Nowadays there are five practical spinning techniques in the field of cotton spinning, namely, conventional Ring Spinning, Open-end Rotor Spinning, Air-jet Spinning, Vortex Spinning and Compact Spinning (improved ring spinning).
The Ring Spinning technique has a history of more than 150 years, and the last four have been developed in recent decades, collectively known as the new spinning methods.
1. Conventional Ring Spinning
A spinning system in which twist is inserted in a yarn by using a revolving traveller is known as Ring spinning. The yarn is wound on since the rotational speed of the package is greater than that of the traveller. It is one of the most widely used types of yarn spinning system, such as combing and blending.
2. Open-end rotor Spinning
A method of open-end spinning which uses a rotor (a high-speed centrifuge) to collect individual fibers into a yarn is known as Rotor spinning. The fibers on entering a rapidly rotating rotor are distributed around its circumference and temporarily held there by centrifugal force. The yarn is withdrawn from the rotor wall and, because of the rotation, twist is generated. With this type of yarn spinning heavy yarns are produced like denim yarn.
The cup spinning has the advantages of large speed, large yarn, wide adaptability, simple mechanism and no ingot, steel collar and wire ring, which can multiply the yield of yarn.
3. Air-jet Spinning
A system of staple-fiber spinning which utilizes air to apply the twisting couple to the yarn during its formation is known as Air-jet spinning. The air is blown through small holes arranged tangentially to the yarn surface and this causes the yarn to rotate. The majority of systems using this technique produce fasciated yarns, but by using two air jets operating in opposing twist directions it is possible to produce yarns with more controlled properties but of more complex structure.
4. Vortex spinning
Murata Machinery has developed a new spinning process called “Murata Vortex Spinning”, which is different from air-jet (false twist) spinning.
Vortex spinning takes drawn cotton sliver and drafts it to the desired yarn count (fineness) via a four-roller apron drafting system. The drafted fibers are then sucked into a nozzle where a high-speed ‘air vortex’ swirls the fibers around the outside of a hollow stationary spindle. A rotating air vortex twists the free fiber ends around the bridge fibers with true twist, producing a ring yarn type of structure.
5. Improved Ring Spinning — Compact Spinning
Compact spinning is also the modifications to the conventional ring spinning process. As the name implies, with compact spinning (also called condensed spinning), the fibers leaving the front drafting roller nip are tightly compacted, making any sign of a spinning triangle at the twist insertion point virtually imperceptible.
This relatively new development reduces the size of the spinning triangle to a minimum. This is achieved through a condensing of the fibers after the main draft by using a perforated roller in combination with a suction unit. The hairiness of the yarn is thus reduced, and the tenacity is higher when compared to ring-spun yarns. The yarn evenness is also improved.
