FABRIC WEAVES AND ITS REPRESENTATION

Interlacement of warp & weft and its representation on point paper.

Design, draft and peg-plan

Plain, twill and Sateen weaves

Introduction

A fabric is a flat structure consisting of fibrous products, either natural or ″man made″. Textile

fabrics are most commonly woven but may also be produced by knitting, felting, lace making,

net making, nonwoven processes and tufting or a combination of these processes. Most fabrics

are two-dimensional but an increasing number of three-dimensional woven technical textile

structures are being developed and produced.

Woven Fabrics are composed of two sets of yarns. One set of

yarns, the warp, runs along the length of the fabric. The other

set of yarns, the fill or weft, is perpendicular to the warp.

Woven fabrics are held together by weaving the warp and the

fill yarns over and under each other.

Non woven Fabrics are made directly from individual fibers that

are matted together by forming an interlocking web of fibers

either mechanically (tangling together) or chemically (gluing,

bonding, or melting together).

Knitted Fabrics made from only one set of yarns, all running in

the same direction. Some knits have their yarns running along

the length of the fabric, while others have their yarns running

across the width of the fabric. Knit fabrics are held together by

looping the yarns around each other. Knitting creates ridges in

the resulting fabric. Wales are the ridges that run lengthwise in

the fabric; courses run crosswise.

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Fabrics

Woven Non - Woven Knitted

Woven Fabric Structure

Woven fabrics are composed of longitudinal or warp threads and transverse or weft threads,

which are interlaced with one another according to the class of structure and form of design

that are desired.

Warp (ENDS):

In woven fabric, the yarns that runs lengthwise and is interwoven with the fill (weft) yarns.

Weft (PICKS):

In woven fabric, the filling yarns that runs perpendicular to the warp yarns.

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Classification of Woven Fabric Structure:

1. Fabrics in which the ends and picks intersect one another at right angles, and in the cloth are respectively parallel with each other.

Examples: Plain, twill, satin, Extra thread, double & treble cloths

2. Cloths in which certain of the ends interweave alternately to right and to left of the adjacent ends.

Examples: Gauze & Leno

3. Pile or Plush fabrics in which a portion of the threads (either warp or weft) project from a foundation cloth and forms a nap or pile on the surface.

Examples: warp pile & weft pile

Important Loom Parts for formation of fabric structure

• Heald shaft

This part is related to the shedding mechanism. The heald shaft is made of wood or

metal such as aluminium. It carries a number of heald wires through which the ends of

the warp sheet pass. The heald shafts are also known as ‘heald frames’ or ‘heald staves’.

The number of heald shafts depends on the warp repeat of the weave.

• Sley

It is made of wood and consists of the sley race or race board, reed cap and metal

swords carried at either ends. The sley mechanism swings to and fro. It is responsible for

pushing the last pick of weft to the fell of the cloth by means of the beat up motion. The

beat up of the lastly laid pick of weft is accomplished through a metal reed attached to

the sley.

• Shuttle

It is basically a weft carrier and helps in interlacement of the weft with the warp threads

to form cloth. The shuttle which is made of wood passes from one end of the loom to

the other. It travels along the wooden sley race and passes between the top and bottom

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layers of the warp sheet. The shuttle enters a shuttle box fitted at either ends of the

loom, after passing through the warp shed. A shuttle normally weighs about 0.45 kgs.

In the latest types of shuttle-less looms the shuttle is replaced by some other means of

yarn transport across the shed.

• Reed

It is a metallic comb that is fixed to the sley with a reed cap. The reed is made of a

number of wires and the gap between wires is known as dents. Each dent can

accommodate one, two or more warp ends. The count of the reed is decided by the

number of dents in two inches. It pushes the lastly laid pick of weft to the cloth fell It

helps to maintain the position of the warp thread. It determines the openness or

closeness of the fabric.

Representation of a Weave

Woven fabrics generally consist of two sets of yarns that are interlaced and lie at right angles to

each other. The threads that run along the length of the fabric are known as warp ends. While

the threads that run from selvedge to selvedge, that is from one side to the other side of the

fabric, are weft picks. Frequently they are simply referred to as ends and picks.

A weave is the interlacing pattern of the warp and weft. Two kinds of interlacing are possible :

(i) Warp overlap in which warp is above weft

(ii) Weft overlap in which weft is above warp

When the warp is lifted above the inserted weft, a warp overlap is obtained. When the warp

thread is lowered, the weft thread is inserted above the warp thread and the weft overlap is

obtained.

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Basic elements of woven design

The three basic elements in a woven design are :

(i) Design

(ii) Draft or drawing plan

(iii) Peg or lifting plan

The design indicates the interlacement of warp and weft threads in the repeat of the design. It

is made up of a number of squares, which constitute the repeat size of a design. The vertical

direction of the squares indicate the picks and the horizontal direction indicates the ends. A

blank in a square indicates that a warp goes below the corresponding weft and ‘X’ mark in the

square indicates that the warp floats above the weft.

The draft or drawing plan indicates the manner of drawing the ends through the heald eyes and

it also denotes the number of heald shaft required for a given weave repeat. The choice of the

type of drafting plan depends upon the type of fabric woven.

The peg or lifting plan provides useful information to the weaver. It denotes the order of lifting

of heald shafts. In a peg plan the vertical spaces indicate the heald shafts and the horizontal

spaces indicate the picks. The peg plan depends upon the drafting plan. In the case of a straight

draft, the peg plan will be the same as the design. Hence no peg plan is necessary in the case of

a straight draft. The design, draft and peg plan are illustrated with the aid of an example shown

below

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Draft

Design Pegplan

DENTING PLAN

Warp ends during weaving are spaced out

across the width of the warp sheet

according to the desired density by the

wires of the reed. The most frequent

order of density is one, two, three, four

ends per dent. There are some types of

fabrics, however, which require an

irregular order of denting to emphasize

certain design feature, and in such cases

the order of arrangement of the ends in

the reed becomes an essential part of the

design and it is indicated carefully and in

the correct relationship in respect of the

weave and the draft.

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Types of Drafts

Straight draft

This is the most commonly used draft. It is the simplest of all the types of draft plans. In this

kind of draft the drafting order progresses successively from first to the last heald frame. Thus

the first warp end of a weave is drawn through the first heald shaft, the second warp through

the second heald frame and so on One important feature of the straight draft that distinguishes

it from other types of draft plans is that the peg or lifting plan is same as the design. Hence it is

sufficient to indicate only the design.

Skip draft

The skip draft is suitable for weaving fabrics having heavy warp thread

density. In this kind of draft plan the number of heald frames may be twice

or more than the minimum required for a weave. The purpose of using

more heald frames than the minimum recommended is only to distribute

the warp threads more uniformly so as to prevent abrasion of the threads

due to overcrowding

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Pointed draft

This is similar to a straight draft. It

is suitable for weaves such as

pointed twill, diamond weaves

and ordinary types of

honeycombs. The straight draft is

reversed after half the repeat

warps way. The number of heald

shafts is about half the repeat size

of the weave.

Broken draft

Here one group of threads is drawn in straight

in one direction and then another group is

drawn in straight in the opposite direction.

Where the direction is reversed the first

thread of the new series is started higher or

lower than the last thread of the preceding

series. In a cloth woven with this draft the twill

runs forward and backward in the order of

drawing-in. Thus instead of symmetrical union

of the two twill lines as obtained by pointed

draft, a break occurs in the weave.

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Divided draft

This draft is used for weaves having two series of warp threads such as terry, double cloth, warp backed cloth etc.

Grouped draftThese drafts are employed for the production of stripe and check designs, in which the stripes

have different weaves or their combinations. This draft (Fig. 2.8) is used for producing the fabric

with two different stripes. The repeat of the draft is determined by the number of stripes and

the number of threads in each stripe. The number of shafts in the draft depends upon the

number of stripes and the warp repeat of weave of each stripe.

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Types of weaves

Plain Weave

Plain weave is the simplest interlacing pattern

which can be produced. It is formed by

alternatively lifting and lowering one warp thread

across one weft thread. The plain weave has the

following characteristics:

(i) It has the maximum number of binding points

(ii) The threads interlace on alternate order of 1

up and 1 down.

(iii) The thread density is limited

(iv) Cloth thickness and mass per unit area are

limited.

Derivatives of plain weave

Rib and matt weaves are the simplest modifications of plain weave fabrics. They are produced

by lifting two or more adjoining warp threads and/or two or more adjoining picks at the same

time. It results in larger warp and/or weft covered surface areas than in a plain weave fabric. As

there are fewer yarn intersections it is possible to insert more threads into a given space, that is

to obtain a higher cover factor, without jamming the weave.

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Plain weave

Warp rib Weft rib Matt

Warp Rib

These are produced by extending the plain weave in warp wary direction. warp rib weaves can

be constructed on regular and irregular basis. Rib weaves are used in gross grain cloths,

matelasse fabrics, repp cloth which is extensively employed for window blinds in railway

carriages and other vehicles, upholstering furniture, and cambric picket handkerchief.

Weft Rib

Weft ribs also tend to be expensive to weave because of their relatively high picks per unit

length which reduces the production of the weaving machine unless two picks can be inserted

at the same time. In both the warp and weft rib weaves, the appearance of the cloth depends

on the respective thread settings. Good effects could be achieved in weft rib with a high

number of picks per inch and a comparatively low number of ends per inch. Similarly the warp

rib effect can be enhanced with a high number of ends per inch and a comparatively low

number of picks per inch. The prominence of the rib can be increased by suitable use of coarse

and fine yarns. The dependence of all rib constructions upon the correct thread settings is

marked.

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Matt weaves (or Hopsack weaves)

Simple matt (or hopsack) fabrics have a similar appearance to plain weave. The simplest of the

matt weaves is a 2/2 matt shown in figure below where two warp ends are lifted over two picks,

in other words it is like a plain weave fabric with two ends and two picks weaving in parallel.

The number of threads lifting alike can be increased to obtain 3/3 or 4/4 matt structures.

Ornamentation of plain weave

• By causing a differential tension between the warp threads during weaving.

• By using various counts of yarn for weaving different types of fabrics.

• By using warp and weft yarns of different counts in the same fabric.

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Twill weaves

A twill is a weave that repeats on three or more ends

and picks and produces diagonal lines on the face of a

fabric. Such lines generally run from selvedge to

selvedge. The direction of the diagonal lines on the

surface of the cloth are generally described as a fabric

is viewed along the warp direction. When the diagonal

lines are running upwards to the right they are ‘Z twill’

or ‘twill right’ and when they run in the opposite

direction they are ‘S twill’ or ‘twill left’.Their angle and

definition can be varied by changing the thread

spacing and/or the linear density of the warp and weft

yarns. For any construction twills will have longer

floats, fewer intersections and a more open

construction than a plain weave fabric with the same

cloth particulars. Industrial uses of twill fabrics are

mainly restricted to simple twills and only simple twills

are discussed here. Broken twills, waved twills,

herringbone twills and elongated twills are extensively

used for suiting and dress fabrics.

Classification of twill weaves

• Ordinary or continuous twills

• Zig zag , pointed or wavy twills

• Rearranged twills

• Broken twills

The above types of twills are further sub-classified as:

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Warp face twills

Weft face twills

Warp and weft face twills

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Satins and sateens

A satin is a warp-faced weave in which the binding places are arranged to produce a smooth

fabric surface free from twill lines. Satins normally have a much greater number of ends than

picks per centimetre. To avoid confusion a satin is frequently described as a ‘warp satin’. A

sateen, frequently referred to as a ‘weft sateen’, is a weft-faced weave similar to a satin with

binding places arranged to produce a smooth fabric free of twill lines. Sateens are generally

woven with a much higher number of picks than ends. Satins tend to be more popular than

sateens because it is cheaper to weave a cloth with a lower number of picks than ends. Warp

satins may be woven upside down, that is as a sateen but with a satin construction, to reduce

the tension on the harness mechanism that has to lift the warp ends. To avoid twill lines, satins

and sateens have to be constructed in a systematic manner. To construct a regular satin or

sateen weave without a twill effect a number of rules have to be observed.

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Practice Point paper

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Practice Point paper

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Practice Point paper

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