4 major processes of insert injection molding

Precision, focusing on metal insert injection molding and customization for more than 10 years, providing one-stop solutions for precision metal stamping, metal drawing, metal insert injection molding, and automated assembly. We all know that insert injection molding is a process that combines metal parts and plastics. It is a common method and a cyclic process. It needs to go through four major processes. Next, let’s take a brief look at these four processes. . 1. In the pre-plastication stage, the screw starts to rotate, and then the plastic conveyed from the hopper is conveyed to the front end of the screw. The plastic is uniformly plasticized under the action of high temperature and shear force and gradually gathers at the front end of the barrel, as the molten plastic gathers , The pressure is getting higher and higher, and then the screw is gradually pushed back by overcoming the back pressure of the screw. When the plastic at the front of the barrel reaches the required injection volume, the screw stops retreating and rotating, and the pre-plasticizing phase ends. 2. Injection stage The screw moves forward under the action of the injection cylinder, pushing the plastic stored in the front of the barrel forward at multi-level speed and pressure, and injects it into the closed mold cavity through the runner and gate. 3. Pressure-holding and feeding process The injection pressure in the holding-pressure stage is called the holding pressure. Under the action of this pressure, the melt in the cavity is fed due to cooling, and the product is compressed and densified. In this process, the holding pressure plays a leading role. The characteristics of the pressure holding stage are: the melt flows slowly under high pressure, the screw has a small feeding displacement, and the material gradually takes shape as the material cools and the density increases. In the pressure holding stage, the melt flow rate becomes very small and does not play a leading role, but the pressure is the main factor affecting the process. In the pressure holding stage, the pressure and specific volume in the mold are constantly changing. 4. Cooling and shaping stage The plastic is kept under pressure in the mold cavity to prevent the plastic from flowing backwards until the plastic is solidified and the pressure in the cavity disappears. A large proportion of cooling setting time in a production cycle. [Related recommendation] Learn more: 精の corporate culture Learn more: Continuous improvement and innovation are the key factors for the survival of stamping companies Learn more: Why most stamping factories are unwilling to quote foreign trade companies