Patents Examined by Bruce H. Reynolds
  • Patent number: 4221952
    Abstract: There is disclosed an electric discharge machining method in which the discharge working gap between an electrode and a work piece is automatically adjusted to prevent the occurrence of a streaky pattern in the surface of the work piece due to variation in the amount of machining. After a plurality of high voltage pulses have been applied for a predetermined time across the working gap, a low voltage pulse is applied across the working gap. In response to the application of the low voltage pulse, the feeding of the electrode is controlled by a pulse motor in a direction to reduce the working gap, and as soon as the discharge is started the feed control is stopped and the discharge machining is then effected in response to the application of high voltage pulses.
    Type: Grant
    Filed: August 1, 1978
    Date of Patent: September 9, 1980
    Assignees: Mitsubishi Denki Kabushiki Kaisha, Nippon Kokan Kabushiki Kaisha
    Inventors: Kunihiko Sato, Tetsuro Urata, Mitsugi Kawano, Terumasa Jinba, Tetsuhiro Asamoto, Takeo Uebayashi