A plasticizing device that plasticizes a material and includes a drive motor, a screw that is rotated by the drive motor and that has a grooved face provided with a groove, a barrel that has an opposed face opposed to the grooved face and that includes a communication hole communicating with the groove at the opposed face, a heating section that heats the material supplied to the groove, a first temperature sensor that measures a temperature of the groove, and a control unit that controls the drive motor, wherein the control unit performs a first process for rotating the screw at a first rotation speed when a temperature measured by the first temperature sensor is a first temperature, and a second process for rotating the screw at a second rotation speed lower than the first rotation speed when a second measured temperature measured is higher than the first temperature.

A plasticizing device includes a drive motor, a screw that is rotated by the drive motor and that has a grooved face provided with a groove, a barrel that has an opposed face opposed to the grooved face and that is provided with a communication hole communicating with the groove at the opposed face, a first heating section that heats the material supplied to the groove, a temperature sensor that measures a temperature of the groove, and a control unit that controls the drive motor and the first heating section, wherein the control unit performs a first process for rotating the screw at a first rotation speed by controlling the drive motor, and a second process for rotating the screw at a second rotation speed higher than the first rotation speed by controlling the drive motor, and the control unit controls the first heating section so that a temperature measured by the temperature sensor falls within a predetermined range when performing the first process and the second process.

A method is described for producing fibre-reinforced plastic moulded parts, wherein endless fibre strands are fed by a fibre braking device and/or cut fibres via a gravimetric metering device, and a plastic material to be melted, by a volumetric metering device are fed to a single-screw plasticizing unit. Plastic material which is molten and is mixed with fibre material is injected into a moulding tool by an injection stroke of the plasticizing screw. According to the application, the ACTUAL mass flow of the plastic material is calculated from the ACTUAL volume flow of the plastic material and from the ACTUAL mass flow of the fibre material. The ACTUAL mass flow of the plastic material is compared to a TARGET mass flow of the plastic material, and the rotation speed n.sub.d of the rotary drive of the metering element of the metering device is adapted.

An injection molding machine having vent mechanism includes a plastication device, an injection device, a junction, a vent-up sensor, and a controller. The vent-up sensor detects vent-up. When the vent-up is detected, the controller switches from normal conditions to vent-up suppression conditions. The vent-up suppression conditions have at least one of the followings: increasing a rotational speed of the plastication screw to be higher than that in the normal conditions; using retreat-metering when the retreat-metering is not performed in the normal conditions, wherein in the retreat-metering, in addition to a pressure of the resin material, a force in a retreat direction is applied to the injection plunger to move the injection plunger at a predetermined retreat speed in the metering; and increasing the retreat speed of the injection plunger to be higher than that in the normal conditions when the retreat-metering is performed in the normal conditions.

An injection device for an injection moulding machine includes an injection drive, which is designed so as to rotate an injection spindle relative to a spindle nut, and injection slide, which is connected to the spindle nut in a rotationally rigid manner on a lateral surface and held so as to be movable along a slide guide, a guide housing, on which a plasticizing cylinder is held, a bearing housing, in which a driveshaft is rotatably supported and which is connected to the injection slide, as well as a metering drive, which is fastened on the injection slide and designed so as to rotate the driveshaft. A force measuring device is externally fastened on a force transmission component that is arranged between the bearing housing and the spindle nut and lies in the flux of force of the injection device.

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 reverse rotation condition estimating apparatus includes: a learning model storage unit for storing a learning model for estimating reverse rotation conditions; an acquisition unit for acquiring a predetermined time series data set supplied from an injection molding machine at least during a pressure reducing step; and an estimation unit for estimating the reverse rotation conditions using the predetermined time series data set acquired by the acquisition unit and the learning model stored in the learning model storage unit.

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.

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.

A control device for an injection molding machine that performs a metering of a resin while the resin is being melted inside a cylinder, includes a pressure acquisition unit that acquires a pressure of the resin, a reverse rotation control unit that causes a screw to be rotated in reverse so as to reduce the pressure of the resin, after the screw has been moved rearward to a predetermined metering position, a judgment unit that judges whether or not the pressure of the resin has reached a predetermined rearward movement initiation pressure, after the reverse rotation of the screw is started, and a rearward movement control unit which causes the screw to be moved rearward, in the case it is judged that the pressure of the resin has reached the rearward movement initiation pressure.