Yarn manufacturing involves several key steps. First, fibres are chosen and sorted according to their desired properties. Fibres are then straightened, and contaminants are removed by cleaning, carding, and combing. Carded fibres are pulled, twisted, and spun to create the required type and thickness of the yarn.
Silk is the only natural fibre you cannot obtain as a staple. All other technically relevant natural fibres come as staple fibres.
Staple fibres vary by their average length. When fibres are spun, they become entangled, increasing friction between them and producing a staple fibre yarn.
You can increase the number of turns per length of the yarn by ring, open-end, friction, and air jet spinning. It is spinning technology that determines yarn properties.
Keep reading to learn more about yarn, raw materials for yarn processing, and the yarn-making process.
Did You Know? With the second largest yarn spinning capacity globally, India holds a significant share of the global cotton yarn market. India produces more than 4700 million kilograms of spun yarn each year.
What Is Yarn?
The term yarn refers to a length of fibre. In fabrics, crocheting, knitting, embroidery and ropemaking, yarn is a continuous length of interlocked fibres used to produce fabrics.
As a result, you can divide yarn into two 'categories'. The yarn (commonly called balls of wool) used in crafts such as knitting and crocheting and the thread used for embroidery or sewing machines are in long lengths.
Alternatively, you can knit or weave fabric from yarn. Textiles can be purchased in lengths as fabric instead of separately buying yarn.
Raw Materials for Yarn Making
The yarn industry uses about 15 different types of fibres.
Common Types of Fibres
Natural and synthetic fibres are two fibre types, with natural fibres obtained from plants and animals. Cotton, derived from mature cotton bolls and seeds, is the most abundant and widely used plant fibre.
Plant and Animal Fibres
Manufacturers utilise fibres from plant leaves or stems to produce ropes, while linen comes from flax and vegetable fibres. Animal fibres include wool from sheep, mohair from goats, angora from rabbits, and silk from silkworms.
Creation of Synthetic Fibres
Synthetic fibres are created by spinning filaments formed through chemical solutions forced through spinneret nozzles. Materials such as acrylic, nylon, rayon, spandex, polyester, polyolefin, and triacetate are commonly used, offering unique properties for various applications. Spandex, for instance, has high elasticity, capable of stretching over 500% without breaking.
Yarn Manufacturing Process
The yarn-making process from synthetic or natural fibres is challenging. Yarn characteristics, such as size, quality, texture, etc., are determined by a series of processes. Here is a breakdown of how fine-quality yarns are processed.
Step-1 - Ginning
In the process of processing cotton, this is the first step. Cottonseed is separated from lint in this process without damaging the fibres.
Manufacturers previously performed this step by hand and traditional machines, including the "Foot Roller" and later its improved version, the "Churka”. Industrialising textile processes led to using three types of gins: Saw Gins, Macarthy Gins, and Roller Gins.
The freshly picked cotton goes to the ginning industry, where the inspection of seeds and unwanted foreign matter like leaves, sticks, dirt, etc., takes place. Cotton is then measured for its moisture content, determining how much heat should be applied to open the fibres.
This is followed by an air dryer to remove moisture. The cotton is then sent to a lint cleaner to remove dirt and other foreign materials.
The lint and cotton seeds are separated from the cleaned cotton at the gin stand, preparing it for separation. A bale compresses 500-pound blocks of clean cotton under hydraulic pressure.
The machine can process between 12 and 60 bales per hour, depending on its capacity. A spinning factory receives the bales after the ginning process.
Step-2 - Blowing
The yarn manufacturing process, also called spinning, begins at this stage. An air process is used for this process, as its name suggests.
Blowing allows you to open compressed fibres, clean them, blend or mix them, remove micro dust, and feed them uniformly into the following process.
Blowing involves the following methods:
- Opening: A bale opener performs the opening function. Small tufts emerge from compressed fibres with a shallow lint loss in this process.
As the fibre tufts slide between two sets of teeth, they pass across another set of teeth.
- Cleaning: Cleaning takes place after the opening of fibres. Due to the small tufts of threads, it is easy to eliminate unwanted foreign particles.
The result is high-quality cotton fibres.
- Blending or Mixing: This is known as mixing when various cotton fibres come together during the spinning process. Combining Indian and American cotton fibres, for example.
Alternatively, blending is combining different threads of the same grade. For example, cotton fibres are blended with polyester or wool fibres with polyester.
Fibres can be reduced in cost through the process, and good-quality yarn can be produced.
Now, the fibres are uniformly fed to the next stage.
Step-3 - Carding
In the spinning process, the second step is carding. This process is also known as the spinning heart.
During carding, loose, unoriented cotton fibres are transformed into slivers. The wire is wound around a series of cylinders to create the card.
Tiny teeth are cut into the wire, and each transports one fibre at a time. Carding's primary purpose of straightening lines and parallel fibres is accomplished by the wire-wound cylinders interacting against one another and the flats (a wire-covered service close to the cylindrical wires).
Furthermore, it removes large amounts of trash. Slivers or flat sheets of uniform thickness are called laps and are temporarily stored for the next step.
Step-4 - Combing
As a result, the fibres are straightened to be arranged parallel to one another. A predetermined length of short fibres is removed from the long staple fibres.
As a result of the combining process, the fibres are cleansed of any remaining trash. As a result of the blowing process, the formed neps are not entirely eliminated during the carding process.
Neps are straightened or removed during the combining process. Doing so makes the yarn more robust, durable, and textured.
Step-5 - Drawing
Drawing straightens the slivers by passing a group of slivers through a series of rollers. The rotation speed increases with each pair of rollers.
During this process, impurities are removed, and unevenness is improved. Reducing elongation at break enhances yarn strength and reduces irregularities. The next step involves feeding the ring frame process with suitable slivers.
Drawing involves two processes:
- Doubling: Doubling combines two or more carded slivers into one sliver. The slivers are fed together to form a single sliver, for example.
- Drafting: Straightening the fibres into carded slivers reduces the weight per yard of the fibre by straightening the crimped and hooked fibres.
Step-6 - Creeling and Drafting
A simplex machine makes roving from drawn slivers in yarn making. Yarn is produced by feeding the roving into the ring frame. This machine performs the following operations:
A simplex machine relies on a mechanism called creeling. Rollers drive slivers through the creel so they can be drafted.
Also, the creel has a sliver break stop function that immediately stops the machine when a sliver breaks. The strands are reduced during drafting, making them suitable for ring spinning.
Step-7 - Ring Spinning
A slight twist is performed after drafting to strengthen the fibre strands before winding. The next step is to load the roving onto the bobbin in a cone drum mechanism.
This is done by moving the bobbin rails in reverse to form conical shapes at both ends. Roving is twisted onto bobbins and then forwarded through the process by the bobbin package system.
Empty bobbins are replaced with full bobbins, either manually or mechanically.
Step-8 - Cone Winding
Yarn manufacturing ends here. A large yarn package called a cone is used for shipping the bobbins to customers.
Electric scanners remove all spinning faults before shipping. Broken yarn pieces are auto-spliced to remove cotton knots, weakly twisted yarns, and other imperfections.
This leads us to conclude that spinning turns fibre into yarn. A yarn is made by twisting cotton fibres to converge and be brought together.
Spinning is a vital step in the textile industry, involving twisting fibre strands together to create yarn. Also, the spinning process consists of the blow room, carding, comber, drawing, simplex, ring spinning, and cone winding stages.
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