US3287245A - Method and apparatus for use in electrolytic machining - Google Patents

Method and apparatus for use in electrolytic machining Download PDF

Info

Publication number
US3287245A
US3287245A US117965A US11796561A US3287245A US 3287245 A US3287245 A US 3287245A US 117965 A US117965 A US 117965A US 11796561 A US11796561 A US 11796561A US 3287245 A US3287245 A US 3287245A
Authority
US
United States
Prior art keywords
electrode
workpiece
work
face
electrolyte
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US117965A
Other languages
English (en)
Inventor
Lynn A Williams
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Anocut Engineering Co
Original Assignee
Anocut Engineering Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL279849D priority Critical patent/NL279849A/xx
Priority to FR1332173D priority patent/FR1332173A/fr
Application filed by Anocut Engineering Co filed Critical Anocut Engineering Co
Priority to US117965A priority patent/US3287245A/en
Priority to CH735862A priority patent/CH419377A/fr
Priority to SE6760/62A priority patent/SE308233B/xx
Priority to GB23642/62A priority patent/GB1004829A/en
Priority to DE19621440278 priority patent/DE1440278B2/de
Application granted granted Critical
Publication of US3287245A publication Critical patent/US3287245A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte

Definitions

  • metalloid is used somewhat specially in referring to those electrically conductive materials which act like metals when connected as an anode in an electrolytic cell.
  • the term as used here and in the claims includes metals and such similarly acting materials as tungsten carbide for instance, and distinguishes from such conductive nonmetalloids as carbon.
  • the electrodes or cathodes of this invention can be so designed as to embrace a very large work area, so that a large part of the surface to be machined is being attacked substantially concurrently by electrolytic action.
  • a conventional cutting tool might remove material more'rapidly than would an electrode or cathode of equal size
  • the singlepoint cutting tool can remove material only where it touches the work, and of necessity this must be a limited area.
  • the surfaces to be formed in ordinary cutting are to be contoured or stepped, this is accomplished by moving the position of the single-point cutting tool in one way or another so as to accomplish this result. While this can be done with cathodes or electrodes, the better method is to design elongated electrodes having the appropriate contours so that the total surface of the work is machined simultaneously to form the desired shape.
  • One object is to provide apparatus for electrolytic turning.
  • Another object is to provide a novel method of electrolytic turning.
  • Another object is to provide apparatus for electrolytic turning which includes automatic controls for moving the cathode electrode toward a revolving workpiece that is connected as an anode.
  • Another object is to provide automatic controls for "ice electrolytic turning in which the infeed or advance of the cathode electrode is controlled in response to mechanical drag of the mechanism which revolves the workpiece.
  • Another object is to provide a control system in which the advance of the electrode is controlled automatically by reference to the flow rate of electrolyte through the electrode.
  • Another object is to provide automatic control means for electrolytic turning in which a pneumatic sensing device is used to control the advance of the'cathode electrode into the work.
  • Another object is to provide a fluid driven mechanism for feeding cathode electrodes toward the workpieces.
  • Another object is to provide cathode electrodes for electrolytic machining in which a portion of the electrode structure is made of insulating material adapted to prevent accidental short-circuiting between the electrode and the work.
  • Another object is to provide cathode electrodes which will remove metal evenly over work surfaces having different diameters.
  • Another object is to provide electrodes which can accurately reproduce contoured shapes of different diameters and of different slopes in the contours.
  • FIG. 1 is a somewhat schematic elevation of one form of apparatus of the invention in which the cathode electrode is advanced toward the end face of a revolving workpiece, with part of the electrolyte supply system being shown in phantom;
  • FIG. 2 is a schematic diagram showing one form of automatic electrode feed control for the apparatus of FIG. 1;
  • FIG. 3 is a schematic diagram showing another form of automatic control system for the apparatus of FIG. 1 utilizing a flow meter in the electrolyte supply line;
  • FIG. 4 is a schematic diagram showing another form of automatic control system for the apparatus of FIG. 1 utilizing a pneumatic sensing device to control the rate of infeed of the cathode electrode toward the end face of the revolving workpiece;
  • FIG. 5 is a partially schematic elevation showing another form of apparatus for the practice of this invention in which the cathode electrode is advanced toward the end face of the work by fluid power;
  • FIG. 6 is a schematic end view showing the application of the fluid driven apparatus of FIG. 5 to the work configuration in which the cathode electrode is advanced in a generally radial direction toward the periphery of a revolving workpiece;
  • FIG. 7 is a top view, again schematic, of the apparatus shown in FIG. 6;
  • FIG. 8 is an isometric view, schematic, showing the apparatus of FIG. 6 applied to a long workpiece With a consequently long cathode electrode and with a multiplicity of pneumatic drive units to advance the electrode toward the work;
  • FIG. 9 is a frontal view of the Working face of a sectortype electrode of a kind used with the apparatus of FIG. 1 or FIG. 5;
  • FIG. 10 is a side view of the electrode of FIG. 9;
  • FIG. 11 is a fragmentary sectional view taken in the direction of the arrows substantially along the line 1111 of FIG. 9;
  • FIG. 12 is a frontal view of another electrode generally like that of FIG. 9;
  • FIG. 13 shows an adaptation to operation upon a rotating workpiece of a composite multiple tube electrode; this figure is taken from my above-identified copending application;
  • FIG. 14 is a frontal view of the working face of an electrode generally like that of FIG. 9 but modified to provide multiple working segments and increase the electrode working area and, consequently, the ability to remove material at high rates;
  • FIG. 15 is an isometric view of an electrode of the general type shown in FIG. 9 in which, however, the working surface is contoured to produce a contour in the workpiece;
  • FIGS. 16 and 16A are, respectively, frontal views and side views of a straight electrode intended for peripheral turning;
  • FIGS. 17 and 17A are, respectively, a frontal view and a side view of an electrode for peripheral turning in which a sloped contour is to be imparted to the work;
  • FIGS. 18 and 18A are, respectively, a frontal view of the working surface and a side view of an electrode in which a step is to be formed in the peripheral surface of a workpiece;
  • FIG. 19 is an elevation partly in section showing a retaining dam in position on the electrode of FIG. 15.
  • the apparatus may take the general form of that shown in copending application entitled, Electrolytic Cavity-Sinking Apparatus and Meth od, Serial No. 73,154, filed September 2, 1960 or copending application entitled, Electrolytic Cavity-Sinking Apparatus, Serial No. 73,155, filed September 2,,1960, now United States Patent 3,130,140.
  • a general frame or base 1 is provided, which may be made of a weldment with suitable openings and doors to permit mounting a tank, pump, filter, valves, gauges, etc., which constitute the electrolyte supply system.
  • the tank, pressure pump and filter are shown in phantom.
  • the pump is adapted to supply electrolyte under a pressure of the order of 50 to 250 psi. as indicated by a gauge visible to the operator. It should be understood that the electrolyte supply system should be under the control of valves, following the general arrangement shown in FIG. 5. For convenience, this detail is not shown in FIG. 1.
  • a drivehead Mounted to the frame 1 on suitable cross slides 2 and under the control of an adjustment wheel or crank 3 is a drivehead generally designated as 4.
  • the drivehead includes a ram element 5 arranged to be driven by a lead screw 7 by means of a sprocket and chain connection comprising sprockets 9 and chain 11,.
  • ram 5 is suitably guided in tight-fitting bearings; for example, of the linear ballbearing type.
  • the extended end of ram 5 is protected by collapsible boot 17 and terminates at its end in a mounting plate 19, to which is fastened an insulating block 21, which in turn carries the electrode holder 23 which carries the electrode itself 25.
  • the electrode holder 23 comprises a manifold through which fluid electrolyte is forced against the workpiece in a predetermined configuration and at a predetermined pressure.
  • Electric power for the electrode 25 is supplied from a cable 27 in the circuit of which may be a shunt and ammeter collectively shown as 29.
  • the enclosure 37 has a raised section 37R equipped with an insulated support 375 for mounting an electrical connector 27C.
  • the portion 27F of the cable 27 that is connected between the connector 27C and the electrode holder 23 is of flexible braid and is arranged in a hook-shaped configuration to undergo free swinging movement in following the travel of the electrode. This introduces a minimum drag.
  • Electrolyte is fed to the electrode 25 through a suitable pressure hose 31 connected to the electrode holder 23.
  • the electrode 25 may be of the form shown in FIGS. 9, and 11 or it may be like that of FIG. 13, or it may be like that of FIG. 14 or, again, like that of FIG. 15.
  • the basic machine includes a worktable 33 arranged for vertical adjustment under the control of hand wheel 35.
  • the elevating mechanism extends up through the floor of a pan mounted on top of frame 1 and having an opening at 36 to provide a drain back into the electrolyte supply tank.
  • the machine includes an enclosure generally designated as 37, which surrounds the work area and is provided with an openable closure along the op-'- is provided with a seal of any suitable type at 40 to prevent accidental entry of splattered electrolyte into enclosure 39, where it might cause damage to the running elements.
  • the work spindle 38 is fitted with current brushes 41 connected to the frame and to a mounting plate 42 that is mounted on the worktable 33 to support the rotating drive mechanism.
  • a supply cable 28 is connected between the mounting plate 42 and the positive side of the direct-current power unit.
  • the work spindle 38 is journalled in a suitable bearing 43 that may be made'so that the work runs accurately and so that thrust from pressure of the electrolyte is absorbed.
  • the work spindle 38 is driven through a reducing gear 45 by an electric motor 47, which may be of the variable-speed type although it is not essential that this be adjustable.
  • the work W is positioned relative to the electrode 25: so that the electrode attacks the work in the position;
  • the location is arranged so that the electrode 25 is in proper position with respect to the center of the workpiece to make its sides align properly with radial lines extending through the center of rotation of the work.
  • the workpiece W is mounted by any suitable means (for example, a chucking clamp, which is not shown) and the electrode 25 is then advanced under manual control until it is in close proximity to the workpiece, a spacing distance of the order of .012" being suitable.
  • the electrolyte supply system is energized, and electrolyte is pumped through the entrance opening in the electrode toward the workpiece.
  • the electric current supply is then turned on, using a potential ranging between about three to four volts at a minimumiandslfi to 20 volts as a maximum, and, concurrently, the feed of the ram 5 toward the work is energized so that as the workpiece rotates the electrode is advanced slowly toward and into its end face.
  • the rate of advance will depend upon the total effective working area of the electrode 25 relative to the total annular surface area on the end face of the revolving workpiece that is swept past the electrode and which may therefore be said to be embraced by the electrode.
  • the electrode could be advanced at an infeed of, say, .200" per minute.
  • the effective area of the electrode amounts to only, let us say, onetenth of the annular area that the electrode embraces by virtue of the rotation of the workpiece, the infeed rate must be reduced to one-tenth of this speed; that is, to .020" per minute, but the rate of material removal remains the same.
  • the infeed is stopped. This may be done manually by reference to a dial indicator which is driven by a booted push rod 49.
  • the indicator itself is not shown, being of a conventional type.
  • the infeed may be arrested by an automatic depth limit switch.
  • the surface of the work will be spaced from the working face of the electrode by a distance of the order of .002" up to as much as .010" or even .015".
  • the electrolyte used consisted of a solution made by first making a mixture of equal weights of sodium chloride and potassium chloride and, then adding this mixture to water, using two pounds of the mixture to each gallon of water.
  • FIGS. 2, 3 and 4 three methods of antomatic control of the apparatus of FIG. 1 are shown in schematic diagrams.
  • the electrode assembly include an element 25A made of insulating material having a face projecting toward the work with the same contour as that of the electrode segment 25.
  • This insulating element 25A may be made of a durable plastic such as Teflon and is mounted a slight distance away from the electrode 25, so that there is free exit space for electrolyte.
  • the insulating member 25A extends toward the work a predetermined distance beyond the working face of the electrode 25. This may be of the order of .002" to .005".
  • the details of the arrangement of the electrode 25 and its projecting insulating element 25A are shown in FIGS. 9 and 10 and are described more completely hereinafter.
  • the detail of the amplifier circuit is not important to the invention, but it is provided with two adjustments, one of which sets a threshold level below which the amplifier 'has no response. This adjustment is set when motor 47 is running without any frictional drag against the workpiece. The other adjustment is the usual adjustment for gain or sensitivity.
  • the amplifier 48 delivers no output signal until the current drawn by motor 47 rises above its no-load condition.
  • the rate of response of the amplifier is very high and it feeds a signal to a power-control circuit 50 to reduce the speed of motor 15 which is powering the advance of the electrode 25 toward the work.
  • the power-control circuit 54 is also conventional and may consist of a rectifier circuit to provide direct current for the field of motor 15 and a thyratron circuit, also intended to provide direct current, which, however, is supplied to the armature of motor 15.
  • the thyratron supply is modulated by signals from the amplifier 48 and, in response to an increase in signal, the voltage supplied to the armature of motor 15 is reduced and the speed of the motor is consequently decreased, and, indeed, the circuit constants should be arranged so that if a strong signal from the amplifier is received motor 15 will not turn at all.
  • a limit switch 51 is provided and is arranged to be engaged by an abutment 5A attached to a ram 5 so that when the electrode 25 is advanced to the desired depth this will automatically deenergize the power control.
  • a relay (not shown) in the power-control circuit 50 is actuated to deenergize the direct current power supply unit for electrolyzing current, so that the instant the limit switch 51 is actuated there will be not only a discontinuation of further advance of the electrode but, also, a discontinuation of electrolyzing current so that there will be no further removal of material from the work.
  • FIG. 3 A somewhat similar general arrangement, which however overcomes this deficiency, is shown in FIG. 3.
  • a flow meter 52 is introduced into the supply line 31 from the electrolyte pressure pump and is arranged to actuate a transducer 54 which, in turn, feeds a signal to the amplifier.
  • the general principle of operation is the same.
  • the electrode 25 When the electrode 25 approaches the work closely, it causes a reduction in the volume of flow of electrolyte through the electrode 25, and this reduction in flow is sense-d by the flow meter 52 which, in turn, actuates the transducer 54.
  • Many flow meters are available for this purpose.
  • an orifice is provided and pressureresponsive transducers are connected upstream and downstream of the orifice. So long as the pressures are far apart, representing maximum flow, a signal is fed to the amplifier, which however is balanced out. However, as the flow rate is reduced because of close proximity of the electrode to the work, the pressure drop across the orifice is reduced, and the two transducers come closer, one to the other, in their signal. This reduction of differential causes the signal which actuates the amplifier 48, which, in turn, feeds the signal to the power control circuit 50, to reduce the speed of infeed motor 15. By adjusting the response of the flow meter 52 and of the amplifier 48, the gap distance between the electrode and work may be held at a predetermined and desired distance.
  • the work should be rotated rapidly enough so as not to cause significant variations in fiow rate and, thus, in control signals as a result of differences in the height of the workpiece with respect to the electrode at the beginning of the work.
  • the workpiece may revolve at, say,
  • the amplifier circuit may be arranged without the integrating circuit but in such a way as to respond to the highest signal level which it receives .as represented by the lowest pressure differential across the orifice of the flow meter. This will occur when the closest part of the work is in front of the electrode.
  • This circuit may be referred to as a peak signal-responsive amplifier, and, inasmuch as such circuits are known in the art and since no invention lies in the electrical circuitry involved, per se, no detailed description of the circuit is given here.
  • a pneumatic control system in which a sensing tube 26 is employed. This is mounted so that it is in the path being cut by the electrode 25.
  • This sensing element 26 consists of a rigid'tube of insulating material which is fed air from a pneumatic system.
  • the pneumatic system consists of an air pressure regulator 53 that may be fed from the air line of a factory, a gauge 55 so that the air pressure may be known, a header or manifold 57, a bleed valve 59, and an air supply line 61 connected to a chambered holder 26H for the sensing tube 26.
  • Air is fed through the pressure regulator 53 into manifold 57 through an orifice element 63 in the supply tube 64 between the regulator 53 and the manifold 57.
  • valve 59 By opening valve 59 slightly, a pressure is established within manifold 57 which remains constant until sensing tube 26 comes in close proximity to the work.
  • the sensing tube 26 is made slightly, but only slightly, longer than the electrode 25, and as it approaches the work the flow of air through it is reduced and, thus, the presure in the manifold 57 rises.
  • This increase in pressure is transmitted to a diaphragm 65, which acts upon a transducer 67 to feed a signal to an amplifier 48 to slow down the motor 15 through operation of the power control circuit 50.
  • the same refinements as those described in FIG. 3 may be added to the circuitry if desired.
  • a work spindle 39 is suitably journaled in bearings 43, appropriately mounted to a frame 1.
  • Power brushes 41 are shown schematically for connection to the positive terminal of the direct-current power supply.
  • a control brush 41A is also provided to permit sensing the voltage actually present in the work spindle 39 after giving account to voltage drops on account of resistance in the cable 28 leading to the brushes 41 and, of course, the losses between the brushes 41 and the work spindle itself.
  • a motor 47 is arranged to drive the work spindle through speed-reducing means, here shown as an arrangement of a belt 47B and pulleys 47F and 39F.
  • the work spindle 39, bearings 43 and motor drive, along with the power-supply brushes 41, are arranged externally of an enclosure 37 provided with a suitable shaft seal 37A.
  • a chuck 68 to hold a disc-like work material is provided and has a clamp plate 69 which holds the work firmly within the chuck.
  • the electrode 25 is mounted on an insulated block 21 and is supplied by conduit 31 with electrolyte and by a flexible cable 27P with negative current from the power supply.
  • the cable 27P is of hook-shaped configuration and is mounted in suspended relation from a connector 270 carried on an insulated support 375 secured within a raised section 37R of the enclosure.
  • the electrolyte system consists of a tank 259, a pressure pump 261 capable of delivering up to 250 or 300 pounds per square inch, a filter 262, a by-pass valve 263, a guage 265 in the by-pass line and another valve 267 and gauge 270 to feed electrolyte to the electrode 25.
  • Facilities are also provided for connecting the electrolyte supply system to the movable electrode in a manner that eliminates all drag effects.
  • These facilities include a casing 71 stationarily mounted within the enclosure 37 and provided with a flow chamber 71C bordered at its opposite ends by aligned guideways 716.
  • a length of pipe or tubing 72 is carried in a support 73 that is secured to the insulating block 21.
  • the tubing 72 projects through the guideways 716 and flow chamber 71C provided in the casing 71 and preferably is rigidly suspended from its support 73 to maintain accurate alignment with the guideways and there is clearance with respect to the casing 71 to avoid actual sliding contact.
  • the guideways are provided with labyrinth sealing grooves to provide the required sealing action without actual contact.
  • the front end of the tubing opens into a connector block 74 mounted on the support 73 and fitted with the pressure hose 31 that communicates with an electrolyte flow passage in the electrode 25.
  • the portion of the tubing within the chamber is provided with a series of holes 72H and electrolyte is supplied from the pump 261 through the filter 262, valve 267 and supply conduit 268 to flow into the chamber'71C, then into the tubing through the holes 72H, and then through the tubingv to the connector block 74.
  • the free end of the tubing is closed and projects from the casing 71.
  • a protective housing 75 is provided onthe casing to shield the free end of the tubing and a vent line 76 is shown extending from the housing.
  • the electrode 25 is advanced by a fluid drive system following the general teaching of my copending applica-1 tion entitled Electrolytic Shaping, Serial No. 772,960,
  • FIGS. 15 and 15A are views in my copending application, together with the full description of the apparatus explain in detail what is eX-.
  • the fluid drive feeding apparatus is designated generally at in FIG. 5.
  • Two movable ram elements 181 extend through a bored block 179 and are supported at each end by recirculating type linear ball ways 183 which are mounted in the block. This permits the ram elements 181 to slide with great smoothness toward and away from the work holding chuck 68.
  • the block 179 is made in two halves which are doweled together as at 179D and held by stay bolts 179B of which only one is shown.
  • piston elements 181 do not touch block 179 at any point and that they are supported solely by the linear ball ways 183 so as to be free of all frictional en-. gagement.
  • piston elements 185 which run in close proximity to the bores of cavities 171 but do not touch the walls.
  • the piston elements 185 may .be grooved with labyrinth rings to prevent excessive blow-by of air.
  • Duct connections 189 and 189A are arranged to feedv the opposite ends of cylinders 171 so that fluid pressure may be admitted under control of a two-way valve 175,
  • a pressure regulator 177 is included in the fluid equilibrium is achieved since the fluid pressure urging the electrode forward is held below the level sufficient to overcome the hydrostatic force of the electrolyte under pressure between the electrode and the work.
  • Vents 191 are provided in such a way as to avoid having blow-by of fluid fill up the protective bellows 17. The vents are connected by tubes, not shown, which lead outside the enclosure 37 so that electrolyte does not at any time enter the electrode feeding mechanism.
  • An electric vibrator 178 may be added to help overcome any sticking friction which would prevent a smooth feed.
  • This same type of feed device may be used to feed an electrode toward a cylindrical workpiece in a generally radial direction so as to accomplish material removal on the periphery of the workpiece.
  • FIG. 6 wherein the pneumatic feeding apparatus is designated generally at 170.
  • FIG. 6 also shows a second electrode 25 on the right-hand side of the piece which is advanced from right to left by the same type of feed mechanism, also designated generally at 170.
  • other electrodes may be mounted top and bottom so as to increase the effective area of electrode confronting the workpiece.
  • FIG. '7 is a fragmentary top view of the apparatus of FIG. 6, and shows a more-or-less conventional lathelike arrangement having tail and head stock assemblies, 47T and 47H, respectively, with a motor 47 arranged to rotate the work W, which is held at one end by a chuck 47C carried by the tail stock and supported at its opposite end by a chuck 47L carried on the live center of the head stock assembly.
  • FIG. 8 is an isometric view of the same kind of feed mechanism 170 shown schematically in which the workpiece W is quite long so that the electrode 25 is extended in length.
  • the electrode is mounted on an elongated support bar 79, which is hinged at the top of upstanding support elements 81, pivoted on the projecting ends of a horizontal pin 83 in a base 1.
  • a plurality of drive mechanisms 170 may be located in spaced apart relation along the bar 79 and may be connected by hinging links 84 to urge the bar 79 toward the workpiece.
  • the electrode is rocked about the pin 83.
  • the curvature on the front of the electrode does not correspond exactly with the curvature of the workpiece, but the angular position of the electrode 25 is optimum to maximize the effective area.
  • the curvature on the electrode comes to correspond more and more closely with the curvature of the work. This would tend to increase the effective working area, but this is offset by the fact that the electrode is being rocked about pin 83, and this angular displacement of the electrode tends to reduce its effective area at the same time that the closer conformity in curvature is tending to increase it.
  • the effective area of the electrode remains nearly constant.
  • Electrode bar 79 may, if desired, be supported solely by the plurality of pneumatic drive elements without any rocking motion at all, as is shown in FIG. 7 with a single pneumatic actuator.
  • the work must be rotated at a high enough rotational speed so that the electrode drive does not follow the initial deviations of the part.
  • This required rotational speed is a function of the mass-and-time response of the entire electrode drive and assembly and of the electrode area and disposition.
  • the electrode segments may be distributed evenly so that in starting the work the higher hydrostatic force in the zone of nearest proximity of the work to the electrode is offset by the lower forces elsewhere.
  • a rotational speed of 1000 to 3000 rpm. produces force pulses too high in frequency to be followed by the drive mechanism.
  • the positive-drive system such as, for example, a gear driven system, is preferred.
  • the fluid drive mechanism has been described as being of the pressure-regulated type, it is also possible to use a hydraulic positive drive with careful regulation of the flow rate.
  • the pistons will be somewhat larger and will employ seals to prevent any leakage.
  • the end seals will be of the positive cup-leather or stufiing-box type instead of the labyrinth type.
  • the available hydraulic pressure is far above the minimum necessary to overcome the back force of the electrolyte on the electrode and the friction of the seals, so that the rate of advance is affected solely by the regulated volume of oil admitted to the pressure cylinders.
  • the electrode 25 used in FIG. 1 and FIG. 5 may be made of copper and, as will be noted, is of the shape of a sector.
  • a feed slot 25G is provided through the center of the electrode sector 25 to divide the same into two sector shaped regions and the feed slot 25G communicates with a chamber 25H provided in a base plate 25] which is fed with a hose connection 251. Electrolyte emerging from the feed slot divides and half flows across each region of the electrode.
  • the base plate 25] is adapted to be bolted to the insulating face plate 23 connected to ram 5. It will be noted that the feed slot 25G is also preferably in the shape of a sector.
  • Feed slots in electrodes of this kind are filled at the ends, as shown particularly clearly in FIG. 11, with a piece 25P of plastic insulating material, so that there is no excessive metal removal over and beyond that brought about by the carefully calculated working surfaces on both sides of the feed slot.
  • the plastic filler elements 251 at the ends of the feed slots are tapered to a feather edge as they approach the work so that electrolyte will be fed uniformly across the working surfaces.
  • the electrode arrangement of FIGS. 9 and 10 is illustrated as including the insulating element 25A of the same contour as the electrode and mounted to project slightly therebeyond to act as a spacer.
  • the insulating element is mounted to provide a sector shaped space 25B alongside the electrode 25 to act as an exit slot for electrolyte.
  • holes 25C may be provided in the element 25A.
  • Screws 25D pass through adjustment slots 25E in the insulating element 25A and anchor in the body of the electrode to accommodate adjustment of the projection of the element 25A beyond the electrode face. This facilitates compensation for wear caused by rubbing of the element 25A against the workpiece.
  • the electrode arrangement of FIGS. 9, 10 and 11 is mounted so that the area of the working surface of each region of the copper electrode segment 25 becomes linearly greater as the surface is farther away from the center of rotation of the work.
  • This increase in area corresponds with the linear increase in surface speed of the work with increasing diameter.
  • the greater area of electrode allows the passage of more current and, consequently, a faster rate of removal over the larger surface areas that are encountered at regions farther from the center of rotation, and, thus, brings about a uniform rate of removal. crease with greater diameter but if instead it remains constant, then a greater removal would occur near the slower moving and hence smaller surface areas encountered adjacent the center of the workpiece, and considerable inaccuracy would result.
  • the feed slot also be in the shape of a segment an electrode configuration such as is diagrammed in FIG. 12 has been successfully employed in the practice of this invention.
  • the electrode itself 25" is substantially in the shape of a segment while the feed slot 25"G is substantially rectangular.
  • the depth of removal on a rotating workpiece would be greater near the center, and, even through the electrode itself might be flat, the bottom of the machined surface would not be fiat.
  • the width of the electrode segment should not exceed about /2" and, if it becomes necessary to work between widely different di ameters on a very large-diameter part, then a muliplicity of individual elements should be used in the electrode in order to preserve the principle that the efiective area of the electrode be increased linearly for increased distances between the point of application and the center of rotation without at any time having any portion of the electrode so wide as to require the electrolyte to proceed more than about /2" from the point where it enters through the feed slot to the point of exit.
  • FIG. 13 shows a composite electrode 225 used for forming grooves 228 in the surface of a rotating workpiece.
  • the electrode is comprised of a plurality of tubes precut to different lengths appropriate to define a desired surface contour.
  • a ring W is held by chuck jaws 230 and rotated upon a spindle 232.
  • the electrode is supported by the electrolyte supply pipe 237 in a tool rest and advanced into the work as the work rotates. Elec- If the area of the electrode does not in- 12 trolyte at a pressure of 25 to 300 pounds per square inch is pumped through the electrode. It thus cuts a smooth slot in the workpiece periphery.
  • FIG. 14 it may be desired to increase the effective working area of an electrode, and this may. be.
  • each segment has a central sector shaped feed slot 256 dividing the same into two substantially equal sector shaped.
  • FIG. 15 a sectorial type of electrode is'shown in which the face is contoured to impart a contour to the work.
  • a central feed slot 125G and an insulating spacer element 125A and plastic filler wedge 1251? are again provided corresponding to the general arrangement of the electrode of FIGS. 9, 10 and 11.
  • the electrode 125 is provided with a mounting base 125 having an entrance opening 1251 for electrolyte.
  • the slope at 126A was 45.
  • the sloped portion of the electrode at 126A may be taken as the hypotenuse of a 45 triangle and, accordingly, the area is approximately 1.4 times the area which would be available if the surface were normal to the line of advance.
  • the Width at this point should be reduced by multiplying its width computed for diametric adjustment by the factor of approximately 0.7. Similar adjustments must be made for every other slope, and where, as indicated here, the
  • the linear advance of the electrode the working surface will be narrowed, and, wherever the contour approaches parallelism with the work surface, the adjustment for contour will approach zero.
  • FIGS. 16, 16A, 17, 17A, 18 and 18A The same technique of electrode design is illustrated in FIGS. 16, 16A, 17, 17A, 18 and 18A.
  • FIG. 16 there is shown a frontal view of the working surface of an electrode 130 intended for straight machining on the periphery of a cylindrical workpiece such as is carried out in the apparatus of FIGS. 6 to 8. passages 131W are shown opening into a central feed elm 1306 (see FIG. 16A).
  • an electrode 131 is shown which is intended to be advanced from the exterior periphery of a cylindrical workpiece toward its center.
  • the electrode is arranged to impart a simple contour to the workpiece so that it is to cut deeper and approach near the center of the workpiece at its right-hand end 131R than at its left-hand end 131L.
  • the right-hand end 131R has its working surface reduced in width as compared with the left-hand end 131L, the amount of reduction being related to be proportionate diflerence in the diameters of the workpiece at the deepest part and the shallowest part of the cut.
  • the diameter at the deepest part of the cut is only about one-half that at the largest diameter. Accordingly, the working surface at the right-hand end is reduced to about one half that at the left-hand end.
  • the electrode 131 is also shown with a central feed slot 131G supplied through passages 1:11P.
  • a slope that may be assumed to be a 45 slope, then at the left-hand end the effective working area is approximately .7 times that of the flat surface to the left, and similarly at the right hand side.
  • the working surface of the sloped portion tapers on account of the change in diameter between the opposite extremities of the sloped portion.
  • contoured electrodes of the kind shown, for example, in FIG. 15 difficulty may be encountered when the electrode is first advanced toward the work as there is a natural tendency for all of the electrolyte which is being pumped through the electrode to escape through that part of the electrode which is remote from the work surface.
  • a dam of insulating material is arranged to surround the electrode and to have a face which engages the work lightly, the face of the electrode being contoured to accord with the face of the work as it is first approached.
  • the contoured electrode 125 of FIG. 15 is shown for the most part in dotted outline and it has a mounting base 125] equipped with an electrolyte inlet 125I.
  • a dam of insulating plastic material for example, an epoxy resin.
  • the dam is shown as having a flat face F to engage the work, on the assumption that the surface of the work part is substantially flat before initiation of the operation of contouring it.
  • the plastic dam is identified generally as D125.
  • the dam completely surrounds the electrode proper, and element 125A, as shown in FIG. 15, should be regarded as being spaced sufliciently away from the electrode proper so as not to interfere with the placement of the plastic dam D125.
  • the dam is guided by a number of guide pins P125 on which the dam is free to move toward or away from the work. Around the pins P125, there are springs S125 which urge the dam toward the work.
  • the dam In the starting position, the dam extends slightly beyond the electrode proper, and, as the electrode is advanced toward the work, the dam first engages it, and, as the electrode assembly is advanced, the dam slides back on the guide pins P125.
  • the free exit of electrolyte from the electrode surface area generally designated as 126D is prevented, and instead some amount of electrolyte is forced to exit at the deepest protrusion of the electrode, thus assuring a flood of electrolyte at this point.
  • the electrode itself running in close proximity to the work prevents free escape of electrolyte at such a point, and the plastic dam continues to serve as a restriction to unintended free exit in the unengaged portion of the electrode until the entirety of the electrode surface has entered the work.
  • the dam and contoured electrode assembly of FIG. 19 is useful both in the machining of rotating workpieces and in cavity sinking in stationary workpieces.
  • FIGS. 18 and 18A there is shown an electrode 132 intended to produce a square step or groove.
  • the projecting portion 132K has a working surface of the shape shown in FIG. 18 which is reduced because it extends to a smaller diameter in the workpiece.
  • the projection 132K has sidewardly extending lips 132L and the sides of the electrode are covered with insulation 1321 in order to prevent sideward erosion.
  • a device for removing material from an electrically conductive and electro-chemically erodible workpiece -by electrolytic action the combination of an electrode having a conductive working face, said workpiece being mounted and rotated about its longitudinal axis, means for moving said electrode face toward the workpiece at a predetermined rate, control means operable in conjunction with said means for moving said electrode for establishing and maintaining a predetermined gap between said face and the workpiece as said face is advanced toward the same, said working face defining a sector generated about an axis coincident with the axis of rotation of said workpiece, said sector having an :arcuate width at any given radial distance which is inversely proportional to the angular velocity of a point on said workpiece at the same radial distance, so that the time required for any point on the workpiece to traverse the Width of said sector will be the same, a source of electrical power connected between said electrode and the workpiece so as to establish the former as a cathode, and the latter an anode,
  • a device as set forth in claim 1 wherein a portion of said working face slopes relative to the axis of generation thereof and said slope portion has an arcuate width such that the area of said portion projected on said workpiece is equal to the projected area of all other portions of said sector relative to the speed of rotation of said workpiece.
  • an electrode having a conductive working face, a spacer providing a contact face having a surface contour like that of said working face, means for rotating the workpiece relative to said electrode and said spacer for sweeping a circular surface path thereof past the working face of said electrode and past the contact face of said spacer, means for moving said spacer and said electrode jointly toward said workpiece to bring said spacer into contact with a workpiece region within said surface path and to bring said working face adjacent another workpiece region within said surface path to establish a gap therebetween, circuit means for impressing an electric potential between the electrode and the workpiece in a sense to make the electrode a cathode, means for supplying electrolyte through said gap to provide a high density current carrying path and remove a circular portion of the workpiece to a depth corresponding to the relative travel of the electrode toward the workpiece and to provide a finish surface contour corresponding substantially to the surface contour of the working face, a mot-or for rotating said workpiece,
  • Apparatus as set forth in claim 3 including means mounting a dam having an insulated contact face with a surface contour like that of said workpiece in relatively movable loose surrounding relation about said electrode, and including yieldable means biasing said dam toward said workpiece, the face of said dam adapted to contact the face of said workpiece when said electrode and spacer are moved into contact there-with, said dam adapted to restrict electrolyte flow to thereby produce flooding throughout the gap between said workpiece and electrolyte during initial travel of said electrode through said dam and into said workpiece.
  • an electrode having a curved conductive working face adjacent and facing the cylindrical face of the workpiece, means for rotating the workpiece about its longitudinal axis for sweeping a path past the working face of said electrode, said working face having a radius of curvature in a range between that of the workpiece prior to and after removal of material is completed, means for moving said electrode toward said workpiece so as to bring an optimum amount of working face area within a predetermined distance from an arcuate portion of said surface path, control means for regulating the rate of advance of said electrode by the last named moving means to establish and maintain a predetermined gap between said working face and the surface vportion of said workpiece that is facing said working face, means for progressively swinging said electrode about an axis parallel to said axis of rotation of said workpiece to compensate the gap configuration for the changing workpiece curvature during removal of material therefrom, circuit means for impressing an electric potential between the electrode and.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
US117965A 1961-06-19 1961-06-19 Method and apparatus for use in electrolytic machining Expired - Lifetime US3287245A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
NL279849D NL279849A (en, 2012) 1961-06-19
FR1332173D FR1332173A (en, 2012) 1961-06-19
US117965A US3287245A (en) 1961-06-19 1961-06-19 Method and apparatus for use in electrolytic machining
CH735862A CH419377A (fr) 1961-06-19 1962-06-18 Machine pour l'usinage électrolytique
SE6760/62A SE308233B (en, 2012) 1961-06-19 1962-06-18
GB23642/62A GB1004829A (en) 1961-06-19 1962-06-19 Improvements in or relating to a method and apparatus for use in electrolytic machining
DE19621440278 DE1440278B2 (de) 1961-06-19 1962-06-19 Aa 19.n6.62 OT 24.10.68

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US117965A US3287245A (en) 1961-06-19 1961-06-19 Method and apparatus for use in electrolytic machining

Publications (1)

Publication Number Publication Date
US3287245A true US3287245A (en) 1966-11-22

Family

ID=22375779

Family Applications (1)

Application Number Title Priority Date Filing Date
US117965A Expired - Lifetime US3287245A (en) 1961-06-19 1961-06-19 Method and apparatus for use in electrolytic machining

Country Status (7)

Country Link
US (1) US3287245A (en, 2012)
CH (1) CH419377A (en, 2012)
DE (1) DE1440278B2 (en, 2012)
FR (1) FR1332173A (en, 2012)
GB (1) GB1004829A (en, 2012)
NL (1) NL279849A (en, 2012)
SE (1) SE308233B (en, 2012)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3365381A (en) * 1965-02-23 1968-01-23 Westinghouse Electric Corp Electrochemical machining including in-process guaging of the workpiece
US3410781A (en) * 1964-11-27 1968-11-12 Ex Cell O Corp Electrochemical machining apparatus for internal surface deburring
US3445372A (en) * 1965-12-13 1969-05-20 Westinghouse Electric Corp Apparatus for electrochemically removing the surface layer from a workpiece
US3450618A (en) * 1966-12-02 1969-06-17 Hammond Machinery Builders Inc Face mill grinder
US3547795A (en) * 1967-10-02 1970-12-15 Heald Machine Co Apparatus for the generation of a surface of revolution by the electrochemical process
US4687563A (en) * 1985-04-01 1987-08-18 Corning Glass Works Electrochemical machine apparatus with drill-depth and rate monitor
CN110919114A (zh) * 2019-12-09 2020-03-27 西安工业大学 大长径比的复杂螺旋类结构高效电解加工装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0227223B1 (en) * 1985-11-27 1991-09-25 Ex-Cell-O Corporation Electrolyte chamber with cathode sealing means for ecm machining

Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB335003A (en) * 1929-07-24 1930-09-18 Wladimir Gusseff Method and apparatus for the electrolytic treatment of metals
US2188631A (en) * 1937-12-03 1940-01-30 Ingersoll Milling Machine Co Trepanning drill
US2654821A (en) * 1948-07-15 1953-10-06 Warner Swasey Co Hot machining of metals
US2698832A (en) * 1951-03-20 1955-01-04 Standard Process Corp Plating apparatus
US2797193A (en) * 1954-02-23 1957-06-25 Bell Telephone Labor Inc Method of treating the surface of solids with liquids
US2818491A (en) * 1955-07-13 1957-12-31 Elox Corp Michigan Electrode wear compensation
US2848410A (en) * 1955-05-13 1958-08-19 Strners Chemiske Lab H Apparatus for the electrolytic polishing of limited surface portions of a metallic workpiece
US2861937A (en) * 1954-09-15 1958-11-25 John F Jumer Apparatus for electropolishing interior surfaces of vessels
US2870836A (en) * 1955-05-19 1959-01-27 Nicola P Rosato Trepanned core cutoff tool
US2905605A (en) * 1953-05-19 1959-09-22 Keeleric Dressing of abrasive tools
US2958636A (en) * 1956-09-10 1960-11-01 Philco Corp Method of the application of liquids to solids
FR1265272A (fr) * 1960-05-18 1961-06-30 Citroen Sa Andre Appareil pour le durcissement superficiel des métaux par étincelles
US3001925A (en) * 1955-02-23 1961-09-26 Ernest V Berry Anode structure
US3019178A (en) * 1959-10-29 1962-01-30 Anocut Eng Co Electrode for electrolytic shaping
US3043766A (en) * 1959-09-14 1962-07-10 Anocut Eng Co Electrolytic grinding apparatus
US3046206A (en) * 1955-02-23 1962-07-24 Richard C Johnson Electro-chemical machining system
US3058895A (en) * 1958-11-10 1962-10-16 Anocut Eng Co Electrolytic shaping
US3095364A (en) * 1959-11-27 1963-06-25 Steel Improvement & Forge Comp Material removal
US3161576A (en) * 1961-12-22 1964-12-15 Clevite Corp Electroetch process for semiconductors

Patent Citations (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB335003A (en) * 1929-07-24 1930-09-18 Wladimir Gusseff Method and apparatus for the electrolytic treatment of metals
US2188631A (en) * 1937-12-03 1940-01-30 Ingersoll Milling Machine Co Trepanning drill
US2654821A (en) * 1948-07-15 1953-10-06 Warner Swasey Co Hot machining of metals
US2698832A (en) * 1951-03-20 1955-01-04 Standard Process Corp Plating apparatus
US2905605A (en) * 1953-05-19 1959-09-22 Keeleric Dressing of abrasive tools
US2797193A (en) * 1954-02-23 1957-06-25 Bell Telephone Labor Inc Method of treating the surface of solids with liquids
US2861937A (en) * 1954-09-15 1958-11-25 John F Jumer Apparatus for electropolishing interior surfaces of vessels
US3001925A (en) * 1955-02-23 1961-09-26 Ernest V Berry Anode structure
US3046206A (en) * 1955-02-23 1962-07-24 Richard C Johnson Electro-chemical machining system
US2848410A (en) * 1955-05-13 1958-08-19 Strners Chemiske Lab H Apparatus for the electrolytic polishing of limited surface portions of a metallic workpiece
US2870836A (en) * 1955-05-19 1959-01-27 Nicola P Rosato Trepanned core cutoff tool
US2818491A (en) * 1955-07-13 1957-12-31 Elox Corp Michigan Electrode wear compensation
US2958636A (en) * 1956-09-10 1960-11-01 Philco Corp Method of the application of liquids to solids
US3058895A (en) * 1958-11-10 1962-10-16 Anocut Eng Co Electrolytic shaping
US3043766A (en) * 1959-09-14 1962-07-10 Anocut Eng Co Electrolytic grinding apparatus
US3019178A (en) * 1959-10-29 1962-01-30 Anocut Eng Co Electrode for electrolytic shaping
US3095364A (en) * 1959-11-27 1963-06-25 Steel Improvement & Forge Comp Material removal
FR1265272A (fr) * 1960-05-18 1961-06-30 Citroen Sa Andre Appareil pour le durcissement superficiel des métaux par étincelles
US3161576A (en) * 1961-12-22 1964-12-15 Clevite Corp Electroetch process for semiconductors

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3410781A (en) * 1964-11-27 1968-11-12 Ex Cell O Corp Electrochemical machining apparatus for internal surface deburring
US3365381A (en) * 1965-02-23 1968-01-23 Westinghouse Electric Corp Electrochemical machining including in-process guaging of the workpiece
US3445372A (en) * 1965-12-13 1969-05-20 Westinghouse Electric Corp Apparatus for electrochemically removing the surface layer from a workpiece
US3450618A (en) * 1966-12-02 1969-06-17 Hammond Machinery Builders Inc Face mill grinder
US3547795A (en) * 1967-10-02 1970-12-15 Heald Machine Co Apparatus for the generation of a surface of revolution by the electrochemical process
US4687563A (en) * 1985-04-01 1987-08-18 Corning Glass Works Electrochemical machine apparatus with drill-depth and rate monitor
CN110919114A (zh) * 2019-12-09 2020-03-27 西安工业大学 大长径比的复杂螺旋类结构高效电解加工装置

Also Published As

Publication number Publication date
GB1004829A (en) 1965-09-15
FR1332173A (en, 2012) 1963-12-16
DE1440278B2 (de) 1970-10-01
SE308233B (en, 2012) 1969-02-03
CH419377A (fr) 1966-08-31
NL279849A (en, 2012)
DE1440278A1 (de) 1968-10-24

Similar Documents

Publication Publication Date Title
US3287245A (en) Method and apparatus for use in electrolytic machining
US3268434A (en) Apparatus for electrolytic machining
US3399125A (en) Electrochemical machining in a pressurized chamber substantially without the formation of gas bubbles
CN111185641B (zh) 一种电解液脉冲式电解加工装置及方法
GB2090555A (en) Drilling electroerosively deep thin holes in workpieces
US3365381A (en) Electrochemical machining including in-process guaging of the workpiece
CN102941383A (zh) 剃须刀静刀盖内壁减薄电解加工装置及其加工工艺方法
GB1181641A (en) Improvements in or relating to Electrical Connectors to a Workpiece to be machined Electrochemically or by Electro-erosion
US3515659A (en) Apparatus for electro chemical machining
US2981822A (en) Electrical machining apparatus
US4029928A (en) Electro-erosion machine tools
US4386248A (en) Electrical machining method and apparatus for forming a 3D surface contour in a workpiece with a traveling-wire electrode
GB2093747A (en) Electrode feed device for electrical machining apparatus
CN112296458A (zh) 一种整体叶轮电解成型加工装置
CN211053700U (zh) 一种满足ndt探伤要求的铸钢件表面机器人切削装置
GB1505065A (en) Methods and apparatus for electrically machining a workpiece
US3318793A (en) Servo feed apparatus for electrical discharge machining
US3444070A (en) Electrolytic shaping apparatus
US3043766A (en) Electrolytic grinding apparatus
US3647671A (en) Electrochemical machining apparatus
US3591473A (en) Method and apparatus for electrochemically machining rotating parts
CN213969385U (zh) 一种整体叶轮电解成型加工装置
CN211028446U (zh) 一种电火花穿孔机旋转头
CN210588222U (zh) 一种数控钻床的工件导向定位装置
CN109396577A (zh) 一种双头丝杆双牛头电火花成型机床