Basic concepts for Cast Film Extrusion Technology

In the cast film extrusion process, the melted polymer travels through a flat die system to adopt its final flat film shape.  

The die system is formed by the die and feedblock (if the process requires multi-layer coextrusion) or simply the die, if the process is that of mono-layer extrusion.  

The process starts with the feeding of plastic resins by means of a gravimetric feeding system to one or more extruders. The materials are then melted and mixed by the extruders, filtered and fed to the die system.

Immediately after exiting the die, the melted curtain enters the cooling unit where its temperature is lowered with a water cooled chill roll to “freeze” the film. The film is then passed downstream where the edges are trimmed, corona treatment is applied (if a fabrication process such as printing or coating is required) and the film is wound into rolls.

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