A study of the drafting force in roller drafting and its influence on sliver irregularity

Drafting force is the direct and intuitive factor resulting in fiber motion in a drafting zone. Utilizing data collected from an ITT Draftometer, this paper discusses the effect of draft ratio and ratch in both the break and the main draft zones on drafting force and the coefficient of variation (CV) of drafting force, and how these in turn affect sliver and yarn irregularity. It is shown that: the draft settings in the break draft zone have a significant effect on the drafting force; the break draft ratio shows distinct relationship with sliver irregularity; the ratch in the main drafting zone has considerable influence on drafting force; and in the experiments reported the drafting force does not directly relate to final yarn irregularity.