Engineer Textile flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Tex definition

Mass in grams of 1000 metres of yarn or fibre. It is a direct linear density system, so a higher tex number means a coarser, heavier product.

Cotton moisture regain

Standard regain is about 8.5 percent at 20 degrees Celsius and 65 percent relative humidity. Wool is near 16 percent and polyester near 0.4 percent, which explains comfort differences.

Limit irregularity

The minimum CV percent achievable if fibres were placed perfectly randomly. The ratio of actual to limit irregularity is the index of irregularity, showing drafting quality.

Twist multiplier formula

In cotton count, twist per inch equals twist multiplier divided by the square root of the English count. It links yarn count, twist level and yarn character.

Warp and weft cover factor

Cover factor equals threads per inch divided by the square root of the cotton count. Combined cover predicts air permeability, stiffness and fabric tightness.

Needlepunch bonding

Barbed needles repeatedly penetrate a fibre web, entangling fibres mechanically. Punch density and depth control strength, density and surface appearance of the nonwoven.

Mercerising effect

Treatment with strong sodium hydroxide under tension swells cellulose, improving lustre, tensile strength and dye uptake. It also removes some immature fibre character.

Reactive dye fixation

Dye reacts covalently with cellulose hydroxyl groups in alkaline conditions. Unfixed hydrolysed dye must be soaped off to reach the required wash fastness.

Kubelka-Munk K/S

K/S equals (1 minus R) squared divided by twice R, where R is reflectance. It relates measured reflectance to dye concentration for colour matching.

Metamerism in colour matching

A pair of samples appears matching under one light source but different under another. Spectrophotometer curves and multiple illuminants are used to detect it.

Standard testing atmosphere

Textiles are conditioned at 20 plus or minus 2 degrees Celsius and 65 plus or minus 4 percent relative humidity before testing, because moisture changes strength and dimensions.

Elmendorf tear test

A pendulum applies a tearing force to a pre-cut fabric specimen. Results depend on yarn strength, float length and interlacement, so weave structure matters greatly.

AQL sampling meaning

Acceptable quality level is the worst tolerable process average percent defective for a lot. ISO 2859-1 tables give sample size and accept or reject numbers.

Four-point fabric inspection

Defects are penalised one to four points according to length, then totalled per 100 square yards. Buyer contracts set the maximum acceptable points per roll.

Condition-based maintenance

Maintenance triggered by measured machine condition such as vibration, temperature or oil analysis, rather than fixed intervals or breakdown. It reduces unplanned stoppages.

Overall equipment effectiveness

OEE equals availability multiplied by performance multiplied by quality. It shows how much of the rated machine time produces good, sellable output.

Break-even quantity

Fixed cost divided by the difference between selling price and variable cost per unit. It gives the output volume at which total cost equals revenue.

Geotextile separation function

A geotextile placed between dissimilar soils prevents mixing while allowing water flow. Tensile strength, puncture resistance and permeability are the key selection properties.

Fibre volume fraction

The proportion of a composite occupied by reinforcement fibres. Higher fibre volume generally raises stiffness and strength, but too high a value causes poor wet-out.

Effluent tertiary treatment

After biological treatment, colour and residual chemicals are removed by ozone, activated carbon, membranes or advanced oxidation. This enables water reuse in processing.

GOTS certification scope

The Global Organic Textile Standard covers organic fibre content plus chemical, wastewater and social criteria through the processing chain, verified by accredited certifiers.

Shirley stiffness tester

A fabric strip bends under its own weight at a set angle, giving bending length. Flexural rigidity follows from bending length, mass per unit area and the cube relation.

Grey scale fastness rating

A five-step scale, with half steps, used to grade colour change and staining after washing, rubbing or light exposure. Grade one is poor and five is excellent.

Comber noil percentage

The proportion of short fibre removed during combing. Higher noil gives a smoother, stronger, more lustrous yarn but raises fibre cost per kilogram.

Rotor spinning principle

Fibres are opened, fed into a high-speed rotor and twisted as they collect in the rotor groove. Production is high but yarn is weaker than ring yarn.

Satin weave characteristics

Long floats produce a smooth, lustrous surface with few interlacing points. Abrasion resistance and slip resistance are lower than in plain weave.

Pad-dry-cure finishing

Fabric is padded through a chemical bath, dried, then cured at controlled temperature and time. Pick-up percentage and nip pressure set the chemical add-on.

Disperse dyeing of polyester

Polyester is dyed with disperse dyes at about 130 degrees Celsius under pressure, or by carrier or thermosol methods. Reduction clearing removes surface dye.

Martindale abrasion test

A specimen rubs against a standard abradant in a Lissajous pattern. End-point is a hole or mass loss, and the same instrument grades pilling.

ISO 17025 accreditation

It confirms competence of testing and calibration laboratories. It is separate from ISO 9001 certification, which applies to a management system.

SMED setup reduction

Single-minute exchange of die aims to cut changeover time to under ten minutes by separating internal and external setup tasks and standardising them.

Thermal protective performance

A test measuring heat transmission through protective fabric under a combined radiant and convective heat exposure, giving a protection rating for firefighter clothing.