Kabushiki Kaisha Komatsu Seisakusho

Yosuke Sasaki

Kazuhiro Mimura

Satoshi Fujimoto

Hideaki Okubo

Makoto Nogawa

Noboru Harashima

Kan-ichi Sato

Makoto Higuchi

Kohji Hayakawa

In an injection and compression molding process wherein molten material is fed by a screw, incorporating a counterflow preventing valve (CPV), through a flow control valve (FCV) into a mold cavity, the injection volume is controlled by: with the FCV closed, feeding a predetermined quantity of material through the CPV into a chamber between the CPV and the FCV, then advancing the screw with the FCV maintained closed to cause the CPV to close, thereby raising the pressure of the material in the chamber, determining when the pressure of the material in the chamber reaches a predetermined pressure, determining whether the movable die is at a predetermined distance from the stationary die, opening the FCV after the pressure of the material in the chamber has reached said predetermined pressure and the movable die is at the predetermined distance from the stationary die, setting as an original point of a determination of the injection volume either (a) a position of the screw at the opening of the FCV or (b) a time at the opening of the FCV, injecting the material into the mold cavity while the mold cavity is open to atmospheric pressure, closing the FCV either (a) when the screw has reached a position advanced a predetermined distance from the thus set original point or (b) at a predetermined time after the thus set original point, and compressing the material in the mold cavity.

Method for controlling injection volume of material into mold

A horizontal injection and compression molding apparatus has an injection device (3) and a compression molding device, wherein the compression molding device (2) includes: a stationary die plate (12) for holding a stationary die (11), a movable die plate (22) for holding a movable die (21), means (30) for rapidly extending and retracting the movable die plate (22), relative to the stationary die plate (12), means (40) for locking the movable die plate (22) to tie bars (51) at a position where the movable die plate (22) approaches the stationary die plate (12), and means (50) for fastening the dies after the movable die plate (22) is locked to the tie bars (51); and wherein the injection device (3) for feeding a molten plastic material into a mold cavity (90) between the stationary die (11) and the movable die (21) is characterized in that it initiates feeding of the molten plastic material into the mold cavity ( 90) when the stationary die (11) and the movable die (21) are parted from each other by a predetermined distance, with the plastic material being compressed and drawn while the movable die (21) is moved towards the stationary die (11) after a predetermined quantity of the molten plastic material has been fed into the mold cavity (90).

Apparatus for injection and compression molding

A molding apparatus with die-clamping and alignment devices has a stationary die plate for holding a stationary die, a movable die plate for holding a movable die, a device for moving forwardly/rearwardly the movable die plate with respect to the stationary die plate, a fastening device for fastening the movable die plate and the tie bar to each other by hydraulic force when the stationary die and the movable die have been approached to predetermined positions, and a tie bar for clamping the movable die and the stationary die by die-clamping force generated by a die-clamping cylinder, and a primary alignment mechanism provided for at least one junction among junctions between a piston of a die-clamping hydraulic cylinder and the tie bar, between a support plate and the tie bar, and between the movable die plate and a movable die plate support member, in order to permit the two dies to be aligned to each other by a secondary position alignment function, such as a guide pie for aligning the two dies at the time of clamping the dies.

Growing community of inventors

Zama, Japan

Yosuke Sasaki