Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 48, Issue 119
Displaying 1-3 of 3 articles from this issue
Paper
  • Katsuaki ENDO, Wataru NATSU
    Article type: Paper
    2014 Volume 48 Issue 119 Pages 171-177
    Published: 2014
    Released on J-STAGE: May 25, 2015
    JOURNAL FREE ACCESS
     Since electrochemical machining (ECM) is a contactless machining method, it is necessary to detect and control the gap-width to estimate the machining amount and improve the machining speed and accuracy. In this study, a tool electrode capable of detecting the gap-width via the suction pressure was proposed. In this method, the electrolyte is confined and circulated beneath the tool electrode using a single suction pump. It was found that the electrolyte is successfully circulated using the pump. In addition, the suction pressure indicates the gap-width and the pressure signal can be used to control the tool electrode feed.
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  • Takeo TAMURA, Daichi MAEDA
    Article type: Paper
    2014 Volume 48 Issue 119 Pages 178-185
    Published: 2014
    Released on J-STAGE: May 25, 2015
    JOURNAL FREE ACCESS
     As a method of processing cemented carbide, sinking electrical discharge machining (EDM) is generally used. However, typical surface defects, such as cracks, microcraters and recast layers, lead to decreased surface integrity and may result in an inadequate tool life. Currently, the recast layer is removed by polishing. However, this process requires a long machining time, causing a high production cost of metal molds. Therefore, it is desirable to eliminate these surface defects. Thus, an on-the-machine surface modification technology in EDM, for the complete elimination of surface defects, was developed in this study. The surface defects are eliminated using a sinking electrical discharge machine in which surface integrity machining for EDM (SIME process) is introduced after applying a finishing processing. The SIME process is carried out by applying voltage to the constant gap between the electrode and the workpiece in deionized water. It can be considered that a recast layer including cracks is selectively eliminated by the dissolution of cobalt through the electrolytic action during the SIME process. As a result, the surface defects generated by EDM could be completely eliminated by incorporating the SIME process into EDM.
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  • Akihiro MANABE, Masanori KUNIEDA
    Article type: Paper
    2014 Volume 48 Issue 119 Pages 186-193
    Published: 2014
    Released on J-STAGE: May 25, 2015
    JOURNAL FREE ACCESS
     In this paper, we describe the tool wear of micro-electrochemical machining (ECM) by the electrostatic induction feeding method. When a pulse voltage is coupled to the ECM working gap, electrolytic current flows only during the rise and fall times of the rectangular pulse, thereby enabling ultrashort-pulse ECM. However, since the electrolytic current is bipolar, there is a concern that the tool electrode wear may be significant. Thus, the tool electrode wear was measured and found to be negligible in the drilling of a plate workpiece made of the same material as the tool electrode. Hence, the influence of the difference in shape between the tool electrode and the plate workpiece on the temperature of the working surface was investigated analytically and experimentally. As a result, it was found that a higher temperature rise on the tool electrode than that on the workpiece, owing to the greater resistance to heat conduction, reduced the tool wear. This result can be verified by the fact that the electrostatic capacity of the double layer may increase with temperature.
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