Tamil Nadu HSE First Year Textile Technology key terms

A fibre is a thin, flexible strand whose length is much greater than its width. Fibres are twisted or bonded together to make yarn, and they may be natural, such as cotton, or man-made.

A staple fibre is a short fibre measured in millimetres or centimetres, such as cotton or wool. Many staples must be twisted together to form a continuous yarn.

A filament is a continuous fibre of great length, measured in metres or kilometres. Silk and most man-made fibres are filaments and can be used directly or cut into staple.

Cotton is a natural cellulose fibre obtained from the seed hairs of the cotton plant. It is absorbent, comfortable and strong when wet, and its staple length usually ranges from about 20 to 35 mm.

Tenacity expresses the strength of a fibre or yarn per unit of linear density, commonly in cN/tex or g/denier. A higher value means the material can carry more load for its thickness.

Moisture regain is the mass of water in a textile expressed as a percentage of its oven-dry mass. It affects fibre properties, yarn processing and the accuracy of textile tests.

Yarn count is a number that expresses yarn fineness or thickness. Indirect systems such as Ne give length per unit mass, while direct systems such as tex give mass per unit length.

Twist is the number of turns given to a yarn per unit length, usually measured as turns per inch or turns per metre. Twist binds fibres together and influences yarn strength, bulk and handle.

Carding is a spinning preparation process that opens fibre tufts into individual fibres, removes trash and neps, and delivers a loose rope called sliver for further processing.

Combing removes short fibres, neps and remaining impurities from card sliver. It makes the fibre arrangement more parallel and produces smoother, stronger and finer yarns.

A sliver is a continuous, untwisted rope of loosely gathered fibres. It is produced by carding or drawing and is fed to later machines such as combers, drawing frames and roving frames.

Roving is a thin, lightly twisted strand of fibres produced on a roving frame. It is wound on a bobbin and supplied to the ring spinning frame, where it is drafted and twisted into yarn.

Draft is the reduction in linear density of a fibre strand when rollers rotate at different surface speeds. Draft is calculated as input count divided by output count.

Ring spinning is a common spinning method in which a drafted roving is twisted by a traveller on a ring and wound onto a cop. It produces strong, versatile yarns for many fabrics.

Warp yarns run lengthwise in a woven fabric. They are prepared in large numbers on a beam, often sized for strength, and are held under tension during weaving.

Weft yarns run crosswise in a woven fabric. They are inserted through the shed by a shuttle, projectile, rapier or air jet and are beaten up to form the cloth.

Shedding is the weaving action that raises some warp yarns and lowers others to form a triangular opening called a shed. The shed allows the weft to pass across the loom.

Picking is the weaving action that passes the weft yarn across the shed from one side of the loom to the other. It may use a shuttle, projectile, rapier or air jet.

Beating-up is the weaving action in which a reed pushes the newly inserted weft yarn to the fell of the cloth. It sets the spacing between picks and makes the fabric compact.

Knitting is a fabric manufacturing method in which loops of yarn are intermeshed. In weft knitting the loops are formed course by course, giving stretchable fabrics such as single jersey.

GSM means grams per square metre and expresses the mass of a fabric per unit area. It is widely used to specify fabric weight, compare qualities and calculate material cost.

Scouring removes natural oils, waxes, dirt and added sizes from greige fabric using alkali, detergent and heat. Clean fabric then accepts bleaching, dyeing and finishing evenly.

Bleaching destroys natural colouring matter so that fabric becomes white and ready for dyeing or printing. Hydrogen peroxide is commonly used for cotton, with controlled concentration, temperature and time.

Mercerisation treats cotton with strong caustic soda solution while holding it under tension. The process increases lustre, strength and dye uptake and is often done after scouring.

Dyeing applies colour uniformly to fibre, yarn or fabric by allowing dye molecules to penetrate the material. Common methods include exhaust dyeing in machines and continuous pad dyeing.

Printing applies colour locally in a designed pattern rather than over the whole fabric. Paste containing dye or pigment is transferred by screen, roller or digital methods and then fixed.

Colour fastness is the resistance of a dyed or printed textile to colour loss or staining during washing, light exposure, rubbing or perspiration. It is judged against standard grey scales.

Finishing covers the final chemical or mechanical treatments that improve a fabric's appearance, handle or performance. Examples include calendering, softening, water repellency and shrinkage control.

Yarn evenness describes how uniform a yarn is along its length in thickness and mass. Uneven yarn gives weak places, shade bands and fabric defects, so evenness is measured and controlled.

Bursting strength is the force required to rupture a fabric by pushing a diaphragm or steel ball through it. It is especially useful for knitted and nonwoven fabrics that stretch in all directions.

Quality control is the planned system of testing, inspection and comparison with standards that keeps products within specified limits. When results deviate, causes are found and corrective action is taken.

Preventive maintenance means scheduled cleaning, lubrication, inspection and adjustment of machines before faults cause breakdowns. It reduces stoppages, spare-part costs and unsafe conditions in textile mills.

Humidification adds moisture to the air in spinning and weaving departments to maintain a suitable relative humidity. Correct humidity reduces static, fibre breakage and yarn hairiness and improves smooth running.

Effluent treatment uses physical, chemical and biological stages to remove dyes, chemicals and solids from textile wastewater. Treated water must meet discharge standards to protect rivers, soil and public health.

Personal protective equipment, or PPE, is gear worn by workers to reduce exposure to hazards. In textile mills it includes ear plugs, dust masks, goggles, gloves and safety shoes.

A safety guard is a physical cover or barrier fitted over gears, belts, chains, shafts or nip points. It prevents workers' hands or clothing from contacting dangerous moving machine parts.

An entrepreneur identifies a market opportunity, gathers money, materials, machines and people, and starts a business while bearing the risk. In textiles this may mean a spinning, weaving, dyeing or garment unit.