Basic Textile interview questions

150 questions with answers (TEX-001 to TEX-150). Try each one aloud before reading the answer.

Textile Fibers

TEX-001 · What is the difference between natural and synthetic fibers?

Natural fibers come from plants or animals, such as cotton, wool, silk and jute. Synthetic fibers are made from petrochemical polymers, such as polyester, nylon and acrylic.

TEX-002 · What is the difference between staple fiber and filament?

Staple fibers have a limited length (millimetres to centimetres), like cotton or wool. Filaments are continuous and effectively endless, like silk or extruded polyester. Synthetic filaments can be cut into staple for blending.

TEX-003 · What is the main chemical constituent of cotton?

Cellulose, a linear polymer of β-glucose units. Raw cotton is about 90% or more cellulose. The rest is wax, pectin, protein and minerals, which scouring removes.

TEX-004 · What proteins make up wool and silk?

Wool is made of keratin, which contains sulphur-bearing cystine crosslinks. Silk consists of fibroin filaments coated with a gum called sericin.

TEX-005 · What is a regenerated fiber?

A fiber made by dissolving natural polymer, usually wood-pulp cellulose, and re-forming it into fiber. Examples are viscose, modal, lyocell and cupro. They are man-made but not synthetic.

TEX-006 · What is moisture regain?

Regain = (mass of water ÷ oven-dry mass) × 100. Standard regain values are about 8.5% for cotton, about 0.4% for polyester, and higher for wool (around 13–16%).

TEX-007 · What polymer is used in polyester fiber?

Polyethylene terephthalate (PET). It is made by polycondensation of purified terephthalic acid (PTA), or dimethyl terephthalate, with monoethylene glycol (MEG).

TEX-008 · What is the difference between nylon 6 and nylon 6,6?

Nylon 6 is made by ring-opening polymerization of caprolactam. Nylon 6,6 is made by condensing hexamethylene diamine with adipic acid. Nylon 6,6 has a higher melting point (about 260 °C against about 220 °C).

TEX-009 · What are bast fibers?

Fibers taken from the phloem (inner bark) of plant stems, such as flax, jute, hemp and ramie. They are extracted by retting and are stiff, strong and low in elongation.

TEX-010 · What is micronaire?

An air-flow test value for a cotton fiber plug that reflects both fineness and maturity. Very low values point to immature, neppy fiber. Very high values point to coarse fiber. The premium range is about 3.7–4.2.

TEX-011 · What is the staple length of cotton?

The typical length of a cotton fiber sample, roughly 20–40 mm. Longer staple gives finer, stronger, more even yarn. Extra-long-staple types such as Pima and Giza are prized for fine counts.

TEX-012 · What is acrylic fiber?

A synthetic fiber with at least 85% acrylonitrile units. It is warm, light and wool-like, and is used in sweaters, blankets and fleece. Modacrylic has a lower acrylonitrile content and better flame resistance.

TEX-013 · What is elastane (spandex)?

A segmented polyurethane fiber with very high stretch, typically 400–700% elongation, and good recovery. It is used in small proportions in core-spun yarns, hosiery and activewear.

Yarn Manufacturing & Spinning

TEX-014 · What is yarn count?

A measure of yarn fineness. Direct systems (tex, denier) give mass per unit length, so a higher number means a coarser yarn. Indirect systems (English count Ne, metric Nm) give length per unit mass, so a higher number means a finer yarn.

TEX-015 · What is the process sequence in cotton ring spinning?

Blowroom → carding → drawframe → (lap former and comber for combed yarn) → finisher drawframe → speed frame (simplex) → ring frame → winding.

TEX-016 · What is the purpose of the blowroom?

To open compressed bales into small tufts, clean out trash and dust, blend fibers from different bales, and feed a uniform flow of material to the cards.

TEX-017 · What does carding do?

It separates tufts into individual fibers, removes remaining trash, neps and some short fibers, partly aligns the fibers, and condenses them into a card sliver. It is often called the heart of spinning.

TEX-018 · What is a sliver?

A continuous, untwisted, rope-like strand of loosely assembled fibers. It is produced by the card, comber or drawframe and stored in cans.

TEX-019 · What is combing?

A process that removes short fibers (noil) and neps and straightens and parallels the fibers. It gives finer, stronger, more lustrous yarn, which is why it is used for fine counts and premium fabrics.

TEX-020 · What is drafting?

Attenuating a fiber strand by passing it through roller pairs running at successively higher surface speeds. Draft = delivery roller surface speed ÷ feed roller surface speed.

TEX-021 · What is doubling?

Feeding several slivers together into one machine, typically 6–8 at a drawframe. Random thick and thin places average out, which improves evenness and blending.

TEX-022 · What is roving?

A thin strand from the speed frame that carries a small amount of twist so that it can be wound on a bobbin and fed to the ring frame for final drafting.

TEX-023 · What are TPI and TPM?

Twists per inch and twists per metre: the number of turns of twist in a unit length of yarn. TPM = TPI × 39.37.

TEX-024 · What is the difference between S twist and Z twist?

The direction of twist is judged by the slope of the fiber spirals when the yarn is held vertically. If they match the centre of the letter S, it is S twist. If they match the centre of Z, it is Z twist. Most singles are spun Z.

TEX-025 · What is the difference between single and ply yarn?

A single yarn is one twisted strand. A ply (folded) yarn is two or more singles twisted together, usually in the opposite direction. Ply yarn is stronger, more even and more balanced.

TEX-026 · What is a ring traveller?

A small C-shaped clip that runs around the ring on a ring frame. It is dragged by the yarn, inserts twist and guides the yarn onto the bobbin. Its weight controls the spinning tension.

Weaving Preparation & Weaving

TEX-027 · What are the basic weave types?

Plain, twill and satin. Plain weave has the most interlacings. Twill gives diagonal lines. Satin has long floats that give a smooth, lustrous surface.

TEX-028 · What is the difference between warp and weft?

Warp yarns run lengthwise, parallel to the selvedge, and are held under tension on the loom. Weft (filling) yarns run across the width and are inserted as picks.

TEX-029 · What is the sequence of weaving preparation?

Winding → warping → sizing → drawing-in (or tying-in) → weaving. Weft yarn needs only winding, or pirn winding for shuttle looms.

TEX-030 · What is the purpose of sizing?

To coat warp yarns with a film of size such as starch, PVA or acrylic. This lays hairs flat and raises abrasion resistance and strength, so the yarns survive repeated rubbing on the loom.

TEX-031 · What are the primary motions of a loom?

Shedding (separating warp into two layers), picking (inserting weft through the shed) and beat-up (pushing the pick into the fell of the cloth with the reed).

TEX-032 · What are the secondary and tertiary motions of a loom?

Secondary motions are let-off, which releases warp from the beam, and take-up, which winds cloth and sets the pick spacing. Tertiary motions are stop motions such as warp stop and weft stop.

TEX-033 · What is a shuttleless loom?

A loom that inserts weft from a stationary package without a shuttle. The main types are rapier, projectile, air-jet and water-jet. They run faster and quieter than shuttle looms.

TEX-034 · What is a heald (heddle)?

A wire or strip with an eye through which a warp end passes. Healds are mounted in heald frames (shafts) that lift or lower groups of warp ends to form the shed.

TEX-035 · What is a reed?

A comb-like set of wires that spaces the warp ends evenly across the width and beats each pick into the fell. Reed count is the number of dents per unit width.

TEX-036 · What are EPI and PPI?

Ends per inch (warp density) and picks per inch (weft density). Together with yarn counts they define fabric construction, for example 40s × 40s, 132 × 72.

TEX-037 · What is the difference between dobby and jacquard shedding?

A dobby controls a limited number of heald shafts (typically up to about 24–28) for small geometric designs. A jacquard controls warp ends individually through hooks and harness cords for large figured designs.

TEX-038 · What is selvedge?

The firmly woven edge along each side of a fabric. It prevents fraying and helps the fabric run through processing. Shuttleless looms use leno, tuck-in or fused selvedges.

TEX-039 · What is crimp in woven fabric?

The waviness of yarn caused by interlacing. Crimp % = (yarn length − fabric length) ÷ fabric length × 100. It affects fabric extension, yarn consumption and GSM.

Knitting

TEX-040 · What is the difference between weaving and knitting?

Weaving interlaces two sets of yarns (warp and weft) at right angles. Knitting forms fabric by interlooping loops of yarn, so it is more extensible and conforming but less dimensionally stable.

TEX-041 · What is the difference between weft knitting and warp knitting?

In weft knitting, a yarn runs across the fabric and feeds loops course by course, as in jersey and rib. In warp knitting, many yarns run lengthwise and each forms loops along a wale, as in tricot and raschel.

TEX-042 · What are courses and wales?

A course is a horizontal row of loops across the fabric. A wale is a vertical column of loops along the length. Their densities set stitch density and fabric weight.

TEX-043 · What is machine gauge in knitting?

The number of needles per inch of needle bed, such as 24 gauge (E24). Higher gauge means finer needles and finer yarns, which gives a finer fabric.

TEX-044 · What is single jersey?

A weft-knit fabric made on one set of needles with all loops pulled to the same side. It shows face loops (V shapes) on one side and back loops on the other. It is used for T-shirts.

TEX-045 · What is rib fabric?

A weft knit with wales of face and back loops alternating on both sides, made on two needle beds. It has high widthwise stretch and recovery and is used for cuffs, collars and waistbands.

TEX-046 · What is interlock fabric?

A double-knit fabric made of two interlocked 1×1 rib structures. Both faces look like jersey face. It is thick, stable, smooth and does not curl.

TEX-047 · What is purl fabric?

A weft knit in which face and back loops alternate course by course, so both sides show back loops. It has high lengthwise stretch and is knitted with double-headed latch needles.

TEX-048 · How does a latch needle work?

The hook takes yarn as the needle descends. The old loop closes the latch, and the new loop is drawn through the old loop, which is cast off over the hook. The latch then reopens as the needle rises again.

TEX-049 · What are the main types of knitting needle?

Latch needles (self-acting, the most common), bearded (spring) needles, which need a presser, and compound needles, which have a separate closing element and are used in high-speed warp knitting.

TEX-050 · What is a sinker?

A thin plate between needles that holds down the old loops, helps form the new loop and knocks over the fabric. It is essential in single-jersey machines.

TEX-051 · What are knit, tuck and miss stitches?

Knit: the needle takes a new loop and casts off the old one. Tuck: the needle takes yarn but does not cast off. Miss (float): the needle does not take yarn. Combinations give piqué and other textures.

TEX-052 · What are tricot and raschel?

The two main warp-knitting machine types. Tricot machines use bearded or compound needles for fine, flat fabrics such as lingerie. Raschel machines use latch or compound needles for laces, nets and spacer fabrics.

Nonwovens

TEX-053 · What are the main steps in nonwoven manufacture?

Fiber or polymer preparation → web formation (dry-laid, wet-laid or polymer-laid) → web bonding (mechanical, thermal or chemical) → finishing and slitting.

TEX-054 · What is dry-laid web formation?

Staple fibers are formed into a web by carding (often followed by cross-lapping) or by air-laying, in which an air stream deposits fibers randomly on a screen.

TEX-055 · What is wet-laid web formation?

Short fibers are dispersed in a large volume of water and deposited on a moving screen, much as in papermaking. It is used for tea bags, filter media and glass-fiber mats.

TEX-056 · What is a spunbond nonwoven?

A fabric made by extruding polymer (often PP or PET) into continuous filaments, drawing them with air, laying them randomly on a belt and bonding them, usually with a hot embossed calender.

TEX-057 · What is a meltblown nonwoven?

Polymer is extruded through fine nozzles while hot high-velocity air attenuates it into very fine microfibers, typically a few micrometres, which collect as a soft web. It is used as the filter layer in masks.

TEX-058 · What is needle punching?

A mechanical bonding process. Barbed needles repeatedly pierce the web and push fibers through its thickness, entangling them. It is used for geotextiles, felts, carpets and automotive linings.

TEX-059 · What is hydroentanglement (spunlace)?

Fine high-pressure water jets entangle the fibers of a web without binder. The result is soft, drapeable and strong, and is used for wipes and medical fabrics.

TEX-060 · What is thermal bonding?

Heat melts thermoplastic fibers or binder fibers so they fuse at crossover points. It is done with heated calender rolls (point bonding) or hot air passing through the web (through-air bonding).

TEX-061 · What is chemical bonding?

A liquid binder such as an acrylic or SBR latex is applied by saturation, spraying, foam or printing, then dried and cured to glue fibers together.

TEX-062 · What is the difference between parallel-laid and cross-laid webs?

A parallel-laid web keeps fibers mostly in the machine direction, so it is strong lengthwise and weak across. A cross-laid web is folded across the line by a lapper, which balances strength and builds weight.

TEX-063 · What is an SMS nonwoven?

A laminate of spunbond–meltblown–spunbond layers. The spunbond layers give strength and the meltblown core gives barrier and filtration. It is used for surgical gowns and drapes.

TEX-064 · What are typical applications of nonwovens?

Hygiene products (diapers, wipes), medical gowns and masks, filtration, geotextiles, automotive insulation, roofing, interlinings, and agricultural crop covers.

TEX-065 · What is the difference between durable and disposable nonwovens?

Disposables such as wipes, diapers and masks are used once. Durables such as geotextiles, roofing, carpets and interlinings are built for long service and often need higher strength and UV resistance.

Wet Processing & Pretreatment

TEX-066 · What is textile wet processing?

All water-based chemical treatments after fabric formation: pretreatment (singeing, desizing, scouring, bleaching, mercerization), dyeing, printing and finishing.

TEX-067 · What is singeing?

Passing fabric rapidly over gas flames or heated plates to burn off protruding surface fibers. It gives a clean surface, reduces pilling and improves print sharpness.

TEX-068 · What is desizing?

Removing the size applied to warp yarns before weaving. Starch size is removed with amylase enzymes, oxidative agents or acids. Water-soluble sizes such as PVA are washed out with hot water.

TEX-069 · What is scouring?

Treating cotton with hot alkali, usually NaOH, plus wetting agents and detergents to remove natural waxes, pectins, proteins and oils. This makes the fabric absorbent.

TEX-070 · What is bleaching?

Removing natural colouring matter to obtain whiteness. Cotton is most commonly bleached with hydrogen peroxide under alkaline conditions. Sodium hypochlorite and sodium chlorite are older alternatives.

TEX-071 · What is grey (greige) fabric?

Fabric as it comes off the loom or knitting machine, before any wet processing. It still carries size, natural impurities, oils and dirt.

TEX-072 · What is an optical brightening agent (OBA)?

A colourless fluorescent compound that absorbs ultraviolet light and emits blue light. This masks residual yellowness and makes fabric look brighter white.

TEX-073 · What is heat setting?

Heating thermoplastic fabrics such as polyester and nylon near their setting temperature under controlled width and tension. This stabilizes dimensions, reduces shrinkage and sets creases or flatness.

TEX-074 · What is degumming of silk?

Removing the sericin gum from raw silk, usually with soap, mild alkali or enzymes. It reveals the soft, lustrous fibroin and causes a weight loss of about 20–30%.

TEX-075 · What is carbonizing of wool?

Treating wool with dilute sulphuric acid and then baking it, so that vegetable matter such as burrs and seeds turns brittle and can be crushed and dusted out. Wool resists the acid far better than cellulose does.

TEX-076 · How is absorbency of pretreated fabric checked?

With a drop test, in which a water drop should sink into the fabric within a few seconds, or a wicking (capillary rise) test. Poor absorbency means incomplete scouring and will cause uneven dyeing.

TEX-077 · What is the difference between batch and continuous processing?

Batch processing treats a fixed lot in machines such as winches, jets or jiggers, which suits small, varied lots. Continuous ranges, for example pad-steam, process fabric non-stop, which suits large runs at low unit cost.

TEX-078 · Why does water hardness matter in wet processing?

Calcium and magnesium ions form insoluble deposits with soaps, some dyes and silicates. This causes spots, harsh handle and uneven shades. Softened water or sequestering agents prevent it.

Dyeing

TEX-079 · What is dyeing?

Applying colourants to fibers so that they are absorbed and held by physical or chemical forces. This gives uniform colour with acceptable fastness. Dyeing can be done at fiber, yarn, fabric or garment stage.

TEX-080 · What is the difference between a dye and a pigment?

A dye dissolves or disperses in the application medium and has affinity for the fiber, so it penetrates it. A pigment is insoluble, has no affinity, and is fixed to the surface with a binder.

TEX-081 · What is a mordant?

A substance, usually a metal salt such as alum or a chromium compound, that binds a dye to the fiber by forming an insoluble complex. Mordants are mainly used with natural dyes and mordant dyes on wool.

TEX-082 · What is the material-to-liquor ratio (MLR)?

The ratio of material mass to dyebath volume, for example 1:8, which means 8 L of liquor per kg of goods. Lower MLR saves water, energy and chemicals.

TEX-083 · What is the difference between exhaustion and fixation?

Exhaustion is the fraction of dye that leaves the bath and moves onto the fiber. Fixation is the fraction that stays permanently bound after washing-off. For reactive dyes, fixation is always lower than exhaustion.

TEX-084 · What does shade % owf mean?

Dye mass as a percentage of the weight of fabric. For example, a 2% owf shade on 100 kg of fabric needs 2 kg of dye.

TEX-085 · At what stages can textiles be dyed?

As loose fiber (stock dyeing), as tops, as yarn (package or hank), as fabric (piece dyeing) or as finished garments. Earlier stages give better penetration. Later stages give more flexibility to respond to fashion.

TEX-086 · What is a jigger?

A batch machine for open-width woven fabric. The fabric winds back and forth between two rollers through a small dye trough. It works at low MLR and causes little creasing.

TEX-087 · What is a jet dyeing machine?

A batch machine in which fabric in rope form is driven through a closed loop by a jet of dye liquor. It gives gentle, fast and level dyeing, and pressurized versions can dye polyester at about 130 °C.

TEX-088 · What is package dyeing?

Yarn wound on perforated tubes or springs is loaded onto carriers, and dye liquor is pumped through the packages in alternating directions. It is the main method for yarn-dyed fabrics.

TEX-089 · What is a levelling agent?

An auxiliary that slows initial dye uptake or promotes migration so that colour spreads evenly. It works by complexing with the dye or competing for dye sites on the fiber.

TEX-090 · Why is salt added when dyeing cotton with direct or reactive dyes?

Cotton develops a negative surface charge in water, which repels anionic dyes. Electrolyte such as NaCl or Na₂SO₄ suppresses this charge and pushes dye onto the fiber, which increases exhaustion.

Printing & Finishing

TEX-091 · What is the difference between dyeing and printing?

Dyeing colours the whole material uniformly. Printing applies colour in a defined pattern, using a thickened paste so that the colour stays where it is placed.

TEX-092 · What are the main styles of printing?

Direct printing applies colour onto white or pale ground. Discharge printing destroys the dyed ground in the print areas, sometimes adding a new colour. Resist printing applies a resist first so that the later dye cannot fix there.

TEX-093 · What is the difference between flat-screen and rotary-screen printing?

Flat-screen printing uses a stationary flat mesh and squeegee, with the fabric moving intermittently, so it is slower and handles large repeats. Rotary printing uses seamless cylindrical screens with internal squeegees on continuously moving fabric, so it is much faster.

TEX-094 · What is digital inkjet printing?

Ink is jetted drop by drop from printheads, directly from a digital file, with no screens. It suits short runs, unlimited colours and fast sampling, but the fabric must be pretreated and ink cost per metre is higher.

TEX-095 · What are the main components of a printing paste?

Colourant (dye or pigment), thickener, and the fixation chemicals the dye needs (alkali, acid or reducing agent). It may also contain urea or humectants, a binder for pigments, defoamer and dispersing agents.

TEX-096 · How does pigment printing work?

Insoluble pigment is mixed with a film-forming binder and a thickener. After printing, the binder is cured, typically by dry heat, to form a film that anchors pigment to the surface. No washing-off is needed.

TEX-097 · What is the difference between mechanical and chemical finishing?

Mechanical finishes change fabric physically, as in calendering, raising, sanforizing, sueding and compacting. Chemical finishes apply substances, such as softeners, resins, repellents and flame retardants, to change properties.

TEX-098 · What is calendering?

Passing fabric between heated, pressurized rolls to give a smooth, flat or lustrous surface. Variants are friction calendering (glaze), schreiner (silky sheen) and embossing (relief pattern).

TEX-099 · What is sanforizing?

A compressive shrinkage process for woven cotton. Fabric is pressed against a stretched rubber belt that then contracts, so the fabric is pre-shrunk lengthwise and residual washing shrinkage is minimized.

TEX-100 · What is raising (napping)?

Lifting fiber ends from the fabric surface with wire-covered rollers to form a soft, fuzzy pile. It increases warmth and softness, as in flannel and fleece.

TEX-101 · What does a softener finish do?

It lubricates fibers to give a smoother, softer handle and better drape and sewability. The main types are cationic, nonionic and silicone, chosen for handle, hydrophilicity and shade effect.

TEX-102 · What is the difference between water-repellent and waterproof fabric?

A water-repellent finish lowers surface energy so that drops bead and roll off, while the fabric stays breathable. A waterproof fabric resists water penetration under pressure, usually through a coating or membrane.

Textile Testing & Quality Control

TEX-103 · What is GSM?

Grams per square metre, the mass per unit area of a fabric. It is measured by weighing a cut sample of known area, often a 100 cm² circular cutter sample, and is a key specification for cost and end use.

TEX-104 · What is the standard atmosphere for textile testing?

About 20 °C and 65% relative humidity, with tolerances defined by the relevant standard. Fiber properties, especially moisture regain and strength, depend strongly on these conditions.

TEX-105 · Why are samples conditioned before testing?

Textiles absorb or lose moisture until they reach equilibrium with the air. Conditioning in the standard atmosphere, typically for 24 h or until mass is constant, makes results comparable and repeatable.

TEX-106 · What is the difference between strip and grab tensile tests?

In a strip test, the full width of a fabric strip is clamped, often after ravelling to an exact width. In a grab test, only the central part of a wider specimen is gripped, so adjacent yarns also contribute. Both report breaking force and elongation.

TEX-107 · What is tenacity?

Breaking force divided by linear density, which gives specific strength. It is expressed in cN/tex or gf/den, so fibers and yarns of different fineness can be compared fairly.

TEX-108 · What is yarn evenness?

The variation in mass per unit length along a yarn. It is measured capacitively and reported as U% or CV%, together with counts of thin places, thick places and neps.

TEX-109 · What is pilling?

The formation of small balls of entangled fibers on the fabric surface through rubbing in wear. It is rated visually from 1 (severe) to 5 (none) after a test in a pilling box or Martindale tester.

TEX-110 · What is abrasion resistance?

A fabric's ability to withstand surface rubbing. It is usually tested on a Martindale tester and reported as the number of rub cycles to specimen breakdown or to a set mass loss.

TEX-111 · How is colourfastness rated?

Change in shade and staining of adjacent fabrics are judged against grey scales from 1 (poor) to 5 (excellent). Lightfastness uses the blue wool references from 1 to 8.

TEX-112 · What is dimensional stability?

A fabric's resistance to shrinkage or growth after washing or steaming. Shrinkage % = (original length − final length) ÷ original length × 100, measured between marked points in warp and weft.

TEX-113 · What is AQL in textile inspection?

Acceptable Quality Level: the worst average defect rate that is still considered acceptable in sampling inspection. Sample size and accept/reject numbers come from standard sampling tables based on lot size.

TEX-114 · What is the 4-point fabric inspection system?

A method that assigns penalty points to fabric defects by length: up to 3 in = 1 point, 3–6 in = 2, 6–9 in = 3, over 9 in or any hole = 4. Points are normalized per 100 square yards.

Garment Manufacturing

TEX-115 · What is the sequence of garment manufacturing?

Design → pattern making → sampling → grading → marker making → spreading → cutting → bundling → sewing → finishing (trimming, pressing) → inspection → packing.

TEX-116 · What are pattern making and grading?

Pattern making creates the templates for each garment part in a base size. Grading scales the base pattern up and down to produce a size set using defined increments at grade points.

TEX-117 · What is a marker?

A layout of all pattern pieces for one or more garments, placed on paper or in CAD to guide cutting. Marker efficiency = (area of pattern pieces ÷ marker area) × 100.

TEX-118 · What is fabric spreading?

Laying fabric plies on the cutting table to the marker length and width. Plies must be correctly aligned, kept at the right tension and face orientation, and kept free of distortion before cutting.

TEX-119 · What cutting machines are used in garment making?

Straight-knife and round-knife cutters for lays, band knives for precise small parts, die cutters for repeated shapes, and automated CNC cutters with a vacuum table for high accuracy.

TEX-120 · What is the difference between lockstitch and chainstitch?

Lockstitch (class 301) interlocks needle and bobbin threads inside the fabric, so it is secure and looks the same on both sides. Chainstitch (class 401) interloops threads with a looper, so it is faster and stretchier but can unravel.

TEX-121 · What is an overlock stitch?

A stitch (class 500) made with loopers that wrap thread around the fabric edge while trimming it. It neatens and seams edges at the same time, especially on knits.

TEX-122 · What is SPI?

Stitches per inch, the stitch density along a seam. Higher SPI generally gives stronger, neater seams up to a limit. Typical values range from about 8 to 14, depending on fabric and use.

TEX-123 · What are the main seam classes?

Superimposed seams (plies stacked, as in a plain seam), lapped seams (plies overlapped, as in a jeans felled seam), bound seams (an edge enclosed by binding) and flat seams (edges butted, as in flatlock).

TEX-124 · What is fusing?

Bonding a thermoplastic-adhesive-coated interlining to garment parts such as collars, cuffs and fronts using heat, pressure and time. It adds shape and stiffness.

TEX-125 · What is SMV (SAM)?

Standard Minute Value: the time a qualified operator needs to complete an operation at standard performance, including allowances. It is used for costing, planning and efficiency calculation.

TEX-126 · What does garment finishing include?

Thread trimming, spot cleaning, pressing or steam finishing, attaching tags and labels, final inspection, folding and packing.

Technical Textiles

TEX-127 · What are the application areas of technical textiles?

The common classification has 12 areas: Agrotech, Buildtech, Clothtech, Geotech, Hometech, Indutech, Medtech, Mobiltech, Oekotech, Packtech, Protech and Sporttech.

TEX-128 · What are the functions of a geotextile?

Separation, filtration, drainage, reinforcement and protection of soil or other materials in civil engineering works such as roads, embankments and landfills.

TEX-129 · What is the difference between para-aramid and meta-aramid?

Para-aramid (for example Kevlar or Twaron) has rigid linear chains, which give very high tenacity and modulus for ballistic use and ropes. Meta-aramid (for example Nomex) is less strong but excellent in heat and flame resistance for protective clothing.

TEX-130 · What is carbon fiber?

A fiber of at least 90% carbon, usually made from PAN precursor by stabilization and carbonization. It has very high stiffness and strength-to-weight ratio and is used in composites.

TEX-131 · What is glass fiber used for in textiles?

It is used for reinforcement in composites, insulation, filtration and fireproof fabrics. It is strong, non-combustible and cheap, but heavy and brittle. E-glass is the common grade.

TEX-132 · What is UHMWPE fiber?

Ultra-high-molecular-weight polyethylene fiber (for example Dyneema or Spectra), made by gel spinning. It has extremely high specific strength and low density and floats on water. It is used in ropes, ballistic armour and cut-resistant gloves.

TEX-133 · What are medical textiles?

Textiles used in healthcare. They include implants (sutures, vascular grafts), non-implantables (bandages, wound dressings), extracorporeal devices (dialysis filters) and hygiene products (gowns, drapes, masks).

TEX-134 · What are coated fabrics?

Base fabrics covered with a layer of polymer such as PVC, PU, silicone or rubber. The coating makes them waterproof, airtight or durable for tarpaulins, conveyor belts, inflatables and protective clothing.

TEX-135 · What fiber is typically used for airbag fabric?

Nylon 6,6 filament yarn woven into a dense fabric, either coated or uncoated. It is chosen for high strength, toughness and heat capacity during rapid deployment.

TEX-136 · What is a textile composite?

A material in which textile reinforcement (woven, knitted, braided or nonwoven) is embedded in a matrix such as epoxy. Prepregs are reinforcements pre-impregnated with partly cured resin.

TEX-137 · What are filtration textiles?

Woven, needle-felt or meltblown media that separate particles from air or liquid. They are used in bag filters, cartridge filters, masks and water treatment.

TEX-138 · What is LOI?

Limiting Oxygen Index: the minimum oxygen concentration (%) in an O₂/N₂ mixture that just supports candle-like burning. Air contains about 21% O₂, so fibers with a higher LOI tend to self-extinguish in air.

Sustainability & Textile Machinery

TEX-139 · What is a circular textile economy?

A system in which textiles are designed to last, then reused, repaired and recycled back into new fibers, instead of following the linear take–make–dispose path.

TEX-140 · What is recycled polyester (rPET)?

Polyester made from post-consumer PET bottles or textile waste. It is produced mostly by mechanical recycling (wash, flake, re-melt, spin) or by chemical depolymerization, and cuts virgin feedstock use.

TEX-141 · What is organic cotton?

Cotton grown without synthetic pesticides, synthetic fertilizers or GM seed, under certified organic farming rules. Claims are verified through certification schemes such as GOTS for textiles.

TEX-142 · What are COD and BOD in textile effluent?

Chemical Oxygen Demand measures the oxygen needed to oxidize all organic matter chemically. Biochemical Oxygen Demand measures the oxygen consumed by microbes, usually over 5 days. High values indicate polluting effluent from dyeing and finishing.

TEX-143 · What is Zero Liquid Discharge (ZLD)?

A wastewater scheme in which effluent is treated, recovered through membranes, and evaporated, so that water is recycled to the process and no liquid effluent leaves the plant. Salts and sludge remain as solid waste.

TEX-144 · Why is lyocell called a closed-loop fiber?

Cellulose is dissolved directly in the amine oxide solvent NMMO without derivatization, and more than 99% of the solvent is recovered and reused. This avoids the carbon disulphide used in viscose.

TEX-145 · What are OEKO-TEX and GOTS?

OEKO-TEX STANDARD 100 certifies that textile products are tested for harmful substances. GOTS (Global Organic Textile Standard) certifies organic fiber content plus environmental and social criteria along the processing chain.

TEX-146 · What is microfiber shedding?

The release of tiny fiber fragments, especially synthetic ones, during washing and wear. They reach waterways and add to microplastic pollution.

TEX-147 · What is a stenter (tenter) machine?

A finishing machine that holds fabric by its selvedges on pins or clips in moving chains through heated chambers. It is used to dry, set width, heat-set and cure finishes.

TEX-148 · What is an automatic cone winder?

A machine that rewinds ring bobbins onto large cones. It removes yarn faults with electronic clearers, joins ends by splicing and builds packages suitable for warping and knitting.

TEX-149 · Why are variable frequency drives (VFDs) used in textile machinery?

They control motor speed precisely, allow soft start, permit speed profiles (for example over the ring frame doff cycle) and save energy on fans and pumps by matching speed to load.

TEX-150 · Why is preventive maintenance important in textile mills?

Scheduled cleaning, lubrication, setting and replacement of wear parts such as aprons, cots and travellers keep machine settings consistent. This reduces breakdowns, quality variation and waste.

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