Garment manufacturing

Textile Technology (B.E./B.Tech) · Garments · free study notes for exams, placements and interviews

In short

Garment manufacturing is the conversion of fabric and trims into finished apparel through a defined chain: design and pattern making, marker planning, spreading, cutting, bundling, sewing, pressing, finishing, inspection and packing. It is the core production subject of textile technology, because India's apparel industry employs the largest share of textile workers and exports roughly US$ 14-16 billion of readymade garments a year (figure varies year to year with DGCI&S data). Exams test stitch and seam classification, machine selection, SAM and line balancing, marker and cut-order planning, and AQL-based inspection. Interviews at Shahi Exports, Arvind, Gokaldas, Raymond, Page Industries, Trident, Pearl Global and buying houses such as Li & Fung focus on efficiency, defects, and cost per minute.

Explained

Pre-production: design to pattern

Product development sequence: tech pack from buyer → first pattern → proto sample → fit sample → size set → pre-production (PP) sample → TOP (top-of-production) sample → shipment sample.
Pattern making methods: (a) flat pattern - drafting from body measurements and a block/sloper; (b) draping on a dress form for complex drapes; (c) CAD systems (Gerber AccuMark, Lectra Modaris, Optitex, Tukatech, Indian systems too) which store, grade and nest patterns digitally.
Block (sloper): a basic master pattern without style features, from which style patterns are developed.
Pattern components: grainline, notches, drill holes, seam allowance, ease (wearing ease + design ease), piece name, size, cut quantity.
Grading: systematically increasing/decreasing a base-size pattern across sizes by fixed grade increments (e.g. 4 cm chest, 2 cm shoulder per size step) - done by shift, radial or cut-and-spread methods; grading changes size, not style proportions.
Measurement charts follow buyer specs; Indian sizing guidance comes from BIS size designation standards and the INDIAsize anthropometric survey (NIFT/BIS), which is being adopted for domestic ready-to-wear.

Marker planning, spreading and cutting

Marker: a scaled or full-size diagram of all pattern pieces laid on fabric width for cutting. Marker efficiency = (area of pattern pieces / total marker area) × 100; typical 80-90% for woven shirts/trousers.
Marker types: single-size vs mixed/multi-size; nap-one-way (N/O/W) for pile and directional prints, nap-either-way (N/E/W) for plain fabric (best efficiency), nap-up-and-down (N/U/D).
Cut order planning (COP): deciding how many lays, how many sizes per lay and how many plies to meet the size-colour ratio with least fabric and least cutting time.
Spreading methods: flat/open single ply, face-to-face (F/F), face-one-way (F/O/W), zig-zag; manual or automatic spreader. Requirements: alignment, correct ply tension (no stretch), ply count accuracy, elimination of static and fabric faults, directional correctness.
Cutting equipment: straight knife (most common in India, 5-13 inch blade), round knife (single/few plies, straight lines), band knife (accurate small parts), die cutting (collars, pockets in bulk), notcher and drill, computerised cutting machine (CAM) with vacuum table, laser/ultrasonic for synthetics.
Cutting quality: vertical cut edge, no fusing/scorching of thermoplastic fibres, blade sharpness, lay height limits (typically 50-200 mm depending on machine and fabric).
After cutting: ply numbering, bundling by size-shade-lot, shade band/shade segregation to avoid shade mix-up in one garment, re-cutting of damaged parts.
Fabric utilisation and loss: end loss, selvedge loss, splice loss, ply-height loss, remnant; fabric is 55-65% of garment cost, so 1% fabric saving matters more than large sewing gains.

Sewing: stitches, seams and machines

Stitch: one unit of thread configuration; SPI (stitches per inch) controls seam strength, elasticity and appearance (typically 8-12 SPI shirts, 7-9 denim topstitch, 12-14 fine shirting).
Stitch classes (ISO 4915 / based on former US Federal Std 751):
1. Class 100 - single thread chainstitch (101) - basting, buttons.
2. Class 200 - hand stitches (saddle stitch, pick stitch).
3. Class 300 - lockstitch (301 plain, 304 zig-zag) - needle + bobbin; strongest, least stretch, unravels less.
4. Class 400 - multi-thread chainstitch (401 two-thread) - strong, extensible, used on jeans side seams, waistbands.
5. Class 500 - overedge/overlock (503 two-thread, 504 three-thread, 512/514 four-thread, 516 five-thread safety stitch) - neatens and seams knits; prevents fraying.
6. Class 600 - covering/flatlock (602, 605, 607) - flat seams on knitwear, decorative coverstitch on T-shirt hems.
Seam classes (ISO 4916): SS (superimposed - plain seam), LS (lapped - lap seam, French seam variants), BS (bound - binding at neck/armhole), FS (flat seam - butted edges), OS (ornamental stitching), EF (edge finishing - hems, facings).
Seam quality terms: seam strength, seam slippage, seam pucker (from differential feed, thread shrinkage, structural jamming), seam grin, needle damage in knits.
Machine types: single needle lockstitch (SNLS), double needle, overlock, flatlock, feed-off-the-arm (jeans inseam/shirt sleeve), bartack, buttonhole (and eyelet-hole for jeans/formals), button attach, blind hem, zig-zag, kansai multi-needle, bottom hemmer, pocket welt, CNC pattern tacker/automat.
Feed mechanisms: drop feed, differential feed, needle feed, puller feed, unison/walking foot - chosen to control ply slippage and pucker.
Needles: size in Nm (metric, = diameter in 1/100 mm) and Singer system - e.g. Nm 80 = Singer 12; points: R (round/sharp) for wovens, ball point (SES/SUK) for knits to avoid yarn cutting; coatings for high-speed sewing.
Threads: spun polyester, core-spun, polyester/cotton, filament; ticket numbers (Tex, Nm, ticket no. e.g. 120, 60, 40). Thread consumption varies by stitch type - overlock consumes far more than lockstitch.
Attachments and work aids: folders, binders, guides, hemmers, feet, templates - raise output without changing operator skill.

Fusing, pressing, finishing and washing

Fusing: interlining bonded to shell fabric by heat + pressure + time (typical 120-160 °C, 2-5 bar area pressure, 8-20 s on continuous fusing press) for collars, cuffs, plackets, waistbands; faults - strike-back, strike-through, delamination, puckering, shade change.
Pressing: under-pressing (during assembly) and final pressing; achieved by heat, moisture, pressure and time plus vacuum for setting; equipment - steam iron with vacuum table, buck/steam press, form/dolly finisher, tunnel finisher, creasing machine.
Garment washing/wet processing: desizing, rinse wash, enzyme wash (cellulase - replaces stone wash), stone wash, acid/snow wash, bleach wash, over-dyeing, tinting; dry processes - whiskering, hand sanding, laser engraving, ozone fading, PP spray. Water and effluent governed by CPCB/State PCB consent and ZLD requirements in several clusters.
Finishing line: thread trimming (thread sucker), checking, measurement audit, spot removal, pressing, needle/metal detection, folding, tagging, polybag, carton packing (solid/assorted/ratio pack), carton marking, shipping marks.
Packing data: cartons specified by GSM of corrugation, ply, dimensions; packing list, cube and gross/net weight for the invoice and shipping documents.

Industrial engineering, productivity and plant layout

Work study = method study (improve the method) + work measurement (set the time). Tools: process chart, flow diagram, operation breakdown, time study with stopwatch, PMTS/GSD (General Sewing Data), synthetic data.
SAM (standard allowed minutes) = basic time × (1 + allowances). Basic time = observed time × rating/100. Allowances typically 10-20% (personal, fatigue, machine delay, bundle handling).
Production systems: (a) progressive bundle system (PBS) - highest WIP, common in India; (b) unit production system (UPS) - overhead conveyor, controlled WIP; (c) modular/team (Toyota Sewing System) - multi-skilled stand-up teams, fast change-over, low WIP; (d) make-through/whole garment - tailoring and samples.
Line balancing: pitch time = SAM of bottleneck or takt; aim to make every workstation's workload ≤ pitch time. Balancing efficiency = Σ station times / (number of stations × bottleneck time) × 100; good lines run 55-75% on-standard efficiency, 80%+ in best Indian export units.
Capacity: theoretical pieces/day = (available minutes × operators × efficiency) / SAM.
Lean tools used in Indian apparel: 5S, kaizen, SMED for style change-over, single-piece flow, kanban, andon, hourly production board, skill matrix.
Layout: straight line, L-shape, U-shape; material flow should avoid cross traffic; storage, cutting, sewing, finishing, packing arranged in process sequence.

Quality, standards and compliance (Indian practice)

Fabric inspection: 4-point system (ASTM D5430-style) - defect points by defect length: up to 3 in = 1 point, 3-6 in = 2, 6-9 in = 3, over 9 in = 4; maximum 4 points per linear yard; roll accepted usually at ≤ 40 points per 100 square yards (buyer-specified). Also 10-point and Graniteville-78 systems.
In-process control: traffic light system (hourly checks at the operator), inline 100% checking at critical operations, end-of-line 100% check, roving audit by QA, measurement audit against spec with tolerance.
Final inspection: AQL sampling per IS 2500 (Part 1) / ISO 2859-1 (equivalent to the older MIL-STD-105E); apparel buyers commonly use AQL 2.5 for major defects and 4.0 for minor, general inspection level II, single sampling, normal plan. Defect classes - critical, major, minor.
Defect types: sewing (skipped stitch, broken stitch, open seam, puckering, uneven topstitch, raw edge), cutting (miscut, notch missing), fabric (hole, slub, shade variation), pressing (shine, scorch, crease), measurement out of tolerance.
Needle policy: broken-needle log, one-for-one issue, metal/needle detector before packing - mandatory for most export buyers.
Testing: fabric and garment tests to IS/ISO/AATCC - dimensional change on washing, colour fastness to washing, rubbing, perspiration and light, seam strength, seam slippage, tensile and tear strength, pilling, azo-free dye and restricted-substance lists (REACH, buyer RSL), OEKO-TEX STANDARD 100.
Labelling: textile care labelling standard (BIS) with GINETEX-type care symbols; Legal Metrology (Packaged Commodities) Rules declarations for domestic retail packs - MRP, net quantity, manufacturer, consumer care details, country of origin.
Labour and factory law: the four Labour Codes (Code on Wages; Industrial Relations Code; Code on Social Security; Occupational Safety, Health and Working Conditions Code) are in force from 21 November 2025 and replace the Factories Act, Minimum Wages Act, Industrial Disputes Act and BOCW Act - these govern working hours, overtime at twice the ordinary rate, welfare facilities, safety committees and appointment letters in garment units.
Social compliance audits: SA 8000, WRAP, BSCI, Sedex/SMETA, buyer codes of conduct; GST on readymade garments is 5% up to ₹2,500 per piece and 18% above that (two-slab structure effective 22 September 2025; the 40% demerit slab does not apply to apparel), so confirm the current threshold before quoting.
Promotion schemes: PM MITRA mega textile parks, Production Linked Incentive for man-made fibre apparel and technical textiles, ATUFS/ its successor capital subsidy, RoSCTL/RoDTEP for export rebates (rates revised periodically).

Key points

Garment manufacturing chain - design → pattern → marker → spreading → cutting → bundling → sewing → pressing → finishing → inspection → packing.
Marker efficiency - pattern area as a % of marker area; the single biggest lever on fabric cost (fabric ≈ 55-65% of garment cost).
Cut order planning - choosing lays, sizes per lay and plies to meet the order ratio with least fabric and cutting time.
Stitch class 301 - lockstitch: strong, low stretch, needle + bobbin, for wovens.
Stitch class 401 - two-thread chainstitch: extensible and strong, used on jeans seams and waistbands.
Stitch class 500 - overlock: seams and neatens edges, essential on knits; high thread consumption.
Stitch class 600 - coverstitch/flatlock: flat, stretchable seams and T-shirt hems.
Seam classes (ISO 4916) - SS, LS, BS, FS, OS, EF defined by how plies are positioned.
SPI - stitches per inch; too low gives weak seams, too high gives needle damage and puckering.
Needle size Nm - blade diameter in hundredths of a millimetre; ball point for knits, round point for wovens.
Fusing - heat, pressure and time bond interlining; faults are strike-back, strike-through and delamination.
SAM - standard allowed minutes = observed time × rating × (1 + allowances); the basis of costing and capacity.
Line balancing - equalise workstation loads to the pitch time; bottleneck sets line output.
Production systems - PBS (high WIP), UPS (conveyor), modular (low WIP, multi-skilled), make-through (samples).
4-point system - fabric inspection; typically accept at ≤ 40 points per 100 square yards.
AQL 2.5 - common acceptance quality limit for major defects per IS 2500/ISO 2859-1 sampling.
Needle detection and broken-needle control - compulsory safety practice before packing export garments.
Labour Codes 2025 - in force 21 November 2025, now govern hours, wages, overtime and safety in garment factories.

Formulas and examples

Marker efficiency (%) = (total area of all pattern pieces / total marker area) × 100
Fabric consumption per garment = (marker length × plies worth of fabric) / number of garments in marker; with allowances: Avg consumption = marker length / garments per marker × (1 + end loss% + splice% + remnant%)
Fabric required for lay = (marker length + end allowance) × number of plies
Basic time = observed time × (rating / 100); SAM = basic time × (1 + allowance fraction)
Pieces per day (capacity) = (working minutes × number of operators × efficiency) / SAM
Line efficiency (%) = (total SAM produced / total minutes attended) × 100 = (output × SAM) / (operators × minutes) × 100
Balancing efficiency (%) = Σ (station work content) / (number of stations × bottleneck time) × 100
Pitch time = total SAM / number of workstations; Takt time = available time / required output
Cost of manufacture (CM) per piece = SAM × cost per minute (₹/min); Cost per minute = monthly factory cost / (operators × available minutes × efficiency)
Thread consumption = stitch-type factor × seam length (factor ≈ 2.5-3 for 301, ≈ 14-18 for 504 overlock; use measured ratios in practice)
4-point system: points per 100 yd² = (total penalty points × 3,600) / (fabric length in yards × usable width in inches)

Example 1 - marker efficiency and fabric consumption. A marker for 4 shirts is 6.00 m long on 150 cm usable width. Total pattern area of the 4 shirts = 7.56 m².

Marker area = 6.00 × 1.50 = 9.00 m².
Marker efficiency = 7.56 / 9.00 × 100 = 84%.
Fabric per shirt (marker only) = 9.00 / 4 = 2.25 m², i.e. 6.00/4 = 1.50 m of 150 cm fabric.
With 3% end-and-splice loss, consumption = 1.50 × 1.03 = 1.545 m per shirt. For 10,000 shirts: 15,450 m; at ₹110/m fabric cost = ₹16,99,500.

Example 2 - SAM from a time study. Observed time for "attach cuff" averaged 0.80 min over 20 cycles, operator rated 110, allowances 15%.

Basic time = 0.80 × 110/100 = 0.88 min.
SAM = 0.88 × 1.15 = 1.012 min (≈ 1.01 min).

Example 3 - capacity, line efficiency and CM cost. A line has 30 operators working an 8-hour shift (480 min) at 60% efficiency; garment SAM = 18 min.

Available minutes = 30 × 480 = 14,400.
Productive (on-standard) minutes = 14,400 × 0.60 = 8,640.
Output = 8,640 / 18 = 480 pieces/shift.
If actual output is 400 pieces, efficiency = (400 × 18) / 14,400 = 50%.
At a cost per minute of ₹6.50, CM = 18 × 6.50 = ₹117 per piece at standard; at 50% efficiency the real absorbed cost = 14,400 × 6.50 / 400 = ₹234 per piece - showing why efficiency, not SAM, decides profit.

Example 4 - line balancing. Five stations with work content 1.0, 1.4, 0.9, 1.2 and 1.0 min (total 5.5 min); bottleneck = 1.4 min.

Balancing efficiency = 5.5 / (5 × 1.4) × 100 = 78.6%.
Hourly output = 60 / 1.4 = 42.9 ≈ 42 pieces/hour.
Split the 1.4 min station into 0.7 + 0.7 (6 stations, new bottleneck 1.2): efficiency = 5.5 / (6 × 1.2) × 100 = 76.4%, but output rises to 60/1.2 = 50 pieces/hour - output and balance efficiency can move in opposite directions.

Example 5 - 4-point fabric inspection. A roll is 120 yards long, 58 inches usable width, with defects: 6 defects under 3 in (1 pt each), 4 defects of 3-6 in (2 pts), 2 defects of 6-9 in (3 pts), 1 defect over 9 in (4 pts).

Total points = 6 + 8 + 6 + 4 = 24.
Points per 100 yd² = (24 × 3,600) / (120 × 58) = 86,400 / 6,960 = 12.4 → well within a 40-point limit, so accept.

Feature	Lockstitch 301	Chainstitch 401	Overlock 504	Coverstitch 605
Threads	2 (needle + bobbin)	2 (needle + looper)	3 (needle + 2 loopers)	5 (3 needles + looper + top cover)
Extensibility	Low	Medium-high	High	High
Unravelling	Secure	Unravels from the looper end	Edge-neatening	Flat, secure
Thread used per cm of seam	Least	Moderate	High	Highest
Typical use	Woven shirts, trousers	Jeans seams, waistband	Knit seams, edge neatening	T-shirt hem, flat join

Production system	WIP	Change-over	Skill needed	Indian use
Progressive bundle	High	Slow	Single-skill	Most large export units
Unit production system	Low-medium	Medium	Single-skill	Capital-intensive shirt/trouser plants
Modular / TSS	Very low	Fast	Multi-skill	Fast-fashion and small-lot lines
Make-through	Minimal	Immediate	Very high	Sampling rooms, bespoke tailoring

Where it is used

Export garment manufacturing: Tirupur (knitwear), Noida-Gurgaon and Faridabad (woven ladies' wear), Bengaluru (Shahi, Gokaldas - shirts and outerwear), Ludhiana (woollens, hosiery), Mumbai and Surat (synthetics), Kolkata (ladies' wear).
Domestic brands and retail supply: Raymond, Arvind, Aditya Birla Fashion, Page Industries (Jockey), Trident, Lux and Rupa - production planning, IE and quality roles.
Job roles: production manager, industrial engineer (IE/work study), cutting-room in-charge, quality assurance/QA head, technical designer, pattern master, CAD operator, merchandising-production interface, vendor QA with buying houses.
Technical and specialised apparel: uniforms and defence clothing (Ordnance Factory supplies), PPE and medical gowns, high-visibility workwear to IS/EN standards, sportswear with bonded and seamless construction.
Denim and washing plants: integrated units in Ahmedabad, Bengaluru and Tirupur with laser, ozone and enzyme washing and ZLD effluent systems.
Automation and services: CAD/CAM vendors, automats and template sewing, RFID in finishing, ERP/shop-floor data systems and 3D sampling (CLO, Browzwear) reducing physical samples.

Interview questions

Q: What is marker efficiency and how do you raise it? A: It is pattern area as a percentage of marker area; raise it by mixing sizes, using nap-either-way where allowed, tilting within grain tolerance, interlocking pieces and using CAD auto-nesting.
Q: Why is an overlock used on knits instead of a lockstitch? A: Overlock seams stretch with the fabric and neaten the raw edge in one pass; a lockstitch has little extensibility and would crack under knit stretch.
Q: Difference between 301 and 401 stitches? A: 301 lockstitch uses a bobbin and is secure but inextensible; 401 chainstitch uses a looper thread, is more extensible and stronger in seam fatigue but unravels if the looper thread is cut.
Q: How do you calculate how many pieces a line can make per day? A: Pieces = (operators × shift minutes × efficiency) / SAM; so 30 operators × 480 min × 0.6 / 18 min SAM = 480 pieces.
Q: What causes seam pucker and how do you fix it? A: Differential feeding of plies, excess thread tension, thread or fabric shrinkage, and structural jamming in tight fabrics; fix by balancing tension, correct needle and thread size, lower SPI, needle feed or walking foot, and pre-shrunk fabric.
Q: What is AQL 2.5 in a final audit? A: With ISO 2859-1/IS 2500 level II sampling, it defines the sample size and the maximum number of major defects allowed; exceeding it fails the lot and it is re-inspected after rework.
Q: Explain the 4-point system. A: Fabric defects are penalised 1-4 points by length, maximum 4 points per linear yard, normalised to points per 100 square yards; most buyers accept at or below 40.
Q: What is a bottleneck and how do you break it? A: The station with the longest cycle time, which sets line output; break it by splitting the operation, adding a parallel operator, using a work aid or folder, or re-allocating elements to adjacent stations.
Q: Why is needle detection done before packing? A: To ensure no broken needle or metal fragment is left in the garment - a safety requirement of almost every export buyer, supported by a broken-needle log and one-for-one needle issue.
Q: Which costs more to save - a minute of sewing or a metre of fabric? A: Fabric, usually: it is 55-65% of garment cost, so a 1% fabric saving typically beats a much larger percentage gain in sewing minutes.
Q: What goes wrong in fusing and why? A: Strike-back and strike-through from excess temperature or pressure, delamination from too little, and puckering or shade change from wrong dwell time; controlled by routine peel-strength and wash tests on fused panels.
Q: Which law now governs working hours and overtime in a garment factory? A: The four Labour Codes, in force from 21 November 2025, which replaced the Factories Act and the Minimum Wages, Industrial Disputes and BOCW Acts; overtime is paid at twice the ordinary wage rate.

Common mistakes

Confusing stitch class with seam class - 301 is a stitch, SSa is a seam; a question asking for a seam specification needs both.
Using a sharp (round-point) needle on knits, which cuts loops and causes needle damage lines along the seam.
Computing line efficiency on attended minutes but output on standard minutes, or ignoring absent operators and helpers in the operator count.
Treating marker efficiency as fabric consumption - consumption must add end loss, splice, remnant, ply-height and rejection allowances.
Forgetting shade segregation and ply numbering, so parts of one garment come from different shade lots or lays.
Mixing units in marker and consumption sums - metres with yards, cm width with inch width - and in the 4-point formula (width must be in inches, length in yards).
Quoting withdrawn or superseded standards and repealed Acts - the Factories Act has been subsumed by the Labour Codes, and ISO 4915/4916 (not old Federal numbers) are the current stitch and seam references.