US3336213A - Cathode for electrolytic machining - Google Patents

Cathode for electrolytic machining Download PDF

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Publication number
US3336213A
US3336213A US288975A US28897563A US3336213A US 3336213 A US3336213 A US 3336213A US 288975 A US288975 A US 288975A US 28897563 A US28897563 A US 28897563A US 3336213 A US3336213 A US 3336213A
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US
United States
Prior art keywords
cathode
working end
dielectric
electrolytic machining
workpiece
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
US288975A
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English (en)
Inventor
Claude H Auger
James D Andrews
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.)
General Electric Co
Original Assignee
General Electric 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
Application filed by General Electric Co filed Critical General Electric Co
Priority to US288975A priority Critical patent/US3336213A/en
Priority to BE647836A priority patent/BE647836A/xx
Priority to DE19641496801 priority patent/DE1496801C/de
Priority to FR975823A priority patent/FR1396178A/fr
Priority to SE7140/64A priority patent/SE300917B/xx
Priority to CH783564A priority patent/CH409178A/de
Priority to GB25048/64A priority patent/GB1065145A/en
Application granted granted Critical
Publication of US3336213A publication Critical patent/US3336213A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • 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
    • B23H3/04—Electrodes specially adapted therefor or their manufacture

Definitions

  • This invention relates to electrolytic machining, and more particularly to an improved cathode of increased life for use in electrolytic machining.
  • the dielectric material at the tip or end of the cathode referred to herein as the working end portion, which iirst enters the surface of the workpiece is subject to considerable wear, abrasion and chipping action. Once part of the dielectric material at the working end portion is removed, side electrolytic action can occur, thus resulting in non-uniformity of the cavity produced and reduction in the usefulness of or damage to the cathode. Generally replacement of the cathode is required.
  • An object of the Ipresent invention is to provide a cathode for electrolytic machining having and improved working end portion.
  • Another object is to provide a cathode having a wear resistant outer peripheral portion including the working end portion.
  • FIG. l is a cross-sectional view of a hollow tubular form of the .present invention having an improved working end portion
  • FIG. 2 is a cross-sectional view of the cathode of the present invention having an .improved outer peripheral wear resistant surface
  • FIG. 3 is an isometric partially sectional view of a solid rectangular cathode including an improved .tip portion according to the present invention.
  • the cathode of the present invention has a working end portion to cooperate with an anodic workpiece as a cathode in electrolytic machining, the working end portion comprising an electrically conductive inner portion, an intermediate portion of a dielectric material and an uncharged outer metalli-c portion electrically insulated from the current carrying inner portion.
  • a preferred form of the present invention particularly useful for the generation of long small diameter passages in jet engine turbine blades, comprises a hollow tubular metallic inner portion, a cured dielectric plastic intermediate coating and an outer metallic sleeve inserted in the cured plastic coating flush with the peripheral sides of the coating yet electrically insulated from the inner portion by a part of the dielectric coating.
  • Cooling passaegs in jet engine turbine blading have been generated through the use of electrolytic machining processes.
  • a number of passages for the flow of cooling air were generated through each blade from the blade tip to the blade shank portion near the blade base.
  • Such passages were, in some instances, in the shape of a hollow tubular passage having a length of about 6 or 7 inches and a diameter of less .than 0.030 inch.
  • a cathode or tool in the form of a hollow tube was tried.
  • a dielectric portion for example a coating of cured epoxy resin or a plastic tetrailuoroethylene polymer coating was applied .to the outer lateral surface of the cathode.
  • Such a dielectric portion concentrates at the working end portion the current flow through 4the electrolyte and obviates the short circuiting and side electrolytic effects -described above.
  • the cathodes In order to generate many closely spaced air cooling passages in an article as a turbine blade, it is essential that the cathodes be very accurately dimensioned and of unusual straightness. Thus .the cost of a suitable hollow tubular cathode is relatively great compared with ordinary tubing. In the production of a large number of air cooled turbine blades, a large number of cathodes are required. However, it was recognized that the usefulness and life of the cathodic tubes was seriously limited by abrasive or chipping action occurring at the working end of the cathode on the dielectric coating.
  • the cathode shown generally at 10 has an uncharged metallic portion 12 embedded at the working end portion 18 in dielectric material 14.
  • the cathode in FIG. 1 in the form of a hollow metallic t-ube, has an electrically conductive inner portion 16, an intermediate portion 14 of a dielectric material and an uncharged outer metallic portion 12 electrically insulated from the current carrying inner portion.
  • the electrically conductive inner portion is a hollow titanium tube with an intermediate dielectric coating of a plastic tetrafluoroethylene polymer sometimes referred to as Teflon material.
  • a titanium tip or sleeve is embedded in the dielectric portion 14 and insulated ⁇ by means of that dielectric portion from the inner conductive member 16.
  • the cathode of FIG. 1 will allow current to flow from the working end portion 18 of inner member 16 while metallic member -12 protects the tip portion from wear and abrasion.
  • FIG. 2 shows another embodiment of the present invention wherein the outer lateral surface of inner member 16 is first covered with a dielectric coating around which is placed an outer metallic portion 12, included at the tip portion as well as along the sides of the cathode.
  • an outer portion 12 can be slipped or pressed over the dielectric material or can be electroplated orl electroformed in place by standard, well known electrodeposition practices after first sensitizing the surface of the dielectric material.
  • the sensitizing can be accomplished by chemically reducinga flash coating, such as of silver from a silver nitrate solution, onto the surface of the dielectric material.
  • standard electrodeposition practices can be used to coat the initial flash coat of silver with other stronger, tougher metals. This practice of electroplating or electroforming the outer metallic, uncharged portion is especially useful in the preparation of solid or hollow cathodes having irregularly shaped outer dimensions.
  • Such an irregularly shaped cathode is the composite solid cathode shown in FIG. 3 wherein over inner conductive member 16 is an intermediate dielectric portion 14 and an electroformed uncharged outer metallic portion 12 at its working end 18. It will be recognized that inner member 16 can be hollow without departing from the scope of ⁇ the .present invention.
  • Electrolytic machining apparatus comprising in combination an improved cathodic-tool including a Working end portion to cooperate with a workpiece in electrolytic machining, the working end portion comprising:

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Mechanical Engineering (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
US288975A 1963-06-19 1963-06-19 Cathode for electrolytic machining Expired - Lifetime US3336213A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US288975A US3336213A (en) 1963-06-19 1963-06-19 Cathode for electrolytic machining
BE647836A BE647836A (de) 1963-06-19 1964-05-12
DE19641496801 DE1496801C (de) 1963-06-19 1964-05-23 Kathode zur elektrolytischen Metallbearbeitung
FR975823A FR1396178A (fr) 1963-06-19 1964-05-26 Cathode pour usinage électrolytique
SE7140/64A SE300917B (de) 1963-06-19 1964-06-11
CH783564A CH409178A (de) 1963-06-19 1964-06-16 Elektrode für elektrolytische Metallbearbeitung
GB25048/64A GB1065145A (en) 1963-06-19 1964-06-17 Improvements for cathodes for electrolytic machining

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US288975A US3336213A (en) 1963-06-19 1963-06-19 Cathode for electrolytic machining

Publications (1)

Publication Number Publication Date
US3336213A true US3336213A (en) 1967-08-15

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Family Applications (1)

Application Number Title Priority Date Filing Date
US288975A Expired - Lifetime US3336213A (en) 1963-06-19 1963-06-19 Cathode for electrolytic machining

Country Status (5)

Country Link
US (1) US3336213A (de)
BE (1) BE647836A (de)
CH (1) CH409178A (de)
GB (1) GB1065145A (de)
SE (1) SE300917B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4797527A (en) * 1985-02-06 1989-01-10 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Electrode for electric discharge machining and method for producing the same
US5320721A (en) * 1993-01-19 1994-06-14 Corning Incorporated Shaped-tube electrolytic polishing process
EP3766618A1 (de) 2019-07-19 2021-01-20 MTU Aero Engines GmbH Kathode für elektrochemische bearbeitung mit optimierten durchflussparametern

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2222977A (en) * 1988-09-21 1990-03-28 Erodex Electrode
DE19960790B4 (de) * 1999-12-16 2006-02-09 Mtu Aero Engines Gmbh Elektrode zum elektrochemischen Feinbohren von Werkstücken sowie Verfahren zu ihrer Herstellung

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1307441A (fr) * 1960-12-01 1962-10-26 Gen Electric Procédé et appareil électrolytiques pour tarauder une pièce électroconductrice
GB938516A (en) * 1960-12-01 1963-10-02 Gen Electric Improvements in electrolytic tapping method and apparatus
US3278411A (en) * 1962-09-10 1966-10-11 Anocut Eng Co Electrolyzing electrode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1307441A (fr) * 1960-12-01 1962-10-26 Gen Electric Procédé et appareil électrolytiques pour tarauder une pièce électroconductrice
GB938516A (en) * 1960-12-01 1963-10-02 Gen Electric Improvements in electrolytic tapping method and apparatus
US3278411A (en) * 1962-09-10 1966-10-11 Anocut Eng Co Electrolyzing electrode

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4797527A (en) * 1985-02-06 1989-01-10 Kanegafuchi Kagaku Kogyo Kabushiki Kaisha Electrode for electric discharge machining and method for producing the same
US5320721A (en) * 1993-01-19 1994-06-14 Corning Incorporated Shaped-tube electrolytic polishing process
EP3766618A1 (de) 2019-07-19 2021-01-20 MTU Aero Engines GmbH Kathode für elektrochemische bearbeitung mit optimierten durchflussparametern

Also Published As

Publication number Publication date
BE647836A (de) 1964-08-31
DE1496801B2 (de) 1973-01-11
DE1496801A1 (de) 1969-07-17
SE300917B (de) 1968-05-13
GB1065145A (en) 1967-04-12
CH409178A (de) 1966-03-15

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