Conceptually, making a thin polymer film is an easy proposition—just melt one or more polymers, force the melt through a long, narrow opening, freeze the extruded melt into a solid film, and wind it into a roll. Like most important things, there is a rich and extremely varied menu of material and process variables that offer the opportunity to create widely differing useful films. The opportunities, and the devils, are in those variables.
Setting aside material for the moment, there are four film-making processes, each with their own pros and cons:
- Cast film
- Air-cooled blown film
- Water quench blown film
Download a full primer on these processes here: “Understanding film manufacturing techniques.”