Injection molding, also known as injection molding, is an injection and molding method. The advantages of the injection molding method are that the production speed is fast, the efficiency is high, the operation can be automated, the patterns and colors are various, the shape can be from simple to complex, the size can be from large to small, and the product size is accurate, the product is easy to update and replace, and can form parts with complex shapes. The injection molding is applicable to the molding and processing fields of mass production and products with complex shapes.
　　At a certain temperature, the fully molten plastic material is stirred by a screw, injected into the mold cavity by high pressure, and then cooled and solidified to obtain the molded product. This method is suitable for batch production of complex parts and is one of the important processing methods.
　　In 1868, Hayatt developed a plastic material, which he named Cellulou. Celluloid has been produced by Alexander in 1851? Parks invented. Hyatt improved it so that it can be processed into finished shapes. Hayatt and his brother Isaiah registered the patent right of the first plunger injection machine in 1872. This machine is relatively simpler than the machines used in the 20th century. It basically works like a huge hypodermic syringe needle. This huge needle (diffusion cylinder) injects plastic into the mold through a heated cylinder.
　　In the 1940s, the Second World War created a huge demand for cheap and mass-produced products., Products with low price and mass production.
　　In 1946, American inventor James Watson Hendry built the first injection molding machine, which made it possible to control the injection speed and quality of products more accurately. This machine also makes the colored or recycled plastics be thoroughly mixed and injected into the raw biomass before the materials are mixed and injected. In 1951, the United States developed the first screw injection machine. It did not apply for a patent. This device is still in use.
　　In the 1970s, Hendry then developed the first gas-assisted injection molding process, which allowed the production of complex, hollow products and rapid cooling. This greatly improves the design flexibility, strength and end-point manufacturing components, while reducing production time, cost, weight and waste.