The blown film towers BFT 300/400 with film haul-offand extrusion die are used to produce high-quality blown film for carrying out optical and physical measurement on the film.The mechanical design corresponds to a production system in laboratory scale.All settings and configuration parameters are stored by the system(touch panel), which means that the film quality can be reproduced at any time.This is particularly important for optical on-/off-line measurement, such as gels, contamination, haze, gloss etc.Reproducible film qualities are also important for on-/off-line density and additive measurement.

The tower height is electrically driven,free adjustableand can therefore be set optimally for all extruded materials.

The take-off nip rolls are driven pneumatically and thetemperature is optionally adjustable.

The film bubble can be stabilised with additional guidingrolls, adjustable wooden grids and Teflon-coated rollsare leading the film bubble into a flat layer film.

The guiding rolls are made of stainless steel. Some guiding rolls are special designed to prevent wrinkles.

The blown film tower is operated via a colour LCD touch panel. All parameter, e. g. haul-off speed, filmtension, winding force, winder diameter, cooling air, film width, etc.can be set here and stored as a configuration file.

An optical device measures the width of the flattened film and controls the diameter of the film bubble. In this way, the desired film width remains constant. The film width is recorded and shown graphically on the touch panel.

The complete operation is visualised on the touchpanel, and parameters such as current winder diameter, alarms, and other data are shown as clear text additionally.

Tension roll measures the film's tension continuously and controls the speed of the rubber nip rolls automatically.In this way, the complete haul-off unit is adjustedautomatically to the film speed and it¡¦s elasticity. The winding shaft is operated pneumatically and permits coreless winding.

The winding force can also be set and thus permits optimum winding behaviour for all materials. The winding tension is measured and regulated. A film break and direction detector is integrated and permits high operating safety, in particular for on-line applications.

The cooling air blower is frequency-controlled and therefore highly accurate. The labyrinth of the cooling ring guarantees an even air flow.

Depending on their size, the dies have 6 or 8 spirals and therefore enable an optimal and even distribution of the melt. The dies have 3 separate heating zones.

An ionising unit reduces static charges, and all motors (three) are maintenance-free three-phase A.C. servomotors with feedback.

The complete unit can be remote controlled.