Understanding the Basics of Plastic Injection Molding Process

publisher: Tea
Time: 2017-10-23

Understanding the Basics of Plastic Injection Molding Process 


Plastic injection molding process begins with the gravity feeding of polyolefin pellets from a hopper into the plasticating /injection unit of the molding machine. Heat and pressure are applied to the polyolefin resin, causing it to melt and flow. The melt is injected under high pressure into the injection mold. Pressure is maintained on the material in the cavity until it cools and solidifies. When the plastic part temperature lower than the material's distortion temperature, the mold opens and the plastic part is ejected.

The complete injection process is called a molding cycle. The period between the start of the injection of the melt into the mold cavity and the opening of the mold is called the clamp close time. The total injection cycle time consists of the clamp close time plus the time required to open the mold, eject the plastic part, and close the mold again, the injection molding machine transfer the resin into molded parts through a melt down, injection, pack, and cool down cycle. A plastic injection molding machine includes the following major components as below.


Injection system: feed the raw materials into cylinder, heat up and melt it down, push the melted materials into the cavity through the spure.
Hydraulic system: to provide the force of injection.
Mold system: to load and assemble the mold.
Clamping system: to provide packing force.

Control system: to control action, cooling system.

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