Structural characteristics of low torque and ring spun yarns

In this paper we present a comparative study on the structural characteristics of three-dimensional fiber configurations in low torque and ring spun yarns. Three-dimensional configurations of tracer fibers in the two types of yarns were measured by a continuous measurement system. Critical parameters were obtained, including the occurrence frequencies of unique features, the radial position, fiber spatial orientation angle, migration frequency, and amplitude. Results reveal that nearly half of the fiber specimens in low torque yarns followed a deformed non-concentric conical helix of which the size of helical loops varies significantly and the axis of the helix does not coincide with the yarn axis. Local reversion phenomena appear on many fiber segments. In addition, most fibers in low torque yarns are located close to the yarn center, and alter their radial position in a yarn with larger amplitude. Those features offer an explanation for the excellent physical properties of low torque yarns, that is, low twist, high strength, and low residual torque.