8. Conclusions and outlook

The polymer cast film extrusion process is a technologically and scientifically complex industrial process for producing polymer films of several tens of micrometers in size. The elongational nature of the flow, combined with the viscoelastic behavior of molten polymers, means that phenomena specific to this process need to be mastered, such as width reduction, inhomogeneous reduction in polymer cross-section, or stretchability limits such as Draw Resonance or film rupture.

The progress made in understanding the process over the last 10 years means that today we can find flat extrusion lines capable of producing 20 µm films with a thickness tolerance of +/– 1 µm over a width of around 2 m, at a speed of 600 m/min (compared with 300 m/min 10 years ago).

The modeling of the flat film extrusion process has contributed to improving this understanding,...