The three main elements of plastic injection molding are "plastic materials", "plastic molds" and "plastic injection machines". These three elements will be subdivided into many different categories due to different manufacturing needs, such as plastic materials can be subdivided into crystalline and non-crystalline; plastic molds can be subdivided into two-plate mold, three-plate mold, and hot-runner mold; plastic injection machine can be subdivided into hydraulic crankshaft type, two-plate direct-pressure type, and all-electric type. Before the manufacturing process of injection molding, let's briefly understand the structure of the injection machine(see Figure 1), the barrel: the location where the raw materials are stored, and the material tube: that is, the channel from the material to the mold, and the material tube is covered with a "screw", which function is to melt the plastic, mix the chain, and inject a certain amount of plastic into the mold. The mold: It is like a model of chocolate. The raw materials are injected into it to shape a product with a specific shape. There is a "thimble" on the mold. The main function is to push the product out of the mold, that is, to separate the product from the mold.
Plastic injection molding can be simplified into a five-stage, continuous cycle process, which can be divided into five stages, which is a continuous cycle process.
The raw materials enter the material tube and are mixed and melted by the screw.
"Filling" the raw materials into the mold through the screw
3. Holding pressure:
After the raw material is filled into the mold, in order to avoid the backflow of the raw material, the space in the mold is continuously pressurized to ensure the compactness of the raw material filling.
The product is quickly cooled and shaped in the mold.
Through the ejector pin on the mold, push the cooled product out of the mold
The principle of plastic injection is like making chocolate. The raw materials are heated and melted and then injected into the model. After the substitute product is cooled, the mold is released, and the finished product is completed. Plastic injection is an easy and rapid prototyping processing method, but because plastic itself has "cooling shrinkage" characteristics, the technology and experience of product designers and processing manufacturers are required to be able to adjust the "size" of the product and with good control on the "appearance", these two together to create a good plastic product.