Toyota Jidosha Kabushiki Kaisha

Gifu Seiki Kogyo Kabushiki Kaisha

Takehito Futamura

Mitsuhiro Karaki

Mikiya Nozaki

Mitsuru Inui

Akira Saitoh

A pressure casting method is disclosed, which permits sufficient pressurizing effect to be obtained for the entire molten metal by varying the speed of advancement of a pressurizing pin according to the state of solidification of the molten metal during pressurizing. In pressure casting using a pressure casting apparatus, while charged molten metal is solidified, it is pressurized by causing advancement of the pressurizing pin into a cavity of the die. During this time, the reaction force received by the pressurizing pin from the molten metal is measured by a pressure sensor, and the speed of advancement of the pressurizing pin is varied through control of the opening degree of a flow control valve according to the measured reaction force. While the reaction force during the progress of solidification of molten metal is high, the flow control valve is controlled to a high opening degree to provide for a high speed of advancement of the pressurizing pin so as to apply a high pressurizing force. On the other hand, while the reaction force is low so that there is a delay in the solidification of molten metal, the speed of advancement is reduced so that no pressurizing force is applied until completion of solidification of molten metal. The pressurizing pin is advanced while its advancement speed is controlled in the above way, and pressurizing over the entire stroke is completed.

Pressure casting method through pressurizing pin advancement speed

The disclosed method of controlling a pressurizing pin, which serves to replenish for the necessary locality with molten metal during solidification of molten metal charged in the cavity, features that the operation of the molten metal replenishment by the pressurizing pin is caused when it is detected that the volume of non-solidified metal has become less than the volume effective for obtaining a molten metal replenishment effect. It is thus possible to obtain efficient replenishment for the necessary locality with molten metal by using a pressurizing pin which is limited in size and stroke.

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Gifu, Japan

Takehito Futamura