Differential-Twist Wrapped Yarns Made on a Hollow Spindle Spinning Machine

A hollow spindle wrapped yarn is a new yarn consisting of a core yarn and a wrapping yarn. In order to improve the wrapped yarn' strength and evenness, it is twisted after the wrapping course in this research, thus forming a differential-twist wrapped yarn. The yarn has a particular differential-twist structure, caused by the different twists and twist directions between the wrapping yarn and the core yarn. The general equation of a twist's change in the twisting course is t' = t ± cos 2 β. This paper discusses two differential-twist wrapped yarns; one is the SWF (strand-wrapping filament) yarn, and the other is the Fws (filament-wrapping strand) yarn. With increased wrapping twists and twisting twists, the yam's tenacity increases, elongation rises, irregularity decreases, and abrasion resistance strengthens. The two yarns have different properties and structures, leading to different fabric styles.