BTEB Diploma in Textile Engineering Examination cheat sheet

Fibre classification: natural (vegetable, animal, mineral) versus man-made (regenerated, synthetic, inorganic); vegetable fibres are cellulose, animal fibres are protein.

Cotton fibre: 88–96% cellulose; lumen and convolutions give maturity; maturity ratio below 0.8 indicates immature fibre prone to neps and poor dye uptake.

Fibre identification tests: burning odour (cellulose = burnt paper, protein = burnt hair, synthetic = melting bead), solubility in 70% H2SO4, and longitudinal/microscopic shape.

Tenacity units: cN/tex equals gf/denier divided by 9; specific strength in textile practice uses tex as the linear density base.

Moisture regain at 65% RH, 20 °C: cotton ~8.5%, viscose ~13%, wool ~16%, polyester ~0.4%, nylon ~4.5%.

Staple length and fineness determine spinning limit; finer fibres give more fibres per cross-section and stronger, more even yarns.

Wool felts due to overlapping cuticle scales; shrink-resist finishing uses chlorine-Hercosett or polymer deposition to mask the scale direction.

Blow-room sequence: opening, cleaning, mixing, and lap or chute formation; beater speed and grid-bar setting control trash extraction versus fibre damage.

Carding draft typically 80–120; carding produces sliver with nep count and short-fibre content reduced; cylinder-to-flat wire settings control quality.

Draw-frame drafting uses roller-pair drafting with break draft 1.1–1.4; doubling n slivers reduces random irregularity by a factor of the square root of n.

Comber noil extraction is typically 12–18% for fine counts; combing removes short fibres below the effective length threshold and raises yarn evenness.

Ring spinning: traveller speed, balloon tension, and spindle speed limit production; yarn twist TPI = twist multiplier divided by the square root of the cotton count.

Rotor spinning reaches 100,000+ rpm rotor speed but produces yarn at roughly 3–5 times ring-spinning delivery rate with lower tenacity and harsher handle.

Yarn count conversions: Nm × Ne relation depends on the indirect/direct system; tex = 1000 divided by Nm; Ne = 0.5905 × Nm for cotton.

Woven fabric sett relations: cover factor K = threads per inch divided by the square root of the yarn count (cotton system); fabric cover depends on K of warp and weft.

Basic weaves: plain (1/1), twill (2/1, 3/1), satin (5-end float); float length controls lustre, drape, and abrasion resistance.

Loom motions: primary (shedding, picking, beat-up), secondary (let-off, take-up), tertiary (weft stop, warp stop, selvedge).

Knitting: weft knitting (single jersey, rib, interlock) versus warp knitting (tricot, raschel); loop length and stitch density determine fabric weight and extensibility.

Gauge in knitting equals needles per inch; machine gauge and yarn count must match or loop length and fabric quality suffer.

Warp preparation: sizing adds size pick-up of 6–12% to reduce hairiness and abrasion; loom efficiency drops sharply if sizing is inadequate.

Fabric weight (GSM) = (warp count contribution + weft count contribution) × 0.6855 for cotton in the indirect system; verify with a GSM cutter.

Singeing removes protruding fibre; desizing removes size (enzyme for starch, oxidative for PVA); scouring removes wax and pectin; bleaching with H2O2 at pH 10.5–11 and 90–95 °C.

Mercerisation uses 18–22% NaOH at low temperature with tension; increases lustre, dye uptake, and tensile strength while reducing shrinkage.

Dye-fibre substantivity: reactive dyes form covalent bonds with cellulose; vat dyes are insoluble pigments reduced to leuco form then oxidised in situ.

Exhaust dyeing kinetics: dye uptake depends on pH, temperature, electrolyte (salt) concentration, and liquor ratio; salt promotes exhaustion of direct and reactive dyes.

Printing methods: screen (flat/rotary), roller, transfer, and digital inkjet; thickener rheology controls sharpness and penetration of the print paste.

Finishing: calendering, sanforising (shrinkage control), resin crease-resist, softening, and flame retardancy; each alters handle and dimensional stability.

Colour fastness tests cover washing, rubbing, light, and perspiration; grey scale rates change, blue wool scale rates light fastness 1–8.

Marker making efficiency = area of pattern pieces divided by marker area × 100; fabric utilisation drives cutting cost.

Cutting methods: straight knife, band knife, die cutting, and computer-controlled knife; lay height is limited by fabric friction and blade deflection.

Stitch classes: 301 lockstitch, 401 chainstitch, 504 overedge (safety stitch), 516 overedge; SPI (stitches per inch) typically 10–14 for wovens.

Seam types: superimposed, lapped, bound, and flat; seam strength and extensibility must match fabric performance.

Production systems: progressive bundle, unit production system (UPS), and modular/team sewing; work-in-progress falls as line balance improves.

Standard allowed minute (SAM) = basic time × allowance factor; line efficiency = earned minutes divided by attended minutes × 100.

Grading and sizing use a size interval; pattern grading shifts and grows pattern pieces according to a grade rule per size step.

Sampling: random and biased sampling; for fibre testing use the zoning technique; for yarn evenness test at least 400 m per sample.

Moisture regain test uses oven-dry mass; standard testing atmosphere is 65% ± 2% RH and 20 °C ± 2 °C.

Yarn count from skein: count = length in yards × 0.001 divided by weight in pounds for the English cotton system (840 yd = 1 hank).

Evenness testing (USTER) reports CV%, imperfections (thin/thick/neps) per km, and hairiness index; spectrogram identifies periodic faults from drafting.

Fabric tests: tensile (strip and grab), tear (Elmendorf), bursting (diaphragm or ball), abrasion (Martindale), pilling, and dimensional stability after washing.

Statistical quality control uses X-bar and R charts; process capability index Cp = (USL − LSL) divided by 6 sigma.

Acceptable quality limit (AQL) sampling per ISO 2859-1: lot size and inspection level determine sample size and acceptance/rejection numbers.

Preventive maintenance schedule: daily lubrication, weekly belt tension checks, monthly gearbox inspection; MTBF and MTTR measure reliability and repair speed.

Ring frame: spindle speed, traveller weight, and ring diameter must match; heavier travellers increase twist insertion and yarn tension.

Carding: cylinder-to-flat setting 0.25–0.30 mm for cotton; wire condition affects nep removal and sliver quality.

Loom: sley, reed, and heald frame settings control beat-up force; warp tension is maintained by let-off motion and back-rest position.

Bearing failure diagnosis: vibration signature analysis detects imbalance, misalignment, and outer-race defects before breakdown.

Energy management: motor load factor, power factor correction, and compressed-air leakage surveys reduce specific energy consumption per kg of yarn.

Spare-parts management uses ABC classification; critical spares must be held on site to avoid long downtime.

Management functions: planning, organising, staffing, directing, and controlling; span of control determines organisational structure.

Productivity = output divided by input; labour productivity = units produced divided by labour hours.

Work study: method study improves process; work measurement sets standard time = observed time × rating factor × allowance factor.

Plant layout types: product (line) layout for high volume, process (functional) layout for varied products; layout affects material handling cost.

Quality management: PDCA cycle, Kaizen, 5S, and Six Sigma (3.4 defects per million opportunities).

Inventory models: EOQ = square root of (2 × annual demand × ordering cost divided by holding cost per unit per year).

Human resource: job evaluation, incentive schemes (piece rate, Halsey, Rowan), and labour turnover calculation.

Cost of production = direct material + direct labour + factory overhead; prime cost excludes overhead.

Yarn cost per kg = (fibre cost × 1 + waste% allowance) + conversion cost + overhead + profit margin.

Contribution margin = selling price − variable cost; break-even quantity = fixed cost divided by contribution per unit.

Depreciation methods: straight line = (cost − salvage) divided by life; reducing balance applies a fixed percentage to book value.

Costing of fabric uses warp and weft consumption: weight per metre = (ends per metre × tex warp + picks per metre × tex weft) divided by 1000.

Entrepreneurship: business plan covers market analysis, technical feasibility, financial projections, and risk assessment.

Working capital cycle = inventory days + receivable days − payable days; shorter cycles improve cash flow.

CAD systems for textile design: Photoshop/Illustrator for prints, specialised textile CAD for repeats, colour separation, and screen engraving.

Colour management: RGB for screens, CMYK for print; ICC profiles and spectrophotometers ensure colour consistency across devices.

Repeat types: straight repeat, half-drop, mirror, and brick; repeat size must divide the fabric width evenly for seamless printing.

Digital textile printing: ink types (reactive, acid, disperse, pigment) must match fibre type; resolution typically 360–1440 dpi.

ERP and MES systems integrate order, inventory, production, and quality data; barcodes and RFID track WIP in real time.

Spreadsheet applications: VLOOKUP, pivot tables, and formulas for costing, production planning, and quality data analysis.

Automation in spinning and weaving uses PLC and SCADA for monitoring; sensors collect production and stoppage data for OEE calculation.

Cotton dust (byssinosis) is a major respiratory hazard; permissible exposure limits and local exhaust ventilation control dust levels.

Noise-induced hearing loss occurs above 85 dB(A); ring spinning and loom sheds often exceed this; hearing protection and noise enclosures are required.

Machine guarding: nip points, gears, and belts must be guarded; lock-out/tag-out procedures isolate energy before maintenance.

Fire safety: cotton dust and lint are combustible; electrical installations must be flameproof; fire extinguishers and sprinkler systems required.

Effluent treatment: dyeing wastewater has high BOD, COD, colour, and TDS; biological treatment plus tertiary treatment is needed before discharge.

Environmental standards: effluent pH 5.5–9.0, TDS limits, and zero liquid discharge (ZLD) requirements in many regions.

Personal protective equipment: ear plugs, masks, safety shoes, and eye protection; ergonomic design of workstations reduces musculoskeletal disorders.

Attachment report structure: company profile, process flow, machinery list, quality control, observations, and conclusions.

Project selection criteria: relevance to industry, feasibility, data availability, and measurable objectives.

Data collection: primary (observation, interview, experiment) and secondary (records, reports); sample size and validity must be justified.

Process flow charting: from fibre to yarn to fabric to garment; identify bottlenecks and quality checkpoints at each stage.

Cost-benefit analysis: compare investment cost with annual savings; payback period = investment divided by annual savings.

Report writing: abstract, introduction, literature review, methodology, results, discussion, conclusion, and references.

Presentation: use charts and tables; state objectives, findings, and recommendations clearly within the allotted time.