Satin weave

Satin is the third basic weave of the woven fabrics. In basic construction, the satin weave is similar to the twill weave but generally uses from five to as many as twelve harnesses, producing a five to twelve-shaft construction. It differs in appearance from the twill weave because the diagonal of the satin weave is not visible; it is purposely interrupted in order to contribute to the flat, smooth, lustrous surface desired. There is no visible design on the face of the fabric because the yarns that are to be thrown to the surface are greater in number and finer in count than the yarns that form the reverse of the fabric. Satin weaves produce a smooth, even and glossy fabric surface. This is due to the interlacing points being covered up by the floats of the neighboring threads. The smoothness of the fabric surface can be improved by:

• High thread density
• Smooth yarn with low twist
• Filament yarn from man-made fibre

Each end and each pick makes one, and only one intersection and the intersections are distributed in an orderly manner. Uniformly separated from each other, and nowhere adjacent. Satin is more loose structure fabric, when compare with plain and twill fabrics. Satin is widely used for the foundation of jacquard design.

Advantages and disadvantages of satin weave :
Satin constructions produce smooth, lustrous, rich-looking fabrics that give reasonably good service if they are not subjected to excessive hard wear. Short-float fabrics are more durable than long-float fabrics, for the former have less exposed yarn to catch on rough objects; long floats, although they increase the sheen of a fabric, snag and pull if there are any protrusions or splinters on furniture. When style calls for luxurious fabrics for formal wear, satin is often chosen. It is an especially suitable fabric for coat linings because its smooth surface allows coats to be slipped on and off very easily. In general, it sheds dirt well, but bright rayon in a long-float satin weave wills often nave a metallic sheen that may appear greasy after continuous wear. Satin weave usually requires more shafts in the weaving than do the plain or twill weaves, thereby increasing the cost of production. Materials that are made in the satin weave include antique satin (millions of yards per year), bridal satin, charmeuse, cotton satin, dress satin, satin bengaline, satin crepe, satin faille, slipper satin, and Venetian satin.

Twill weave

The second basic weave pattern used in manufacturing fabrics is the twill weave. This weave is characterized by diagonal lines or ribs (twill lines) on the face, and often on the back, of the fabric. The face diagonal can vary from reclining twill, with a low 14-degree angle, to steep twill, with a 75-degree angle. A twill angle of 45-degrees is considered to be medium diagonal or regular twill; it is the most common. The angle of the twill line is determined by the closeness of the warp ends, the number of yarns per inch, the diameters of the yarns used, and the actual progression forming the repeat. These twill lines are produced by letting all warp ends interlace in the same way but displacing the interlacing points of each end by one pick relative to that of the previous end. While the plain weave can only be woven in one form, there exist several options with regard to twill. Twill lines are formed on both sides of cloth. The direction of diagonal lines on the face side of cloth is opposite to that on the wrong side coinciding respectively with the weft and warp floats on the other side. Thus, if warp floats predominate on one side of the cloth, weft floats will predominate in the same proportion on the other side. Twills differ from plain weaves in the increased number of picks and ends needed to complete a repeat pattern. Whereas a plain weave requires two ends and two picks for a repeat, the simplest twill requires three picks and three ends. At least three healed-shafts are needed to make a twill weave. Normally straight drafting system is used to produce regular twill fabric. The smallest possible repeat for a twill weave is 3 ends x 3 picks, and there is no theoretical -upper limit to the size of the repeat.

Plain Weave

The plain weave is the simplest of the weaves and the most common. It consists of interlacing warp and weft yarns in a pattern of over one and under one. Imagine a small hand loom with the warp yarns held firmly in place. The weft yarn moves over the first warp yarn, under the second, over the third, under the fourth, and so on. In the next row, the weft yarn goes under the first warp yarn, over the second, under the third, and so on. In the third row, the weft moves over the first warp, under the second, and so on, just as it did in the first row. Plain weave is obtained by raising all even-numbered warp ends at one pick and raising all the odd numbered ones at the other pick. It means threads interlacing in alternate order.

Main features of plain weave :

• Threads interlacing in alternate order.
• The repeat contains two ends and two picks.
• Both sides of the weave are identical.
• Each thread gives maximum amount of support to the adjacent threads.
• Texture is stronger and firmer than any other ordinary cloth.
• Made from all kind of textile raw materials and yarns i.e. cotton, linen, jute, man-made fibres, both spun and continuous filament yarns.
• It comprises a high production of the total output of woven fabrics.
• Two heald shafts are sufficient to produce plain weave, when the number of ends/inch is large (more than 50), four or six heald shafts are used with skip draft.

Advantages of plain weave fabric :

• Wears well.
• Offers appropriate background for printing, special finishes, and applied surface designs.
• It is snag-resistant.
• It has good dimensional stability if of high fabric count, i.e. high thread density.
• It is reversible if not printed or finished with special effects.

Disadvantages of plain weave fabric :

• Ravels.
• Appears uninteresting.
• Shows wrinkle.
• Has lower tear strength than some other weaves.
• Shows soil readily.

Identification of End & Pick

Warp and weft yarns have different demands placed on them and may differ in their structure or fibre type. Thus, a fabric may not have the same performance characteristics for warp and weft. The warp must withstand the high tensions of the loom and the abrasion of weaving, so the warp yarns are stronger and more uniform with higher twist. Filling yarns are more often fancy or special-function yarns such as high-twist crepe yarns, low-twist napping yarns, or boucle yarns.

Identification of End (warp) & Pick (weft) : Differentiating between warp and weft is possible by carefully examining both the fabric and the length-wise and crosswise yarns.

1. The selvedge always runs in the lengthwise (warp) direction of all fabrics.
2. Most fabrics have lower elongation in the warp direction.
3. The warp yarns lie straighter and are more parallel in the fabric because of loom tension.
4. Fancy or special-function yarns are usually in the filling direction.
5. Fabric characteristics may differentiate between the warp and weft directions. For example, poplin has a weft rib and satin has warp floats.
6. Warp yarns tend to be smaller, are more uniform in structure and appearance, and have higher twist.
7. Fabric crimp is usually greater for weft yarns since they must bend or flex over or under warp yarns due to the way the loom operates.

Fabric Structure

Woven fabrics are composed of longitudinal or warp threads and transverse or weft threads, interlaced with one another according to the class of structure and form of design that are desired. The terms chain or twist are applied to the warp and the warp threads are known individually as ends, while the terms picks and filling are applied to the weft threads. In the following the term threads is used in referring to warp and weft collectively, but in order to distinguish clearly one series from the other the warp threads are mostly described as 'end' and the weft threads as 'picks'.

According to weave structures woven fabrics may be conveniently divided into two principal categories as follows :

Simple Structure : In which the ends and the picks intersect one another at right angles and in the cloth are respectively parallel with each other. In these constructions there is only one series of ends and one series of picks and all the constituent threads are equally responsible for both the aspect of utility or performance in a fabric and the aspect of aesthetic appeal.

Compound Structure : In which there may be more than one series of ends or picks some of which may be responsible for the body of the fabric, such as ground yarns, whilst some may be employed entirely for ornamental purposes such as 'figuring', or 'face' yarns. In these cloths some threads may be found not to be in parallel formation one to another in either plane, and indeed, there are many pile surface constructions in which some threads may project out at right angles to the general plane of the fabric.

Classification Of Fabric

There are three principal methods of mechanically manipulating yarn into textile fabrics : interweaving (interlacing or interlacement), interlooping and intertwining. All three methods have evolved from hand-manipulated techniques through their application on primitive frames into sophisticated manufacturing operations on automated machinery.

Interweaving : It is the intersection or interlacement of two sets of straight threads, warp (ends) and weft (picks or filling), which cross and interweave at right angles to each other. Weaving is by far the oldest and most common method of producing continuous lengths of straight-edged fabric.

Interlooping : It consists of forming yarn(s) into loops, each of which is typically only released after a succeeding loop has been formed and intermeshed with it so that a secure ground loop structure is achieved. The loops are also held together by the yarn passing from one to the next. Knitting is the most common method of interloping and is second only to weaving as a method of manufacturing textile products. It is estimated that over seven million tons of knitted goods are produced annually throughout the world. Although the unique capability of knitting to manufacture shaped and form-fitting articles has been utilized for centuries, modern technology has enabled knitted constructions in shaped and unshaped fabric form to expand into a wide range of apparel, domestic and industrial end-uses.

Intertwining and twisting : It includes a number of techniques, such as braiding and knotting, where threads are caused to intertwine with each other at right angles or some other angles. These techniques tend to produce special constructions whose uses are limited to very specific purposes. There is another method of manipulating directly fibre into textile fabrics is so called nonwoven process. This relatively young branch of the textile industry has expanded enormously after the c world-war because of the high production rates and the resulting cost savings.

Classification Of Yarn

Classification of yarn according to their structure :
Staple fibre yarns or Spun yarns (Single yarn) : Spun yarns are made by mechanical assembly and twisting together (spinning) of staple fibres. Ring spinning, Rotor spinning, Warp spinning, Air-jet spinning etc. machines are used to produce this spun or single yarns

Ply yarn : Single yarn are used in the majority of fabrics for normal textile and clothing applications, but in order to obtain special yarn features, particularly high strength and modulus for technical and industrial applications, ply yarns are often needed. A folded or ply yarn is produced by twisting two or more single yarns together in a operation, and a cabled yarn is formed by twisting together two or more folded yarns or a combination of folded and single yarns. The twisting together of several single yarns increases the tenacity of the yarn by improving the binding-in of the fibres on the outer layers of the component single yarns. Ply yarns are also more regular, smoother and more hard weaving. The direction of twisting is designated as S or Z, just as in single yarns. Normally the folding twist is in the opposite direction to that of the single yarns.

Filament yarn : A filament yarn is made from one or more continuous strands called filaments where each component filament runs the whole length of the yarn. Those yarns composed of one filament are called monofilament yarns, and those containing more filaments are known as multifilaments yarns. For apparel application, a multifilament yarn may contain as few as two or three filaments or as many as 50 filaments. In carpeting, for example, a filament yarn could consist of hundreds of filaments. Most manufactured fibres have been produced in the form of a filament yarn. Silk is the only major natural filament yarn.

Classification of yarn according to their use :
Weaving Yarns : Yarns for woven cloth are prepared for the intended end use. Yarns to be used in the warp, the lengthwise direction of a cloth, are generally stronger, have a tighter twist, and are smoother and more even than are yarns used for filling, the crosswise direction of a cloth. Novelty yarns may be used in the warp, but they are generally found in the filling. Highly twisted crepe yarns are usually found used as filling yarns.

Knitting Yarns : These may be divided into yarns for hand knitting and yarns for machine knitting. Knitting yarns are more slackly twisted than yarns for weaving. Hand knitting yarns are generally ply, whereas those for machine knitting can be either single or ply.

Classification of yarn according to their manufacturing process :

1. Carded yarn
2. Combed yarn