Yarn Fineness

There are many ways to express the fineness of yarn, such as number, metric count, imperial count, denier, etc. The twist of the yarn is expressed in the number of turns per meter or inch. The direction of twisting is divided into S twist and Z twist. Within a certain twist range, the strength of the yarn increases as the twist increases. The twist direction of the single yarn and the twist direction of the strand are selected according to the purpose of the strand. Usually single yarns and strands use the opposite twist direction, that is, ZS or SZ. There is an optimal ratio between the twist of the single yarn and the strand. In this range, the strength of the strand increases with the increase of the twist of the strand, and the strength of the strand decreases when the critical value is exceeded.