The Plastic Injection Process generally includes several steps of feeding, plasticizing, Plastic Injection filling and demolding.

 

 

 

1) Feeding

 

Since Plastic Injection molding is an intermittent production process, quantitative feeding is required to ensure stable operation, uniform plasticization and finally obtain good plastic parts. Too much feeding, too long heating time, etc. will easily cause thermal degradation of the material and increase the power loss of the Plastic Injection machine; if feeding is too little, the pressure transmission medium in the barrel is lacking, the pressure of the plastic melt in the cavity is reduced, and it is difficult to feed (ie Pressure compensation), it is easy to cause defects such as shrinkage, dents, and cavities in plastic parts.

 

 

 

2) Plasticization

 

The process of heating the plastic in the barrel to transform it from a solid (granular or powder) state into a viscous fluid state with good plasticity is called plasticization. The main factor that determines the quality of plasticization is the heating condition of the material and the shearing effect it receives.

 

         

 

The requirements for plasticization of plastics are: the plastic melt must be fully plasticized before entering the cavity, not only to reach the specified molding temperature, but also to have a uniform melt temperature, and to minimize the content of thermal decomposition products, and It can provide enough molten plastic to ensure that the plasticization of the plastic is accelerated, and the mixing effect of the plastic is also strengthened to expand to the level of polymer molecules (not only static melting), which makes the temperature distribution of the plastic melt , Material composition and molecular morphology have changed, and tend to be more uniform. Therefore, the plasticizing effect of the screw Plastic Injection machine is much better than that of the plunger Plastic Injection machine.

 

         

 

3) Plastic Injection filling type

 

Plastic Injection filling refers to the process of using a plunger or screw to push the plasticized plastic melt to quickly fill the mold cavity, and the melt is cooled and solidified under pressure. The Plastic Injection Process can be divided into several stages, such as mold filling, pressure holding, backflow, and cooling after the gate is frozen.