Abstract:

In order to study the effect of draft ratio and number of draft zones on yarn evenness, this paper researched two draft zones ring spinning machine and three draft zones ring spinning machine. 9.7tex and 7.3tex cotton yarn are taken as examples, yarns are spun on the QFA1528 ring spinning machine and TH558 ring spinning machine respectively. QFA1528 ring spinning machine has two draft zones while TH558 ring spinning machine has three draft zones. Both cut-middles method and polynomial fitting method are used to analyze the faster fibers distribution and slower fibers distribution. Then, the friction field distribution and theoretical position of floating fibers accelerated points of the front drafting zone in two spinning system are compared, and the effect on yarn quality can be concluded. The results indicate that for 9.7tex cotton yarn, theoretical position of floating fibers accelerated points in three drafting zones system is more near than that in two drafting zones system and the yarn evenness is worse. For 7.3tex cotton yarn, three draft zones can improve the sliver structure in front draft zone, and yarn quality can be improved.

Key words: two-zone draft, three-zone draft, fibers distribution, cut-middles method, polynomial fitting method