Blow molding is a method of producing hollow plastic products that is widely used in the packaging, health, pharmaceutical, chemical and automotive industries. Polymeric materials are melted in an extruder and exit the die in the form of a molten tube called a parison. The mold is closed around the parison and by blowing compressed air, the materials adhere to the mold wall and take the shape of the product. After cooling, the product is removed and finishing operations are performed.