Injection Molding Process and Principles
As one of the most widely used plastics processing technologies in modern manufacturing, injection molding embodies sophisticated engineering wisdom in its process flow and operating principles. Under high temperature and high pressure, it transforms solid plastic raw materials into a variety of plastic products.
The injection molding process begins with the precise metering and drying of the raw materials. Plastic granules undergo a three-stage heating and melting process within the injection molding barrel: a conveying stage for conveying the raw materials, a compression stage for compaction and plasticization, and a metering stage for precise control of the melt volume. Once the melt reaches a well-flowing state, the screw, driven by a hydraulic system, injects the melt into the mold cavity.
The injection mold system is the "heart" of the entire process. Its precisely arranged cooling channels achieve rapid cooling and final shaping through heat conduction, while the ejector mechanism gently ejects the solidified molded product.
The synergistic effect of external heat and mechanical shear forces breaks down the secondary bonds between polymer molecules, allowing them to enter a viscous flow state-the "plastic window." Precise control of temperature, pressure, and speed directly determines the dimensional accuracy, surface quality, and mechanical properties of the injection molded product.