Mitsubishi Jukogyo Kabushiki Kaisha

Yukio Tamura

Ryoji Mouri

Yukio Goto

Yoshinori Murata

Takashi Mizuno

Kiyoshi Kinoshita

Toshio Miki

Masayoshi Kasai

Hideo Kuroda

Tetsuo Uwaji

Yoshio Shikase

Kouji Kubota

Masaki Ishikawa

A process and apparatus for effecting injection molding of plastic resin products on an injection molding apparatus including a metal mold composed of a slidable mold element and a fixed mold element defining together the mold cavity, an actuator for sliding the slidable mold element and an injection nozzle for adjusting the nozzle flow path section, which comprises a first molding step of injecting a molten resin into the mold cavity which has been preset by the slidable mold element so as to include a post-compression margin to be compressed afterwards in a second molding step, to effect the injection under a reduced molding pressure, while causing a temperature elevation and, thus, a viscosity reduction of the molten resin, until the mold cavity has been filled up, and a second molding step of compressing the resin so charged in the mold cavity by operating the slidable mold element to compress the charged resin to compensate the post-compression margin, so as to allow an effective pressing force to be imposed onto the charged resin within the mold cavity also after the gate has been sealed.

Process for injection molding and apparatus therefor

In a serial two-stage extruder, the first-stage extruder has a screw including a feed screw section having a length within a range of 5 to 9 the major diameter thereof, a mixing screw section having a hexagonal cross section and a pitch of 1 to 3 times the major diameter thereof, and a metering screw section having a screw groove of an appropriate depth. The second-stage extruder includes an extruding screw and a barrel. The extruding screw has a screw groove of an appropriate depth and a dulmage formed at the tip end of the screw. The dulmage has a plurality of fins cooperating with fins of the barrel. Alteratively, in the second-stage extruder, the dulmage may have a plurality of axially spaced stages of fins. Configurations of the fins in each respective stage are identical but various characteristics of the fins vary from stage to stage. In this case, the barrel does not have fins.

Serial two-stage extruder

A plasticizing screw for an injection molding machine or the like having one or more lands in a crest portion of a screw flight to prevent the screw flight from coming into contact with a cylinder wall surface when the plasticizing screw is rotated during a molding operation. The land has a smaller diameter than that of a crest portion of the screw flight and is provided at the screw flight crest portion either between leading and trailing surfaces of the screw flight or extending from the leading edge of the screw flight. The land can also be provided as a plurality of circumferentially spaced-apart lands on the side of a front surface of the screw flight, or provided at a central portion between the leading and trailing surfaces of the screw flight.

Plasticizing screw

The invention is an extruding device which includes a screw and a barrel wherein the screw includes a kneading portion whose cross-section differs from the cross-section of the remainder of the screw and the barrel includes a kneading portion whose cross-section differs from the cross-section of the remainder of the barrel and is opposite to the kneading portion of the screw, the cross-sections of the two kneading portions being such that the distance between a point on the periphery of the kneading portion of the screw and the nearest point on the interior surface of the barrel, measured in a radial direction, varies on rotation of the screw in the barrel. The extruding device exerts an improved kneading effect upon extruded material.

Extruding device for high molecular materials

Growing community of inventors

Nagoya, Japan

Yukio Tamura