Twisting refers to the relative rotation of two cross-sections of the yarn, when the fibers in the yarn that were originally parallel to the yarn axis are tilted into a spiral line. Generally speaking, in the spinning process, the yarn (sliver, yarn, thread, silk) is twisted and twisted around its axis or axially wound, so that the yarn is twisted, wrapped, intertwined, etc., which are all called twisting.
Twist converts a loose assembly of fibers or filaments into a coherent, continuous linear structure by imparting helical geometry and radial compression. Twist level is controlled during spinning and is measured as twists per unit length (e.g., TPM — twists per metre, or TPI — twists per inch). Direction of twist is described as S or Z depending on the helix sense. Twist changes fiber orientation, contact pressure between fibers, yarn diameter, hairiness and the yarn’s mechanical and surface properties. In practice, an optimum (critical) twist exists where tensile strength is maximized; beyond that point further twist tends to stiffen the yarn and can reduce strength and flexibility.
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Which raw materials can be Twisted
In the process of spinning production, short fibers need to be twisted in order to be spun into yarn, and filaments also need to be twisted in order to facilitate processing or increase compactness. A single yarn can also become a twisted yarn.
Staple yarn (short fibers)
On the basis of overlapping the ends of the fibers, they are consolidated to make them into continuous yarns, giving the yarns a certain strength.
Details & examples: Cotton, wool, flax (linen), rayon and acrylic staples must be twisted to form a cohesive yarn. Twist produces inter-fiber friction, mechanical entanglement and end-overlap consolidation; the required twist depends on fiber length, fineness and crimp. Shorter or coarser fibers require higher twist to obtain the same strength as longer, finer fibers.
Filament yarn
Form a compact structure that is not easily damaged laterally, improve processability, improve resistance to pilling and snagging, and strong twisting makes the fabric style unique.
Details & examples: Continuous filaments such as silk, polyester, nylon, viscose/filament rayon and technical filaments (aramid, glass, carbon) are often given twist to:
- bind multiple filaments into a single workable yarn,
- adjust surface compactness and handle for weaving/knitting,
- enable post-processing (e.g., false-twist texturing for bulk and stretch). Low-twist filaments give smooth, glossy fabrics; medium-to-high twist improves abrasion resistance and reduces filament slippage.
Twisting single yarn into ply yarn
making the yarn structure uniform, increasing strength, reducing strength unevenness, and improving physical properties such as gloss, feel, elasticity, and elongation.
Details & techniques: Plying combines two or more single (singles) yarns—often twisting them together in the opposite direction to the singles—to produce a balanced yarn that resists torque, has improved uniformity, and higher breaking strength. Examples include 2-ply, 3-ply, and cable yarns, plus core-spun constructions where a filament core is wrapped with staple fibers for improved comfort and strength.
Advantages Of Twisted Yarn
- Increase the strength and wear resistance of nylon yarn (within the critical twist range) to reduce fuzzing and breakage, and improve the fastness of silk fabrics.
- Make the yarn have a certain shape or color, have good length, friction and cohesion, and strong spinnability. Give the fabric appearance with refraction, terry and other effects.
- Increase the elasticity of nylon yarn, improve the wrinkle resistance and breathability of the fabric, and make the fabric cool and comfortable to wear.
- It has certain strength, elongation and elasticity, and can withstand various mechanical forces in textile dyeing and finishing processing and use.
- It has hygroscopicity and thermal instability, which is conducive to dyeing and finishing processing and comfort when wearing.
Conclusion
In the process of yarn production, the twisting technology can make the yarn easily twisted together to form a thicker thread. The purpose of twisting is to increase the strength and elasticity of the yarn, reduce the fuzzing or breakage of the yarn, and at the same time, improve the resistance of the yarn to deformation such as stretching, twisting and deformation.
Selecting twist level, twist direction (S/Z), and post-treatment (heat-setting, plying, texturing), manufacturers tailor yarns for specific end-uses—from fine silky dress fabrics to heavy-duty industrial cords—while balancing trade-offs between strength, softness, bulk and appearance.