The Japan Steel Works, Ltd.

Koichi Tamada

Akihiro Naito

Hiromasa Uezono

Katsuyuki Araki

Hideaki Nakashima

The interior of a heating cylinder () is divided into a first stage () and a second stage () due to the shape of a screw (). A first compression zone in which a resin is compressed is formed in the first stage (). A starvation zone () in which an inert gas is injected and a second compression zone in which the resin is compressed are formed in the second stage (). A barrier flight () that is obtained by combining a main flight () and a sub-flight () having a greater lead angle than the main flight is provided to a section of the screw (), said section corresponding to the first compression zone. A multiple flight is provided to another section of the screw (), said section corresponding to the second stage ().

Screw of injection molding machine for foam molding, and injection molding machine

The present disclosure relates to a screw of an injection molding machine in which a heating cylinder is formed with a first compression section, a starvation section, and a second compression section, and in which an inert gas is to be introduced into the starvation section. At a portion of the screw corresponding to the first compression section, a barrier flight as a double flight including a combination of a main flight and a sub-flight having a lead angle larger than that of the main flight is formed, and a dam flight having a predetermined-width ring shape is formed, downstream of, i.e., in front of the barrier flight. A seal structure to prevent backflow of the resin may be provided between the dam flight and the starvation section.

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Hiroshima, Japan

Koichi Tamada