Abstract:

Yarn unwinding from packages plays an essential role in many textile processes. The stability of unwinding has a direct influence on the efficiency of the textile processes in general and on the quality of the final products. Calculations based on a theoretical model of unwinding can help us in our pursuit of an optimal design of packages and an optimal unwinding process. We will derive expressions for the time dependence of the angular velocity of the balloon rotation around the package axis, of the unwinding velocity and the winding angle during yarn unwinding from the cylindrical package. We will demonstrate a mathematical model for simulating the unwinding from cylindrical packages. We will show how the winding angle influences the angular velocity and tension oscillations of the yarn during unwinding. Since the centrifugal forces on the yarn in the balloon depend on the angular velocity, this velocity has a large influence on the tension that we wish to reduce.