The main stages of injection molding

The Injection molding China or thermoplastic injection, allows the manufacture of medium or very large series, in the right field. These series parts are produced for many areas. They can be used for household appliances or in the automobile, for example.

The principle of injection molding

The thermoplastic injection consists of injecting a molten polymer (thermoplastic material) under high pressure into a mold, using an injection press.

How injection molding works  

Injection molding uses thermoplastic materials. The latter is in the form of granules before the transformation phase. They are diminished under the consequence of heat. Once in liquid form, the material is injected into a mold and takes the imprint thereof. Then it will cool down and solidify. When it has regained its hardness, the part can be extracted, which becomes usable.

The main stages of injection molding  

Make a mold. The latter is composed of two parts, a fixed part, and a mobile part. The design of the mold should allow easy ejection of the parts.

Install the mold on a specific machine: the injection press. The two pieces of the mold are powerfully pressed next to one another. The material (in the form of granules) is poured into a plasticizer (or worm screw), heated. The rotation of the screw combined with the temperature, will soften the granules, which turn into molten plastic. The molten and deformable material is stored in front of the screw, before injection.

Inject under high pressure. The plastic materials softened under the effect of heat in the mold. In this phase, it must be ensured that the mold is filled before the material solidifies. This is why Plastic Molding Company continues to send material under pressure to compensate for the shrinkage that occurs when the material cools.

Cool everything, using cooling circuits inside the mold. After this process, the object is turned out from the mold.

Eject the part.

Start over with the next piece.

Molds and techniques used for plastic molding

Injection molding

It is usually a tool machined from steel, which supplies the dose of molten plastic material produced by the press to the conformation of the part to be printed and injected. It ensures the aesthetic and dimensional quality of the part. The part when the cooling phase is complete. This is the basis of injection molding.

Low-pressure injection molding

This is a steel or aluminum tool in which a dose of molten plastic is injected with an open mold. The part is filled and compacted by closing the tool.

The plastic injection allows a higher flow rate that shell, filling time of the mold of between 3 and 8 seconds. Therefore, the dimensional accuracy of parts approaching that of the casting and mechanical characteristics of the castings improved by approximately 10%.

Composite molding

It allows the manufacture of light, strong, and durable structures of any shape and style. A composite molded part is quickly produced, all shapes are possible as soon as they can be released with or without a key.

Thermoforming molding

It makes it possible to form parts by creeping a thermoplastic plate under temperature conditions and vacuum. Ideal for small and medium series, the thermoforming Plastic Molding is generally used for less complex geometry.

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