Structural changes in yarns during extension and their relationship with subsequent processes

This paper reports the study on structural changes in the ring-spun and rotor-spun yarns of different linear densities during elongation. It is important to understand the structural changes of a yarn during extension to predict its behaviour during process subsequent to spinning. An experimental setup has been designed and fabricated for this purpose. The tracer fibre technique has been adopted to study the internal structure of the yarns. The yarns are subjected to different levels of extensions and the changes in yarn structure in terms of yarn diameter, mean fibre extent, helix angle and mean fibre position have been studied for both ring-spun and rotor-spun yarns of two different linear densities. The yarn diameter, helix angle and mean fibre position decrease with the increase in yarn extension, but the mean fibre extent increases as the yarns get extended. The extents of change in structural parameters depend on the linear density and type of yarns.