Weaving Concepts and Terminology for woven fabric

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Weaving Concepts and Terminology 

Woven fabrics, with a few exceptions (such as triaxial fabrics, discussed later in chapter 15) are constructed by interlacing warp (lengthwise) yarns and filling (crosswise) yarns at right angles. In theory, warp and filling yarns should intersect at right angles. When this relationship is perfect, the fabric is said to be on true grain or grain perfect. As a result of the stresses and strains imposed during weaving or finishing, these yarns’ may not lie in the proper position, and when this occurs, the woven fabric is said to be off-grain. The off-grain relationship of warp and filling yarns is described by different terms, depending on how the distortion lies. Warp yarns are usually straight, as they are subject to lengthwise tension throughout the processing of fabrics. 

Filling yarns are usually responsible for the distortion, but they may be distorted in a straight line (skewed) or in a curved line (bowed). Woven and other fabrics can be designated as reversible that is, having the same appearance on both front and back, or not reversible. For fabrics that are not reversible the side to be displayed in the finished textile is termed the face of the fabric and the other side is the back. 

Within the textile and apparel industries, comparative measurement systems are necessary. The concept of yarn size expressed as yarn number was discussed in chapter 13. When dealing with fabrics, comparisons of size are made in terms of the number of yarns per inch or fabric count, the width of the fabric, and the weight of the cloth. 

The closeness of the weave is expressed as the fabric count. With a small magnifying glass calibrated in inches or centimeters, it is possible to count the number of yarns in 1 inch or centimeter of warp and in 1 inch or centimeter of filling. When the number of yarns in the warp is similar to the number of yarns in the filling, the weave is said to be a balanced weave. The fabric count is often expressed in numerical form as 80 X 64, indicating that there are 80 warp yarns per inch by 64 fillings. 

When warp and filling are perfectly balanced, or equal, the count may be stated as 80 square, meaning there are 80 yarns per inch in the warp and 80 yarns per inch in the filling. Alternatively, the number may be doubled, in which case a count of 180 would indicate a count of 90 yarns per inch in each direction. Balanced weave fabrics with the same type of yarns in warp and filling are more durable because the fabric wears evenly in both warp and filling directions. 

Fabric count is usually measured with a calibrated, square magnifying glass called either a linen tester or pick glass. The glass is marked off in fractions of an inch or in centimeters, and the number of warp and filling yarns beside these calibrations can be viewed in magnified form with the glass and counted. In those fabrics where fabric counts are not balanced, the larger number of yarns will usually be found in the warp direction

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