Toshiba Kikai Kabushiki Kaisha

Tai Matsuda

Norihiro Iwamoto

Hiroshi Yokoyama

Masayuki Takamura

A method for controlling the injection of a die casting machine in which immediately after molten metal is injected into a cavity of metal molds at a high speed, the pressure oil in the chamber at the rod side of an injection cylinder is discharged into a tank side to commence the increase in pressure. A reference point for a switching-over position where a high speed charge is switched over to the increase in pressure is determined by computing a necessary length along the path for keeping the increased charging pressure on the basis of the supplied molten metal quantity during the previous injection process and subtracting the length from the length between the starting position and the position of limit of the forward movement at the previous injection process.

Method for controlling injection of die casting machine

A stroke S of a squeeze pin under no load condition of a squeeze pin cylinder for driving the squeeze pin is detected. A value (S-.alpha.) obtained by subtracting a small value .alpha. from the detected stroke S of the squeeze pin is determined as a set stroke of the squeeze pin. After a predetermined waiting time has elapsed from when melted metal is charged into a cavity completely, the squeeze pin is advanced. Here, the actual stroke Sf of the squeeze pin is detected, and the detected stroke Sf is compared with set stroke (S-.alpha..+-..beta.), where .beta. is an allowable deflection. As the result of comparison, if Sf oversteps the set limits (S-.alpha..+-..beta.), at least one of parameters (the pressure and the flow rate of hydraulic fluid supplied to the squeeze pin cylinder and the waiting time) is corrected, so that the detected stroke value Sf approaches the set stroke (S-.alpha.) for the succeeding casting cycle.

Growing community of inventors

Kawasaki, Japan

Tai Matsuda