A method of influencing a melt temperature in a plasticizing cylinder of a plasticizing unit (1) for an injection molding machine having a plasticizing screw (4) arranged rotatably and displaceably in a cylinder bore of the plasticizing cylinder which extends axially, wherein metering of plastic granular material fed to the plasticizing unit (1) is effected in dependence on a desired melt temperature in the plasticizing unit (1).

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.

An injection molding machine includes a screw provided in a cylinder having a nozzle at a tip so that the screw is allowed to be driven in a rotational direction and an axial direction, a drive device configured to drive the screw, and a control device configured to control an operation of the drive device, wherein the drive device has a rotatably provided ball screw shaft and a nut screwed onto the ball screw shaft and moved forward and backward in response to rotation of the ball screw shaft, and includes a ball screw configured to drive the screw in the axial direction by forward and backward movement of the nut, and the control device sequentially moves a screw position before injection and a screw position after injection in a molding process cycle so that a forward/backward movement range of the nut in the molding process cycle is dispersed.