Woven Effects

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Hand embroidery has been used for many centuries to add decoration to fabrics. With the invention of the automatic loom came the production of looms that would create ornamental effects similar to that of embroidery. 

Clipped or Unclipped Spot Weave 

Embroidery like designs may be achieved through the use of extra warp and extra filling yarns. In the clipped spot weave, either an extra shuttle or an extra set of warp yarns interlace to create a simple woven design. The extra yarns are carried along as a float on the wrong side of the fabric when they do not appear in the design. After the cloth is completed, the long floats may be cut away (clipped) or left uncut (unclipped). 

If clipped, which is the most common practice, the yarns form a characteristic “eyelash” effect. Sometimes these fabrics are used inside out for design interest. 

The durability of the design depends on the closeness of the weave of the fabric into which it is woven. Some domestic dotted Swiss fabric is constructed by the clipped spot weave. This sheer cotton fabric uses small clipped spot yarns in contrasting color to create a dotted surface design. Dotted Swiss may also be made with flocking or with plastic dots, much cheaper options. 

Interwoven, or Double-Cloth, Fabrics 

Interwoven fabrics are also called double-cloth fabrics. They are made with three, four, or five sets of yarns.

Double-faced fabrics are made with three sets of yarns. Woven either from two sets of warp yarns and one filling yarn or from two sets of filling yarns and one warp yarn, the effect of the weave is to produce the same appearance on both sides of the fabric. Some blankets and double-faced satins are examples of fabrics that are woven in this way. Fabrics made with four sets of yarns use two sets of warp yarns and two sets offilling yarns. 

Yarns from both layers move back and forth from one layer to another, as required by the design. In some areas the two fabrics are totally separated; in others, all four sets of yarns are interwoven. The two layers of these fabrics cannot be separated without destroying the fabric. The cut edge of the fabric will show small “pockets” where fabric layers are separate. The pocket boundaries are the point at which yarn sets interchange from one side of the fabric to the other. 

Fabrics with five sets of yarns are produced in the same way as double-woven pile fabrics. Two separate fabric layers are constructed. Extra yarns travel back and forth between the two layers to hold them together. These fabrics are often reversible, with one side being of one color and one side of another color. If the connecting yarn is cut, the two segments of the fabric can be separated into two individual pieces of cloth 

Triaxally Woven Fabrics 

Research and development of new fabric construction is constantly in progress. There is, however, another method of constructing fabrics that is closely related to traditional weaving, and it is known as triaxial weaving. The term is derived from trimeaningm “three” and axial, meaning “of or pertaining to the axis or center line.” In other words, triaxial fabrics have three axes or center lines. Traditionally, woven fabrics have a biaxial form or two axes, the lengthwise and crosswise axes. 

Triaxial fabrics are usually woven by interlacing two sets of lengthwise yarns with one set of crosswise yarns. Special cams in the loom manipulate the yarns so that the double set of yarns is carried in a diagonal direction. All three sets of yarns interlace. Triaxial weaves are not entirely new. Snowshoes and some forms of basketwork sometimes have been made using a triaxial construction. The major advantage of triaxial weaving is in its stability against stretching not only in the length and crosswise directions but also in the bias. Even those biaxial fabrics with good stability in the warp and filling will stretch in the bias direction. Triaxially woven fabrics have high bursting strength resistance and strong resistance to tearing and raveling. Strength is uniform in all directions. 

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Basket Weave; Variation of plain weave fabric

The manner in which groups of warp yarns are raised by the harnesses to permit the insertion of the filling yarn determines the pattern of the weave, and in large measure the kind of fabric produced. Weave patterns can create varying degrees of durability in fabrics, adding to their usefulness and also to their appearance. In a simple weave construction, consisting of the filling going under one warp and over the next, two harnesses are needed: one to lift the odd-numbered warp yarns, and econd to lift the even-numbered warp yarns. More than two harnesses are required for advanced weaves, and as many as forty for figured weaves. The most commonly weave structure used for maximum woven fabrics are plain weave twill weave and satin weave, with some variation. There are some valuable structures and designs are also achieved from the following weaves: gauze, pile, double cloth, lappet, dobby, swivel, and Jacquard. 

Variations of Plain Weave:

Basket weave is one of the most popular woven fabric structure and design. The basket weave, a variation of the plain weave, uses two or more warp and/or two or more filling yarns side by side as one yarn. The resultant cloth is fairly loose in weave. The following are among the more common basket-weave fabrics. Basket Weave is made by having groups of two or more warp yarns simultaneously interlaced with group of two or more (proportionally equal) filling yarn. 2 X 2 basket weave is most common, in this two pairs of warp interlaces two pairs of filling yarn. 

Characteristics of basket weave: 

• It is a decorative weave. 

• Plain weave fabrics are reversible unless some finish is given on one of the sides. 

• Fabric made of this weave is inexpensive & easily produced. 

• Fabrics are not as durable as plain weave. 

• Eg: Monk’s cloth, oxford. 

2*2 Basket Rib weave

Basket weave

1. Monks cloth is a coarse cloth of large yarns. Monk’s cloth uses four or more yarns as one in the weave. Its major uses are in household textiles such as curtains, spreads, and the like. 

2. Hopsacking is made of many different fibers. This fabric simulates the fabrics used in bags for gathering hops. It has a 2-2 or 3-3 basket weave and is commonly used in upholstery. 

3. Modified basket weaves may use double yarns in one direction but not in the other. Oxford cloth, which is made in this way, is a soft fabric, often made of cotton or cotton blends, that is used for shirts. Frequently, it is made with narrow colored stripes in the warp, or a colored warp. 

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4. Duck and canvas are heavy, tightly woven, and very stiff plainweave fabrics made of even yarn for industrial use. They usually have an uneven weave pattern. Because of the tight weave, these fabrics are often used for outdoor purposes. 

b) RIB WEAVE: Ribbed effects are further variations of the plain weave. The rib may be produced in the warp or in the filling by alternating fine yarns with coarse yarns, or single yarns with doubled yarns. 

Characteristics of rib weave:

• Drapes well 

• Durability affected by pronounced ribs • Ex: Faille, Poplin

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Balanced Plain-Weave Woven Fabrics

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The balanced weaves are the most common. Unbalanced weaves, or rib weaves, and another variation, basket weaves, will be discussed later. It is helpful to classify balanced plain weaves by weight as light, medium, or heavy. Lightweight Plain Weave Fabrics. Lightweight plain-weave fabrics may be light in weight because they have either a low fabric count or are constructed of fine yarns and are usually sheer. The following low-fabric-count balanced plain weaves have somewhat specialized uses. 

1. Cheesecloth is open weave soft fabric originally used in producing cheese, serving as a wrapper or strainer for curds. 

2. Crinoline and buckram are heavily sized to serve as stiffening fabrics. 

3. Gauze, with a higher count than cheesecloth, is used in theatrical costumesand medical dressings, as well as for blouses and dresses. 

The following are high-count balanced plain weaves with fine yarns. 

• Chiffon is made from fine, highly twisted filament yarns. Because of the tightly twisted crepe yarns, chiffon has excellent drape, and although it is delicate in appearance, it is relatively durable. Sheer evening dresses, blouses, lingerie, and other dressy apparel are constructed from the fabric. 

• Ninon, a sheer plain weave of filament yarns, is often used in sheer curtains and draperies. 

• Organdy is a sheer cotton fabric that is given a temporarily or permanently stiffened finish. 

• Organza is a stiff sheer fabric made of filament yarns. 

• Voile, a soft fabric with somewhat lower fabric count and higher twist yarns, has a distinctive two-ply warp and ooddrapability. Medium- Weight Plain- Weave Fabrics. Medium weight balanced plain weaves usually have fairly high fabric counts, contain medium-weight yarns (12 to 29 tex), and are opaque. Distinguishing characteristics may be design, color, finish, or fabric count. 

1. Calico is a closely woven fabric with a small printed design. 

2. Chambray fabrics have colored warp yarns and white filling yarns that produce a heather appearance. Some contemporary chambrays may have warp and filling yarns of different colors. 

3. Chintz is a fabric printed with large designs that is often given a polished or glazed finish. Solid color glazed fabrics are called polished cotton. 

4. Gingham is a woven check or plaid design made with yarns of different colors. 

5. Muslin, generally woven from cotton or cotton blends, is made in both heavily sized, bleached qualities and in better grades for sheets and pillow cases. Muslin sheets are not combed and have a lower count (128 to 140 total yarns per inch) than do percale sheets. 

6. Percale, a closely woven, plain weave of cotton or blended fibers, is made from yarns of moderate twist. Percale yard goods are generally carded, but percale sheets are finer and more luxurious in feel and are made of combed yarns. 

Percale sheets have a count of 180 to 200 yarns (warp plus filling) per inch. 

Heavyweight Plain- Weave Fabrics. The following are common heavyweight plain weave fabrics. 

1. Butcher linen is a plain, stiff, white fabric made from heavy yarn. 

2. Crash is made from thick and thin yarns, giving the fabric a nubby look. 

3. Homespun is a furnishing fabric made with irregular yarns to resemble hand spun and hand-woven fabrics. 

4. Osnaburg is made of low-quality cotton for industrial use and in interior fabrics for curtains and upholstered furniture.

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The plain weave | Pattern Design to produce plain woven fabric

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Weave plan is the most popular topic of fabric structure and design in textile engineering courses. The manner in which groups of warp yarns are raised by the loom harnesses to permit the insertion of the filling yarn determines the pattern of the weave, and in large measure the kind of fabric produced. Weave patterns can create varying degrees of durability in fabrics, adding to their usefulness and also to their appearance. In a simple weave construction, consisting of the filling going under one warp and over the next, two harnesses are needed: one to lift the odd-numbered warp yarns, and econd to lift the even-numbered warp yarns. More than two harnesses are required for advanced weaves, and as many as forty for figured weaves. The three basic weaves in common use for the majority of fabrics are plain weave, twill weave, and satin weave, with some variations. Important constructions are also obtained from the following weaves: pile, double cloth, gauze, swivel, lappet, dobby, and Jacquard. 

The plain weave is the simplest of the weaves and the most common used to produce plain woven fabric. It consists of interlacing warp and filling yarns in a pattern of over one and under one. Imagine a small hand loom with the warp yarns held firmly in place. The filling yarn moves over the first warp yarn, under the second, over the third, under the fourth, and so on. In the next row, the filling yarn goes under the first warp yarn, over the second, under the third, and so on. In the third row, the filling moves over the first warp, under the second, and so on, just as it did in the first row. Plain 

Weave is the simplest and the most used weave.In a plain weave also called single weave, each warp yarn passes alternately over one and then under one filling yarn, for the whole length of the fabric. 

Characteristics of plain weave: 

• Plain weave fabrics are reversible unless some finish is given on one of the sides. 

• Fabrics made of this weave are inexpensive & easily produced. 

• Fabrics of this weave are durable. 

• Ex: Muslin, Organdy, Chiffon, Voile, Cambric etc. 

plain weave structure

The weave can be made with any type of yarn. Made with tightly twisted, single yarns that are placed close together both in the warp and filling, and with the same number of yarns in both directions, the resulting fabric will be a durable, simple, serviceable fabric. If, however, the warp were to be made from a single yarn and the filling from a colorful boucle yarn, a quite different, much more decorative fabric would result. Both are the product of the same, basic, plain weave. 

Plain-weave fabrics are constructed from many fibers and in weights ranging from light to heavy. Weaves may be balanced or unbalanced. Decorative effects can be achieved by using novelty yarns or yarns of different colors. Together with many of these novelty fabrics, a number of standard fabric types are made in the plain weave. In the past these standard fabrics were always constructed from specific fibers. At present suitable manufactured fibers are also woven into many of the standard fabric constructions.

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WEAVING; METHOD OF FABRIC MANUFACTURING

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Weaving is the most popular method of fabric manufacturing. Different types of woven fabric could be produced with this process. This post is mentioning the basic concept on weaving mechanism. Soon I will publish more articles on advance weaving mechanism. 

Fabrics can be constructed in a variety of ways, ranging from the matting together of fibrous materials to the intricate interlacing of complex yarn systems. A major method of fabric construction is weaving. Weaving is interlacing of two sets of yarns (warp & weft) at right angle. The technique probably became known before spinning. Primitive people may have observed the interlaced grasses and twigs in the nests of birds, and thus discovered how they could make clothing for themselves, baskets and nets, and thatch like huts and fences. Or they may have seen rushes naturally interlacing as they grew. Spinning developed when people discovered that the raw materials could be improved before they were woven. In the course of time, rude looms were made, which were crudely simple and handoperated. 

The modern power loom used in the textile industry today essentially performs the same operations as the simple hand-operated loom. Fabrics can be woven from yarns on a simple handloom or on a highly complex, totally automated power loom. In either case, the fabric that is produced will be made by interlacing one yarn with another. The lengthwise-direction yarns in a woven fabric are called the warp yarns or ends. Crosswise yarns are called filling yarns, weft yarns, or picks. Warp and filling yarns normally interlace with each other at right angles. 

Automation of Weaving 

To transform weaving from a hand to a mechanical operation, several conditions had to be satisfied. The various motions made in hand weaving had to be automated. The Encyclopedia of Textiles (1980) notes, “the power loom of today is essentially the hand loom adapted to rotary driving” (p. 30). A further requirement of power looms was that a power-operated loom had to stop automatically when a warp or filling yarn had broken. If the loom continued to function, the cloth would be flawed. 

The first automatic loom was devised by Edmund Cartwright in 1784. Although it had a number of defects, this loom did work well enough to demonstrate that automatic loom weaving was feasible. Gradually, inventions by different individuals each contributed to the development of an economically viable automatic loom. 

Eventually, upper limits on production speed of shuttle looms were reached. Also, shuttle looms are extremely noisy. To overcome these deficiencies, looms were invented that transported filling yarns without a shuttle. These shuttle-less weaving machines are faster and less noisy than shuttle looms. Currently, their operations are monitored by computers. 

Modern Weaving Processes 

Present-day weaving machine or looms can be divided into two major classifications: those that produce cloth in flat form and those that produce cloth in tubular form. Looms that produce flat woven cloth predominate. Flat looms can be further subdivided into two categories: 

(1)Those that use a shuttle to transport filling yarns and 

(2)Shuttle-less weaving machines, those that use some other means for carrying the filling from side to side. 

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Preparing the Warp Yarns for Weaving in loom

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Preliminary Steps for warp yarn preparation:

Before their use on the weaving loom, warp and filling yarns must be prepared for weaving. The essential characteristics of suitable warp and filling yarns differ. Warp yarns undergo greater stress and abrasion during weaving than do filling yarns; therefore, warp yarns must be strong enough to withstand these pressures. Warp yarns must be clean, free from knots, and uniform in size. A single warp yarn is called an end warp yarns are wound onto the warp beam from many cylindrical packages of yarns, which are called cheeses. To strengthen and lubricate warp yarns, sizing or slashing is added. Size is made up of starches or synthetic polymers such as polyvinyl alcohol (PVA) that act as lubricants. The yarns are passed from one warp beam through a solution of sizing material. The sized yarns are dried immediately after treatment and are wound into another warp beam. Sizing is not always required on filament yarn warps.

The warp beam containing the sized yarns is placed on the loom. In preparation for weaving, each warp end (yarn) must be threaded through its own drop wire, heddle eye, and reed dent. The drop wire is a device that will stop the loom if an end should break, the heddle eye is the opening in a heddle that carries the yarn, and the reed dent is an opening in the reed, the comb like device that will push each filling yarn close against the completed fabric.Placing the warp yarns on the loom is done either by drawing-in or by tying-in. If warp yarns from a previously woven fabric are in place and if that fabric had the same number of warps, the new warps are tied into place by attaching them to the warps already on the loom.If the new warp is different from that previously woven or if there is no warp on the loom, then the warps must be drawn-in. To draw-in or tie-in each end by hand would be enormously time consuming; therefore, a variety of machines has been developed for drawing-in. A separate machine can be used fot each step (that is, drawing through the drop wire, the heddle eye, and the reed dent), or one machine can perform all three steps. When a loom makes the same fabric, warp after warp, the new warp can be tied-in to the old.

Heddle wires are held in frames called harnesses. The number of harnesses required for the loom is determined by the weave. 

The warp beam: - warp beam, located in the back of the loom, is a large roller on which all of the warp yarns to be used for the cloth are wound parallel to each other If the fabric is to have warp stripes, the various yarns are wound onto the beam in color groupings to obtain the desired colored stripe effect.

Heddles: - Each with a hole (eye) in the middle. Each warp yarn is threaded through the eye of one heddle. Thus being controlled by that harness.

Harnesses: - The warp yarns pass through the harnesses, which look like picture frames holding many thin vertical wires called heddles, each with a hole (eye) in the middle. Each warp yarn is threaded through the eye of one heddle. Thus being controlled by that harness. The purpose of the harnesses is to raise and lower the warp yarns. The number of harnesses varies from twc to about thirty, depending upon the complexity of the weave.

Shuttle:- A shuttle is used, which is a boat-like device to carry the filling yarn on a stick called a quill or bobbin, As the shuttle moves from one side of the loom to the other, it leaves a trail of filling yarn behind it. The shuttle passes over the lower set of warp yarns and under the upper set. The shuttle stays in a box located at the end of the shed. When a bobbin becomes empty, a full one automatically replaces it.

Reed:- The reed is a frame with thin, vertical non-movable wires. Narrow openings or dents exist between the wires, the purpose of which is to keep the warp yarns separated. The reed resembles a comb and pushes the loose pick in the shed up to the edge of the already made cloth and returns to a position near the harnesses. The shuttle passes in front of the reed.

Cloth roll:- The cloth is slowly wound onto the cloth roll, located in the front of the loom.

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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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Essential Weaving Operations in loom

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Essential Weaving Operations

On the conventional loom or weaving machine, the warp beam is mounted at the back and the warp yarns are conveyed to a cylinder called the cloth roll, which is at the front of the loom and on which the fabric is rolled as it is constructed. Supported on the weaving machine frame between these two cylinders (the warp beam and the cloth beam), the warp yarns are ready to be interlaced by the filling yarns that run in the width of the cloth, thus producing the woven fabric. 

Textile yarn that is to be used for the filling must be packaged in some form that allows it to be unwound easily for transport through the shed. In shuttle looms the device that carries the yarn across the shed is called a shuttle and is made up of a wooden carrier into which a quill, or prim, is placed. The filling yarn is wound onto the quills from larger packages of yarn. For shuttle-less looms this step of winding quills is unnecessary because filling yarn is drawn directly from large packages carIn any type of weaving, four operations are fundamental. They are performed in sequence and are constantly repeated: 

• Shedding –raising specific warp yarns by means of the harness or heddle frame. The shed is formed by raising the harnesses to form an open area between the sets of warps. The formation of the shed is known as shedding. 

• Picking –inserting filling yarns through the shed. While the shed is open, the yarn is transported across the opening, laying a filling yarn across the width of the loom. The insertion of the filling is known as picking. A single filling yarn is known as a pick. Speed of weaving machines is generally expressed as the number of picks per minute, yards or meters of filling inserted per minute, or yards or meters of fabric per hour. Speed obviously is related to the width of the loom. Wider looms, weaving wider fabrics, would require more time for one filling insertion. 

• Beating Up (Battening)–pushing filling yarns firmly in place by means of the reed 

• aking up and letting off–winding the finished fabric on the cloth beam and releasing more of the warp from the warp beam. 

• Monitoring Yarn Breakage - There is always the danger that a warp or filling yarn may break during weaving, causing a flaw in the cloth. Warp yarns are threaded through drop wires, small metal plates with holes, which are drawn down when a yarn breaks or they may be monitored by electronic scanners that indicate when a yarn is broken. Through signals resulting from either the drop wires or a break in the electronic contact, the loom is shut off, allowing the broken yarn to be repaired 

YARN TRANSPORT METHODS 

The carrier used for transporting the filling yarn may differ from one kind of loom to another. The different devices used form the basis for classifying different types of looms. Within the industry many people refer to newer equipment as weaving machines rather than looms. Weaving machines vary from older, shuttle looms to modern shuttle-less machines with sophisticated electronic controls.

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