The mechanism of package unwinding

الملخص EN

Variations in yarn tension and/or unwinding mode when removing the yarn from the package by over-end unwinding during different manufacturing processes will affect the length of the yarn drawn from the package and hence result in a significant variability in the finished product.

Therefore, understanding the mechanism of unwinding is of great importance.

In this work it was shown that, the unwinding of yarn from a package can proceed according to one of three modes : free unwinding, yarn drag, and yarn ballooning from the package surface.

A series of experiments were carried out to show how the unwinding tension and the unwinding mode vary with the guide distance above the package, cone angle, package dimensions, package winding tension, yarn count, yarn friction, and unwinding speed.

On the basis of the results obtained, optimum unwinding conditions that result in low take-off tensions are derived by means of an empirical equations in order to avoid great variability in the finished product.