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Concept and difference between twisting and false twisting

tiem:2022/12/27 14:44:00

What are the concepts and differences between twisting and false twisting? The yarn or silk thread used in our fabric has different structural forms. The difference is that there are untwisted, twisting and false twisting. Let's briefly talk about them
  1、 Twist. When one end of the spinning fiber is caught and the other end is rotated, yarn can be formed. The twist directly affects the physical and mechanical properties and appearance of the tow, yarn and thread, thus affecting the properties, appearance and use value of the fabric. For short fiber yarn, twisting is a necessary condition to increase the strength and other properties of the yarn. For example, cotton, hemp, rayon, Modal, etc. are all made by twisting; For filament yarns and strands, twisting can make them have a strong ability to resist lateral external forces. Twisting can also be made into textured spun yarn and fancy yarn. The twist ratio and twist direction will affect the handle and appearance of the yarn, as well as the internal quality of the yarn
  1. Purpose and requirements of twisting. Twisting is a necessary means to make fiber bundles into yarns. Before twisting, it is generally necessary to condense loose fibers into fiber bundles. After twisting, the outer fiber of the fiber can be squeezed to the inner layer to generate centripetal pressure, so that the whiskers can obtain friction along the length of the fiber. Twisting requirements: the yarn shall have * good strength, elongation, elasticity, flexibility, luster and feel; The structure and form of yarn are diversified; Improve twisting efficiency of yarn
  2. An indicator of yarn twist. The indicators of yarn twist degree include twist, twist angle, twist amplitude and twist coefficient. The index indicating the twisting direction is called the twisting direction
  A. Twist. The two sections of the yarn produce a 360 ° angular displacement, which becomes a twist, that is, a turn as the saying goes. The number of twists per unit length of yarn is called twist. Cotton yarn in China adopts special twist system, which is expressed by the number of twists within 10cm of yarn length; Combed wool yarn and chemical filament yarn use metric count twist, that is, the number of twists per meter; In addition, there is an inch count twist expressed in turns per inch
   B. Twist back angle. Before twisting, the fibers in the yarn are parallel to each other, and after twisting, the fibers incline. The greater the twisting degree of the yarn, the greater the fiber inclination. You can use the fiber to tilt the yarn at one time - twist back angle β To indicate the degree of twisting. Two yarns with the same twist have different twist degrees due to different thicknesses. Coarse yarns have larger twist degrees and twist back angles β It is also large
C. Twist. If the yarn section is regarded as a circle, the included angle between the fiber and the yarn axis at different radii is different. In order to express this situation, the twist width is introduced
  D. Twist factor. Twist cannot be used to compare the twist degree of different thick and thin yarns, because with the same twist, the fiber inclination of thick yarn sliver is greater than that of thin yarn sliver. In practical production, twist coefficient is often used to express the twist degree of yarn. Twist coefficient is a relative value that represents the twist degree of yarn in combination with linear density, and can be used to compare the twist degree of yarns of different thicknesses