Journal of The Japan Society of Electrical Machining Engineers
Online ISSN : 1881-0888
Print ISSN : 0387-754X
ISSN-L : 0387-754X
Volume 37, Issue 85
Displaying 1-5 of 5 articles from this issue
  • Noboru MORITA, Kiwamu ASHIDA
    2003 Volume 37 Issue 85 Pages 5-9
    Published: July 31, 2003
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Download PDF (9294K)
  • Takeo TAMURA, Yoshinobu KOBAYASHI
    2003 Volume 37 Issue 85 Pages 10-17
    Published: July 31, 2003
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Heat-affected zones (HAZs) are generated by electrical discharge machining of cemented carbides. A surface modification method using an oxidation treatment of cemented carbides has been proposed as a removal method for the HAZs. The HAZs can be completely removed in the form of oxides through the oxidation treatment. In this study, a wire-drawing die with a bearing diameter of 10 mm was fabricated by wire electrical discharge machining (WEDM). Subsequently, this surface modification method for finishing the die was introduced to improve the die quality and to reduce the die manufacturing time. As a result, the surface integrity of the die is superior to that of the die finished by a conventional removal method. Defects such as cracks partially exist on a polished surface in the latter case. The HAZs are completely removed in 3 minutes by this oxidation treatment. It only takes 20 minutes to polish the die by incorporating this method into the die manufacturing process. The completion time of a wire-drawing die is approximately 50% shorter than that obtained by the conventional removal method.
    Download PDF (10763K)
  • Kai EGASHIRA, Katsumi MIZUTANI
    2003 Volume 37 Issue 85 Pages 18-23
    Published: July 31, 2003
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The possibility of EDM at open-circuit voltages of lower than 30V has been examined using an RC circuit, because low voltages are preferable in terms of machining accuracy; however, machining at such voltages had not been attempted before. EDM of holes in copper is carried out with tungsten electrodes of 15μm or 7μm diameter to investigate the machining rate. At open-circuit voltages of 5V or higher, the average electrode feed speed, which is defined as the feed per machining time, is higher than 5μm/min under certain electrical conditions. Although the machining rate is very low, machining is possible even at an open-circuit voltage of 2V. These voltages are much lower than those usually used for EDM. A tungsten rod of 1μm diameter can be fabricated at an open-circuit voltage of 20V by wire electrodischarge grinding (WEDG), indicating the possibility of future applications of EDM to submicron machining and nanomachining.
    Download PDF (5950K)
  • Akira OKADA, Yoshiyuki UNO, Youhei NAKASHIMA
    2003 Volume 37 Issue 85 Pages 24-31
    Published: July 31, 2003
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    The reduction in friction between machine elements is an important subject for machine design and manufacturing, and many studies on friction have been carried out so far. However, the control of friction characteristics is very difficult, since friction is an unstable phenomenon and is affected by many factors. This study aims to obtain fundamental data for controlling the friction characteristics of EDMed surfaces. First, by changing the shape and the arrangement of craters on the surface, the possibility of controlling the friction and wear characteristics was discussed. The effects of EDM conditions such as discharge duration and discharge current on the friction characteristics were experimentally investigated. As a result, it was pointed out that under low crater density, the coefficient of friction between a crater-arranged surface of an alloy tool steel and bearing steel ball became larger with an increase in crater density. It was clarified that the friction coefficient of an EDMed surface became smaller than those of ground surfaces and crater-arranged surfaces. Moreover, the friction coefficient of an EDMed surface increased with its surface roughness, as long as the resolidified layer remained on the surface.
    Download PDF (10610K)
  • Improvement of Surface Finish, Tool Life and Productivity in Cutting
    Koichi SAITO
    2003 Volume 37 Issue 85 Pages 32-37
    Published: July 31, 2003
    Released on J-STAGE: March 12, 2010
    JOURNAL FREE ACCESS
    Download PDF (7771K)
feedback
Top