• Factories use plastic injection molds to create plastic covers for a variety of products.factory image by cico from Fotolia.com
  
  Plastic injection molds are very common in factories where a wide various of goods are produced. These molds allow manufacturers to create plastic components in nearly any shape they want. This is especially useful for electronics and other smaller products. Plastic injection mold systems all use relatively similar components and processes to create the plastic shapes.
  
  

Pellets

• Pellets are the base material that plastic injection systems use. Factories do not create their own plastic --- this is an entirely separate process and requires many dedicated machines --- so manufacturers tend to buy plastic from others. They cannot simple buy and transport liquid plastic, so they buy pellets instead --- small chunks of the type of plastic they want to use. These pellets come in bulk and are fed into the system as needed.
  
  

Heating Compartments

• Heating compartments are used to melt the plastic pellets. These compartments range in size depending on the system, but are made out of a heat-resistant metal that can be used to hold the pellets. A stirring mechanism is sometimes used. Manufactures install ventilation systems to channel away any toxic fumes the melting plastics produce.
  
  

Mold Chamber

• The molding chamber is the part of the system that actually shapes the plastic. This is the mold itself, typically made from metal or another material that the plastic will not bond to. The mold can often open or close to trap the plastic inside, or the plastic is literally injected into the mold through a series of small holes. Here the plastic cools off until it is completely solid.
  
  

Ejection Equipment

• Once the plastic has cooled and formed its required shape, it must be ejected from the mold. Factories typically have a simple injection system involving pistons or a similar device that pops the mold open and the plastic shape out. This step is rarely done by hand, since multiple plastic products are made at once in factories.