Injection molding is a method of injecting heated and molten plastic material into a mold, and then cooling and solidifying to obtain a molded product. This method is suitable for mass production of products with complex shapes and occupies a large proportion in the field of plastic processing.

Injection molding is a high-precision manufacturing process that injects molten plastic into carefully designed molds where the plastic cools and hardens into a specified part or product. The workpiece is then removed from the mold and sent for secondary finishing as a final product or as a near-final product.

The injection mold consists of a core and a cavity. The space created by these two parts when the mold is closed is called the part cavity (the void that receives the molten plastic). Depending on production needs, “multi-cavity” molds can be designed to create multiple identical parts (up to 100 or more) during the same run. China’s current injection mold design follows these basic principles.

Designing a mold and its various components (called tooling) is a highly technical and often complex process that requires high precision and scientific knowledge to produce high-quality parts with compact dimensions. For example, the appropriate grade of steel must be selected so that components that operate together do not wear out prematurely. The hardness of the steel must also be determined to maintain the proper balance between wear and toughness. Waterlines must be placed properly to maximize cooling and minimize warping. Mold engineers also need to calculate gate/runner size specifications for proper filling and minimum cycle times, and determine the best closing method for mold durability over the life of the program.