| 摘要 |
PURPOSE:To produce a casting having excellent quality with an injection molding device such as die casting machine by measuring the time for intensifying the pressure to be exerted to a molten metal to be injection-cast, preventing the erroneous measurement by a surge pressure and to inject the molten metal in a satisfactory condition. CONSTITUTION:The molten Al alloy 15 in a casting sleeve 11 is injected and cast by a plunger 3 connected to a piston 2 of an injection cylinder 1 into a cavity 14 formed of metallic molds 12, 13. The measurement of the time DELTAt from the start of the injection till the end thereof is started by a time measuring means when the pressure at the start point in the time t0 after the start of the injection attains P1 in the curve P of the injection pressure of the molten metal 5 with respect to time. The measurement of the time is stopped when the pressure drops to P1 or below before the end point pressure P2 is attained. The measurement of the time is restarted when P1 is attained. The pressurization for injection is stopped when P2 is attained. The injection pressure is intensified from P1 to P2 in the time DELTAt without the error in the measurement of the DELTAt by detecting the surge pressure in the mid-way. The injection of the molten metal 15 into the cavity 14 is thus correctly controlled and the die casting product having the excellent quality is cast.
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