A Step-by-Step Process of Cotton Yarn Manufacturing

By Eman Abdallah Kamel

Cotton is one of the most widely used natural fibers. This article explains the cotton production process step by step, including its various treatments.

Introduction

Cotton is one of the most remarkable natural fibers, valued for its combination of desirable properties, comfort, and wide range of applications. Cotton is known for its softness, breathability, durability, absorbency, and adaptability.

Cotton is a warm-season perennial shrub grown as an annual crop. Different varieties are bred to thrive in various environments. During growth, cotton plants must be protected from insects, diseases, and weeds. To learn more about cotton cultivation, visit How Cotton is Grown.

From everyday apparel to specialised clothing, including astronauts’ in-flight spacesuits, cotton is used in sheets, towels, tarpaulins, tents, wipes, and numerous personal-care products. Despite the rapid development of modern materials, cotton remains an essential and highly versatile natural fiber. Its journey from field to fabric provides thousands of useful products and supports millions of livelihoods worldwide, making cotton truly nature’s wonder fiber.

Diagram illustrating the stages of cotton production.

Cotton Production Steps

1. Ginning

Raw cotton is transported from the field to nearby gins, where it is dried to reduce moisture and cleaned to remove impurities. It then passes through the ginning units, where rotating saws separate the fibers from the seeds. The fibers are removed from the saws by air or rotating brushes and pressed into bales weighing approximately 227 kilograms. The bales are stored in warehouses until they are shipped to textile mills for further processing.

Did You Know?

A typical gin factory processes about 12 bales per hour, while some modern gin factories may process as many as 60 bales per hour.

Remember:

The production of basic spun yarn begins in the blowing room, where the raw fibers are opened, mixed, and cleaned to make cotton lap, which is then carded to make sliver.
Cotton sliver is drawn, and roving is made at this stage. Then roving is done; the roving process helps ensure that the fibers are properly aligned and held together, preparing them for spinning.
Ring spinning is done on a single thick roving to produce yarn or threads, and the yarn is wound to form the final product.

2. Blowing Room

All operations in the blowing chamber are aimed at improving the fiber quality before it is transferred to the carding machine.

Opening is the first fibre operation, where compressed cotton is gently loosened and separated into small tufts, achieving high openness with minimal fibre loss.
Raw cotton contains trash that must be removed. Measuring the quantity and composition of waste helps assess cleaning efficiency.
While mixing is the blending of different types of fibres or different grades of different fibres, such as cotton and polyester or cotton and viscose, blending is the blending of fibres from different classes of the same type.

Did You Know?

Proper opening and cleaning facilitate the carding process, but remember not to overwork cotton, as this can easily lead to breakage, weakened threads, and unevenness.

3. Carding

From the blow room, the fibres undergo carding, where wire-covered cylinders open and separate the fibres, remove remaining trash and neps, and align them into a thin web.

4. Combing

Combing improves sliver quality by removing short fibres, neps, and remaining trash while further aligning the fibres. This produces cleaner, longer fibres that are easier to ring-spin. Compared with carded yarn, combed yarn contains fewer neps and is smoother and more suitable for spinning.

5. Drawing

Drawing combines and drafts several slivers into one, improving yarn evenness and uniformity. Drafting also straightens, thins, and elongates the fibres through friction.

6. Roving

The product of the roving machine is called roving, a continuous strand that is slightly twisted and requires further drafting and twisting to form yarn. The three main operations are drafting, twisting, and winding. During drafting, the drawn sliver is fed into the roving frame’s drafting system, usually a 3-over-3 double-apron roller arrangement. The linear speed of the delivery roller is called the delivery (production) speed. Twisting strengthens the staple fibres.

Increasing yarn strength depends on fiber binding, which prevents slippage. Proper twisting binds fibers and allows stretching without slipping, but excessive twisting reduces strength. Longer fibers require lower twist factors. The required twists per unit length must be calculated to set the spinning machine correctly.

7. Spinning

A roving bobbin feeds the roving into drafting rollers, which attenuate it to the final count. The fibre strand then passes through the front roller, where twist is inserted by the high-speed spindle to give strength. Twist can be S or Z. The spindle rotates slightly faster than the traveller, and this speed difference allows the yarn to wind onto the package simultaneously with spinning.

8. Weaving and Knitting

Weaving is the process of interlacing yarns to make fabric. On a loom, warp yarns run lengthwise, while filling (weft) yarns run widthwise and are interlaced with the warp. Modern shuttleless looms use rapiers, projectiles, or compressed air to insert filling yarns quickly and quietly.

Three basic weaves:

Plain weave: Filling passes over and under alternate warp yarns; used for gingham and percales.
Twill weave: Creates diagonal ridges; used for denim and gabardine.
Satin weave: Fewer interlacings produce a smooth, shiny surface; used for cotton sateen.

Did You Know?

Optical scanners may monitor fabric continuously to detect and locate defects for later removal.

What is knitting?

Knitting is a method of making fabric by interlocking yarn loops with needles.

Wales: lengthwise rows of loops (like warp yarns).
Courses: crosswise rows (like filling/weft yarns).
Knitting can be done by hand or machine.
Most cotton is knitted using circular knitting machines, where needles rotate around a cylinder to produce tubular fabric.
Cylinder diameter, usually 9–60 inches, determines the fabric width.
Hand knitting: Uses 2 needles to form one stitch at a time.
Modern knitting machines: May use 2,500+ needles and many yarn cones simultaneously. Example: A 32-inch cylinder can have 2,700+ needles and 128 yarn cones.
Flat knitting machine: Has a flat bed with needles arranged in a straight line; produces flat fabric. It can make over 1 million stitches/minute. It can automatically add or drop stitches to widen or narrow fabric and create specific shapes.

9. Dyeing

Dyeing is the process of applying chemical dyes to fibres or textiles to give them colour. The color originates from the chromophore and auxochrome groups present in the dyes, which also contribute to pollution. In the dyeing process, water is used to transport the dyes, and steam is used to heat the treatment baths. Cotton requires a significant amount of water for treatment. For instance, 0.6–0.8 kg of sodium chloride, 30–60 grammes of dye, and 70–150 litres of water are needed to dye one kilogram of cotton with reactive dyes.

Did You Know?

Every year, over 80,000 tonnes of reactive dyes are produced and used. The different treatment baths, including the high-color dyeing bath, which has high concentrations of organic matter and salts, are emptied after the dyeing process is finished. Wastewater must be treated before reuse.

10. Printing

Printing is described as “localised dyeing”, or dyeing that is verified for a specific area of the fabric that makes up the design. It is a form of dyeing in which the essential reactions involved are the same as those in dyeing. In printing, colour is applied as a thick paste of the dye, but in dyeing, colour is applied as a solution.

11. Finishing

Both natural and synthetic textiles undergo various finishing processes. This is done to improve specific properties of the final fabric, and all these finishing processes contribute to water pollution.

Cotton Treatments

1. Desizing

The presence of sizing agents in textiles hinders processes such as dyeing, printing, and finishing. For example, starch may prevent dye penetration into the fibers, necessitating starch removal before dyeing or printing. Starch is removed or converted into simple, water-soluble products either by hydrolysis with enzyme preparations or dilute mineral acids, or by oxidation with sodium bromide and sodium chlorite.

Generally

Approximately 50% of water pollution is attributed to wastewater from desizing, which has a high biological oxygen demand (BOD), rendering it unusable. This problem can be mitigated by using enzymes that hydrolyze starch into ethanol rather than anhydroglucose.

2. Bleaching

The natural colors in yarns give fabric a creamy appearance. To obtain white yarns that facilitate the production of light colors, the yarn must be bleached. One of the earliest bleaching agents is hypochlorite. The formation of highly toxic chlorinated organic byproducts during bleaching is reduced by using an absorbable organic halogen (AOX).

Did You Know?

Over the past few years, hypochlorite has been replaced by other bleaching agents. Peracetic acid is an environmentally safe alternative to hypochlorite, as it decomposes into oxygen and acetic acid and is fully biodegradable.

3. Neutralization

Replacing acetic acid with formic acid to neutralise the fabrics after scouring, bleaching, mercerising, and reducing processes is an effective, economical, and environmentally friendly method. This method also allows for achieving sufficient neutralisation in a short time, requires minimal water, and results in lower biological oxygen demand (BOD).

4. Mercerization

Cotton is treated with 18–24% sodium hydroxide (NaOH) for 1–3 minutes under tension after bleaching. This process increases luster and strength, improves dye uptake, and prevents shrinkage.

Did You Know?

High concentrations of sodium hydroxide in wash water can be extracted using membrane techniques. Using zinc chloride (ZnCl₂) as a substitute increases fabric weight and dye absorption and also facilitates sodium hydroxide (NaOH) recovery. Furthermore, this process is environmentally friendly and does not require neutralisation with formic or acetic acid.

Sources

About the author: Eman is a textile engineer and writer. She holds a bachelor’s degree in textile science from Egypt’s Faculty of Applied Arts.

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