Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 24, Issue 47
Displaying 1-3 of 3 articles from this issue
  • Kiyonori MASUI, Takumi SONE
    1990 Volume 24 Issue 47 Pages 1-11
    Published: November 05, 1990
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Finishing technology on the wire spark erosion has been investigated for improving the integrity on the machined surface. However, in relaxation type generator used in many factories, some DC leakage current under the de-ionized water causes electrolytic affection and may attack microstructure and/or decrease the hardness on its machined surface.
    For the improvement on these problems, this paper describes transformer coupling circuit as an adaptor for relaxation type generator.
    This circuit constructed with pulse transformer is installed between the capacitor and the working gap and converts the waveform to AC out put. Since the gap is isolated from DC source, such electrolytic affection is suppressed.
    In machining tool steels, no electrolytic corrosion is observed and it is also useful to finish the machined surface with excellent quality.
    Another advantage of this circuit installed on the rectangular pulse generator can deliver micro-power pulses to the working gap at high performance, and make it possible to keep the surface roughness less than 2μm R even in a dielectric water of high conductivity.
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  • 2nd Report; Detection of WIRE EDM Discharging Position
    Haruki OBARA, Yuuji OKUYAMA, Masatomo KOMEYA, Tadaaki IOKA
    1990 Volume 24 Issue 47 Pages 12-22
    Published: November 05, 1990
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Local concentration of dischargings during machining causes poor cut results on Vertical EDM, also wire breakage on WIRE EDM. If discharging position is detected during machining, various controls are possible, examples; prevention of wire breakage, current wave control depending on working area or to avoide corner wear of electrode and control of reverse direction on Vertical EDM.
    In previous report we measured discharging position for insulated plates on WIRE EDM and found local concentration of dischargings took place just before wire breaks down. But this measuring method is not useful for nomal machining.
    Recently Muto, L.Ydreskog reported that AE is useful to detect discharging position. But it is difficult to detect discharging position for abnormal dischargings with this method because of too low AE level.
    In this 2nd report we describe a method to detect discharging position from discharging currents, and its characteristics on various conditions for WIRE EDM.
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  • Wansheng ZHAO, Takahisa MASUZAWA
    1990 Volume 24 Issue 47 Pages 23-31
    Published: November 05, 1990
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    A new method for controlling the electrode setback (JUMP) in EDM is presented in this paper. The static characteristics of JUMP are established experimentally and show that there is a safe range for the JUMP condition. By using self-tuning adaptive control theory, the JUMP parameters can be controlled so that the machine functions in the safe range automatically. The effectiveness of this system was confirmed by experimentation.
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