Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 13, Issue 26
Displaying 1-4 of 4 articles from this issue
  • Eiichi SUGANUMA
    1980 Volume 13 Issue 26 Pages 3-20
    Published: March 31, 1980
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    A potentiostatic transient study was made on the passivation of tungesten carbide alloy in NaNO3 solution. The initial stage of the passivation process was discussed in terms of the current-time relation. The oxides formed were stripped from the specimen surface with constant current stripping pulse. The amount of charge associated with oxide layer was determined as a function of the working parameters such as current density, electrode potential and machining time.
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  • Tadao TSUTSUI, Takeo TAMURA, Takenori TOMITA
    1980 Volume 13 Issue 26 Pages 21-29
    Published: March 31, 1980
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    By a rotary electrode, WC-Co cemented carbide i s machined under low voltage (not exceeding 100 volts) and the machinability is compared by using the dielectric liquid such as kerosene or service city water. The results are as follows:
    (1) The maximum value of the discharge current in water is lower than the one in kerosene under the same electrical condition.
    (2) In water the electrode wear rate is lower and also the stock removal rate becomes larger than in kerosene when the source voltage increases or the charging resistance decreases.
    (3) The electrolytic action is recognized in water (specific resistance: 103-104Ωcm) and it influences both the removal rate and the machining accuracy.
    (4) In water the surface roughness is smaller and then the machining accuracy becomes lower than in kerosene. When using the isolated electrode in water, the accuracy is remarkably improved.
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  • Relationship between Energy Supplying Duration, Peak Discharge Current and Stress Distribution
    Yoshitsugu MUKOYAMA, Isao OGATA, Masahiko HIHARA
    1980 Volume 13 Issue 26 Pages 30-41
    Published: March 31, 1980
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    In the electric discharge machining, the stress that generates on surface of the electrodes (workpiece and tool electrode) causes to produce cracks, and directly affects on the quality of the working objects (workpieces) after the machining as a residual stress, Previously, the theoretical analysis by means of the Monte Carlo method about stress distribution in the electric discharge machining had been reported by the same writers, but further it is very important matters to measure the stress distribution practically in various working conditions. Accordingly, the stress that generates on surface of the workpiece is measured by the method for X ray measuring, and this paper mainly deals with the relationship energy supplying duration, peak discharge current and stress distribution in rectangular energy supplying form about impulse discharged crater.
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  • Pulse Discharge Phenomena in Small Electrode Gap
    Mamoru KUBOTA, Yuji TAMURA, Hiroyuki TAKAHASHI, Tomio SUGAYA
    1980 Volume 13 Issue 26 Pages 42-56
    Published: March 31, 1980
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Single pulse discharge phenomena in the electrode gap smaller than 0.1mm filled with NaCl or NaNO3 solution are studied to make clear the working mechanism of electro-chemical discharge machining (ECDM). Gap voltage and current in discharge process and marks remained on the anode surface are investigated. Besides, ECDM with a square wave pulse generator is tried to obtain the optimum pulse width in this process.
    Discharge in electrolyte between carbon rod cathode and steel plate anode gets a type of either spark or arc. Fine spark discharge occurrs through gas bubbles between electrode and electrolyte, and it has no effect of metal removal. Developed arc discharge takes place between two electrodes and makes crater on the work surface.
    The influences of electrolyte, electrode gap, applied voltage and pulse width to the discharge in electrolyte are discussed in view of ignition delay. It is remarkable that discharge occurrs more easily in the electrolyte of higher concentration. Working voltage wave form in ECDM with a square wave pulse generator is similar to that of the single pulse discharge. Metal removal rate of it shows maximum when the pulse width is about 10-15ms.
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