What are the molding methods of plastic products


Plastic products are products that can be seen everywhe […]

Plastic products are products that can be seen everywhere in daily life. Whether it is daily consumer goods or industrial products, there are many different production methods. The following is an introduction to the most common molding methods of several plastic products, I hope it will help you choose the molding method that suits your project.
Injection molding
About 80% of plastic products in daily life are injection molded. Injection molding is produced by using an injection molding machine with an aluminum mold or a steel mold. The mold is composed of a core and a cavity. The injection molding machine heats the resin raw material until it melts, and uses pressure to inject the molten plastic material into the cavity of the mold. Then the core and the cavity are separated, and the product is ejected from the mold.
The advantages of injection molding are large quantity, high speed, low cost, and good surface effect. However, the structural complexity of the injection mold depends on the geometry of the product. The more complex the structure, the higher the cost of the mold. In addition, the engineering design of the mold must be refined to prevent defects and optimize product quality and processing speed.
The mold used in rotational molding is also composed of a core and a cavity, but the working principle is different. Rotational molding is to first add plastic raw materials to the mold, and then the mold is continuously rotated and heated along two vertical axes, so that the plastic raw materials in the mold are gradually and evenly spread, melted and adhered to the mold cavity under the action of gravity and heat energy. . Subsequently, the mold is unloaded, cooled and shaped, and then the product is taken out and used in the next round of production.
Rotomolding is suitable for the production of large, hollow or curved products, such as kayaks or water tanks for outdoor use. Because the product is formed under a high-temperature rotating process and the product is seamless, it has high strength, and the mold is relatively simple and low in cost. The disadvantage is that the mold needs to be repaired after being used thousands of times, and the product quality is average, so it is not suitable for precision products.
Extrusion blow molding
Extrusion blow molding is often used to make thin-walled and inexpensive containers, such as disposable water cups or water bottles. The production speed is extremely fast, and the mold making is simple, but it is not suitable for manufacturing complex or high-precision products.
The softened plastic forms a parison, which is placed in a two-piece open-close mold. After the mold is closed, compressed air is blown into the parison to inflate it until it all adheres to the cavity wall. After the mold wall is water-cooled, the plastic part is quickly solidified, and then demolded to obtain the finished product.
Injection blow molding
Injection blow molding is the process of using air pressure to inject molten resin into the mold cavity. This process is easier to control and repeatable. It is usually used to produce transparent plastic beverage bottles. The surface effect is very good, but it is not suitable for producing wall thickness. Thicker product.
Polyester and polyester ether ketone are common raw materials for plastic bottle manufacturing, because these two resin particles have transparent and stable characteristics, and as consumer products, they are rated as safety grades, and they are also easy to recycle.