Blow molding, also known as blow forming, is a fast-developed manufacturing process by which hollow plastic parts are formed from thermoplastic.The basic process has two fundamental phases. First, a preform (or parison) of hot plastic resin in a somewhat tubular shape is created. Second, a pressurized gas, usually air, is used to expand the hot preform and press it against a female mold cavity.

History
In the second war,the Blow Molding Process is used to produce low density polyethylene vial.While in late 50th,the blow molding technology is widely used with the naissance of high-density polyethylene and development of blow molding machine. 

Material
The material always used are:Polyethylene, polyvinyl chloride, polypropylene, polyester and so on.And the products is widely used as industrial packaging containers.

Category
In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and stretch blow molding.