Theoretical Study of Wrapping Twist in Single Jet False Twist Spinning

Abstract

A new mathematical approach is presented to explain the structure of a jet-spun staple yarn. The mechanism of how edge fibers wrap around the yarn core is explained, and the effects of the main parameters that determine the wrapping twist are inves tigated. The important factors are the position of the edge fiber when contacting the yam core, the length of the edge fiber, and the twis level of the core upstream from the twisting element. The twisting configuration al g a single wrapping fiber is con sidered, as well as the resulting average twist of multiple edge fibers. The effect of the edge fiber length on its wrapping efficiency is also determined.