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Composition and working principle of injection molding machine

Update:08-07-2021
Summary:

The injection molding machine is a special equipment th […]

The injection molding machine is a special equipment that combines the thermal processing characteristics of plastics and the principle of metal melting and die casting. The early plunger injection molding machine did not develop a pre-plasticized screw injection molding machine until the end of the 1940s. Since then, the development mainly revolves around the pre-plasticized screw injection molding machine, and advanced forms such as twin screw and exhaust type have appeared in the future.

The working principle of injection molding machine

Injection molding machine is abbreviated as injection molding machine. Injection molding uses the thermophysical properties of plastics to add materials from a hopper to a barrel. The outside of the barrel is heated by a heating ring to melt the material. The barrel is equipped with a rotating drive driven by an external power motor. Screw, the material is gradually plasticized, melted and homogenized under the double action of the screw shear. When the screw rotates, the material pushes the melted material to the head of the screw under the action of the friction force of the groove and the shear force. At the same time, the screw retreats under the reaction of the material, so that the head of the screw forms a storage space to complete the plasticization process. Then, under the inference of the injection cylinder piston, the screw passes the molten material in the storage chamber at high speed and high pressure. The nozzle is injected into the cavity of the mold. After the melt in the cavity is pressure-maintained, cooled, solidified and shaped, the mold is opened by the clamping mechanism, and the shaped product is lifted from the top of the mold through the ejector device. Fall out.

The composition of the injection molding machine

The injection molding machine is a highly mechatronics machine based on the requirements of the injection molding process. It is mainly composed of injection parts, mold clamping parts, frame, hydraulic system, heating system, control system, feeding device, etc.

 At present, common injection molding devices have single-cylinder type and double-cylinder type.

There are two types of plasticized parts: plunger type and screw type. In the continuous pushing process of the rotating screw, the plastic realizes the change of the physical state, and finally is injected into the mold cavity in a molten state. Therefore, the plasticized component is the core component for uniform plasticization and quantitative injection.

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