Fiber Migration and Twist Radial Distribution in Rotor Spun Yarns

In this study, using a tracer fiber technique, the three dimensional trajectory of a tracer fiber in a rotor spun yarn is tested with the Questar Hi-scope video microscope system. Measuring the half pitch and maximum height of a bow-shaped segment along the spatial helix tracer fiber, the twists of any radial position are calculated. The results show that the twists distribute unevenly along the radial direction of the rotor spun yarn. A quadratic parabola model for twist radial distribution in rotor spun yams is revealed by polynomial regression analysis. The migration coefficient of a random tracer fiber is also obtained. The results may provide a foundation for further study of the structure and mechanical properties of rotor spun yarns.