| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for controlling an injection speed where, when the injection speed is improper and air is involved in molten metal, the entrainment of the air is detected and the optimum injection speed can be decided. SOLUTION: In a diecasting machine where molten metal 40 is press-fed to the cavity 13 of a die 10 by the injection plunger 20, the method for controlling the injection speed of an injection plunger by detecting the entrainment of air into the molten metal 40 includes: a first detection stage where, at a first position in the axial direction on the injection sleeve (the arrangement position of an ultrasonic sensor 24), whether ultrasonic waves have penetrated through the molten metal to the axial perpendicular direction of the injection sleeve is detected; and a second detection stage where, at a second position in the axial direction closer to the die than the first position in the axial direction on the injection sleeve (the arrangement positions of the ultrasonic sensors 26 and 28), whether the ultrasonic waves have penetrated through the molten metal in the axial perpendicular direction is detected. Except the case in which the penetration of the ultrasonic waves is detected in the second detection stage after the detection of the penetration of the ultrasonic waves in the first detection stage, the injection speed of the injection plunger is controlled. COPYRIGHT: (C)2005,JPO&NCIPI
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