US2951142A - Method and arrangement for spark erosion by alternating current - Google Patents

Method and arrangement for spark erosion by alternating current Download PDF

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Publication number
US2951142A
US2951142A US647163A US64716357A US2951142A US 2951142 A US2951142 A US 2951142A US 647163 A US647163 A US 647163A US 64716357 A US64716357 A US 64716357A US 2951142 A US2951142 A US 2951142A
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United States
Prior art keywords
electrode
spark gap
spark
workpiece
generator
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Expired - Lifetime
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US647163A
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English (en)
Inventor
Ullmann Werner
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Agie Charmilles SA
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Agie Charmilles SA
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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
    • B23H1/00—Electrical discharge machining, i.e. removing metal with a series of rapidly recurring electrical discharges between an electrode and a workpiece in the presence of a fluid dielectric
    • B23H1/02—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges
    • B23H1/022—Electric circuits specially adapted therefor, e.g. power supply, control, preventing short circuits or other abnormal discharges for shaping the discharge pulse train

Definitions

  • the present invention relates to a method of and arrangement for detaching material by means of spark erosion using alternating current.
  • the invention is characterized by the fact that a half cycle of the alternating voltage applied to the spark gap is at least partly suppressed for the purpose of altering the voltage course and, accordingly, the gap configuration.
  • an electrode and a workpiece are bridged so that polarity may be reversed by a control member having a variable forward resistance which is dependent on the direction of current.
  • Fig. 1 is a basic circuit diagram of an embodiment of the invention
  • Fig. 2 is a circuit diagram of the electrical devices used in spark erosion with a relaxation generator
  • Fig. 3 is a circuit diagram of the electrical devices used in spark erosion with an oscillatory circuit
  • Fig. 4 is a circuit diagram of the electrical devices used in spmk erosion with an impulse generator
  • Fig. 5 is a circuit diagram of the electrical devices used in spark erosion with another impulse generator
  • Fig. 6 is a section of a workpiece manufactured by means of a method according to the concepts of the invention.
  • Figs. 7a and 7b are sections of another workpiece manufactured by means of a method, illustrating the electrode disposed in the workpiece.
  • the circuit shown in Fig. 1 comprises a generator 1 which supplies the spark gap 2 with arrangements whereby the voltage and frequency may be altered.
  • the spark gap may be surrounded by a liquid dielectric.
  • a first polarity reversal switch 3 is arranged in the circuit.
  • a valve or rectifier 4 Arranged parallel with the erosion gap via a further reversing switch 5 is a valve or rectifier 4 which is connected to the input circuit and suppresses part of the total energy in the one or the other half-wave cycle of the current.
  • a variable resistance 6 is connected in series with the valve 4, by means of which the action of the valve on the spark gap can be influenced.
  • This basic arrangement may be applied to all generators so far employed for electric erosion; the generator 1 in Fig. *2 is a relaxation generator, in Fig. 3 an oscillatory circuit generator, and in Figs. 4 and 5 an impulse generator.
  • the prerequisite for the operation of these generators is that the consuming member passes current in either direction; this condition is fulfilled in the am rangement disclosed.
  • any of the known rectifier types may be used as a valve, in particular, inductances having an acute saturation bend and DC. bias; magnetization by an additional winding.
  • the voltage between the tool and the work may be altered.
  • the dimension of the spark gap varies depending on the magnitude of the voltage.
  • the amount of material detached at an electrode in spark or are operations is determined by the polarity of the spark gap. If the cathode of the spark gap in the application according to Fig. 1 is formed by the work to be' treated, and the anode by a working electrode, the amount of material removed from the work is proportionately smaller than that removed from the electrode. If switch 5 is actuated and the rectifier polarity thereby reversed, both the work and electrode will change their polarity; a larger amount of material is then removed from the work than from the electrode.
  • the ratio between the detachment per unit current in both directions depends on the type of material; however, it corresponds to approximately 1:4.
  • Fig. 6 shows an example of a workpiece produced with the method described.
  • a bore with a recessed end is to be produced in a workpiece.
  • procedure is as follows:
  • the electrode 7 is connected with the positive pole of the voltage, workpiece 8 with the negative pole, and the electrode then inserted in the workpiece in the known manner.
  • this arrangement causes more material to be detached at the electrode than at the workpiece so that the neck of the bore is obtained.
  • the two switches are actuated to reverse polarity; a larger amount of material is then detached at the workpiece and the widened blind end thereby produced.
  • Selection of polarity, voltage at the workpiece, electrode material and the portion of energy conducted through the shunt, the quantity of the material detached may be varied in the manner known.
  • variable valve forward resistance of which the polarity may be reversed all bores may be obtained between these extreme dimensions and, if desired, continuous transitions intermediate of the said values.
  • a further application of the method is in the production of workpieces having the shape shown in Fig. 7b. It has been found that projecting edges (A) may best be obtained, when the work is treated by means of spark erosion, if the workpiece is the positive pole and the electrode the negative pole of the spark gap. In the case of recessed edges (B) in Fig. 7a it is most advantageous to connect the work with the negative pole and the electrode with the positive pole.
  • an electrode having the cross-section'shownin'Fig. 7a' is" first used; the projecting edges (A) are not provided'on the electrode. With this electrode only the edges (B) areobtained.
  • the electrode is the positive pole and'the work the negative pole in this stage of production.
  • thesecond electrode which is shown in'cross-section in Fig. 7b, is applied. In the second stage,'the edges' (B) are not treated While the projecting edges (A) are produced, theconneo tions being reversed in this second operation.
  • a device for detaching material from a metallic bodylby means of spark erosion comprising a voltage generator for generating an alternating voltage having a positive and a negative wave portion, a metallic electrode forming one pole of a spark gap, a metallic body arranged in'said device and forming a second pole of said spark gap, rectifying means, variable resistor means, respective means connecting said spark gap with said voltage generator and connecting said rectifying means and said variable resistor means in parallel with said spark gap to suppress at least part of one of said wave portions, and a selectively operable reversing switch arranged between said rectifying means and said spark gap to thereby suppress at least a part of a selected one of said wave portions of said alternating voltage.
  • a device for detaching material from a metallic body by means of spark erosion comprising a voltage generator for generating an alternating voltage having a positive and a negative Wave portion, a metallic electrode forming one pole of a spark gap, a metallic body arranged in said device and forming a second pole of said spark gap, rectifying means having a rectifier and an adjustable resistor arranged in series connection, connecting means connecting said spark gap with said voltage generator and connecting said rectifying means in parallel with said spark gap, respectively, and a two-position reversing switch arranged between said rectifying means and said spark gap, whereby said rectifying means suppress at least a part of said positive wave portion in one position of said reversing switch and said negative wave portion in the other position of said reversing switch to thereby influence the sparking process.
  • a device in which said connecting means includes a second reversing switch arranged between said generator means and said spark gap.
  • a device in which said generator means include an oscillatory circuit.
  • a device in which said generator means include -a pulse generator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
US647163A 1956-03-19 1957-03-19 Method and arrangement for spark erosion by alternating current Expired - Lifetime US2951142A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH860118X 1956-03-19

Publications (1)

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US2951142A true US2951142A (en) 1960-08-30

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US647163A Expired - Lifetime US2951142A (en) 1956-03-19 1957-03-19 Method and arrangement for spark erosion by alternating current

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US (1) US2951142A (de)
CH (1) CH337282A (de)
DE (1) DE1008428B (de)
FR (1) FR1169785A (de)
GB (1) GB860118A (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3062985A (en) * 1960-11-08 1962-11-06 Elox Corp Michigan Impedance matching circuit for spark machining
US3098149A (en) * 1960-06-06 1963-07-16 Inoue Kiyoshi Spark discharge maching apparatus for hard metals
US3109120A (en) * 1960-10-20 1963-10-29 Gen Motors Corp Electrical stock removal apparatus
US3158728A (en) * 1960-07-26 1964-11-24 Elox Corp Michigan High voltage-reverse polarity edm
US3213257A (en) * 1960-07-19 1965-10-19 Gen Motors Corp Electrical stock removal apparatus
US3433919A (en) * 1960-08-26 1969-03-18 Soudure Elec Languepin Apparatus for electrically treating workpieces with electrodes
US3624338A (en) * 1970-08-06 1971-11-30 Ibm Electrical discharge machining pulse-polarity-reversing control
US3732392A (en) * 1971-03-10 1973-05-08 Elox Inc Polarity reversal system for electrical discharge machining apparatus
US3777102A (en) * 1972-07-19 1973-12-04 Colt Ind Operating Corp Electrical discharge machining power supply circuit
US4277668A (en) * 1978-03-07 1981-07-07 Inoue-Japax Research Incorporated High-frequency power feeder circuitry and supply method for electrical discharge machining
US4350863A (en) * 1978-03-07 1982-09-21 Inoue-Japax Research Incorporated High-frequency power feeder circuitry and supply for electrical discharge machining
US5399825A (en) * 1991-03-01 1995-03-21 Creare, Inc. Inductor-charged electric discharge machining power supply
US20140116990A1 (en) * 2012-10-30 2014-05-01 Mitsubishi Electric Corporation Electric discharge machining apparatus
CN112122721A (zh) * 2020-08-11 2020-12-25 查世樑 啮合副加工方法

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1109801B (de) * 1957-12-12 1961-06-29 Siemens Ag Verfahren zur Herstellung einander arbeitsmaessig zugeordneter Metalloberflaechen von Werkstuecken mittels Elektroerosion
NL125592C (de) * 1958-11-10
NL258818A (de) * 1959-12-08
JP3331077B2 (ja) * 1994-12-21 2002-10-07 株式会社ソディック 放電仕上げ加工用電源装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2273819A (en) * 1940-01-01 1942-02-24 Kapella Ltd Apparatus for electrically etching metallic articles

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2273819A (en) * 1940-01-01 1942-02-24 Kapella Ltd Apparatus for electrically etching metallic articles

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3098149A (en) * 1960-06-06 1963-07-16 Inoue Kiyoshi Spark discharge maching apparatus for hard metals
US3213257A (en) * 1960-07-19 1965-10-19 Gen Motors Corp Electrical stock removal apparatus
US3158728A (en) * 1960-07-26 1964-11-24 Elox Corp Michigan High voltage-reverse polarity edm
US3433919A (en) * 1960-08-26 1969-03-18 Soudure Elec Languepin Apparatus for electrically treating workpieces with electrodes
US3109120A (en) * 1960-10-20 1963-10-29 Gen Motors Corp Electrical stock removal apparatus
US3062985A (en) * 1960-11-08 1962-11-06 Elox Corp Michigan Impedance matching circuit for spark machining
US3624338A (en) * 1970-08-06 1971-11-30 Ibm Electrical discharge machining pulse-polarity-reversing control
US3732392A (en) * 1971-03-10 1973-05-08 Elox Inc Polarity reversal system for electrical discharge machining apparatus
US3777102A (en) * 1972-07-19 1973-12-04 Colt Ind Operating Corp Electrical discharge machining power supply circuit
US4277668A (en) * 1978-03-07 1981-07-07 Inoue-Japax Research Incorporated High-frequency power feeder circuitry and supply method for electrical discharge machining
US4350863A (en) * 1978-03-07 1982-09-21 Inoue-Japax Research Incorporated High-frequency power feeder circuitry and supply for electrical discharge machining
US5399825A (en) * 1991-03-01 1995-03-21 Creare, Inc. Inductor-charged electric discharge machining power supply
US20140116990A1 (en) * 2012-10-30 2014-05-01 Mitsubishi Electric Corporation Electric discharge machining apparatus
US9440300B2 (en) * 2012-10-30 2016-09-13 Mitsubishi Electric Corporation Electric discharge machining apparatus
CN112122721A (zh) * 2020-08-11 2020-12-25 查世樑 啮合副加工方法

Also Published As

Publication number Publication date
DE1008428B (de) 1957-05-16
GB860118A (en) 1961-02-01
CH337282A (de) 1959-03-31
FR1169785A (fr) 1959-01-06

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