Twist Flow in Ring Spinning

Abstract

A simple and easy method for measuring the twist density in the yarn between the roller-nip and thread-guide of a ring spinning frame has been compared with the high speed photography technique and has been shown to be reliable. Measurements using the method have brought out the influence of such factors as doff-stage, chase cycle, etc. on this twist density. It has been shown, for example, that there is, over the chase, a peri odic variation in the twist density—the maximum twist density is at the nose of the chase and is slightly more than or almost equal to the mechanical turns per inch, while the minimum is at the shoulder and is about two to three turns per inch less than the mechanical twist. The collected data show that while, in general, the twist density in the roller nip—thread guide yarn is determined by both the yarn tension and the balloon shape, the balloon shape becomes increasingly important with decreasing balloon height. Also, an increase in yarn tension, accompanied by a change in balloon shape, which renders the angle of yarn wrap less at the traveller and more at the thread guide, results in a reduction of the twist density in the roller nip—thread guide yarn or, at best, leaves it unaltered.