US3801489A - Tool for electrolytic drilling of holes - Google Patents

Tool for electrolytic drilling of holes Download PDF

Info

Publication number
US3801489A
US3801489A US00160474A US3801489DA US3801489A US 3801489 A US3801489 A US 3801489A US 00160474 A US00160474 A US 00160474A US 3801489D A US3801489D A US 3801489DA US 3801489 A US3801489 A US 3801489A
Authority
US
United States
Prior art keywords
tube
wire
tool
electrolyte
tubes
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
US00160474A
Other languages
English (en)
Inventor
D Samson
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.)
UK Secretary of State for Defence
Original Assignee
Secr Defence
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
Application filed by Secr Defence filed Critical Secr Defence
Application granted granted Critical
Publication of US3801489A publication Critical patent/US3801489A/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
    • B23H7/00—Processes or apparatus applicable to both electrical discharge machining and electrochemical machining
    • B23H7/26—Apparatus for moving or positioning electrode relatively to workpiece; Mounting of electrode
    • B23H7/265—Mounting of one or more thin electrodes

Definitions

  • a tool for use in the electrolytic drilling of holes comprising a self-supporting tube of electrically insulating material having an operative free open end, an electrically conducting wire which extends along the bore of the tube, with clearance between the wire and the bore, to permit flow of electrolyte, and a support which fixes the wire axially relatively to the tube so that a free end of the wire is within the tube and spaced axially from the free end of the tube, and which provides for electrical connection to the wire, and for supply of electrolyte to the clearance.
  • an elongated tubular tool is fed axially into a workpiece while at the same time a flow of electrolyte is maintained through the tool, and an electric current is maintained between the tip of the tool and the workpiece.
  • the rate of feed is matched to the rate at which metal is removed from the work at the bottom of the hole by electrolytic action.
  • the arrangement must be designed to avoid any short circuit from the tool to the work.
  • the most common form of tool is a tube of metal, coated externally with insulation.
  • a tool for use in the electrolytic driling of holes comprises a self-supporting tube of electrically insulating material having an operative free open end, an electrically conducting wire which extends along the bore of the tube, with clearance between the wire and the bore, to permit flow of electrolyte, and a support which fixes the wire axially relatively to the tube so that a free end of the wire is within the tube and spaced axially from the free end of the tube, and which provides for electrical connection to the wire, and for supply of electrolyte to the clearance.
  • the preferred insulating material is glass.
  • the external diameter of the tube can be greater than the tube of an equivalent metal tool, because there is no layer of insulation.
  • glass can be made in suitable sizes, and sufiiciently straight, and it has mechanical properties which are superior to metal, in particular a higher yield point.
  • the wire which serves as the electrode, does not require to contribute significantly 'to the mechanical strength of the tool.
  • the tube and the wire are of circular cross section and the internal diameter of the tube is about /3, and the diameter of the wire is about /s, of the external diameter of the tube.
  • the termination of the wire upstream of the free end of the tube ensures that the electrolyte can emerge from the free end of the tube as a coherent stable stream, despite the fact that the wire may be eccentric in the tube or may move laterally in the tube.
  • the distance axially between the free end of the wire and the free end of the tube is between 2 and 20 times the internal diameter of the tube.
  • the invention is of particular value in tools for making a plurality of holes.
  • FIG. 1 is an elevation of the apparatus as a whole.
  • FIG. 2 is a section on the line II-II in FIG. 1 drawn to an enlarged scale.
  • FIG. 3 is a section on the line IIIIII in FIG. 2.
  • FIG. 4 is a further enlarged detail of FIG. 2.
  • a work table 10 is arranged to be raised or lowered relative to a tool 11 by means of a screw 12 through which the table is connected to a frame 13.
  • the tool includes a shank 14 by which it is connected to the frame and through which an electrolyte supply pipe 15 is fed to the tool.
  • a workpiece is indicated at 16, and the tool and the workpiece are connected electrically to the respective poles of current supply 17 as shown.
  • the tool comprises a plurality of electrodes having the form of wires 20 situated in tubes 21.
  • the wires 20 terminate upstream of the ends of the tubes 21 by a distance 22 (FIG. 4).
  • a plurality of parallel wires and tubes are provided for the purpose of drilling a plurality of parallel holes.
  • the tool comprises a manifold 23 supporting the tubes 21 and through which these tubes are supplied with the electrolyte from the tube 15.
  • the tubes 21 are located in a slot 24 (FIG. 4) in a nose 25 of the manifold and are secured in position by means of a resin.
  • the manifold which is made of a metal which is resistant to corrosion in the electrolyte, e.g. 18% chromium stainless steel, comprises a base 26 to which the nose 25 is secured, and a housing 27 removably secured to the base.
  • the base has secured thereto a clamp 28 comprising a pair of jaws 29, 30 for gripping the Wires 20.
  • the jaw 30 is pivoted to the jaw 29 on an axis such that the clamping force is normal to the length of the wires, and a screw 31, located in a pivotal stirrup 32, is provided for locking and releasing the clamp.
  • the jaw 29 is supported for sliding motion in the direction of the length of the wires by a guide 33.
  • a screw 34, nut 35, and spring 36 are arranged so that rotation of the nut in one direction raises the clamp 28 against the spring 36. In this way the longitudinal position of the wires 20 in the tubes 21 can be adjusted during the initial assem bly of the wires and before the housing 27 is attached to the base 26.
  • the tool and workpiece are mounted in the correct machining relationship on the frame 13 and table 10 respectively, and the table is raised by means of the screw 12 to perform the feed motion between the tool and workpiece in a manner well understood per se.
  • the diameter ofthe electrode is 0.0015 inch (0.04 mm.), and the internal and external diameters of the tubes are 0.005 and 0.0075 inch (0.13 and 0.19 mm.) respectively.
  • the feed rate for such holes would be 0.050 inch (1.30 mm.) per min.
  • the unsupported length of the tubes is 0.4 inch mm.) so that the maximum depth of hole which can be drilled is of the order 0.35 inch (9 mm.), to avoid secondary machining problems which can arise if a conducting path is established between the nose 25 and the workpiece.
  • the voltage applied between the wires and the workpiece is about 100 volts, and the electrolyte is supplied to the manifold at room temperature at about 100 lbs/sq. in (700K N/m.
  • any variation in the length of the wire due to, say, straightening from a somewhat bent state, would produce an undesirably large percentage variation in the gap between electrode and workpiece.
  • the distance 22 must not be smaller than about 2 times the internal diameter of the tube.
  • the distance 22 should not be larger than is required for process stability, and a dimension of about to times the internal diameter of the tube has been found to be the maximum necessary for practical purposes.
  • the distance 22 is independent of the length of the tubes 21, and no change in voltage, for example, is necessary if the length of the tubes and wires is changed to suit different depths of drilling.
  • the provision of the distance 22 makes it possible for electrolyte flow to establish a coherent stream at the electrolyte pressure used. In this way there is overcome the disturbing effect on uniformity of flow which would be produced by the wire not being perfectly concentric with the tube or by any vibration of the wire in operation. Nevertheless it is desirable for the wires to have as much stiffness as possible to diminish flutter in the tube and to diminish the possibility of bending these fine wires when they are being mounted in the tool.
  • the wires are preferably made of platinum containing 10% rhodium, although they could be made from any noble metal, provided they can be made sufficiently stiff to be threaded up the tubes, and as a final operation before assembling the wires in the tool they are rolled between glass plates for the purpose of straightening and work hardening them.
  • the clamp is opened and the wires are individually fed into the tubes 21 from the free ends thereof, and when all the wires have been so fed the clamp is tightened, gripping the wires between an anvil 40 on the clamp body and the jaw 29 of the clamp.
  • the wires may be spot welded to the anvil, and the clamp jaw 29 can be eliminated.
  • the wires are then cut substantially flush with the ends of the tube and are thereafter withdrawn into the tubes by 4. shifting the clamp by means of the nut 35, so as to vide the same distance 22 for all the wires.
  • the distance 22 can also be produced by electrolytic erosion.
  • the wires are passed into the tubes and are held by the clamp Welding as described above. Short lengths of wire are allowed to project outside the ends of the tubes and are trimmed substantially flush with these ends. Thereafter a flow of a suitable electrolyte is intro quizd down the tubes and an electric circuit is established between the wires and a common electrode (not shown) arranged below the tool, so that the wires are elecrolytically eroded, i.e. the current flow is in the opposite sense to that used when drilling the workpiece.
  • a suitable electrolyte would be 20% potassium cyanide.
  • the common electrode cn be a carbon block placed on the work table.
  • the table is adjusted so that the tips of the tubes are spaced a short distance from the surface of the carbon block.
  • the main advantage of this process is that different wires 21 are eroded to different distances 22 due to the effect of differences in the internal diameters of the tubes, and this in turn produces uniformity in the rate of machining of the holes to be drilled and in the diameters of these holes.
  • the upper limit to the diameter of the wire is determined by the need for an adequate clearance between the wire and the tube for flow of electrolyte.
  • the lower limit to the diameter of the wire is determined by the need to avoid melting of the wire by the electric current. Moreover the thinner the wire, the more difficult it is to manipulate into position.
  • the invention overcomes the difi'iculty of making drillalthough not limited to this range, up to a length to diameters of the order mentioned.
  • the invention thus provides a stable process for drilling holes of the order of 0.004 to 0.020 inch (0.10 to 0.50 mm.) diameter, using tools having an external diameter in the range 0.0035 to 0.017 inch (0.09 to 0.43 mm.), although not limited to this range, up to a length to diameter ratio of the order of 100, with a substantially constant voltage of the order of volts.
  • the diameter of the holes drilled can be varied using the same drill by varying the feed rate and voltage.
  • the invention is also applicable to drilling of shaped holes by having tubes of shaped cross-section.
  • the pitch of the tubes (i.e. the distance between their axes) has a lower limit determined by the surface tension of the electrolyte and the length/diameter ratio of the tubes. If the pitch is too small, the tubes tend to deflect from their parallel relationship and to adhere together.
  • a pitch of 0.040 inch (1 mm.) has'been found to be the minimum that can be maintained without this adhesion, when using 20% nitric acid as the electrolyte and using the dimensions of tubes as described in the example above. But if a surface tension reducing agent is added to the electrolyte, the pitch can be reduced.
  • a suitable agent is dodecylbenzinesulphonic acid.
  • a further means of preventing this latter effect would be to make the nose from an insulating material or to coat it with such-a material.
  • a tool for use in the electrolytic drilling of holes comprising a self-supporting tube portion of electrically insulating material having an operative free open end and defining a bore of uniform cross section throughout its length and communicating directly with surrounding space proat said free open end, an electrically conducting wire which extends along said bore, with clearance between the wire and the bore, to permit flow of electrolyte, and a support which fixes the wire axially relatively to the tube portion so that a free end of the wire is within the bore and spaced axially from the free open end by a distance between two times and 20 times the internal diameter of the tube, and which provides for electrical connection to the wire, and for supply of electrolyte to enter the clearance and emerge to surrounding space at said free tube open end.
  • a tool according of claim 1 in which the tube portion and the wire are each of circular cross section and the internal diameter of the tube is about and the diameter of the wire is about /5, of the external diameter of the tube.
  • a multiple tool for use in the simultaneous electrical drilling of a plurality of holes comprising a plurality of self-supporting tubes of electrically insulating material, each having an operative free open end and defining a bore of uniform cross section throughout its length and communicating directly with surrounding space at said free open end, a support which fixes the tubes with their bores parallel to each other, and a plurality of electrically conducting wires each of which extends along the bore of a respective one of the tubes, with clearance between the wire and the bore, to permit flow of electrolyte, the support including a manifold to which the tubes are attached, a clamp by which the wires are gripped, and means for adjusting the clamp relatively to the manifold to shift the wires along the bores of the tubes, enabling fixing of each wire axially relatively to the respective tube so that a free end of the wire is within the tube and spaced axially from the free open end of the tube, by a distance between two and 20 times the internal diameter of the tube, and the support also providing for electrical connection to the

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)
  • Re-Forming, After-Treatment, Cutting And Transporting Of Glass Products (AREA)
US00160474A 1970-07-16 1971-07-07 Tool for electrolytic drilling of holes Expired - Lifetime US3801489A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3458570 1970-07-16

Publications (1)

Publication Number Publication Date
US3801489A true US3801489A (en) 1974-04-02

Family

ID=10367465

Family Applications (1)

Application Number Title Priority Date Filing Date
US00160474A Expired - Lifetime US3801489A (en) 1970-07-16 1971-07-07 Tool for electrolytic drilling of holes

Country Status (6)

Country Link
US (1) US3801489A (enExample)
JP (1) JPS5386429U (enExample)
AU (1) AU461604B2 (enExample)
DE (1) DE2135207A1 (enExample)
FR (1) FR2101785A5 (enExample)
GB (1) GB1348480A (enExample)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928163A (en) * 1973-09-11 1975-12-23 Agie Ag Ind Elektronik Spark discharge and electro-chemical erosion machining apparatus
USB534314I5 (enExample) * 1974-12-19 1976-02-10
US4083760A (en) * 1975-08-30 1978-04-11 Mtu Motoren-Und Turbinen-Union Munchen Gmbh Electrolytic precision drilling device and process
US4769118A (en) * 1985-12-13 1988-09-06 Ae Plc Process for the curvilinear formation of holes
US4988425A (en) * 1989-11-20 1991-01-29 Technology Tool Company Electrode with both outside and inside flow of electrolyte for electrochemical machining
US5096379A (en) * 1988-10-12 1992-03-17 Rolls-Royce Plc Film cooled components
US5320721A (en) * 1993-01-19 1994-06-14 Corning Incorporated Shaped-tube electrolytic polishing process
US5605639A (en) * 1993-12-21 1997-02-25 United Technologies Corporation Method of producing diffusion holes in turbine components by a multiple piece electrode
CN115815718A (zh) * 2022-11-18 2023-03-21 宜兴市鑫煜科技有限公司 一种多压力多路径的高精度电液束供液调压装置

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3327220C1 (de) * 1983-07-28 1985-01-24 MTU Motoren- und Turbinen-Union München GmbH, 8000 München Elektrolytische Feinbohrvorrichtung
GB8830152D0 (en) * 1988-12-23 1989-09-20 Rolls Royce Plc Cooled turbomachinery components
DE10255455B4 (de) * 2002-11-28 2004-11-18 Mtu Aero Engines Gmbh Vorrichtung zum Einbringen von Bohrungen
US10144077B2 (en) * 2015-04-23 2018-12-04 Mitsubishi Electric Corporation Wire electrical discharge apparatus and initial hole machining method
CN107309511B (zh) * 2017-08-24 2023-06-23 重庆望江工业有限公司 一种大型轴件端键槽的电解加工装置

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3928163A (en) * 1973-09-11 1975-12-23 Agie Ag Ind Elektronik Spark discharge and electro-chemical erosion machining apparatus
USB534314I5 (enExample) * 1974-12-19 1976-02-10
US3981786A (en) * 1974-12-19 1976-09-21 United Technologies Corporation ECM and EDM tooling for producing holes in airfoil trailing edges
US4083760A (en) * 1975-08-30 1978-04-11 Mtu Motoren-Und Turbinen-Union Munchen Gmbh Electrolytic precision drilling device and process
US4769118A (en) * 1985-12-13 1988-09-06 Ae Plc Process for the curvilinear formation of holes
US5096379A (en) * 1988-10-12 1992-03-17 Rolls-Royce Plc Film cooled components
US4988425A (en) * 1989-11-20 1991-01-29 Technology Tool Company Electrode with both outside and inside flow of electrolyte for electrochemical machining
US5320721A (en) * 1993-01-19 1994-06-14 Corning Incorporated Shaped-tube electrolytic polishing process
US5605639A (en) * 1993-12-21 1997-02-25 United Technologies Corporation Method of producing diffusion holes in turbine components by a multiple piece electrode
CN115815718A (zh) * 2022-11-18 2023-03-21 宜兴市鑫煜科技有限公司 一种多压力多路径的高精度电液束供液调压装置

Also Published As

Publication number Publication date
DE2135207A1 (de) 1972-01-20
JPS5386429U (enExample) 1978-07-15
GB1348480A (en) 1974-03-20
AU3128271A (en) 1973-01-18
FR2101785A5 (enExample) 1972-03-31
AU461604B2 (en) 1975-05-29

Similar Documents

Publication Publication Date Title
US3801489A (en) Tool for electrolytic drilling of holes
US3917148A (en) Welding tip
CN109570666B (zh) 电解线切割加工用双极性工具电极及制作与加工方法
US3995134A (en) Apparatus for electric discharge machining of holes
US3276987A (en) Electrolytic shaping apparatus
JPH06226539A (ja) 形状管電解研磨方法
JP2002346837A (ja) 電解放電加工装置及び加工方法
US3268434A (en) Apparatus for electrolytic machining
US4113587A (en) Method for electrochemical machining
US4721838A (en) Tool for electrical discharge piercing of intricately-shaped holes and method of using same
IT8267492A1 (it) Procedimento ed apparecchio per la lavorazione elettroerosiva di pezzi
EP0248068A1 (en) Device for forming holes.
US3793170A (en) Electrochemical machining method and apparatus
US3803018A (en) Electrolytic hole forming cathode electrode
US3196093A (en) Electrolytic cavity sinking apparatus and method for non-parallel workpiece surfaces
JP4460132B2 (ja) 異形穴の電解加工方法
CN105108250A (zh) 柔性化在线制备微细群线电极的方法
AU2021101009A4 (en) Copper graphene nanocomposite electrode
US3436331A (en) Electro-chemical machining electrode
US4052274A (en) Electrochemical wire cutting method
US3278411A (en) Electrolyzing electrode
JP3330368B2 (ja) 超微細な円筒型電極の製作のための電解加工方法
US3842480A (en) Method of making guide for electrochemical drilling
KR102390213B1 (ko) 방전가공 금형장치
US3257300A (en) Method for electrolytically forming tapered or contoured cavities