6 Conventional spinning and other spinning methods

U. Ratna

epgp books







The process by which fibers are converted into yarns is known as spinning. The fibers during spinning are gently pulled out, drawn and twisted. This process helps to hold the fibers together, thereby increasing the strength of yarn. Spinning also helps to make the yarn smoother and finer, and to improve its strength.

  1. Objectives:
  • To understand the concept of spinning.
  • To gain knowledge about different spinning methods.
  • To enable the students about the functioning of different spinning machine.

In this we are going to see the convention spinning and other spinning methods in detail.

  1. Spinning:

To carry out the various process in spinning, a wide range of machines and methods are used. Different processes are as follows,

  • Opening – Loosens, open and fluffs the fibres
  • Picking – This process also Loosens, cleans and form fibres into ‘lap
  • Carding – In this process fibres are strengthened and forms the sliver
  • Combing – fibresare straightened and shortfibres are removed.
  • Drawing – parallels, blends and reduces the size of strand.
  • Roving – Reduces the size further
  • Spinning – Twist is given and the final yarn is wound

The diagram shows the different process of yarn manufacturing conventional ring spinning process.


2.1 Opening and Picking


The masses of fibres from these numerous bales will be fed into a machine called a blending feeder. As these masses of fiber are loosened and thoroughly mixed, some remaining heavy impurities such as dirt, remnants of seeds, leaves or stems, are removed by a line of

2.6   Spinning


Spinning is a continuation of the roving and on the spinning frame many spools containing the roving pass through the ring spinning mechanism which further draws and give twists to a yarn of the required size and winds it on bobbins.


Spinning includes all the processes required to prepare and clean the fibers from the opening of the bale to the twisting of the yarn and its preparation for fabric construction.This process is called conventional ring spinning method.

  1. Open end spinning method

Open-end spinning also referred to as O.E. Spinning or break spinning. The technique has reached wide acceptance as a satisfactory process for spinning coarser yarns of counts upto about


The open-end spinning process begins with the carded sliver (combed sliver is not used) is fed on succession of rollers. Each advanced set of which revolves at a progressively faster speed which completely opens up the sliver and fibers can be fed virtually individually into the spinning operation (this effect breaks apart the sliver, hence it is termed as open-end or break). As the fibers are thus separated, they are transported forward by an air stream and are collected as a thin layer in a groove on the inner surface of a funnel – shaped rotor which rotates at a very high speed. The centrifugal force of the rotor builds up a multilayer of fibers which is collected and it is twisted by the rotation of rotor and withdrawn continuously and formed into yarn.


The primary difference between the conventional ring spinning and open end spinning is that in open end spinning the spool does not need to rotate in order to twist the yarn. Larger spools can be wound, thereby providing very long knot free yarn. Open-end spinning can produce yarn spun at a rate of 3 to 5 times that of the conventional ring spinning on the other hand open end spinning has its limitations. It is difficult to spin yarns of 100% manmade staple which gets deposited in the rotor and causes clogging. The yarn counts are generally lower than 40 which limits their use to heavier, coarser fabrics such as denims, towels, some poplins and interlinings. Open end yarns are spun with 20 per cent more twist and they are 15 to 20 per cent weaker due to their coarseness.

  1. Friction spinning

   Dr. Ernst Fehrer got a patent for a friction spinning process which was commercialized under the trade mark DREF. This system was modified and identified as DREF which is a variation of open end spinning process.


Friction spinning is an open end spinning technique. Instead of using a rotor, two friction rollers are used to collect the opened-up fibres and twist them into the yarn in the same direction and because of the friction between the fibres strand and the two drum surfaces, twist is inserted into the fibre strand. The yarn is withdrawn in the direction parallel to the friction drum axis and delivered to a package forming unit.


There are certain advantages to the DREF. The fiber preparation costs are lower because direct feed of card slivers to the spinning zone is done. The high speed elements required for ring and rotor spinning are eliminated. Yarn breakage is avoided because there is no tension in the spinning area. The process allows the use of a wide variety and quality of fibers that can be used independently or blended into the slivers. Friction spinning have a higher productivity than both rotor and air jet spinning. Novelty speciality yarns, such as boucle and nub can be produced. Friction spinning is however restricted to coarse count range.

  1. Airjet Spinning

It is a variation of spinning yarn with the aid of an air stream. Air Jet spinning technology was first introduced by DU Pont in 1963, but it has only been made commercially successful since 1980. It is a pneumatic process that produces yarn directly from high quality drawing sliver of wool, manmade staple or manmade and cotton staple blends.


The air jet spinning technique drafts the sliver to a predetermined size and passes it through rollers over a friction plate into a cylindrical pneumatic twisting chamber. As compressed air is released from jets set in the walls of the chamber at predetermined angles to the central axis of the tube, the fibers are whirled around each other. special rings and specific grooves within the tube are used to loosen the fibers from the sides and to control the twist and strength parameters of the forming yarn. As the fibers are whirled through the first chamber, they are given either an s or z twist. With the aid of air suction the strand is passed into a second chamber where it is first stabilized and then given an equal amount of twist in the opposite direction. The strand is again stabilized to prevent back twist as delivery rolls draw on the yarn which is wound onto a take up package.


The air jet spinning produces a yarn of uniform diameter. Yarn can be produced in counts equal to or somewhat finer than those made by open-end spinning.The tensile strength of air-jet spun yarn has been reported to be less than of ring-spun yarn, it may be greater than that of open-end yarn.

  1. Vortex spinning method

Vortex spinning technology is a modified form of air jet spinning and has a high productivity rate. In the vortex system drafted fibers are introduced into a spindle orifice by an air vortex. While entering and passing through the orifice, fibers are twisted by the swirling air and it can deliver yarn at upto 400mpm. Vortex spinning which adopts high speed airflow to insert twist into the yarn, is one of the most promising technological innovations in the textile  industry. In vortex spinning the dynamic behaviour of the fiber inside the nozzle, which involves fiber-air flow interaction and fiber – wall contact, plays an important role in the twist insertion process. The moving parts in the machine are eliminated in this technique which in turn provides a considerable cost savings. The yarns produced are weak and irregular.

  1. Siro spinning

Siro spinning is a process to produce doubled yarn directly in spinning machine. Instead of one roving two rovings are passed in the drafting zone and they are twisted by the same spindle.


Traditionally, two fold yarns have been used for weaving because they are stronger and the twisting operation binds the surface fibers into the yarn structure so that it is smoother and more resistant to abrasion during weaving. The siro spun process adapted some of the self twist discoveries to the ring spinning technology of the worsted system and combined spinning and doubling in one operation. In siro spinning process, two rovings are led in parallel through the drafting system, separated by two specially developed condensers and drafted separately. The twist is introduced as for a normal single yarn by means of ring and traveller. The roving strands which are drafted parallel are combined after passing the front rollers at the exit from the drafting system, with some twist being produced in the individual strands right up to the nip point. Once past the front roller of the drafting system, the two strands are combined producing a two fold like yarn. The yarn has uni-directional twist like a single yarn but the fibers are bound sufficiently for the yarn to survive in weaving process. A mechanical yarn break detector located below the drafting system continuously controls the yarn path of both single yarns throughout the spinning process.


The main advantage of the siro spun process is a reduction in spinning costs for pure fine wool weaving yarn. It reduces cost by combing spinning and two-folding allowing a twofold-like yarn to be produced in one step.

  1. Electrostatic spinning

In order to increase yarn strength and improve spinning efficiency researchers tried to develop a system that would improve the uniformity, strength and appearance of cotton yarn. They began to exploring the possibility of removing the short cotton fibers from the longer ones by an electrostatic process. The principle is that widely differing materials can be separated from each other electro statically .The idea of separating different sizes of the same material and more particularly cotton was a novel approach. Under controlled conditions of humidity, it is possible to separate short fibers from long ones in an electrostatic field. A mechanism was also developed to remove the short fibers from the long fibers as they passed through the electrostatic field and transport the desired long fibers by an air current.


Thus from the carded stage, the fibers are drawn out or drafted by rollers and are fed over rotating cylindrical electrodes of high field intensity which direct the long fibers to either an air current or an electrostatic field for transport to the combed sliver stage. The short fibers which   move more slowly are carried by rotating electrodes of low field intensity. The modification of this electrostatic device has shown that it can replace all textile processing equipment from opening through spinning. It can produce clean, nep free strand with excellent fibre orientation.

  1. Twistless spinning process

This is the techniques of making yarns of staple fibers without the need for twisting them around each other to achieve choesiveness and strength are being developed. The methods are basically designed to place the fibers parallel to each other and have them adhere together with bonding agent which is removed after the yarns are constructed into fabrics.’’’




One such process is Twilotwistless spinning.


The TwiloTwistless spinning process forms yarn by temporarily binding the fibers together with an adhesive and subsequently removing the adhesive after the yarn has been made into a fabric.A carded sliver of cotton, rayon, polyester or acrylic staple is blended on drawing frame with a sliver of water. Soluble poly vinyl alchol (PVA) binder fibers.The blended sliver is then drafted 5 to 10 fold in a dry condition, wetted to activate the binder, wet drafted given a tangential water injection which causes a vortex that imparts a false twist, drafted 6 to 40 fold in its wet condition, and again passed through the false twister while steam or hot water is applied. The wet, untwisted yarn is dried on a rotating heated drum and wound on a cheese at the rate of about (400m) per minute.


The resultant yarn is ribbon shaped and consists of parallel fibers held together by the water soluble binding agent. After the Twilo yarn is woven or knitted into a fabric, the binder is removed by washing. Since the fibers can move slightly in the fabric, the fabric’s appearance may be affected in the finishing process and have a different appearance from that of comparable fabrics made of other yarns.


Fabrics made of this twistless yarn have an attractive luster because the fibers in the yarn are relatively parallel to each other, thereby providing a flat smooth surface. Dyes are more accessible to the fibers and deeper shades can be achieved. Fabrics of twistless yarn have been found to shrink less than those made of conventional yarn. The strength of fabrics made of Twilo yarn depend upon the inherent strength of the particular fiber used in that yarn and the strength of twisted yarn that may be combined in the warp structure of a woven cloth.

  1. Filament yarns

The filament yarns are produced by different methods and they can be formed directly into yarn without the use of technique to connect fibers together to form the required lengths. They are produced by two methods – Melt spinning and solvent spinning

The spinning process used for a particular polymer is determined by the polymer’s melting point, melting stability and solubility in organic or inorganic solvents.


  1. Melt spinning process
  • Uses heat to melt the polymer to a viscosity suitable for extrusion.
  • Polymer chips are melted in an electrically heated screw extruder.
  • Alternatively, the molten polymer is processed in an inert gas atmosphere, usually nitrogen, and is meteled through a precisely machined gear pump to a filter assembly consisting of a series of metal gauges interspersed in layers of graded sand.’
  • The molten polymer is extruded at high pressure and constant rate through a spinnerette into a relatively cooler air stream that solidifies the filaments.
  • Lubricants and finishing oils are applied to the fibers in a spin cell.
  • At the base of the spin cell, a thread guide coverages the individual filaments to produce a continuous filament yarn or a spun yarn, that typically is composed of between 15 to 100 filaments.
  • Once formed, the filament yarn either is immediately wound onto bobbins or is further treated for certain desired characteristics or end use.
  • Lubricants and oils are sometimes added during the spinning of the fibers to provide certain properties necessary for subsequent operations such as lubrication and static suppression.
  • These lubricants and oils vaporize, condense, and then coalesce as aerosols primarily from the spinning operation.
  • Treatments include drawing, lubrication, crimping, heat setting, cutting and twisting.
  1. Solvent spinning

12.1 Dry solvent spinning

  • This process begins by dissolving the polymer in an organic solvent.
  • This solvent is blended with additives and is filtered to produce a viscose polymer solution, reffered to as ‘dope’ for spinning.
  • The polymer solution is then extruded through a spinnerette as filament into a zone of heated gas or vapour.
  • The solvent evaporates into the gas stream and leaves solidified filaments, which are further treated using one or more of the processes.
  • This type of spinning is used for easily dissolved polymers such a cellulose acetate, acrylics and modacrylics.
  • Dry spinning is the fiber formation process potentially emitting the largest amounts of VOCs per pound of fiber produced.
  • Air pollutant emissions include volatilized residual monomer, organic solvents, additives and other organic compounds used in fiber processing.
  • Unrecovered solvent constitutes the major substance.
  • The largest amounts of unrecovered solvent are emitted from the fiber spinning step and drying the fiber.
  • Other emission sources include
  1.  Dope preparation (dissolving the polymer, blending the spinning solution and filtering the dope)
  2.  Fiber processing (drawing, washing and crimping and solvent recovery).

12.2 Wet solvent spinning


  • Wet spinning also uses solvent to dissolve the polymer to prepare the spinning dope.
  • The process begins by dissolving polymer chips in a suitable organic solvent, such as DMF (dimethylformamide), DMAc (dimethylacetamide) or acetone, as in dry spinning, or in a weak inorganic acid, such as zinc chloride or aqueous sodium thiocyanate.
  • In wet spinning, the spinning solution is extruded through spinnerettes into a precipitation bath that contains a coagulant such as aqueous DMAc or water.
  • Precipitation or coagulation occurs by diffusion of the solvent out of the thread and by diffusion of the coagulant into the thread.
  • Wet span filaments also undergoes one or more of the additional treatment processes include drawing, lubrication, crimping, heat setting, cutting and twisting.
  • Air pollution emission points in the wet spinning organic solvent process are similar to those of dry spinning.
  • Wet spinning processes that use solutions of acids or salts to dissolve the polymer chips emit no solvent VOC, only unreacted monomer and are therefore, relatively clean from an air pollution stand point.
  • Hope you have understand the different spinning methods.



you can view video on Conventional spinning and other spinning methods

Web links