Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 40, Issue 93
Displaying 1-4 of 4 articles from this issue
Paper
  • -Application of micro sized cutting tool-
    Masaaki SANO, Koji YATSUSHIRO, Akira YONEYAMA, Katsuzo OKADA
    2006 Volume 40 Issue 93 Pages 13-20
    Published: April 14, 2005
    Released on J-STAGE: June 26, 2008
    JOURNAL FREE ACCESS
    In this report, various materials(tungsten, cemented carbide, high-speed steel, and polycrystalline diamond) were machined by micro-electric-discharge-machining. Then, their surfaces were evaluated by SEM observation, surface roughness measurement, residual stress measurement and X-ray diffraction analysis. The following are the results of the experiment; 1) Few layers were affected in the cemented carbide and the polycrystalline diamond, but many layers were affected in the machining of high-speed steel and tungsten. Moreover, the cemented carbide and polycrystalline diamond showed the tendency to have a smooth surface roughness when they were machined in the finishing condition. 2) When electric discharge machining was performed on the minute stick material, the tensile stress on the end and the compression stress on the side were existed. 3) The cutting hole experiment was performed with a drill made of cemented carbide. But extra burr existed around the hole, it was possible to drill a copper plate.
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  • Yasuhiro OKAMOTO, Norio KATAOKA, Yoshiyuki UNO, Eiji YUASA, Shin-ichir ...
    2006 Volume 40 Issue 93 Pages 21-28
    Published: 2006
    Released on J-STAGE: June 26, 2008
    JOURNAL FREE ACCESS
    Machining characteristics and the quality of microboring for fine powder cemented carbide by diode-pumped Q-switched YAG laser irradiation were experimentally investigated in order to obtain microaccurate holes with a high aspect ratio. In general, it is difficult to cut and polish the microhole of a hard material accurately for observing the inside of the machined hole. Therefore, micro-EDM was used as a cutting and polishing method in this study. Evaluation of the sectional surface of the microhole clarified the following facts. The low pulse frequency of laser oscillation led to the reduction of cracks and of the resolidification layer inside the machined hole. The bulge along the inside of the machined hole hardly appeared in thin-workpiece and high-peak-power conditions, in which the penetraction hole could be obtained in a short time. Therefore, it is considered that laser penetrating time was the important factor affecting the formation of the bulge. Laser irradiation consisting of two stages was proposed in order to reduce the laser beam irradiation time per process. In the first pocess, laser irradiation for 1 second was perfomed. Then, in the second process, the laser beam was irradiated after moving the focus point inside the workpiece is two-stage irradiation made it possible to improve the quality of the machined hole.
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  • Takayuki ABE, Takeshi MASAKI, Toshihiko WADA, Takahisa MASUZAWA
    2006 Volume 40 Issue 93 Pages 29-35
    Published: June 23, 2005
    Released on J-STAGE: June 26, 2008
    JOURNAL FREE ACCESS
    Electrochemical machining (ECM) has the advantage that it can quickly produce mirrorlike surfaces without causing any additional damage and stress on the workpiece surface. However, it has a limit in machining accuracy in the machining of microshapes. In this study, short current pulses of microsecond order are introduced to achieve selective dissolution and their effectiveness on the precision of machining is experimentally investigated. The differences among various electrode materials are also tested in terms of durability and machining accuracy, changing machining gap and pulse duration. As a result, it was found that titanium is a suitable material for the electrode for micro-ECM. The condition of 20 μs pulses and a 5 μm machining gap could achieve the machining of 5-μm- deep micropatterns of 50/50 μm line/space into stainless steel.
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  • Katsumi MIZUTANI, Kai EGASHIRA, Kazuo MURATA, Masanori ITOH
    2006 Volume 40 Issue 93 Pages 36-41
    Published: July 11, 2005
    Released on J-STAGE: June 26, 2008
    JOURNAL FREE ACCESS
    In this paper, we clarify EDM conditions for shaping a hemispherical tool tip (ball end) via the electrode wear phenomenon. Electrodischarge drilling in brass wire with a rotating tool of tungsten or cemented carbide using an RC circuit and an oil-type working fluid was carried out under various conditions of parameters such as polarity, open-circuit voltage, capacitance, tool feed speed and tool feed. The results obtained are as follows. (1) Rough machining, where the tool is the anode and the wire is the cathode, followed by fine machining, where the tool is the cathode and the wire is the anode, enables the fabrication of hemispherical tool tips of 10μm and 20μm diameters with a shape error of 3%. (2) When boll-end shapes can be fabricated in rough machining, the experimental relation vhp=c (v: tool feed speed, h: tool feed, p and c: characteristic constants) is found. (3) Estimative v-h relations for fabricating ball-end shapes of various diameters can be derived from the v-h relation experimentally obtained for a certain diameter and the geometrical relation obtained on the basis of the assumption that these shapes are realized when a hemispherical cavity is produced in the wire.
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