Injection molding is a molding method that uses a mold. A material such as synthetic resin (plastic) is heated to melt it, fed into the mold, and then cooled to produce the desired shape. It is called "injection molding" because it resembles the way a syringe feeds liquid into a mold. The processing flow begins with "melting" the material, followed by "pouring," "hardening," "removing," and "finishing. With injection molding, parts of various shapes, including complex shapes, can be manufactured continuously, quickly, and in large quantities. For this reason, it is used in a wide range of products, including daily necessities.