The Stretch-Roll and Winder System CRS-6 was developed for the quality control of polymers which need to be stretched before optical analysis can be performed.

An example of this would be the contamination count in PET material. The optical control of the extruded cast film with this unit is an easy and consistent method of quality control of the raw material.

Materials, which are difficult to extrude, also can be processed into a qualitatively and optically high-standard film using this unit. The highly polished chill rolls and a specially developed air knife are responsible for this. The chill rolls are double walled. A very narrow opening leads to high fluid speeds, and therefore to a very precise temperature distribution on the surface of the roll.

The chill roll unit consists of two separately driven chill roll groups, each with three rolls. Both groups have separate servo-drives, which are electronically linked. The temperature of the rolls can be individually set. Usually, the first two rolls are used for cooling, the third for heating, and the last group again for cooling. After heating, the film is stretched. The degree to which the film can be stretched is infinitely variable between 0 % and 300 %. The film can then be hauled off, either at a constant speed or tension, and wound at an adjustable force.

Any extruder with a cast die of 50 mm to 150 mm can be used. The unit can be equipped with a remote diagnostic system, which would allow access to all the system's parameters via a modem.