Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 28, Issue 59
Displaying 1-5 of 5 articles from this issue
  • Fabrication of Micro-mechanical Elements
    Koichi KAWATA, Takeshi MASAKI, Takeo SATO, Takahisa MASUZAWA
    1994 Volume 28 Issue 59 Pages 1-10
    Published: November 30, 1994
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Several important features of micro-EDM were tested and the feasibility to the parts production for micromachines was confirmed through the fabrication of practical micro components.
    Main results are as follows.
    It was clarified that silicon wafers which have the resistivity range of 0.02 to 50ohm-cm are machinable by micro-EDM. Machining time and electrode wear are less than those in the case of metals. The reason is assumed to be that the machining mechanism mainly involves the generation of microcracks and fracture rather than melting.
    Through the analysis of electrode wear, a process sequence was found to be preferable for machining complex shapes. That is:1. The rough shape is machined by the axial movement of the electrode repeated along the contour. 2. The side wall is finished by a continuous movement of the electrode along the surface.
    A micro-air turbine with 2.2mm diameter and a micro-polygon mirror with 2mm side length are successfully manufactured with the developed micro-electrodischarge machine and the shaft-making machine using the principle of wire electrodischarge grinding (WEDG).
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  • Masayuki SUZUKI, Toshiyuki IKEDA, Naotake MOHRI, Nagao SAITO
    1994 Volume 28 Issue 59 Pages 11-20
    Published: November 30, 1994
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    A rapid change of machining rate in EDM process under certain conditions has been known. In this paper, this change of machining rate is discussed with machined volume in each discharge through observation surface roughness, radius of removed particles, electrical states in gap region and discharge position on machined surface.
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  • Masanori KUNIEDA, Masahiro MORI
    1994 Volume 28 Issue 59 Pages 21-30
    Published: November 30, 1994
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    This paper describes a simulation of workpiece geometry eroded by the die-sinking EDM. The geometry of workpiece is determined by the worn geometry of the tool electrode and the gap width distribution. The paper found that the local gap width is a function of the curvature and the inclination of the surface of the tool electrode from the feed direction, and that the local wear ratio of the tool electrode is affected by the local gap width. Moreover, the geometrical factors such as the curvature and the inclination are closely related to the local wear of the tool electrode. Starting with given contours of thin plate electrodes, the change of the workpiece geometry was simulated considering the tool wear and the gap width distribution. The erosion experiment was carried out by placing the tool and workpiece electrodes in a level position and feeding the tool electrode in a horizontal direction. Under these conditions, the debris concentration and the deposited carbon layer thickness, which influence the gap width and the anode wear, respectively, are thought to be uniform over the working surface. The simulation result coincided well with the measured geometry of the workpiece.
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  • Heng XIA, Masanori KUNIEDA, Nobuhiko NISHIWAKI
    1994 Volume 28 Issue 59 Pages 31-40
    Published: November 30, 1994
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The pulse duration of discharge current greatly influences the removal amount of anode and cathode in EDM process. The purpose of this research is to find out the reason for such a phenomenon. At first, the energy distributed into anode and cathode in the case of the single discharge process is obtained by means of measuring the temperature rise and removal amount of electrodes. Then the influence of the carbon adhesion onto the anode surface on the anode removal amount is investigated. It is found that the energy distributed into the anode is more than that into the cathode, and the influence of pulse duration on the energy distribution is small. Besides, it is concluded from the experimental results that the removal amount difference between anode and cathode in the EDM process is mainly caused by carbon adhesion, not by the energy distribution.
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  • Katsushi FURUTANI, Naotake MOHRI, Toshiro HIGUCHI
    1994 Volume 28 Issue 59 Pages 41-50
    Published: November 30, 1994
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Conventional types of electrode feeding devices consist of a screw, gears and an electromagnetic motor, or a hydraulic cylinder. Several new types of electrode feeding devices using piezoelectric devices have been developed. This paper deals with comparisons of electrode feeding devices for machining small holes with the electrical discharge machining.
    The criteria of suitability to the electrode feeding device for machining small holes are proposed by considering requirements in machining small holes with EDM. The criteria are the resolution of the electrode feeding, the response of the mechanism in case of servo-control, the size of whole mechanism and the stroke of the electrode feeding.
    The conventional types and the new types of electrode feeding devices are classified into mechanisms and into chucking methods. Their characteristics and the suitability are discussed. The electrode feeding devices using piezoelectric elements are suitable for machining small holes. The chucking method should be chosen according to the purpose.
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