improvements on the method and apparatus disclosed in my prior U.S. Pat. No. 4,127,459 dated Nov. 28, 1978. In a preferred embodiment the surface to be electro-polished is a pattern-free, directionless, abrasively finished metal surface. When such a surface is electro-polished in accordance with this invention the resulting polished surface is waveless, ripple-less and uniformly smooth in all directions so as to exhibit superior anti-stick and release properties. Such a surface is particularly suited for numerous purposes such as head box components for paper-making machines.

Abstract: Apparatus for releasably clamping a plurality of elements, such as electrodes associated with an electrical machine, are provided wherein a housing generally defines a cavity with at least one of the elements protruding into the cavity. A fluid medium adapted for hydrostatic pressurization is disposed within the cavity and means are provided which are also disposed within the cavity and responsive to hydrostatic pressurization of the medium for generating a force for clamping the element.

Abstract: This invention relates to the electrochemical machining of integrally formed prosthetic heart valve structures in which both the structural integrity of the valve and the blood flow through the valve is improved as a result of the integral formation of the valve structure. In particular, such heart valves comprise a ring and a pendant structure, such as a strut, for supporting the opening and closing of a discoid valve occluder. Integral formation of the strut with the ring permits the cross-sectional shape of the strut to be machined without overheating and distortion to conform to a teardrop shape having favorable fluid-dynamic characteristics thereby improving the flow of blood through the valve across the strut. The integral formation of the strut with the ring further results in the elimination of the weld fillet between the strut and the ring, thereby permitting the height of the ring to be reduced, which further improves the fluid dynamic characteristics of the valve.

Abstract: An improved wire-electrode support and guidance assembly for electrical machining comprise a first wheel rotatable about a first axis and formed along its periphery with a continuous annular recess of a uniform depth and adapted to receive and retain therein a continuous wire electrode which is axially advanced and transported from a supply reel to a collection reel through the region of a workpiece. The assembly includes a second wheel rotatable about a second axis parallel to the aforesaid first axis and having a flange of a profile substantially complementary to that of the aforesaid recess, and includes means for urging the first and second axes relatively towards each other to drive the flange of the second wheel into a mating engagement with the recess of the first wheel so that the wire electrode when passed through the recess is squeezed surfaces of the recess and the flange.

Abstract: The electrochemical working method according to the invention comprises the use of two electrodes whereof one oscillates with respect to the other. Voltage pulses are applied to the electrodes in synchronization with the oscillation and are continued to be applied thereto when the electrodes are found at a minimum distance from one the other. As the electrodes are brought apart, cavitation is produced in the interelectrode gap, which phenomenon is accompanied by a change in the relative resistance of the gap. A cavitation transducer is used to measure a parameter which unambiguously determines the cavitation intensity corresponding to a preset minimum gap. In order to control the electrochemical treatment process, a comparator produces a signal equal to the difference between a signal corresponding to the actual relative value of the parameter function and formed by a computing unit, and a signal corresponding to a predetermined value of the parameter.

Abstract: An electrode assembly for electro-chemically machining an article, such as an aerofoil shaped blade for a turbo machine. The assembly comprises a plurality of electrodes 2,3 for location adjacent a workpiece 7. Each electrode 2,3 is constrained to move in a first direction towards each other and towards the workpiece 7 and has two side members 22,23 carried by a main body 21. The side members 22,23 are constrained to move with the main body 21 and also relative to the main body in directions parallel to the first direction. The side members 22,23 advance ahead of the main body 21 and when they abut the side members 22,23 of the other electrodes 2,3 their advancement is stopped while the main bodies 21 of the electrodes 2,3, continue to approach each other for a predetermined distance. In this way edge effects during machining are eliminated enabling an accurate shape of article to be produced.

Abstract: An electrode tool for the electrochemical machining of metal components, such as the cavities of internal combustion engine valves, is adapted for mounting on a machine tool mandrel and comprises a shaft upon which a flexible, elongate electrode is axially slidable, and which defines axially a conduit for conveying electrolytic fluid to the workpiece. The working end of the tool is constituted by a releasable electrode guide head which defines a part-circularly-curved electrode guide passage and the end portions of the conduit. The guide passage guides the axial sliding of the electrode so that an end portion of the latter projects radially relative to the axis of the tool by an angle determined by the radius of curvature of the passage. The guide head is interchangeable with at least one other guide head having a passage with a different radius of curvature.

Abstract: Disclosed is apparatus and method for electrochemically finishing the edges of airfoils and other thin edged objects. When the edge on an airfoil varies in thickness along its length, a tapered electrode is provided which has both a decreased diameter and increased spacing distance, providing a means for obtaining an edge with a radius proportioned to the thickness. Generally, in the system having an electrode with a unit surface area A, and with an electrode-workpiece surface spacing distance S, both A and S are changed so that the ratio A/S is lowered for electrode portions proximate to edge portions having lowered thickness.

Abstract: A method and control system for a machining fluid pump in which the machining fluid is displaced by the pump to the machining site. The pump speed is controlled electrically, usually in response to a machining parameter or to a machining liquid parameter to minimize pumping of the liquid and heat rise therein.

Abstract: Pulses of a pulse duration not greater than 100 microseconds are applied by an electronic switch between a tool electrode having abrasive particles distributed over its surface and a workpiece across a polishing gap supplied with an electrolyte.

Abstract: Deburring, polishing, surface forming and the like are carried out by electrochemical machining with conformable electrode means including an electrically conducting and an insulating web. The surface of the work to be processed is covered by a deformable electrically insulating web or cloth which is perforated and conforms with the work. The web is covered by a deformable perforated electrically conducting screen electrode which also conforms with, and is insulated from, the work by the insulating web. An electrolyte is conducted through the electrode and insulating web and along the work through a perforated elastic member which engages the electrode under pressure pressing the electrode and web against the work. High current under low voltage is conducted betwen the electrode and work through the insulator, removing material from the work.

Abstract: A traveling wire electrical machining system makes use of a single-strand traveling wire which is guided in a plurality of passes across a workpiece to cut through the latter at a plurality of parallel locations. According to the invention, the machining power supply has a plurality of outputs each of which is connected to a respective stretch of the traveling wire, thereby equalizing the machining current for each of the multiple stretches.

Abstract: A buccal tube device has a body attached to a tooth band. The body contains at least one channel with a non-circular cross-section. The channel is formed in the body by an electroerosion process. In a preferred form, the channel cross-section is four cornered and is inclined. The invention also includes a process for forming such buccal tubes by providing an electroerosion electrode with a non-circular cross-section and using it to form a channel of corresponding cross-section. The electroerosion process may include flushing the channel thus formed during the electroerosion.

Abstract: An electrode guide is used in an apparatus for electrochemically drilling an axial hole in a longitudinally extending workpiece such as a suture needle. An electrode is telescopically received in one end of the tubular guide and the workpiece in the other. Electrically non-conductive inserts are provided in the guide to position the electrode and the workpiece in axial alignment. The depth of the hole to be drilled is limited by one of the inserts which abuts the end of the needle to prevent further axial motion when the hole has reached a predetermined depth. A plurality of the electrodes are disposed in a side by side arrangement. The inlet end portions of adjacent electrodes diverge to facilitate connecting an electrolyte conducting conduit to each electrode.

Abstract: The disclosure illustrates a method and apparatus for precision balancing a rotatable element such as the turbine shaft assembly of a turbocharger. The turbine-shaft assembly is placed in a machine that detects the position and degree of unbalance. The material contributing to the unbalance is then removed from the wheel using electrochemical machining in which material is removed from the turbine through anodic dissolution of the turbine wheel material by passage of a current through a conductive work piece and electrolyte to the wheel. A means is provided to indicate the time integrated current flow of the electrochemical machining process. The time integrated current flow is related to unbalance units so that the electrochemical machining is terminated when the desired amount of mass is removed to achieve balance by reaching the determined time integrated current flow.

Abstract: An improved apparatus for electrolytically removing material from a workpiece includes a plurality of electrodes which are movable relative to each other through working strokes. In order to coordinate the movement of the electrodes, they are stopped at one or more predetermined intermediate positions during their working strokes. When all of the electrodes have arrived at intermediate positions, the electrodes are simultaneously moved away from their intermediate positions toward their end of stroke positions. In order to accommodate variations in the rate at which material is electrolytically removed from a workpiece, the speed of movement of the electrodes and/or the electrical potential established between the electrodes and the workpiece can be varied. Relatively large diameter rams connected with the electrodes are supplied with fluid from relatively small diameter piston and cylinder type pumps.

Abstract: A process for obtaining propellant samples from case bonded motors compri the use of electrolytic machining to remove two narrow bands of the case to expose the propellant liner, severing of the sample section from the rocket motor by means of a piano wire cutter, and removal of the propellant sample by means of a spool type piano wire cutter.

Abstract: Disclosed is apparatus and method for electrochemically finishing the edges of airfoils and other thin edged objects. When the edge on an airfoil varies in thickness along its length, a tapered electrode is provided which has both a decreased diameter and increased spacing distance, providing a means for obtaining an edge with a radius proportioned to the thickness. Generally, in the system having an electrode with a unit surface area A, and with an electrode-workpiece surface spacing distance S, both A and S are changed so that the ratio A/S is lowered for electrode portions proximate to edge portions having lowered thickness.