From fibre to finished fabric

From fibre to yarn: spinning. A yarn is a continuous strand suitable for weaving or knitting. Short staple fibres go through these steps:

• Cleaning: removing dirt, seeds and leaves, and forming the fibres into a sheet called a lap.
• Carding (and, for finer yarns, combing): straightening the fibres so they lie parallel, forming a loose rope called a sliver.
• Drawing out and attenuating (thinning) the sliver on the roving machine.
• Spinning: twisting the strand into yarn.
• Manufactured filaments can be used directly, as a single filament (monofilament, like fishing line) or several together (multifilament), or cut into staple lengths and blended with natural fibres: polyester with cotton gives terecot, polyester with wool gives terewool, combining comfort with easy care.

Yarn terms:

• The yarn number (count) shows fineness: the higher the number, the finer the yarn. Fine yarns are used for shirts; coarse ones for towels and furnishings.
• The amount of twist per inch affects the yarn: less twist gives softer, more lustrous yarn; more twist gives a harder, stronger one.
• A simple (single) yarn is one strand; two or more twisted together make a ply yarn (2-ply, 3-ply); several ply yarns twisted together make a cord. Fancy (novelty) yarns, such as slub or boucle, are uneven on purpose, for decoration rather than strength.
• Thread is the special yarn used for sewing.

From yarn (or fibre) to fabric:

• Felts and non-wovens are made straight from fibres, without making yarn: fibres are matted or bonded with heat, moisture, pressure or chemical binders. Wool felt, interlinings and disposable wipes are examples.
• Weaving interlaces two sets of yarns at right angles on a loom: the lengthwise warp and the crosswise filling (weft). The selvedge is the firm edge along the warp, and fabric is strongest along the warp (lengthwise). The basic weaves are plain (over one, under one, as in a cotton shirt), twill (diagonal lines, as in denim) and satin (long floats giving a smooth, shiny surface).
• Pile fabrics (terry towels, velvet, corduroy) use an extra set of yarns that form loops or a raised surface.
• Knitting interloops a yarn into rows of loops. Weft knitting is done by hand or machine; warp knitting on industrial machines. Knits are stretchy, porous and comfortable, ideal for vests, socks, sweaters and sportswear. Vertical columns of loops are called wales; horizontal rows are courses.
• Braiding plaits yarns diagonally (shoelaces, ropes); nets are made by knotting yarns; lace combines twisting, looping and knotting.

Finishing. Fabric straight off the loom, called grey goods, is often rough and dull. Finishes are given to change:

• Appearance: scouring (washing out impurities), bleaching (whitening), calendering (pressing between heated rollers for smoothness and shine).
• Texture: starching for crispness.
• Behaviour: wash and wear (wrinkle-resistant), water repellent, mothproof, flame retardant, and sanforised (pre-shrunk so it will not shrink after washing).
• Durable finishes last through the life of the fabric; renewable finishes, such as starch or blue, must be repeated after washing.

Colour can be added at the fibre, yarn or fabric stage (dyeing). Printing applies colour only to parts of the fabric to form a design, using wooden blocks, stencils, screens or engraved rollers.