Blown film extrusion

Manufacturing process for producing tubular films by inflating a plastic tube from an annular die.

What is blown film extrusion?

Areas of application

Process parameters & quality

01 What is blown film extrusion?

Blown film extrusion is a continuous manufacturing process for producing tubular films from thermoplastic polymers. In this process, the molten polymer is forced through an annular die and inflated with compressed air to form a film tube. The tube cools in the air, is flattened and then wound up. The process enables the production of films with uniform thickness and adjustable mechanical properties.

02 Areas of application

Blown film extrusion is the most commonly used process for producing PE films for industrial packaging. Typical products include liners for drums and containers, bags, sacks, shrink films and multi-layer films with barrier properties. Blown-extruded films are used particularly in the pharmaceutical, chemical and food industries, as they can be flexibly adapted to different requirements.

03 Process parameters & quality

The key process parameters are the melt temperature, the blow-up ratio (BUR), the take-off speed and the cooling air flow. By adjusting the blow-up ratio and take-off, the film properties in the machine direction and transverse direction can be set precisely. Modern systems have gravimetric dosing and automatic thickness measurement to ensure consistently high film quality.

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