Everything from automobile parts to plumbing tools is made using injection molding. That’s because injection molding is a common method of manufacturing. Manufacturers love the process because it is easy to make huge quantities of the same object. The process shapes plastic and other materials by melting and injecting them into a predesigned mold. Injection molding was loosely based on metal die casting.
Have you ever wondered how to injection mold? The main different between working with metal and plastic is that hot metals are poured, while plastic has to be injected. First, manufacturers use large injection molding machines. The machine may appear complex but it has two basic parts, the injection unit and the clamping unit. A mold is clamped under pressure and plastics are put in the machine. In addition, if color is needed, it is added at this time. The plastic is melted to the boiling point in the injection barrel and then injected into the mold. Pressure is applied to the mold to make sure plastic is filling every inch. Next, the plastic stays in the mold until it cools down. Finally, the plastic part is removed from the mold and inspected for quality. This process requires complicated calculations in order to complete. Every material shrinks differently and the shrinkage has to be calculated in the molding. If the shrinkage value is incorrect, the finished product will not be the right size.
Injection molding is an expensive process but manufacturers expect to get their money back through mass production and sales. An engineer usually designs the mold and a toolmaker forms the mold out of metal. Molds are so expensive they are usually only made for mass production. Injection molding affects so many aspects of our lives. It is used to make toys, milk containers, combs, utensils and so much more. In addition, injection molds are used with rubber to make things like rubber hoses, valve steam seals and oil seals for engines. Metal is also used in injection molding for items like knitting needles, ball bearings and spark plugs. This painstaking manufacturing process contributes a lot to the way we live.