When a pulverized material resin material including a pulverized material as at least a part is plasticized and injection-molded by rotating a screw inserted in a heating tube, before use of the pulverized material, the area of a particle shape of the pulverized material in one direction is measured, a pulverized material shape index indicating the relative size of the area with respect to the depth of a screw groove is determined by computation processing, and when the size of the pulverized material shape index is equal to or greater than a preset setting value, the screw is determined to be inappropriate, and at least the result of the determination is displayed.

When a pulverized material resin material including a pulverized material as at least a part is plasticized and injection-molded by rotating a screw inserted in a heating tube, before use of the pulverized material, the area of a particle shape of the pulverized material in one direction is measured, a pulverized material shape index indicating the relative size of the area with respect to the depth of a screw groove is determined by computation processing, and when the size of the pulverized material shape index is equal to or greater than a preset setting value, the screw is determined to be inappropriate, and at least the result of the determination is displayed.

A method for producing an injection molded article including a highly-filled fiber-reinforced resin composition includes a step of charging a first resin feedstock including a thermoplastic polymer into an injection molding machine through a first inlet port; a step of charging a second resin feedstock into the injection molding machine through a second inlet port disposed downstream of the first inlet port, the second resin feedstock including a masterbatch that includes long fibers impregnated with a resin mixture including a thermoplastic polymer and an acid-modified polyolefin; a step of melt-kneading the first resin feedstock and the second resin feedstock together in the injection molding machine to give a fiber-reinforced resin composition melt; and a step of injection molding the fiber-reinforced resin composition melt in a mold, the first resin feedstock being charged intermittently or continuously from the start to the end of the charging of the second resin feedstock.

A method for producing an injection molded article including a highly-filled fiber-reinforced resin composition includes a step of charging a first resin feedstock including a thermoplastic polymer into an injection molding machine through a first inlet port; a step of charging a second resin feedstock into the injection molding machine through a second inlet port disposed downstream of the first inlet port, the second resin feedstock including a masterbatch that includes long fibers impregnated with a resin mixture including a thermoplastic polymer and an acid-modified polyolefin; a step of melt-kneading the first resin feedstock and the second resin feedstock together in the injection molding machine to give a fiber-reinforced resin composition melt; and a step of injection molding the fiber-reinforced resin composition melt in a mold, the first resin feedstock being charged intermittently or continuously from the start to the end of the charging of the second resin feedstock.

A plasticization device includes: a cylinder having a supply port through which a material is supplied; a spiral screw configured to rotate inside the cylinder; a nozzle configured to discharge the material plasticized inside the cylinder; and a first heating unit provided between the supply port in the cylinder and the nozzle. The cylinder includes a first portion having the supply port and a second portion provided with the first heating unit, and a shortest distance between an inner wall surface of the second portion and an outer surface of the screw is longer than a shortest distance between an inner wall surface of the first portion and the outer surface of the screw.

In a method for operating an injection moulding machine in the absence of a backflow barrier, plastic melt is injected by a plasticising device into a cavity in a screw antechamber of a plasticising screw adapted to rotate about a longitudinal axis and to move translationally by a drive unit during an injection phase and a holding-pressure phase. A rotational drive of the drive unit is controlled such that a speed of the plasticising screw causes overlay of a backflow of the plastic melt from the screw antechamber back into screw threads of the plasticising screw by an opposing delivery flow as a result of a rotation of the plasticising screw due to a translational injection movement of the plasticising screw. A differential flow is established from the backflow and the opposing delivery flow and influenced at least during the injection phase by influencing the speed of the plasticising screw.

In a method for operating an injection moulding machine in the absence of a backflow barrier, plastic melt is injected by a plasticising device into a cavity in a screw antechamber of a plasticising screw adapted to rotate about a longitudinal axis and to move translationally by a drive unit during an injection phase and a holding-pressure phase. A rotational drive of the drive unit is controlled such that a speed of the plasticising screw causes overlay of a backflow of the plastic melt from the screw antechamber back into screw threads of the plasticising screw by an opposing delivery flow as a result of a rotation of the plasticising screw due to a translational injection movement of the plasticising screw. A differential flow is established from the backflow and the opposing delivery flow and influenced at least during the injection phase by influencing the speed of the plasticising screw.

A plasticizing device includes a barrel including a resin material supply port portion and a fiber supply port portion which is formed on a distal side from the resin material supply port portion; and a screw that comprises a shaft body and a flight, and is received in the barrel. The barrel is disposed with a posture in which its axial line intersects a gravitational direction. A maximum length of an opening in the barrel of the fiber supply port portion along an axial direction of the barrel is 1 time or more and 2 times or less as much as a pitch of the flight disposed in a portion of the screw which faces the opening in the barrel of the fiber supply port portion in a direction perpendicular to the axial line of the barrel.

1. A plasticizing device includes a barrel including a resin material supply port portion and a fiber supply port portion which is formed on a distal side from the resin material supply port portion; and a screw that comprises a shaft body and a flight, and is received in the barrel. The barrel is disposed with a posture in which its axial line intersects a gravitational direction. A maximum length of an opening in the barrel of the fiber supply port portion along an axial direction of the barrel is 1 time or more and 2 times or less as much as a pitch of the flight disposed in a portion of the screw which faces the opening in the barrel of the fiber supply port portion in a direction perpendicular to the axial line of the barrel.

A liquid injection molding apparatus is provided. The liquid injection molding apparatus comprises a mold assembly; a clamping unit; an injector including a barrel; a feed screw concentrically located in the barrel; and a motor having a drive shaft removably coupled to the feed screw via a bayonet connector.