What is the principle of injection molding?

What is the principle of injection molding?

Injection molding is a plastic processing process, the principle is to melt plastic raw materials through high temperature into the mold, after cooling to obtain the required shape and size of the plastic products.

The following is the detailed principle of injection molding:

(1) Melting of plastic raw materials: the first step in injection molding is to heat the plastic raw materials to melt them into a liquid. The way of heating is usually through the heating element inside the barrel, and the plastic raw materials can be stirred and mixed by the rotation of the screw to make it uniformly melted.

(2) Injection and filling: the melted plastic raw material is injected into the mold, which requires the use of the injection screw and the pump of the injection molding machine. The control of injection pressure and speed is very important for the quality and dimensional accuracy of the product, and it is usually necessary to accurately control the injection volume and speed to avoid problems such as shrinkage, deformation or bubbles of the product.

(3) Mold cooling and plastic products curing: After plastic raw materials are injected into the mold, they need to be cooled to the curing temperature of the plastic and maintained for a certain time to make the plastic products finalize. The cooling efficiency of the mold is very important for the cooling and curing process of the product, and it is usually necessary to use cooling waterways or cooling media to accelerate the cooling process.

(4) demoulding and taking out plastic products: when the plastic products are cooled and cured, the products need to be removed from the mold, and the necessary post-processing, such as dressing, packaging, etc. In the demoulding process, care should be taken to avoid scratches or damage to the surface of the product.

Injection molding has the advantages of high production efficiency, high precision and wide application range, so it has been widely used in the automobile, home appliances, electronics, toys and other industries. However, injection molding also has some disadvantages, such as high equipment costs, production process will produce a certain amount of waste and pollution. In order to overcome these problems, some new injection molding technologies such as hot runner technology and gas-assisted injection technology continue to emerge, providing more options for the production of plastic products.