Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 45, Issue 109
Displaying 1-3 of 3 articles from this issue
  • Kei SHISHIHARA, Haruki OBARA, Ikkou MATSUBARA, Tohru SASAKI
    2011 Volume 45 Issue 109 Pages 54-63
    Published: 2011
    Released on J-STAGE: October 05, 2011
    JOURNAL FREE ACCESS
    In this paper, methods of obtaining fine-finish surfaces in wire electrical discharge machining are discussed. Some countermeasures to reduce the stray capacitance of wire EDM, which restricts the surface roughness on an EDMed surface, are described. A surface roughness of 0.6[μm] Rz is obtained using a 0.1[μs] pulse width group type AC pulse generator. However, we observed a problem of streaking on the machined surface. To determine the causes of such streaking, the wire behavior during the machining is observed. The mechanism of fine finish wire EDM and the reason of the streaking are discussed.
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  • Akira OKADA, Toshiyuki YAMAUCHI, Masanori NAKAZAWA, Toshiaki SHIMIZU, ...
    2011 Volume 45 Issue 109 Pages 64-70
    Published: 2011
    Released on J-STAGE: October 05, 2011
    JOURNAL FREE ACCESS
    The purpose of this study is to develop a new type of coated wire electrode for fine-wire EDM. A piano wire with a very high tensile strength is coated with an electrically conductive brass layer to achieve high-speed and high-precision wire EDM. In our previous studies, by using a thin wire of 50 μm in diameter, the thickness and quality of the brass coating layer were optimized, and the effect of surface unevenness was also discussed. In this paper, the effects of the oxidation of the wire surface and high-resistance layer on the wire electrode were experimentally investigated. It was found that more sparks occur selectively in front of the wire and less sparks on the side surface of wire with the high-resistance layer on the wire surface. Consequently, the kerf width decreased and the removal rate increased with the optimum thickness of the layer. Also, the occurrence of a short circuit between the wire and the machined surface was reduced because of presence of a high-resistance layer on the wire surface.
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  • Masahide YAMASHITA, Tomoo KITAMURA, Ken YAMASHITA, Yasushi FUKUZAWA
    2011 Volume 45 Issue 109 Pages 71-79
    Published: 2011
    Released on J-STAGE: October 05, 2011
    JOURNAL FREE ACCESS
    Electric discharge machining has been widely used in making the arbitrary shapes for various metallic materials, and appropriate conditions for such machining have been selected mostly by trial machining in actual processes. However, the removal rate are depends on the fundamental thermal properties of the materials used. In other words, adequate machining conditions can be determined uniquely by only studying thermal properties even without machining trials. In this study, determine the most effective thermal properties using 12 fundamental types of pure metal. The respective thermal properties were confirmed using heat conduction equations, which were solved to predict the discharge machining behavior on material surfaces. The relationships between the thermal properties and the removal rate were confirmed from the elimination quantities obtained in the impulse discharge machining trials, and the behaviors were also discussed on the basis of the XRD measurements of machining surfaces.
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