Crimp based on warp and weft yarn on fabric

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CRIMP
When warp and weft yarns are interlaced in a fabric they follow a WAVE or CORRUGATED configuration, the plane of the weave being substantially perpendicular to that of the fabric. This WAVINESS OF YARN is called CRIMP of yarn and is expressed quantitatively either as a fraction, c or as a percentage, c per cent:

c = (Ly - Lf)/Lf; and, c per cent = (Ly – Lf) x 100/Lf

Where Ly = the un crimped length of the yarn, and, Lf = its extent in the fabric.

The expression c = (Ly – Lf) / Lf may be written as:

c = Ly / (Lf - 1), from which

(1 + c) = Ly / Lf;

where (1 + c) is called the crimp ratio. It is useful in fabric calculations.

MATH: Calculate the length of warp required to weave 160 yds. of cloth if the warp crimp is 12 percent.

We know,
Lf = 160 yd. and c1 percent = 12; so c1 = 0.12, where c1 is fractional warp crimp, and

Ly = Lf (1 + c) = 160 x 1.12 = 179.2 yd.

So, to prepare 160 yds of fabric 179.2 yds of warp is required.

MATH: What length of cloth can be woven from 800 yds of warp if the crimp is 8 percent?

We know
Ly = 800 Yd., and c1 percent = 8, so c1 = 0.08; where c1 is fractional warp crimp, and

Lf =Ly/(1+c) = 800/1.08 = 740.8 yds.

So, 800 yds. of warp will weave 740.8 yd of cloth.

When the shuttle inserts the weft in the open shed, the weft is un crimped, and each pick has a length Ly, which is equal to the width occupied by the warp in the reed. This is called the reed width. When it is beaten up by the reed and incorporated into the cloth at the cloth fell, the weft attempts to crimp under the scissors-like pressure exerted by the warp threads. At this stage, it is prevented from crimping freely by the temples, whose function is to hold out the cloth near the fell to reed width, so as to prevent excessive abrasion of the warp threads near each selvedge by the reed. As the cloth moves forward towards the breast beam, it leaves the temples and is free to contract to a length Lf, called loom-state width. The weft is now crimped. We have three variables, i) reed width, ii) the width of the loom-state cloth, and iii) the weft crimp in the loom-state cloth. If we know two of these variables, the third can be calculated as illustrated by the following examples.

MATH: Calculate the reed width required to give a cloth with a loom-state width of 38”, if the weft crimp in the loom-state cloth is known to be 6 percent.

We know
Lf = 38”, and c2 percent = 6; so c2 = 0.06, where c2 weft crimp, and

Ly = Lf (1 + c) = 38 x 1.06 = 40.28”

which is the required reed width.

MATH: Calculate the loom-state cloth width if the reed width is 60”, and the weft crimp is known to be 9 percent.

We know

Ly = 60” and c2 percent = 9; so c2 = 0.09, where c2 is weft crimp, and

Lf = Ly/ (1+c) = 60/1.09 = 55.05”

which is loom-state cloth width.

MATH: Calculate the weft crimp in the loom-state cloth if the reed width is 44” and the loom-state cloth width is 40”.

We know

Ly = 44”, and Lf = 40”.

Therefore (1+c) = Ly/Lf = 44/40 = 1.10, so c2 = 0.10 and c2 percent = 10

which is the weft crimp.

In any of the above examples we could substitute the width of the finished cloth for that of the loom-state cloth, provided that we also substitute the weft crimp in the finished cloth for that of the in the loom-state cloth. The calculation would be valid, if no unrecoverable shrinkage had occurred during finishing, but not, for example for a milled woolen cloth.

EFFECT OF CRIMP OF YARN ON FABRIC PROPERTIES
a) RESISTANCE TO ABRASION: With the increase of crimp %, the abrasion resistance will also increase
b) SHRINKAGE: With the increase of crimp %, shrinkage of fabric will decrease.
c) FABRIC BEHAVIOUR DURING TENSILETESTING: With the increase of crimp%, breaking load of fabric will also increase.
d) FABRIC COSTING: With the increase of crimp%, fabric costing will also increase. Because crimp decrease the length of yarn as a result more yarn will be needed for fabric manufacture in case of more crimp on yarn.
e) FAULTS IN FABRIC: If there is variation of crimp in the threads then the following faults may be found in fabric; A) Reduction in strength may occur, and B) Stripes will be seen in yarn dyed cotton fabric.
f) FABRIC DESIGN: To achieve satisfactory appearance and required shape in finished fabric control of crimp in warp and weft yarn is necessary..
g) FABRIC STIFFNESS: If crimp is increased then stiffness of fabric will decrease.
h) ABSORBENCY: With the increase of crimp % absorbency of the fabric will increase.
i) DIMENSIONAL STABILITY: Dimensional stability will decrease with the increase of crimp%.
j) FABRIC HANDLE: If crimp is increased then the fabric will be soft in handle.
k) DYE TAKE-UP: With the increase of crimp the take-up percentage of dye-uptake will also increase.

Wish You Good Luck..................................
You Should Interested to read RELATED POST on the topics

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Pile Weave; Produce woven fabric with Warp Pile and Filling Pile

Pile Weave

Extra sets of warps or fillings are woven over ground yarns of plain or twill weave to form loops. Pile fabrics have been defined as “fabrics(s) with cut or uncut loops which stand up densely on the surface” (Klapper 1967,64). Pile fabrics may be created by weaving or through other construction techniques, such as tufting, knitting, or stitch through. To create the loops that appear on the surface of woven pile fabrics, the weaving process incorporates an extra set of yarns that form the pile. Construction of woven pile fabrics, therefore, represents a complex form of weaving in which there are at least three sets of yarns. 

Woven pile fabrics are divided into two categories depending on whether the extra set of yarns is in the warp direction or the filling direction. Warp pile fabrics have two sets of warp yarns and one set of filling yarns. Filling pile fabrics have two sets of filling yarns. Pile fabrics are woven by one of several methods, depending on whether they are warp pile or filling pile fabrics. 

Warp Pile Fabrics 

Warp pile can be made by the wire method, the double-cloth method, or by slack tension weaving.In the wire method one set of warp yarns and the filling yarn interlace in the usual manner and form the “ground” fabric in either a plain or twill weave. The extra set of warp yarns forms the pile. When the pile yarns are raised by the heddles, the machine inserts a wire across the loom in the filling direction. When the warps are lowered, they loop over the wire to make a raised area. The next several filling yarns are inserted in the usual manner. The wire is then withdrawn, leaving the loop, which is held firmly in place by the other yarns. Frieze, a fabric often used for upholstery, is an example of an uncut, looped pile fabric that can be made by the wire method. If the fabric is to have a cut pile, the wire has a knife blade at the end that cuts the yarns as the wire is withdrawn. 

Velvets may be made in this way. If the fabric is to have an uncut pile, the wire has no cutting edge. The double-cloth method is used for cut pile fabrics. Here, two sets of warps and two sets of fillings are woven simultaneously into a layer of fabric. A third set of warp yarns moves back and forth between the two layers of fabric, holding them together and being held by each fabric. The resultant fabric is cUt apart by a sharp knife, thereby creating two lengths of fabric, each with a cut pile. Velvets and flushes can be made with the double-cloth method. Velvets are usually made of filament yarns. Other nonpile fabrics can be made by the double-cloth method, and are discussed later.Terry cloth is made by the slack tension method. Terry cloth is made with uncut loops. Usually, two sets of warps and one set of filling yarns are used; however, more expensive fabrics may use two sets of yarns in each direction. The ground of the fabric is of warp yarns held under tension, the pile of warp yarns that are allowed to relax. 

Periodically (usually after every three picks), tension is released on the warp pile yarns at the same time as the next three filling yarns are pushed firmly into place. The first two of each three picks are only beaten up part way. The loose warp yarns loop up on the surface to form the terry pile. Loops may remain uncut to form the traditional terry cloth with loops on both sides. 

Sometimes one side is sheared to make an attractive velour face. Such fabrics do not wear as well as uncut loop fabrics. Pile yarns in velour toweling tend to become dislodged more easily, thereby shortening the wear life of the material. Terry pile may appear on one or both sides of the fabric. 

Filling Pile Fabrics 

Filling pile fabrics are woven by the filling pile method. In this method there are two sets of filling yarns and one set of warp yarns. The extra set of filling yarns forms floats that are from four to six yarns in length. The floating yarns are cut at the center of the float, and these ends are brushed up on the surface of the fabric. In some filling pile constructions, the filling yarn that makes the pile is interlaced with the ground one time before it is cut;’ in others, the filling pile interlaces twice. Those fabrics in which there are two interlacings are more durable than when only one interlacing has taken place. Floats for corduroy are placed in lengthwise rows, and floats for velveteen are spaced to produce an overall pile effect. Velveteens are characterized by a uniform, overall pile. The even spacing of corduroy floats produces a strip or wale characteristic of this fabric 

Corduroys are given names according to the numbers of wales. Feathercord corduroy has about 20 to 25 lengthwise wales per inch; fine wale or pinwale corduroy, about 16 to 23 wales; mid, medium, or regular wale corduroy, about 14 wales; wide wale corduroy, about 6 to 10 wales; and broad wale corduroy, about 3 to 5 ribs per inch. Novelty wale corduroys are also produced in which thick and thin wales are arranged in varying patterns. Some corduroy fabrics are now made with 100 percent cotton yarns in the pile filling and polyester and cotton blends in the ground yarns. Other decorative effects can be achieved by cutting floats selectively to vary pattern and texture. Most filling pile fabrics are made from spun yarns.

Variations of the Weaves; Different types of special woven fabric

Variations of the Basic Weaves

Dobby Fabrics 

The dobby weave is like a jacquard weave in miniature. The Dobby weaves have small, repeated patterns, that are usually geometric. The following are some of the fabrics made on the dobby loom. 

1. Birds eye, a cloth made with small diamond-shaped figures, has a weave that is said to resemble the eye of a bird. Bird’s eye is also called diaper cloth. 

2. Pique is a medium- to heavyweight fabric, often of cotton, with a pronounced lengthwise cord, often combined with other small figures or patterns such as honeycomb or waffle effects. 

3. White-on-white has a white dobby figure woven on a white background and is often used for men’s shirting. 

Jacquard Fabrics 

Jacquard patterns, when carefully analyzed, may be seen to contain combinations of plain, twill, and satin weaves, even in the same crosswise yarn. Many decorative fabrics are made by the jacquard technique. Jacquard-woven tapestry fabrics should not be confused with true tapestries (see below) even though some fashion promotions may refer to jacquard fabrics as “tapestry fabrics.” 

The following are some of the best-known jacquard patterns. 

1. Brocade features an embossed or embroidered appearance. Elaborate patterns, often of flowers and figures, stand out from the background. Pattern and ground are usually different weaves. Brocades are made from a wide range of fibers and with a wide range of price and quality. Fabrics are used for upholstery, draperies, and evening and formal clothing. 

2. Brocatelle is similar to brocade, but with figures or patterns standing in high relief Brocatelle is used mostly for upholstery fabrics and draperies. 

3. Damask is a flatter fabric than brocade and often has a fine weave. Damask figures often use a satin weave to reflect light from the pattern, whereas the background is made in a plain or twill construction. Linen damasks have long been used for luxurious tablecloths. Damasks are reversible. Cotton and linen damasks are made either with four-yarn float or a seven-yarn float in the satin weave. The longer floats are more lustrous, but the shorter floats are more durable, as they are less likely to snag or be subject to abrasion. 

4. Tapestry-like fabrics have an appearance that simulates handwoven tapestries. Used extensively in fabrics for interiors, these jacquard-woven fabrics have highly patterned designs on the face. Although the back is also figured, the colors within the design differ. For example, a leaf that appears on the face as green will be some other color on the back.

Others Variations of Weaves 

Leno or Gauze Weave: 

In leno or gauze weave pairs of warps are twisted over each other with each passing of filling yarn. The leno weave is the modern descendant of a technique called twining that was used thousands of years ago for making fabrics. In leno-weave fabrics, the warp yarns are paired. A special attachment, the doup or leno attachment, crosses or laps the paired warp yarns over each other, while the filling passes through the opening between the two warp yarns. Leno-weave fabrics are made in open, gauzelike constructions. The twined (not twisted) warp yarns prevent the filling yarns of these open fabrics from slipping. Curtain fabrics are often made with leno weave. Two of the more popular leno-weave fabrics are marquisette and grenadine. Many fruit sacks are leno-woven of slit films 

Characteristics: 

• Open-mesh appearance with yarns securely held 

• Sheer but durable for its weight 

• Ex: Grenadine, Marquisette 

5. Pile Weave: 

Extra sets of warps or fillings are woven over ground yarns of plain or twill weave to form loops. Pile fabrics have been defined as “fabrics(s) with cut or uncut loops which stand up densely on the surface” (Klapper 1967,64). Pile fabrics may be created by weaving or through other construction techniques, such as tufting, knitting, or stitch through. 

There are two types of pile fabric
1. Filling Pile Fabrics
2. Warp Pile Fabrics

6. Swivel Weave: 

The swivel weave is the method by which decorative effects, such as dots, circles, or other figures, are interwoven on the surface of a fabric while it is being constructed on the loom. The weaving of the design requires an extra filling yarn and additional small shuttles or insertion devices. Similar fabrics can be made in the swivel weave, which is sometimes used in decorative fabrics for interiors. The design is made by supplying an extra filling yarn on a small shuttle or swivel. The filling design yarns are carried several times around a group of warps by the motion of the swivel to prevent the yarn from pulling out ofthe background fabric. The long floats between designs are knotted and clipped off. Occasionally, imported dotted Swiss fabrics may use a swivel weave rather than a clipped spot weave. The swivel weave is more durable than the clipped spot weave because the design yarns are woven in and cannot pull out of the fabric as easily as in the latter method. When the floats at the back have been cut away they are called clipped swivel patterns 

6. Lappet Weave: 

Lappet weave is also used to superimpose a small design on the surface of a fabric while it is begin woven. In the lappet weave, the design is stitched into the fabric by needles that operate at right angles to the construction. Thus the lappet weave is very similar to embroidery. Lappet weaves have an extra warp yarn that may interlace in both the warp and filling direction with the ground fabric. The extra set of warps is threaded through needles set in front of the reed. The yarns are carried in a zigzag direction, back and forth to form an embroidery like design. 

The design is created on the right side of the fabric, the excess yarn being carried along on the wrong side. Extra yarn is not clipped away from the back of the fabric but can be seen as it is carried from one design area to another. 

7. Dobby Weave: 

The dobby weave is a patterned weave used to construct small. Geometric designs composed of short floats created on a loom by a special attachment called a dobby, which raise or lowers as many as twenty-four to forty harnesses. The design is usually small and does not make use of long floats. 

8. Jacquared Weave: 

A jacquard pattern is a design, which contains very detailed, unlimited range of intricate designs. Any combination of weaves and patterns is possible.Since these designs exceed the capacity of the harness looms, a special loom called a Jacquard looms, a special loom called a Jacquard loom is used. Here, each warp is individually controlled. Almost any design desired can be made. Durability depends upon weave and yarn. E.g.: Brocade, tapestry, damask

Novelty Fabrics from Basic Weaves

Novelty effects in fabrics are in large part a result of selection of novelty yarns for incorporation into fabrics made in one of the basic weaves. 

Crepe Fabrics 

Crepe weave fabrics is special novelty fabrics from basic weaves may be defined as fabrics characterized by a crinkled, pebbly surface. Originally, crepe fabrics were made from crepe yarns, that is, yarns with an exceptionally high degree of twist, up to sixty-five turns per inch. Most standard crepe fabrics were made in the plain weave, some with rib effects, and some in satin weave, as in crepe-backed satin. With the advent of synthetic fibers, however, many crepe effects are achieved through the use of textured yarns, bicomponent yarns in which uneven shrinkage creates a crepe like surface, or embossing or stamping a crepe like texture on the surface of the fabric. Most fabrics made from these more recent processes will be durable only if they are made from heat-treated thermoplastic fibers. Another method uses a special crepe weave that breaks up the surface of the cloth into a random sequence of interlacings. Careful examination of fabrics having a crepe like appearance will reveal that relatively few of them are actually woven with crepe yarns. 

Seersucker 

Seersucker, another plain-weave fabric, is created by holding some warp yarns at tight tension, some at slack tension. Those at slack tension puff up to form a sort of “blister effect.” Seersucker surface effects are permanent. Often the slack and tight yarns are each made from a different colored yarn, to provide a decorative striped effect. Seersucker should not be confused with fabrics having puffed effects created by chemical finishes, such as plisse or embossing, which are much less durable. 

Hand-Woven Tapestries 

Tapestries woven by traditional methods differ from jacquardwoven fabrics having the appearance of a tapestry in that the traditionally woven tapestries are made using hand techniques. Jacquard-woven tapestry fabrics generally use repeated patterns of finite size. Traditional tapestry weaving is used to produce enormous fabrics that can form one large picture. Tapestry weaving may be compared to painting with yarn. Since it is basically a hand technique, tapestry is made on an elementary loom. 

In the weaving of European tapestries, the loom followed the basic form of the two-bar loom. The loom was set up either vertically or horizontally, and warp yarns were measured and affixed to the loom. Filling yarns were prepared in the appropriate colors. The design of the tapestry was first worked out in a drawing, or cartoon, as it was called. The artist who created the drawing may have been one of great stature, and painters such as Raphael and Rubens served as designers of sixteenth- and seventeenthcentury tapestries. The cartoon was sometimes traced onto the warp yarns. In other instances it was mounted behind the loom, and the tapestry weaver looked through the warp yarns to the design, following the plan of the drawing. The tapestry was woven with the wrong side facing the weaver. Sometimes a mirror was set up beneath the tapestry so that the weaver could check the progress on the right side. The various colors of yarns were wound onto sharp, pointed bobbins that were introduced into the warp, and the weaver proceeded to fill in the area of that particular color. When the weaver reached the end of one color, a new bobbin was used for the next section. This created a problem, because as the weaver worked back and forth in a particular segment of the 

design, the yarns of one color did not join with the yarns of the adjacent color. This produced slits in the fabric at the place where each new color began. Sections of the tapestry could be sewn shut, but this caused the fabric to be weaker at the spots where the fabric was seamed together. Two other methods were also used to prevent the formation of slits. Where the color of one section ended and another began, both the old and the new color could be twisted around the same warp yarns. This system worked well except that it created a slightlyindistinct or shadowy line. Where clear, well-defined lines were required, the yarns of adjacent colors were fastened together by looping one yarn around the other.In traditional tapestry weaving, all the warp yarns are completely covered by filling yarns, so it is the filling yarns that carry the design. The warp yarns serve only as the base.

Satin Weave; Produce woven fabric with Warp faced satin weave and Weft-faced Satin (Sateen) weave

Weft-faced Satin (Sateen) weave

It is characterized by long floats on the surface of the fabric. In basic construction, the satin weave is similar to twill weave but floats in satin fabric may cross from four to twelve yarns before interlacing with another yarn. No pronounced diagonal line is formed on the surface of the fabric because the points of intersection are spaced in such a way that no regular progression is formed from one yarn to that lying next to it. When warp yarns form the floats on the face of the fabric, the fabric is a warp-faced satin. They are usually made from filament yarns and are called SATINS. When filling yarns float on the face, the fabric is a filling-faced satin. This is called SATEEN WEAVE Satin-weave fabrics are made by allowing yarns to float over a number of yarns from the opposite direction. Interlacing are made at intervals such as over four, under one (using five harnesses); over seven, under one (eight harnesses); or over eleven, under one (twelve harnesses). Floats in satin fabrics may cross from four to twelve yarns before interlacing with another yarn. No pronounced diagonal line is formed on the surface of the fabric because the points of intersection are spaced in such a way that no regular progression is formed from one yarn to that lying next to it.When warp yarns form the floats on the face of the fabric, the fabric is a warp faced satin. 

When filling yarns float on the face, the fabric is a filling faced satin. Satin-weave fabrics made from filament yarns are called satins; those from spun yarns are sateen. Most warp-faced weaves have filament yarns because filament yarns do not require a tight twist to serve as warp yarns, whereas cotton, being a staple fiber, must be given a fairly high degree of twist if it is to serve as a strong warp yarn. Therefore, sateen fabrics are usually filling faced, although some warp sateens are made. 

Warp faced satin weave Weft faced satin

Satin-weave fabrics are highly decorative. They are usually made from filament yarns with high luster to produce a shiny, lustrous surface and tend to have high fabric counts. They are smooth and slippery in texture and tend to shed dirt easily. The long floats on the surface are, of course, subject to abrasion and snagging. The longer the float, the greater the likelihood of snags and pulls. Satins are often used as lining fabrics for coats and suits because they slide easily over other fabrics. The durability of satin-weave fabrics is related to the density of the weave, with closely woven, high count fabrics having good durability. Satins made from stronger fibers are, of course, more durable than those made from weaker fibers. 

The following are some names given to satin fabrics. 

1. Antique satin, a satin made to imitate silk satin of an earlier period, often uses slubbed filling yarns for decorative effect. 

2. Peau de soie is a soft, closely woven satin with a flat, mellow luster. 

3. Slipper satin is a strong, compact satin, heavy in weight. It is often used for evening shoes. 4. In crepe-backed satin, loosely twisted, lustrous warp yarns are combined with tightly twisted, creped filling yarns. The floats on the surface are created by the warp, so that the face of the fabric is chiefly made up of warp yarns with a satin appearance, whereas the back of the fabric is made up largely of tightly twisted filling yarns that produce a crepe or rougher surface texture with a flat, less shiny appearance.

• Satin weaves are lustrous because of more yarn showing on surface 

• Fabric is comparatively weaker due to long floats, which represents minimum of interlacing. 

• Satin weave has a distinctive reversible side 

• Excellent drapability 

• Easily to slip on and off the fabric i.e. the fabric is smooth to touch that’s why used as lining material also 

• Ex: Satin, Sateen, etc.

Selvags, Two edge of woven fabric

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Selvags
Selvage is one of the most important parts of woven fabric. It plays vital roles during weaving. Selvage could be defined as the two end of the woven fabric width or the edge of woven fabric. This is different from main fabric. Most of the selvage made with strong thread like nylon thread. It holds the woven fabric and helps to maintain the shape of fabric. It takes all the pressure of weaving machine and protect the fabric from damage.
Selvags (Selvedges) As the shuttle moves back and forth across the width of the shed, it weaves a self-edge called the selvage, or selvedge, on each side of the woven fabric. The selvage prevents the woven fabric from raveling. 

It is usually made more compact and stronger than the rest of the woven fabric by using more or heavier warp yarns or by using a stronger weave. There are different kinds of selvages. The kind of selvage used depends upon economy of production and the expected use of the woven fabric. 

Plain Selvages 

These selvages are constructed of the simple plain weave with the same size yarn as the rest of the fabric, but with the threads packed more closely together. Such selvages are fairly durable and firm. 

Tape Selvages 

The tape selvages are sometimes constructed with the plain weave but often are made of the basket weave, which makes a flatter edge. Tape selvages are made of heavier yarns or ply yarns, which provide greater strength. 

Split Selvages 

Split selvages are made by weaving a narrow width fabric twice its ordinary width with two selvages in the center. The woven fabric is then cut between the selvages, and the cut edges are finished with a chain stitch or hem. 

Fused Selvages 

These selvages are made on fabrics of thermoplastic fibers, such as nylon, by heating the edges of the fabric. The fibers melt and fuse together, sealing the edges. This technique is sometimes used to split wide fabrics into narrower widths. 

Leno Selvage 

The leno selvage is used on some shuttle less looms as well as weaving machine. The construction utilizes a narrow leno weave, which locks the cut ends along the fabric edge. A loose weave generally requires a tight leno selvage, whereas a light weave may have a leno selvage with less tension. 

Tucked Selvage 

The tucked selvage is a technique used on some shuttle less looms. A device is used to tuck and hold the cut ends into the fabric edge. The construction of the selvage is dependent upon the particular weave and a number of other factors. A formula for weaving the tucked selvage considers fiber density, the diameter of the yarns (which is also affected by twist, ply, and count variation), as well as the yarn diameter balance, or ratio of the diameter of the filling yarn to that of the warp yarn in effect, if the diameter of the filling yarn is finer than the diameter of the warp yarn, fewer fillings can be inserted in themfabric selvage, because the warp intersection requires more space between the fillings than one diameter of the filling.

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