Abstract: An immersion type wire cut electric discharge machine is provided with a sealing structure for sealing a gap between a machining liquid tank and a lower arm while permitting movement of the tank relative to the arm, and nozzles for preventing sludge from adhering to the inner surface of a slide member of the sealing structure. A slide seal includes a slide plate through which the lower arm extends. A guide mechanism for guiding the slide plate while keeping the plate in close contact with a tank wall of the machining liquid tank is formed in the tank wall, through which the lower arm extends. The nozzles are arranged inside the machining liquid tank and inject fluid toward the inner surface of the slide plate.

Abstract: A working-condition detecting method for a wire electric discharge machine and an apparatus therefor are provided, for positively and experimentally determining a working condition for optimum and most efficient wire electric discharge machining. Test machining is carried out while gradually increasing off-time of a transistor of a discharge power source of the machine every predetermined working section. Unfulfillment of a linear relationship between an average working electric current and a working speed is determined when a ratio of an increment of the working speed with respect to that of the average working electric current between the preceding and present working sections becomes smaller than a value, equal to the product of a coefficient and an average value of the ratios in the entire working sections until this time and smaller than the average value. The off-time at this time is identified as the working condition which is used to carry out actual machining.

Abstract: The present invention relates to an area cutting method for cutting the interior of an area (AR) by moving a tool along a plurality of offset paths successively offset in an inward direction from a closed curve (AR) specifying the area. The area cutting method includes determining whether the area (AR) bounded by the closed curve (OLC) is to be divided, obtaining, if division is necessary, division suitability a division value for all sets of apices, in which any two apices form a set, by using an evaluation function indicative of a preset division suitability or value, dividing the area by a straight line connecting the two apices (P5, P7) of the set having the maximum suitability, executing similar processing for each divided area (PG1, PG2), deciding tool paths on the basis of the final divided areas, and performing area cutting by moving a tool along the tool paths.