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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