Common plastic molding processes and their application ranges

The plastic molding process is a technical method for making plastics in various forms (powder, pellets, solutions, and dispersions) into products or blanks of the desired shape. At present, there are more than thirty kinds of plastic molding process methods. For example, the commonly used methods for processing thermoplastic plastics are extrusion, injection molding, calendering, blow molding, and thermoforming. Thermosetting plastics generally use molding, transfer molding, and injection molding. But in actual application, most manufacturers only use a few types. Next, let’s take a detailed look at the common plastic molding processes and their application ranges.

Extrusion molding: Extrusion molding, also known as extrusion molding, uses screw rotation and pressure to continuously squeeze the plasticized plastic into the mold. When passing through a die of a certain shape, a plastic that matches the shape of the die is obtained. Profile processing methods.

The characteristics of extrusion molding are continuous forming, high productivity, simple mold structure, low cost, tight organization, etc. Except for fluoroplastics, almost all thermoplastics can be extruded, and some thermosetting plastics can also be extruded. Extrusion molding accounts for about 30% of plastic products and is mainly used for various plastic profiles with a certain cross-section and large length, such as plastic pipes, plates, rods, sheets, strips, materials, and special-shaped materials with complex cross-sections.
Injection molding: injection molding, also known as injection molding, is a method that uses an injection machine to quickly inject molten plastic into a mold and solidify it to obtain various plastic products. This method can be used for almost all thermoplastics (except fluoroplastics), and can also be used for the forming of some thermosetting plastics.

Injection molding accounts for about 30% of the production of plastic parts. It has the advantages of being able to form parts with complex shapes at one time, accurate dimensions, and high productivity. The most common products of injection molding include computer case casings, connectors, mobile phone casings, keyboards, mice, Audio, etc.
Blow molding: Blow molding, also called hollow blow molding, is a method that uses gas pressure to inflate the hot melt parison closed in the mold to form a hollow product. It is the third most commonly used plastic processing method and is also the fastest-developing method of plastic molding.

The tubular plastic parison obtained by extrusion or injection molding of thermoplastic resin is placed in a split mold while it is hot (or heated to a softened state). After the mold is closed, compressed air is immediately introduced into the parison to blow out the plastic parison. It expands and adheres closely to the inner wall of the mold. After cooling and demoulding, various hollow products are obtained. The common bottles, barrels, cans, boxes, and containers for packaging food, beverages, cosmetics, medicines, and daily necessities in our lives are made using the blow molding process.
Blister molding: Blister molding, also called vacuum forming, is one of the thermoforming methods for thermoplastic plastics. That is, the sheet or plate material is clamped on the frame of the vacuum-forming machine. After heating and softening, it is vacuum-adsorbed to the mold through the air channel on the side of the mold. After a short period of cooling, the formed plastic product is obtained.

The equipment used in blister molding is relatively simple. The mold does not need to withstand pressure and can be made of metal, wood, or gypsum. The molding speed is fast, and the operation is easy. It is widely used in automobile accessories, lighting, advertising, decoration, large machinery casings, displays, consumer electronics, large appliances, sanitary ware, and other industries.