Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 19, Issue 38
Displaying 1-4 of 4 articles from this issue
  • Masakazu KISHI, Yasuo SUZUKI, Yuusuke TONOKI
    1986 Volume 19 Issue 38 Pages 1-11
    Published: March 31, 1986
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The planetary machining technique is one of important techniques to improve machining performance in die sinking EDM. For obtaining higher machining performance by using the planetary machining technique, it is necessary to clarify the machining characteristics during planetary machining. This paper describes some characteristics of surface roughness by planetary EDM. The surface roughness is analyzed using Abbott's bearing curve and form factor, and following results are obtained. (1) Volume of the formative region of the surface roughness can be estimated by form factor and maximum height. (2) Transient surface condition when changed roughness is quantitatively measured. (3) By low electrode wear machining, the valley of a stage surface forms in the neighborhood of the valley of the privious stage surface.
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  • Nagao SAITO, Naotake MOHRI, Toshiaki ETOH, Hirosada OHTAKE
    1986 Volume 19 Issue 38 Pages 12-23
    Published: March 31, 1986
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    This paper describes a new method to make metallized die by EDM. In this process, the three dimensional stainless steel core by cutting process is used as a model in stainless steel metallizing process and also used as an electrode in EDM on to the backed-up metallized shell. This core is also used as one of the die sets in injection molding. With this process die can be produced rapidly with high relative accuracy. The main results in this paper are as follows: (1) The removal rate of sprayed metal in EDM increases by several times of that in the case of the original metal sprayed, stainless steel. (2) And in the case of EDM to sprayed metal, the low-wear EDM is realized because the thermal conductivity of sprayed metal decreases to about a third of that of the original metal sprayed owing to its porosity. (3) The final surface roughness and the hardness of sprayed metal are 0.4μm Rmax and 600HV 0.2 respectively. (4) The relative accuracy between cavity and core is improved to less than 10μm after EDM. (5) The result of a trial plastic injection molding using this die shows that this method is effective to apply to rapid die making for mass production.
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  • [in Japanese], [in Japanese], [in Japanese], [in Japanese]
    1986 Volume 19 Issue 38 Pages 24-32
    Published: March 31, 1986
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
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  • On the surface defects and the transverse rupture strength of cemented carbides
    Tadao TSUTSUI, Takeo TAMURA
    1986 Volume 19 Issue 38 Pages 33-42
    Published: March 31, 1986
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The generation of micro-cracks by EDM of cemented carbides has been often discussed as an important problem. However, a clear explanation has not been made regarding the effect of the surface defects containing micro-cracks on material strength. In this study, the surface defects of cemented carbides were examined experimentally and its influence on the transverse rupture strength (TRS) was clarified. Moreover, the temperature dependence of the TRS was studied and the fracture stress distribution was obtained from the statistical analysis. The results are as follows:
    (1) The surface damage of cemented carbides by EDM mainly consists of micro-cracks and deep micro-craters.
    (2) The TRS is shown by a curve with both minimum and maximum value as the discharge energy increases.
    (3) At higher temperature above 600°C, the defects such as micro-cracks and deep micro-craters indicate the structure insensitive property on the TRS. And the scatter of the TRS can be explained by using Weibull's equation.
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