CHAPTER THREE:FABRIC DESIGN

3.1 Fundamental WeavesWeft or warp threads must have only one warp or weft overlapping within the repeat.The number of warp threads in a repeat must be equal to the number threads.There are 3 kinds of fundamental weaves:PlainTwillSateenEach weave is determined by 2 parameters:The repeat, R of weave.The shift, S of overlapping either vertical shift, Sx or Horizontal shift, Sy

3.1.2 Plain Weave

The simplest weave where the threads interlace in alternate order and classified as balanced and unbalanced.

In trade, such terms as tabby, calico, batiste are applied to plain weave fabrics.

3.1.3 Twill Weaves

The twill order of interlacing produces diagonal lines on the cloth.The purpose is to make cloth havier, closer setting and better drapping.The parameters: R 3 Sx = Sy = + 1

3.1.4 Regular Sateen and Satin and Irregular Sateen Weaves

3.1.4.1 Sateen WeavesIn pure sateen weaves the surface of the cloth consists almost entirely of weft floats.The parameters of sateen weaves: R 5; 1 < S < (R 1)For regular sateen the shift (S) and repeat (R) must be expressed by prime numbers, its called weft face fabric.The sateen weave is denoted by a fraction and the numerator of this fraction is equal to the repeat of weave.The denominator is equal to the shift (Sy) of overlaps.

3.1.4.2 Satin (Warp Face Fabric)

Usually constructed using the vertical shift (Sx).Satin has the warp effect, and the density of warp is much higher than the density of weft.

Sx=3

3.1.4.3 Irregular Sateen

Regular sateen cannot be constructed with a repeat of four or six threads, because the repeat and shift cannot be expressed by mutually prime numbers.It is impossible to construct the regular sateen if R = 6, because among the possible values of shift found from the formula 1 < S < (R - 1), i.e. 1 < S < 5, the number 2, 3, 4 have a common divisor with 6.In this case, we cannot choose a constant shift, but the sateen with a variable shift can be constructed.This sateen is called irregular sateen.4-shaft irregular sateen can be constructed by using the shifts 1, 2, 3, 2 as shown aside.6-shaft irregular sateen with constructed shifts 2, 3, 4, 4, 3, 2 as shown aside.

3.2 Derivatives of Fundamental Weaves

Constructed by means of deriving from plain, twill and sateen weaves, and retain their structural features

3.2.1 Plain Weave Derivatives

This group of structure comprises various simple weave which are varieties of the plain weave and can be produced on two heald shafts.

Warp Rep Weaves:Denoted by a fraction.The numerator shows the number of warp overlapping and the denominator, the number of weft overlapping on the same thread within repeat.Extending the plain weave vertically.

Weft Rep Weave:Opposite to warp rep weave.Extending the plain weave horizontally.Denoted by a fraction.Sum of the fraction numerator and denominator equal to the warp repeat.

Rug from Rep Weave:

Hopsack Weaves:Constructed by extending the plain weave both vertically and horizontally.There are 2 or more warp threads working in the same manner and 2 or more weft threads grouped in the same shed.Its denoted by a fraction, the numerator is the number of warp overlapping, and the denominator is that of weft overlapping on each thread.The sum of the numerator and denominator shows the repeat on warp and weft.

Fabric from Hopsack Weave:

Fabric from Hopsack Weave:

3.2.2 Weaves Constructed on Twill Bases

Regular twill are often used as the bases for the construction of new weaves.

Reinforced Twills:Warp overlaps are added to the single warp overlaps of the basic weft-face twill.The simplest reinforced twill is twill 2/2 (widely used).In producing this twill the same four shafts can be used for making the selvedges on the warp rep weave (necessary to coordinate the operation of shedding and picking mechanisms).Retain the property of the original twill.

Reinforced twill 2/2 (left hand twill, Sy = -1)

Compound Twill:It is obtained in parallel construction of two or more twill weaves on the same area.The number of shafts for producing compound twill is equal to its repeat.Retain the property of the original twill.

Fabric from compound twill:

Angled Twill:

Constructed by changing the sign of shift from plus to minus, after an assigned number of threads.With the change of sign, the direction of twill diagonal is also changed.To construct: i. Calculate its repeat ii. Weft repeat = Repeat of basic twill iii. Warp repeat can be determined by the formula, Rx = 2Kx - 2 Rx = repeat of warp Kx = number of warp threads after the sign of shift changes. Ryb = repeat of the basic twill Ky = no of weft threads after the sign of shit changes

Example:Construct the angled twill on the basis of twill 2/4. The repeat of basis twill is 6.

Answer:Ry = Ryb = 6Rx = 2Kx 2 = 2 (6) 2 = 10

Diagonal Twill:

Construct the basic twill with an increased vertical shift (to increase the inclination angle of the diagonal changes).The increase of the shift from one to two is equivalent to the doubling of warp density (practically the shift can be accepted equal to two or three).Can be constructed into 2 cases:i. The repeat of basic twill can be divided by the increased shift.Warp repeat, Rx = R SoWeft repeat, Ry = Rii. The repeat of the basic twill cannot be divided by the increased shift.

Example 1:Construct a diagonal weave on the basis of twill 4 . 4 . 1 , if Sx = 2.1 . 2 . 2

Answer:Warp repeat;Rx = R SxR = 14 = 14 2Sx = 2 = 7Weft repeat;Ry = R = 14First warp constructed according the basic twill.Second warp constructed according to the same formula but the shift equal to two, and so on.If the repeat of the basis twill is nit divided by the increased shift the diagonal weave will have repeat Rx = Ry = R.

Example 2:Construct a diagonal weave on the basis of twill 5 . 1 . 1 , if Sx= 21 . 2 . 1

Answer:In this case, Rx = 11 and Ry = 11

Fabric from diagonal twill:

Shaded Twill:

Represent a gradual transition from twill with weft effect to the twill with warp effect and vice-versa.Mostly used Jacquard weaving for large-pattern fabrics.The repeat on warp and weft for the shaded twill is determined by the formula;Warp repeat, Rx = Rxb (Rxb 1)Weft repeat, Ry = RybOnly straight draft is used.

Example:Construct a shaded twill weave on the transitions of shaded twill 1 to 4 . 4 1

Answer:Rx = Rxb (Rxb 1)= 5 (5 -1)= 5 X 4= 20Ry = Ryb= 5

Fabric from shaded twill:

3.2.3 Weaves Constructed on Sateen Bases

In simple derivatives, a new design is built up by using the original sateen as the base and adding overlaps, as required to each base overlap.

Reinforced Sateen:

Similar to reinforced twill.If it is necessary to construct the reinforced sateen on the basis of simple sateen 8/5.One more overlap should be added to every overlap of the basis sateen.Widely used in cotton weaving (additional overlaps in the repeat make the fabric structure stronger).

Shaded Sateen:

Like the shaded twill.Shaded sateen represents a gradual transition from the sateen with weft effect to the sateen with warp effect, vice versa.The repeat Ry and Ro of the shaded sateen is determined by the formula;Ry = RybRo = Rob (Rob 1)

Example:Construct a shaded sateen weave on the transitions of shaded sateen 5/3.Answer:Ry Ryb = 5Ro = Rob (Rob -1) = 5 (5 1) = 5 X 4 = 20

3.3 Combined or Fancy Weaves

These weaves are constructed on the basis of two or more fundamental weaves and their derivatives. Divided into groups of crepe weaves, honeycomb weaves, corkscrew weaves, huckaback weaves, stripe and check weaves

3.3.1 Crepe Weaves

Crepe weave are characterized by a pebbly or crinkle surface.The size of pebbles and their arrangement on the fabric surface determine the type of crepe fabric (crepe-de-chine, crepe-georgette and so on).

Georgette: Georgette describes a sheer silk (or silk-like) fabric with a dull, creped surface.

Crepe-de-chine:

Construction of Crepe by Drawing One Weave Over the Other:Choose at least two weaves (one of the weave is Sateen).Warp repeat determines the number of shafts (type of shedding motion of the loom should be taken into consideration).It is common to choose the second weave with the same repeat as the first one. If the second weave is not equal the repeat of the crepe weave is found as the least common multiple of the repeats of base weaves.

Construction of Crepe by Arranging the Warp Overlaps in Sateen Order:

Constructed on the basis of sateen weave by adding the warp overlaps.Different groups containing two or more shaded squares can be added at one of the sides of each of shaded squares arranged in sateen order.

Construction of Crepe by Rearranging Warp

Twill weave can be chosen as basic weave.The order of warp threads of the base weave should be changed.The warp repeat changed very often but the weft repeat remains. (These crepe weave can be produced on the same number of shaft).The arrangement is done by changing the position of threads on the shafts and then constructing the weaving plan.The construction begins with the lifting plan, where the crosses are placed in the same manner as the shaded squares in the base weave.The lifting plan determines the number of shafts in the draft.Arrange the warp threads on the shafts.No general rules for the arrangement of the warp threads because a variety of arrangements are possible (depends on the designer).

Example:

3.3.2 Honeycomb Weave or Cellular Fabrics

A group of weaves forms an embossed cell-like appearance of fabric. Widely used for bathroom towels, bed covers, quilts, winter garment, etc.

Example 1:The pointed draft should be drawn with the number of shafts from 4 to 8.The example used the number of shafts equals 5, A.The number of crosses for lifting plan equal to the number of circles on the draft (the arrangement similar to the position of circles).The space under the lines of crosses is filled in with crosses is filled in with crosses leaving one row of squares between the space and the lines of crosses blank.The third element, weave diagram are formed by both element; drafting and lifting plan.As a result when all the repeat combined a hollow is formed in the centre part.

Example 2:

3.3.3 Corkscrew Weaves

Kind of diagonal rib weaves.Two types of corkscrew weaves:Warp CorkscrewLong warp floats on the face and on the wrong side of the fabric.It has greater warp density compare to weft and the weave produces warp effect on both side of the fabric.Weft CorkscrewIt has a weft surface.

Warp CorkscrewConstructed on the basis of sateen weaves such as, 5/2, 7/2, 9/2, 13/2, i.e. with odd numbers of threads in the repeat.It can be considered as a derivative of sateen weave.Constructed by adding the marks on the fundamental sateen weave.

Weft CorkscrewConstructed by turning warp corkscrew into weft corkscrew weave by rotating the weave diagram by 90 and then by substituting the warp overlaps with the weft ones, and vice versa, A.The direction of diagonal ribs of the weave can be changed, if necessary, by rearranging the weft threads in the reverse order.

3.3.4 Huckaback weaves

Contains, on one hand, a number of warp and weft threads with long floats which make the fabric soft and moisture absorbent, and on the other hand, the plain weave threads which ensure the firmness of the structure.Used for bathroom towels, glass cloths, and for counterpanes.Constructed on the basis of plain weave.

Example 2:

The use of long floats in each quarter of repeat.If there are long warp floats in the left bottom and right top quarters, the long weft floats are constructed in the left top and right bottom quarters.The long warp floats on the threads 2, 4, 9 and 11 on the face of the weave.4 long weft floats are placed on the threads 3, 5, 8 and 10 where the weft thread in the place of float passes over 5 warp threads.

3.4 Compound Weaves

Compound weave fabric are of a specific structure, therefore special methods and mechanisms used in their production

3.4.1 Back Warp Weaves

It is applies when it is necessary to increase the thickness or the mass of the fabric by adding warp system.

Construction:Choose the weave of the face (the warp-faced weaves is chosen as the base weaves). Example twill 3/1, A (the base weave must have long weft floats on the back side.The warp and weft repeat of this weave equals 4.The roman digits used to mark the threads of the face weave.The section cut through the warp at the weft thread 1.The section for warp threads are represented circles of the upper row, and back warp by the circles of the lower row.Weft thread 1, is placed below warp threads 1, 2, 3 and above 4.To bind, the suitable thread is warp thread II because the point of binding is in the middle of long float of the fabric (it is also for better appearance).The weft thread 1 has to be interlaced with the warp threads of both systems.The interlacing of the weft thread 1 with the back warp at B can be transferred to the diagram C.

The face and back warp threads are arranged alternately or in the proportion of one face thread to one thread, D.The cross section of the fabric through the weft thread 1 is represented at E.The longitudinal section of the fabric through the warp threads 1 and I is shown at F.

The weaving plan is shown at G (divided draft is suitable in this case).4 front heald shafts are used for a face warp and 4 other shaft for a back warp.The ratio of the face and back warps is 1:1, 2 warp threads should be drawn in one dent of the reed (the face and back threads).

3.4.2 Back Weft Weaves

To increase either the thickness or mass of the fabric.2 systems of weft and one system of warp.

Construction:Choose either warp-faced or weft-faced weave.Long warp overlaps are necessary on the back side of the weave for binding the back weft to the fabrics.Weft-face weave should be chosen.Example, weft-faced twill 1/3,A.The longitudinal section of the fabric at warp 1 is shown at B (weft threads are arranged in 2 vertical rows).There is a long float of the warp thread on the back side of the weave.The most suitable point of binding is the middle of the long float.The interlacing of the warp and the back weft, C.

In this double weft weave, the face and back weft threads alternate with each other, D.The longitudinal section of the weave is, F and the cross section at the weft threads 1 and I, at E.

The weaving plan is shown at G. The warp repeat of this weave is 4, so the 4 heald shaft are sufficient. The straight draft is used.

3.4.3 Terry Toweling Weaves

Characterized by the formation of loops which are raised above the surface of the fabric either on one or both sides.Used for toweling, bath mats, bed covers and dress (posses good wet ability, hygroscopisity and heat conductivity).Two systems of warp threads and one system of weft threads are usually used.One warp interlacing with weft forms the ground structure.The second warp is used for forming the loops which are firmly held in the ground structure.

AConstruction:There should be two weavers beams (difference tension during weaving).The ground warp has a great tension. The warp is loosely held in the loom.The loom equipped with a special slay motion, where the first two strokes of reed are shot, but the third one is normal.The loop threads, marked by Arabic digits, alternate with ground threads which are marked by roman digits.Two warp repeats and four weft repeats, B and C.The simple base weave used to construct this terry weave.The interlacing of weft threads with the ground warp threads is shown at B, and that with loop warp threads at C.Four heald shafts are sufficient for producing this weave. The divided draft is preferable.The longitudinal section of this weave is shown at D.

Fabric in which the loops are distributed on face surface

3.5 Jacquard Weaves Large patterns fabrics using several hundreds warp threads interlacing with the same number of weft threads in the repeat equipped with a particular type of shedding motion called Jacquard machine.