YARN TWIST IN THE RING-SPINNING BALLOON

A dynamical theory of twist insertion in ring-spun yarns that brings t ogether the previous work of the authors and their colleagues on the s tability of the ring-spinning balloon, and the recent work on yarn twi sting dynamics by Miao & Chen (1993), in a single comprehensive theory is derived. It is shown that, to first order in small terms, the equa tions governing the yarn path and the equations governing the movement of twist along the yarn path are independent of each other. The gener al solution of the time-dependent twist flow equations is derived. The se results are then used to determine formulae for the twist variation in the ring-spinning balloon and in a false twisting system. Some res trictions on the applicability of the theory are also noted.