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 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.

An injection molding machine for foam molding includes: a heating cylinder; a screw disposed in the heating cylinder; and a plurality of inlet portions provided in the heating cylinder and configured to introduce inert gas. An inside of the heating cylinder includes a starvation section on an upstream side in which a pressure of the resin is decreased, and the inert gas from the plurality of inlet portions being to be supplied in the starvation section. Each of the plurality of inlet portions is provided with a check valve or an opening and closing mechanism. A product P×N of an interval P of the plurality of inlet portions and a number N of the inlet portions is 0.5H or more and 1.71H or less with respect to a length H of the starvation section.

An injection molding machine for foam molding includes: a heating cylinder; a screw disposed in the heating cylinder; and a plurality of inlet portions provided in the heating cylinder and configured to introduce inert gas. An inside of the heating cylinder includes a starvation section on an upstream side in which a pressure of the resin is decreased, and the inert gas from the plurality of inlet portions being to be supplied in the starvation section. Each of the plurality of inlet portions is provided with a check valve or an opening and closing mechanism. A product P×N of an interval P of the plurality of inlet portions and a number N of the inlet portions is 0.5H or more and 1.71H or less with respect to a length H of the starvation section.

To provide a plasticizing device capable of easily executing maintenance of a barrel. A plasticizing device includes: a drive motor; a flat screw having a groove forming surface in which a groove is formed, and rotating around a rotation axis of the drive motor; a barrel having a facing surface facing the groove forming surface and having a communication hole formed therein; and a heating unit configured to heat a material supplied between the flat screw and the barrel. The barrel has a separate structure including, when viewed from a direction orthogonal to the rotation axis, a first barrel having the facing surface, and a second barrel separated from the facing surface.

To provide a plasticizing device capable of easily executing maintenance of a barrel. A plasticizing device includes: a drive motor; a flat screw having a groove forming surface in which a groove is formed, and rotating around a rotation axis of the drive motor; a barrel having a facing surface facing the groove forming surface and having a communication hole formed therein; and a heating unit configured to heat a material supplied between the flat screw and the barrel. The barrel has a separate structure including, when viewed from a direction orthogonal to the rotation axis, a first barrel having the facing surface, and a second barrel separated from the facing surface.

A plasticizing device includes: a flat screw that has a groove forming surface on which a spiral first groove is formed, and that rotates; a barrel that has a facing surface facing the groove forming surface and that includes a communication hole through which a plasticizing material flows; a heater that heats resin pellets; and a screw case that accommodates the flat screw and that includes a passage port through which the resin pellets pass toward the flat screw, in which the flat screw has a first side surface on which a first supply port for supplying the resin pellets to the first groove is formed and a second side surface formed on a side farther from the barrel than the first side surface, and a first distance, which is a shortest distance between the first side surface and the screw case, is larger than a second distance, which is a shortest distance between the second side surface and the screw case.

A plasticizing device includes: a flat screw that has a groove forming surface on which a spiral first groove is formed, and that rotates; a barrel that has a facing surface facing the groove forming surface and that includes a communication hole through which a plasticizing material flows; a heater that heats resin pellets; and a screw case that accommodates the flat screw and that includes a passage port through which the resin pellets pass toward the flat screw, in which the flat screw has a first side surface on which a first supply port for supplying the resin pellets to the first groove is formed and a second side surface formed on a side farther from the barrel than the first side surface, and a first distance, which is a shortest distance between the first side surface and the screw case, is larger than a second distance, which is a shortest distance between the second side surface and the screw case.

An injection unit includes an injection cylinder and a plasticizing screw in the injection cylinder. The plasticizing screw is rotatable about a longitudinal axis for plasticizing plastic raw material and is movable linearly along the longitudinal axis for injecting molten plastic raw material. The injection cylinder has an infeed and plasticizing zone for the plastic raw material with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, a metering zone in front of the infeed and plasticizing zone along the longitudinal axis in the injection direction with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, and a nozzle head in front of the metering zone in the injection direction with a nozzle-shaped inner wall. The diameter of the circular-cylindrical inner wall of the metering zone is smaller than the diameter of the circular-cylindrical inner wall of the infeed and plasticizing zone.

An injection unit includes an injection cylinder and a plasticizing screw in the injection cylinder. The plasticizing screw is rotatable about a longitudinal axis for plasticizing plastic raw material and is movable linearly along the longitudinal axis for injecting molten plastic raw material. The injection cylinder has an infeed and plasticizing zone for the plastic raw material with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, a metering zone in front of the infeed and plasticizing zone along the longitudinal axis in the injection direction with a circular-cylindrical inner wall with a constant diameter along the longitudinal axis, and a nozzle head in front of the metering zone in the injection direction with a nozzle-shaped inner wall. The diameter of the circular-cylindrical inner wall of the metering zone is smaller than the diameter of the circular-cylindrical inner wall of the infeed and plasticizing zone.