Blow molding is a primary method for forming hollow plastic objects such as soda bottles. The process includes clamping the ends of a softened polymer tube which can be either extruded or reheated, inflating the polymer against the mold walls with a blow pin, and then cooling the product via conduction or evaporation of volatile fluids in the container.
Extrusion blow molding is usually used to make items of weight greater than 12 oz. such as containers for food, laundry, or waste.
This process normally uses commodity materials such as PVC, PS, PP, LDPE, and HDPE.
Injection blow molding is used to achieve very accurate wall thickness very accurate wall thickness, high-quality neck finish, and to process polymers that cannot be extruded. Usual applications include pharmaceutical bottles, cosmetic packaging, and single serving liquor bottles that weigh less than 12 oz.
