注射装置的主要作用是将各种形态的塑料均匀融化，并以足够的压力和速度将一定量的熔体注射到模具的模腔内，当熔体充满型腔后，仍需保持一定的压力和作用时间，使其在合适压力作用下冷却定型。
The main function of the injection device is to melt all kinds of plastic evenly, and inject a certain amount of melt into the mold cavity with enough pressure and speed. When the melt fills the mold cavity, it still needs to maintain a certain pressure and action time, so that it can be cold and shaped under the appropriate pressure.