A method for controlling an injection cycle of an injection molding machine incudes advancing an injection screw axially forward toward an injection nozzle from a shot-size position to an injection position to inject melt from a shot chamber into a hot runner of a mold and from the hot runner to fill cavities of the mold. Then the injection screw is retracted away from the nozzle, from the injection position to a decompression position axially rearward of the shot-size position, to relieve melt pressure in the hot runner. Then the screw is advanced toward the nozzle from the decompression position to an intermediate position axially intermediate the injection position and the shot-size position. The method then includes rotating the screw to re-fill the shot chamber with melt and urge the screw to retract from the intermediate position to the shot-size position.

An injection unit for a molding machine includes a plasticizing cylinder having at least two grooves, and a carrier part having a notch. The plasticizing cylinder is arranged in the notch. The at least two grooves are spaced apart axially from each other. At least two engaging elements are provided, which engage with the at least two grooves, in order to create a positive-locking connection between the plasticizing cylinder and the carrier part, through which an axial movement of the plasticizing cylinder relative to the carrier part is inhibited.

An injection unit for a molding machine includes a plasticizing cylinder having at least two grooves, and a carrier part having a notch. The plasticizing cylinder is arranged in the notch. The at least two grooves are spaced apart axially from each other. At least two engaging elements are provided, which engage with the at least two grooves, in order to create a positive-locking connection between the plasticizing cylinder and the carrier part, through which an axial movement of the plasticizing cylinder relative to the carrier part is inhibited.

A control device for an injection molding machine is equipped with a pressure acquisition unit configured to acquire a resin pressure, a pressure reduction control unit configured to, after the screw has reached a predetermined metering position, reduce the resin pressure to a target pressure by performing at least one of reverse rotation and sucking back of the screw, and a standby pressure control unit configured to, after the resin pressure has reached the target pressure, keep the resin pressure within a predetermined range by causing the screw to be rotated in a state in which a position of the screw in an axial direction of the cylinder is maintained.

A control device for an injection molding machine is equipped with a pressure acquisition unit configured to acquire a resin pressure, a pressure reduction control unit configured to, after the screw has reached a predetermined metering position, reduce the resin pressure to a target pressure by performing at least one of reverse rotation and sucking back of the screw, and a standby pressure control unit configured to, after the resin pressure has reached the target pressure, keep the resin pressure within a predetermined range by causing the screw to be rotated in a state in which a position of the screw in an axial direction of the cylinder is maintained.

An injection apparatus of the invention injects a molding material supplied from a material supply port, and includes a die, a material supply apparatus that extrudes the molding material that is thread-like or strip-like via the die, and a material guide apparatus that guides the molding material supplied via the die to the material supply port. The material discharge port of the material supply apparatus and the die protrude downward in the material supply apparatus, and a pressure inside the material guide apparatus is reduced by a pressure reducing apparatus from a pressure reducing port provided above the material discharge port of the material supply apparatus and the die.

An injection apparatus of the invention injects a molding material supplied from a material supply port, and includes a die, a material supply apparatus that extrudes the molding material that is thread-like or strip-like via the die, and a material guide apparatus that guides the molding material supplied via the die to the material supply port. The material discharge port of the material supply apparatus and the die protrude downward in the material supply apparatus, and a pressure inside the material guide apparatus is reduced by a pressure reducing apparatus from a pressure reducing port provided above the material discharge port of the material supply apparatus and the die.

A nonreturn valve includes two half-shells, arranged in a portion of the screw with a reduced screw diameter. One or more channels for the melt to flow through from the screw into the space in front of the screw is/are provided in each of the half-shells, the channels lie substantially parallel to the longitudinal axis of the nonreturn valve or of the screw. In each of the channels are a ball and, following the ball in the direction of flow of the melt, a pin arranged substantially transversely to the direction of flow of the melt. In the direction of flow of the melt, the channels have a first channel portion, with a channel diameter less than the diameter of the ball, and a second channel portion, with a channel diameter greater than the diameter of the ball, the ball and the pin are arranged in the second channel portion.

A nonreturn valve includes two half-shells, arranged in a portion of the screw with a reduced screw diameter. One or more channels for the melt to flow through from the screw into the space in front of the screw is/are provided in each of the half-shells, the channels lie substantially parallel to the longitudinal axis of the nonreturn valve or of the screw. In each of the channels are a ball and, following the ball in the direction of flow of the melt, a pin arranged substantially transversely to the direction of flow of the melt. In the direction of flow of the melt, the channels have a first channel portion, with a channel diameter less than the diameter of the ball, and a second channel portion, with a channel diameter greater than the diameter of the ball, the ball and the pin are arranged in the second channel portion.

A control device for an injection molding machine including a cylinder into which a resin is supplied and a screw that moves forward and rearward and rotates inside the cylinder, includes a metering control unit that performs metering of the resin inside the cylinder by controlling forward rotation and rearward movement of the screw until the screw has been moved rearward to a predetermined metering position, based on predetermined metering conditions, a rearward movement speed acquisition unit acquiring a rearward movement speed of the screw, a speed determination unit that determines a suck back speed for causing a resin pressure to reach a target pressure, based on the rearward movement speed acquired during metering by the rearward movement speed acquisition unit, and a suck back control unit causing the screw to move further rearward based on the suck back speed, after the screw has reached the predetermined metering position.