The injection device is a device that melts the resin material and then injects it into the mold. The resin was extruded into the cylinder from the head as shown, and the melt was transferred to the front end of the barrel by the rotation of the screw. In that process, heating by the heater heats the resin material in the barrel, and the resin is brought into a molten state by the shear stress of the screw, and the molten resin corresponding to the molded product and the main channel and the runner is retained. At the front end of the barrel (known as metering), the screw continues to advance material into the mold cavity. When the molten resin flows in the mold, the moving speed (injection speed) of the screw must be controlled, and the pressure (maintenance pressure) is used to control after the resin fills the cavity. When the screw position, injection pressure reaches a certain value, we can switch speed control to pressure control.