New method for measurement of wound-in-tension in webs wound into rolls

Abstract

The Wound-In-Tension (WIT) is the tension in the outermost layer of a winding roll. The Wound-In-Tension is an important parameter that controls the stresses inside the wound roll which in turn determines the quality of the wound roll. Existing on-line methods of measuring or inferring WIT can be interfering measurements or suffer from inaccuracy. This paper documents a method of on-line WIT measurement that is based on the change in deformation of the web from a first location upstream of the winder, where the web tension is known, to a second location where the web has become the outer layer of the winding roll. It will be shown that these measurements can be made by non-contacting means such as Laser Doppler Velocimetry or by contacting means where encoders are employed. Results of the WIT measurement by the new method are compared to traditional WIT measurements on wound rolls of various materials.