Example of Cast Film Extrusion Process

The cast film process involves the extrusion of molten polymers through a flat die to form a thin film. This film is "pinned" to the surface of a chill roll with an air knife or vacuum box. The molten polymer quenches immediately creating a very clear film. As in blown film, co-extrusion can also be utilized to create multilayer film structures.

Cooling
The Air Knife promotes web quenching by gently blowing a low-velocity, high-volume air curtain over the molten film pinning it to the chill roll for solidification. By increasing the impinging surface area, film properties and clarity may be improved. The temperature and air speed must be controlled to produce film with the desired aesthetic properties.

Finishing
Use sharp, rigidly mounted razor blades for trimming film edges. Use a winder with good tension control and a proximity lay-on roll. Use static reduction devices prior to winding or as needed throughout the film line.Use sharp, rigidly mounted razor blades for trimming film edges. Use a winder with good tension control and a proximity lay-on roll. Use static reduction devices prior to winding or as needed throughout the film line.