Abstract: Provided is an injection molding method for resin that contains reinforcing fiber, the method being capable of easily eliminating uneven distribution of added components. The injection molding method is provided with: a plasticizing step for supplying resin pellets P and added components to a cylinder equipped with a screw 10, which has a rotating axis as the center is capable of rotating normally and in reverse, and generating molten resin by rotating the screw 10 in the normal direction; and an injecting step for injecting the molten resin M comprising the added components into a cavity. In the plasticizing step, a reverse rotation operation for reversing the rotation of the screw 10 is performed or a screw-stopping operation of stopping the normal rotation of the screw 10 is performed with a prescribed timing and for a prescribed period.

Abstract: Provided is a screw that is for use in an injection molding machine and that makes it possible to benefit from the kneading effect of a multi-start screw while minimizing the received friction resistance. The screw for an injection molding machine is provided with a first stage 20 on the upstream side and a second stage 30 on the downstream side. The screw for an injection molding machine is characterized in that: the first stage 20 is provided with a compression section 22 comprising a main scraper 25 and an auxiliary scraper 26 having a smaller outer diameter than the main scraper 25; and the second stage 30 is provided with a multi-start screw section 31, said multi-start screw section being provided on the upstream side and comprising a plurality of scrapers, and a fin kneading section 32 provided downstream from the multi-start screw section.

Abstract: There is provided a screw of an injection molding machine that can eliminate uneven distribution of reinforcing fibers without giving an excessive shear force to the reinforcing fibers. A screw is provided inside a heating cylinder of an injection molding machine to which a resin pellet is fed on an upstream side in a conveyance direction of resin and to which reinforcing fibers are fed on a downstream side therein, and includes: a first stage at which the resin pellet which is fed is melted; and a second stage that continues to the first stage, and at which molten resin and the reinforcing fibers are mixed with each other. A second flight provided at the second stage includes: a large-diameter flight with a relatively large outer diameter; and a small-diameter flight with a relatively small outer diameter.

Abstract: An injection molding method includes: a plasticizing process of feeding a resin pellet and additive components to a heating cylinder including a screw that can rotate around a rotation axis and can advance and retreat along the rotation axis, and generating molten resin by rotating the screw in a normal direction; and an injection process of injecting to a cavity the molten resin containing the additive components. In the plasticizing process, retreat operation of forcibly retreating the screw is performed at a predetermined velocity by a predetermined stroke or a predetermined time.

Abstract: Provided is an injection molding method in which a constricting section is provided at a boundary between a first stage and a second stage of a screw. When a mixture of a molten resin and reinforcing fibers passes through the constricting section, compression force higher than compression force on an upstream side of the constricting section is applied to the mixture. A supply section on a downstream side of the constricting section has a shaft diameter smaller than an outer diameter of the constricting section. Therefore, the vicinity of the supply section becomes a reduced-pressure region with respect to the mixture having passed through the constricting section, and the mixture is accordingly expanded. As a result, spring-back occurs on the reinforcing fibers and a Barus effect occurs on the molten resin, thereby making it possible to produce a state that is advantageous to open the fiber bundle.

Abstract: Provided is a screw that is for use in an injection molding machine and that makes it possible to benefit from the kneading effect of a multi-start screw while minimizing the received friction resistance. The screw for an injection molding machine is provided with a first stage 20 on the upstream side and a second stage 30 on the downstream side. The screw for an injection molding machine is characterized in that: the first stage 20 is provided with a compression section 22 comprising a main scraper 25 and an auxiliary scraper 26 having a smaller outer diameter than the main scraper 25; and the second stage 30 is provided with a multi-start screw section 31, said multi-start screw section being provided on the upstream side and comprising a plurality of scrapers, and a fin kneading section 32 provided downstream from the multi-start screw section.

Abstract: In an injection molding method, using a heating cylinder having on the front end thereof a discharge nozzle, a single axis screw is rotatable inside the heating cylinder, a fiber-supplying device fills reinforcing fiber into the heating cylinder, and injection molding is performed while supplying the reinforcing fiber and the resin starting material separately and supplying the reinforcing fiber on the front side of the resin starting material. The method includes a plasticization process for obtaining a specified amount of a kneaded product by retracting the screw while rotating in the normal direction to melt the resin starting material and knead reinforcing fiber into the melted resin starting material, and an injection process for discharging the kneaded product from the discharge nozzle by advancing the screw. Reinforcing fiber is supplied into the heating cylinder in the injection process.

Abstract: Provided is an injection molding method for resin that contains reinforcing fiber, the method being capable of easily eliminating uneven distribution of added components. The injection molding method is provided with: a plasticizing step for supplying resin pellets P and added components to a cylinder equipped with a screw 10, which has a rotating axis as the center is capable of rotating normally and in reverse, and generating molten resin by rotating the screw 10 in the normal direction; and an injecting step for injecting the molten resin M comprising the added components into a cavity. In the plasticizing step, a reverse rotation operation for reversing the rotation of the screw 10 is performed or a screw-stopping operation of stopping the normal rotation of the screw 10 is performed with a prescribed timing and for a prescribed period.

Abstract: The injection molding apparatus of the present invention includes: a heating cylinder; a screw that is provided rotatably in an inner portion of the heating cylinder; a resin feed hopper that feeds a resin pellet; and a fiber feed device that is provided ahead of the resin feed hopper and feeds reinforcing fibers into the heating cylinder. The screw includes a first stage that is located on a rear side, and in which the resin pellet is melted, and a second stage that is located on a front side, and in which the melted resin pellet and the reinforcing fibers are mixed, and a lead of a second flight provided in the second stage is larger than a lead of a first flight provided in the first stage.

Abstract: In an injection molding method of fiber reinforced resin of the present invention, a resin accumulation region is provided closer to a downstream side than an injection completion position inside a heating cylinder, an injection pressure is given to molten resin that occupies the resin accumulation region in an injection process of a preceding cycle, and a shear force is given to the molten resin that occupies the resin accumulation region in a plasticizing process of a subsequent cycle. An inside of massive reinforcing fibers F is impregnated with the molten resin by giving a high injection pressure to the molten resin that occupies the resin accumulation region. Next, dispersion of the reinforcing fibers is promoted by giving a shear force in the plasticizing process of the subsequent cycle.

Abstract: There is provided a screw of an injection molding machine that can eliminate uneven distribution of additive components without giving an excessive shear force to the additive components. An injection molding method of the present invention includes: a plasticizing process of feeding a resin pellet P and additive components to a heating cylinder 201 including a screw 10 that can rotate around a rotation axis C and can advance and retreat along the rotation axis C, and generating molten resin M by rotating the screw 10 in a normal direction; and an injection process of injecting to a cavity the molten resin M containing the additive components. In the plasticizing process, retreat operation of forcibly retreating the screw 10 is performed at a predetermined velocity by a predetermined stroke D1 or a predetermined time.

Abstract: There is provided a screw of an injection molding machine that can eliminate uneven distribution of reinforcing fibers without giving an excessive shear force to the reinforcing fibers. A screw is provided inside a heating cylinder of an injection molding machine to which a resin pellet is fed on an upstream side in a conveyance direction of resin and to which reinforcing fibers are fed on a downstream side therein, and includes: a first stage at which the resin pellet which is fed is melted; and a second stage that continues to the first stage, and at which molten resin and the reinforcing fibers are mixed with each other. A second flight provided at the second stage includes: a large-diameter flight with a relatively large outer diameter; and a small-diameter flight with a relatively small outer diameter.

Abstract: The injection molding apparatus of the present invention includes: a heating cylinder; a screw that is provided rotatably in an inner portion of the heating cylinder; a resin feed hopper that feeds a resin pellet; and a fiber feed device that is provided ahead of the resin feed hopper and feeds reinforcing fibers into the heating cylinder. The screw includes a first stage that is located on a rear side, and in which the resin pellet is melted, and a second stage that is located on a front side, and in which the melted resin pellet and the reinforcing fibers are mixed, and a lead of a second flight provided in the second stage is larger than a lead of a first flight provided in the first stage.

Abstract: In an injection molding method, using a heating cylinder having on the front end thereof a discharge nozzle, a single axis screw is rotatable inside the heating cylinder, a fiber-supplying device fills reinforcing fiber into the heating cylinder, and injection molding is performed while supplying the reinforcing fiber and the resin starting material separately and supplying the reinforcing fiber on the front side of the resin starting material. The method includes a plasticization process for obtaining a specified amount of a kneaded product by retracting the screw while rotating in the normal direction to melt the resin starting material and knead reinforcing fiber into the melted resin starting material, and an injection process for discharging the kneaded product from the discharge nozzle by advancing the screw. Reinforcing fiber is supplied into the heating cylinder in the injection process.

Abstract: A plasticizing screw for injection molding according to the present invention is a plasticizing screw for injection molding that is installed in an injection molding machine which performs injection molding by plasticizing granular thermoplastic resin feedstock containing reinforcement fibers, and includes a shaft, a flight, and a mixer. The mixer is provided in plural stages in an axial direction, and the number of fins of the mixer of each stage increases toward a leading end side in the axial direction from a rear end side in the axial direction. Further, the protrusion height of each fin from the peripheral surface of the shaft is lower than the protrusion height of the flight from the peripheral surface of the shaft.

Abstract: A plasticizing screw for injection molding according to the present invention is installed in an injection molding machine that performs injection molding by plasticizing thermoplastic resin feedstock containing reinforcement fibers, and includes a shaft, a main flight, and a sub-flight. The protrusion height of the main flight from the circumferential surface of the shaft is formed to be constant in at least an area in which the sub-flight is provided.

Abstract: A plasticizing screw for injection molding according to the present invention is a plasticizing screw for injection molding that is installed in an injection molding machine which performs injection molding by plasticizing granular thermoplastic resin feedstock containing reinforcement fibers, and includes a shaft, a flight, and a mixer. The mixer is provided in plural stages in an axial direction, and the number of fins of the mixer of each stage increases toward a leading end side in the axial direction from a rear end side in the axial direction. Further, the protrusion height of each fin from the peripheral surface of the shaft is lower than the protrusion height of the flight from the peripheral surface of the shaft.

Abstract: A plasticizing screw for injection molding according to the present invention is installed in an injection molding machine that performs injection molding by plasticizing thermoplastic resin feedstock containing reinforcement fibers, and includes a shaft, a main flight, and a sub-flight. The protrusion height of the main flight from the circumferential surface of the shaft is formed to be constant in at least an area in which the sub-flight is provided.

Abstract: A molded resin product for a vehicle structural member or an aircraft structural member according to the present invention is formed by injection-molding of thermoplastic resin feedstock containing reinforcement fibers by using a screw provided at a leading end portion thereof with a mixer protruding in a radial direction. In the injection-molded product, the reinforcement fiber content ratio is greater than or equal to 20% by weight and the weight-average fiber length of the reinforcement fibers in an evaluation target area having a certain size is greater than or equal to 1 mm and less than or equal to 3 mm.