Analysis of Structure Formation of Spun Yarns

The effects of spinning conditions and fiber size on two-layered spun yarns were investigated by a method for evaluating yarn structure quantitatively. The yarn structure analysis method is based on HPD-analysis. In this analysis, HPD (Helical Path Difference) is defined as the accumulation of difference between the mean helical paths of two fiber assemblies consisting of the two-layered yarn. The yarn structure change is caused by the variation of mutual dynamic balance of two fiber assemblies. Then it can be analyzed by investigating the mutual relation between two helical paths that represent these two fiber assemblies. It is proved experimentally that the doubling of two fleeces gives no particular influence on the yarn structure formation in spinning process. Our results therefore may be useful and valuable in controlling the yarn structure.