Developed in the late 1930s, blow molding is a manufacturing process that is used to form hollow plastic parts. It is most commonly used to make plastic bottles. In principal, the basic blow molding process is similar to glassblowing. Plastic resin (pelletized raw plastic material) is melted and formed into a hollow tube or parison which is then placed into a mold. The parison is then inflated using compressed air to form a finished part.
In the early 1960s, PFC founder Peter T. Schurman realized that he could combine two hollow blow molded parts to form the lid and base of a portable container or enclosure, and the “double‐wall blow molded carrying case” was born. Read more about blow molding here.