Twisting is to make the two sections of the yarn produce relative rotation, then the yarn in the original parallel to the yarn axis of the fiber tilt into a spiral line. For staple fibers, the main purpose of twisting is to increase yarn strength. The twisting of filament yarn can not only improve the strength of yarn, but also produce some effect. The amount of yarn twisting and the combination of twist direction and twist degree in the fabric have great influence on the appearance and properties of the product.

The twisting properties of the indicators are

Represents the degree of twist, twist coefficient, twist direction

Twist: Twist Angle of yarn into one twist. The number of twists per unit length of yarn is called twist.

The special twist is used in Chinese cotton yarns, that is, the number of twists within the length of 10 cm yarn. The metric branch twist is used in worsted yarn and chemical fiber filament, which is expressed by twists per meter. In addition, there is the imperial branch twist, expressed in turns per inch.

Twist factor: The twist is not used to compare the twisting of yarns of different thicknesses, because the fibers of thick yarns tilt more than those of thin yarns with the same twist.

In practical production, twist coefficient is often used to indicate the twisting degree of yarn. Twist coefficient is the relative value of yarn twisting degree combined with linear density, which can be used to compare the twisting degree of yarns of different thicknesses. The twist factor can be calculated from the twist and linear density of the yarn.

Twist direction: Twist direction refers to the inclination of the fibers in a single yarn or the single yarn in a twine. It is divided into Z twist and S twist two.

After twisting, the yarn twist from the lower right corner to the upper left corner, tilt direction and the middle of "S" consistent called S twist or smooth twist; The yarn twist is tilted from the bottom left to the top right, and the tilt is consistent with the middle of the "Z", called the Z twist or backhand twist. Single yarn usually uses Z twist and twine uses S twist.

The twist of the twine according to the twist of the twist has always indicated. For example, single yarn with Z twist, initial twist with S twist, and double twist with Z twist, its 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 combining the twist direction of the warp and weft yarn with the fabric structure, different fabrics with different appearance and feel can be woven.