Changes of sliver irregularity in two-zone roller drafting

A theoretical calculation is made to simulate the effect of drafting upon the sliver irregularity in two-zone drafting of three-over-three roller system. Two types of slivers, i.e., random sliver and optional sliver are considered. The effects of sliver count, staple fiber length, fineness of fiber, draft distribution between two drafting zones, maximal moving distance and distribution type of speed changing point are calculated on a computer. Furthermore, we have a try for clarifying the relation between irregularity of the supplied sliver and irregularity due to the movement of speed changing point upon irregularity of sliver after drafting. Study results are discussed.