Extrusion blow molding is a method of making hollow thermoplastic articles. Well-known blow molded objects are bottles, barrels, cans, boxes and all containers for food, beverages, cosmetics, pharmaceuticals and daily necessities. Large blow molded containers are commonly used in the packaging of chemical products, lubricants and bulk materials. Other blow molded products include balls, bellows and toys. For the automotive industry, fuel tanks, car shock absorbers, seat backs, center brackets, and armrest and headrest covers are blow molded. For machinery and furniture manufacturing, blow molded parts have outer casings, door frames, frames, clay pots or boxes that have an open side.

The most common blown plastic extruded material is high density polyethylene, and most milk bottles are made from this polymer. Other polyolefins are also often processed by blow molding. Depending on the application, styrenic polymers, polyvinyl chloride, polyester, polyurethane, polycarbonate and other thermoplastics can also be used for blow molding.

Recently, engineering plastics are widely accepted in the automotive industry. Material selection is based on mechanical strength, weatherability, electrical properties, optical properties and other properties.