Abstract
In this paper, a method for quantifying and characterizing the change of fiber bundle deformation during the twisting process, which relate to yarn structure closely, is described. Mean helical path difference between the two component fibers in both sides of fiber bundle (HPD) was proposed in order to study the form deformation. The HPD at unit length (HPD density; ρ) was measured by analyzing each cross sectional pattern of “two layer yarn” at 1mm intervals by an image processing system using a reflecting microscope, a TV camera, an image frame memory and a micro computer. It was observed that HPD density changed periodically and the average HPD density <ρ> varied depending on delivery direction. The average of the integration of deviation ρ-<ρ>, which may be net HPD relating to the periodical change, was independent of spinning parameters except spinning tension. It is explained in terms of HPD as the difference of fiber stretching extent in both sides of fiber bundle that the average deformation form and the degree of form varied with the delivery direction and the spinning tension respectively. The method described in this paper was useful for the study of twisting process.
