Modelling of tension in yarn package unwinding

Abstract

Yarn unwinding from a package is an essential step in many textile processes. The quality of the yarn is numericallyexpressed mainly by values of mechanical quantities. In the unwinding process viscoelastic properties are the mostimportant ones. They depend on how the yarn is stressed. The quality of the yarn that is being unwound should not bereduced, unless this reduction doesn’t significantly lower the quality of the textile fabric. During unwind the yarn tensionis not constant, but it oscillates within some interval. Even when the yarn is not strongly stressed, the yarn still can breaksometimes. This is why we think that a cross-wound package is not an ideal form of a package and that such packagesaren’t always made without flaws. We strive to achieve as large warping and weaving speeds as possible, therefore ouraim is to improve the theory of cross-wound package unwinding and to find the necessary modifications of the yarnunwinding process.