Injection molding is a manufacturing process that allows plastic parts and products to be made in mass production keeping tight specifications and allowing them to be made quickly and efficiently. In the injection molding process granules of polymers and plastics are fed from a hopper into a screw like feed system. In the feed system the granules are heated up, melting them into a molten state before they are pressed into a mold as high pressure.  Once injected into the mold the plastic cools and the parts are formed.