WEAVING | FOOD SCIENCE & NUTRITION | L-25|

weaving, production of fabric by interlacing two sets of yarns so that they cross each other, normally at right angles, usually accomplished with a hand- or power-operated loom.

A brief treatment of weaving follows. For further discussion, see textile: Production of fabric.

In weaving, lengthwise yarns are called warp; crosswise yarns are called weft, or filling. Most woven fabrics are made with their outer edges finished in a manner that avoids raveling; these are called selvages. They run lengthwise, parallel to the warp yarns. The three basic weaves are plain, twill, and satin. Fancy weaves—such as pile, Jacquard, dobby, and leno—require more complicated looms or special loom attachments for their construction.

The manner in which the yarns are interlaced determines the type of weave. The yarn count and number of warp and filling yarns to the square inch determine the closeness or looseness of a weave. Woven fabrics may also be varied by the proportion of warp yarns to filling yarns. Some effects are achieved by the selection of yarns or of combinations of yarns.

In the plain weave each filling yarn passes over and under the warp yarns, with the order reversed in alternating rows. Fabrics made in the plain weave include percale, muslin, and taffeta. Ribbed effects in such fabrics as faille and bengaline are produced by employing heavier yarns for either the warp or the filling. In the basket weave one or more filling yarns are passed alternately over and under two or more warp yarns, as seen in monk’s cloth.

Twill weaves are made by interlacing the yarns in a manner producing diagonal ribs, ridges, or wales across the fabric. Wales may run from the upper right to the lower left of the fabric, or the reverse. The herringbone weave has wales running both ways. Twill fabrics include denim, gabardine, and flannel.

Satin weaves have a sheen produced by exposing more warps than fillings on the right side of the fabric. The exposed warps are called floats. In the sateen weave the process is reversed, and the exposed fillings form the floats. The amount of twist in the yarns and the length of the floats produce variations. Fabrics made in these weaves include slipper satin, satin crepe, and various sateen types.

Pile weaves produce fabrics with raised, dense surfaces. They can be made by weaving extra warp yarns over wires, producing loops that are cut as the wires are withdrawn; by adjusting loom tension to produce loops that are frequently left uncut; by using extra filling yarns to produce floats that are cut after weaving; or by weaving two cloths face to face, binding them together with an extra set of warps that form the pile when the fabrics are cut apart. Examples of woven pile fabrics include velvet, plush, terry cloth, and many of the synthetic furs.