Talking about the twist direction and twist of yarn

Twist: The twist angle of the yarn is twisted for one turn for one twist. The number of twists per unit length of yarn is called twist. Cotton yarns in China use a special twist, that is, the number of twists within a length of 10 cm; combed wool yarns and chemical filaments use a metric count, that is, the number of twists per meter; in addition, There are also inch count twists expressed in internal twists per inch.
Twist factor: The twist cannot be used to compare the twisting degree of different thickness yarns, because the same degree of twist, the thickness of the fiber of a thick sliver is greater than that of a thin sliver. In actual production, the twist factor is often used to indicate the degree of twist of the yarn. The twist coefficient is a relative value that indicates the degree of twist of the yarn in combination with the linear density, and can be used to compare the degree of twist of different thickness yarns. The twist factor can be calculated based on the twist of the yarn and the linear density of the yarn.
Twist direction: The twist direction refers to the inclined direction of the fibers in a single yarn or the single yarn in a strand after the yarn is twisted. It is divided into Z twist and S twist. After twisting, the twist direction of the yarn is inclined from the lower right corner to the upper left corner, and the inclined direction is the same as the middle of the "S", which is called S twist or hand twist; the twist direction of the yarn is inclined from the lower left corner to the upper right corner. The middle of Z "is called Z twist or backhand twist. Generally, single twist is used for Z twist, and strand twist is used for S twist.
The twist direction of the strands is indicated by the twist direction of successive twists. For example, for a single yarn with a Z twist, an initial twist with an S twist, and a multiple twist with a Z twist, the twist direction is represented by ZSZ.
The twist direction of the yarn has a great influence on the appearance and feel of the fabric. By using the twist direction of the warp and weft yarns to match the fabric structure, fabrics with different appearances and feels can be woven.