Woven Fabrics - Fairchild Books

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Figure 5.5 Various types of selvages: (a) Selvage as produced by the shuttle loom. Selvages made on a shuttleless loom such as (b) fringe, (c) leno, and (d) tucked-in selvage. c d Various techniques are used to make the selvage area stronger than the body of the cloth, including using heavier warp yarns; more warp yarns per inch; plied warp yarns; greater twist, if spun warp yarns; and different weave. Because the selvage is usually constructed differently than the body, it is fairly easy to identify. If the selvage warp yarns are different from the body warp yarns, their shrinkage characteristics may be different. If the selvage warp yarns have greater shrinkage during the finishing process, a tight selvage occurs, resulting in the puckering of an area within several inches of the fabric edge. This is a problem when the material is unrolled on the cutting table and the cloth does not lie flat. Identifying Warp Yarns and Filling Yarns One way to better understand the characteristics of woven fabric is to know the differences between the warp yarns and the filling yarns. Because fabric swatches are mounted with the warp yarns vertically, it must be determined which set of yarns is the warp so the mountings are correct. More importantly, garments are usually cut with the warp yarns running lengthwise, so the FABRIC SCIENCE A 94 F a drapability of the fabric must be checked by the designer to ensure that it meets the garment requirements. In all cases, distinguishing warp from filling is necessary. Finally, a textile expert making a complete analysis of a cloth must be able to identify both the warp and filling yarns in order to report such information as size, amount of twist, and fiber content. The following are some of the ways warp yarns can be distinguished from filling yarns: Selvage The warp yarns are always parallel to the selvage. Yarn sizes Usually the warp yarns are thinner, so they abrade less as they pass through the loom and rub against the various parts (e.g., heddles, reed). A fabric that contains both filament yarns and spun yarns usually has the filament yarns as the warp set. Twist For the most part, spun warp yarns have more twist than spun filling yarns. Because they usually are thinner, more twist is necessary to enable them to have sufficient strength to withstand the tensions exerted on the yarns in weaving and in finishing. b
Yarns per inch Usually there are more warp yarns per inch than filling yarns per inch, making the fabric stronger in the lengthwise direction. This is necessary because most of the tension exerted on the fabric in the finishing processes is in the lengthwise direction. Sometimes, however, the ends and picks per inch are equal (e.g., 80 square-print cloth) or occasionally the picks per inch is greater (e.g., soft filled sheeting). Ply yarns As discussed in Chapter 4, a plied yarn is stronger than a single yarn of the same size. Thus, the warp yarns are occasionally plied to give added strength, and the filling yarns usually remain single. Stiffness In 100 percent spun-yarn fabrics, the warp yarns are generally stiffer than the filling yarns because they usually have more twist. In 100 percent filament-yarn fabrics, the filling yarns are usually stiffer because they generally are thicker. A stiffer set of yarns usually results in less fabric drapability in that direction. Stretchability Usually there is more elongation in the width-wise direction. In most cases there are more ends per inch, so the picks usually have more crimp as they interlace (go under and over the warp yarns more frequently) to a greater degree. Stripes Most woven stripes appear in the lengthwise direction. Warp-wise woven stripes only require the appropriate color yarns to be properly grouped when the warp is made on the warp beam. When fabric is cut with the stripe in the length direction, the garment gives the wearer the illusion of more height and a leaner look. Checks and plaids are created by making stripes in both the warp direction and the filling direction. Face and Back Fabric developers generally address issues such as quality or durability, with the yarns on the face of the fabric. Thus, fabrics have a technical face side and a technical back side. The face side has the better appearance and usually forms the outside of the garment (or other textile product). Sometimes fashion dictates the use of the back of a fabric as the outside of the garment for the particular effect desired. Fabric developers generally address quality or durability issues with the yarns on the face of the fabric. There are various reasons that the face and back of cloth appear different. The two sides of a fabric may be different because of the weave or finish. Any fabric in WOVEN FABRICS A 95 F which the warp yarns or the filling yarns appear more on one side than on the other shows a difference between the face and back. <strong>Fabrics</strong> with a plain weave (see p. 97) or leno weave (see p. 103) are reversible, but fabrics with a satin weave are not (see p. 101). In a satin fabric, the warp yarns predominate on the face and the filling yarns on the back so that the two sides differ greatly in appearance. Usually the shinier, smoother side is the face. An exception is antique satin in which slub filling yarns create the slightly irregular effect on the surface. Some finishes, such as napping or brushing, affect only one surface of the cloth, whereas others, such as mercerizing, penetrate the entire fabric. Napping gives a fabric an obvious face side as, for example, in a flannel material. Mercerizing, however, produces the same change on both sides, as in a broadcloth fabric; thus a reversible fabric results. In printed fabrics, the color is usually placed only on one side. Therefore, unless the fabric is very sheer, the printed side is obvious and is considered the face. Some sheer printed fabrics may appear to be reversible because the print design seems to be the same on both sides. Caution: A garment should not be made with some parts cut from one side of the fabric and other parts cut from the other side. Even though both sides of the fabric may initially appear alike, there is often a slight difference in luster or color that does not become obvious until the garment is made and worn. This difference may become significant after cleanings and wear. Top and Bottom Besides having a face and a back, some fabrics have a top and a bottom on the face side. Where there is a difference, it is usually caused by the weave or the finish. In pile fabrics such as velveteen and corduroy, the pile is not perfectly erect, but lies at an angle. The color may vary from dark to light as the fabric is turned 180° on a flat surface because of the difference in the angle of light reflection. Sometimes these fabrics are used in garments where the pile lies upward in order to obtain a richer or darker color. With fabrics having an obvious top and bottom, the garment must be made with all its parts in the same top-down or bottom-down direction. A fabric with a woven or printed figure in an obviously upright position (e.g., horse, tree) can be cut in only one direction because in every piece forming the garment, the figure must be in the upright position. Printed fabrics that can only be used in one direction are called directional prints. Most fabrics, however, when resting on a flat surface with the face side up and the warp yarns vertical, have
Page 2 and 3: j.j. pizzuto’s FABRIC SCIENCE ten
Page 4 and 5: Executive Editor: Olga T. Kontzias
Page 6 and 7: Preface xv Acknowledgments xvii 1 T
Page 8 and 9: Secondary Manufactured Fibers for C
Page 10 and 11: 7 Other Types of Textiles 147 Objec
Page 12 and 13: Nonhazardous 224 Recycling 224 Work
Page 14 and 15: Fabric Performance Testing 316 Text
Page 17 and 18: air-jet bare elastic yarn blended y
Page 19 and 20: Identifying Spun and Filament Yarns
Page 21 and 22: Uses of Spun and Filament Yarns Som
Page 23 and 24: Fabrics made from worsted yarn are
Page 25 and 26: this system, one end of a fiber is
Page 27 and 28: textured yarn a b heater c d high p
Page 29 and 30: Table 4.1 Comparison oF sTreTCh Yar
Page 31 and 32: warp yarn Figure 4.14 Making chenil
Page 33 and 34: Table 4.2 Yarn number Conversions W
Page 35 and 36: Table 4.4 Thread Finishes and Their
Page 37: FABRIC SCIENCE / Swatch Kit Assignm
Page 40 and 41: Over 4,000 years ago, man created f
Page 42 and 43: yarn package yarn package yarn pack
Page 46 and 47: the same appearance as when the fab
Page 48 and 49: More fabrics are made with plain we
Page 50 and 51: Most twills are either warp face or
Page 52 and 53: Figure 5.15 (a) Five-shaft warp-fac
Page 54 and 55: Figure 5.18 Filling-pile weave fabr
Page 56 and 57: Sometimes the pile loops are cut in
Page 58 and 59: light-pattern changes to create a r
Page 60 and 61: A product that can be considered as
Page 62 and 63: Glossary of Classic Woven Fabrics A
Page 64 and 65: Frieze: Heavy, thick, rough-surface
Page 66 and 67: Taffeta: Medium-weight, plain-weave

Woven Fabrics - Fairchild Books

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