What is Tapestry Weave ?

What is Tapestry Weave

Tapestry is the name given to a weave in which two basic principles are found at play:

1. The hiding of the warp with a closely packed weft to secure solid planes of color.
2. Weaving of independent weft each confined to its own area within any given pick.

The places where the two colors junction intermingle, any one of the following methods may be employed:

If the two weft picks interlock each other, it is called interlock.

If the interlocking is on alternate rows it is called single interlock.

If it is practiced on each row it is called double interlock.

If the two weft picks interlock around a common warp without simultaneously interlocking with each other, it falls within the category of dovetail tapestry.

If there is no interlocking at color junction this is called slit tapestry or Kilim.

 

Twill Variations-1

Twill Variations:

1. Regular or continuous twills

In regular twills the diagonal lines are formed by advancing the order of interlacing in step of one in either directions.

In four threads the three orders of interlacing can be made viz. ½, 2/3 and 3/1, each can be made to incline in either direction, therefore, six different effects can be formed.

2. Zig Zag or Wavy twills

Wavy twills are those in which the direction of twill is frequently reversed. Wavy twills are normally made on point drafts. The following is an example of wavy twill:

3. Herring-Bone Twills

Unlike wavy twills, the herring-bone twill does not come to a point where it changes the direction, but instead one twill line in said to cut into the other at the point of reversal.

Construction of Herring Bone twills

We will construct a simple Herring-Bone twill. We construct it on eight ends.

Step-1 :

Construct a simple, 1/3 twill on 4 ends

Step-2:

Now working of 5th end will be exactly opposite to that of 4th end i.e. where crosses are replaced by blanks in 5th end and blanks by crosses i.e

Step-3 :

Similarly working of 6th end is opposite to that of 3rd; 7th, opposite to that of 2nd and so on; so that the final herringbone twill will look like:

4. Broken twills

A large variety of effects can be produced by breaking a regular twill.

There are two ways of obtaining broken twills:

1. Break and reversal methods.

2. Entering and skipping method

1. Break and Reversal method

In this we first decide the break unit i.e after how many threads the twill will be broken. Generally it is half the number of threads in the repeat of a regular twill.

Same examples

1. 2/2 twill (break point : half the number of threads)

The regular twill is indicated as

In this case we run the twill in regular direction till half the threads, however the ends in the second half of repeat are run in reverse order:

2. 4/4 twill (Break point 2 threads)

the original twill in indicated as

There we run the twill for 2 threads, then for next 2 threads reverse it, again we run as regular twill for 2 threads and again we reverse it as shown:

2. Entering and skipping method

This method is applicable to twills that are composed of equal warp and weft floats. In this, threads in the ordinary twill are entered and skipped. Generally the number of threads to skip is one less than half the number of threads in the repeat of the twill.

Thus in a 2-and-2 twill the no of threads to skip will be 2(6/2-1) and in a 3-and-3 twill the no of threads to skip will be 3(8/2-1).

Some examples

2-and-2 twill

Step 1

Calculate the number of treads that will be taken of regular twill in order to enter and skip.

For n-and-n twill it will be (n+n) x 3

Thus for 2-and-2 twill no of threads = (2+2) x 3 = 12

Thus for 3-and-3 twill, no of threads = (3+3) x 3 = 18

Step 2

Make repeats of the no of threads calculated as above with the twill given. Thus we make 2-and-2 twill on 12 threads as:

Step 3

Now we prepare another design from this by taking 2 ends and then skipping one alternately. Thus is every 3 ends 1 end will be skipped, in 12 ends 4 ends will be skipped so design will be of 8 ends.

 

 

Introduction to Twill Weave

TWILL WEAVE

The twill order of interlacing causes diagonal lines to be formed on the cloth.

Comparison with plain weave

As comparison to plain weave, twill weave has greater weight, closer setting and better draping quality

Construction of simple twill- Step-by-Step

Step – 1 : We use a minimum of three threads (i.e. warp and weft) to construct a twill. We first try the twill 1/2 (1 up 2 down). We make a 3x3 square as:

Step – 2 : Now we start from the first end and first pick we make our first mark here (it represents the point of interaction).

Step-3:
Now in next pick the point of intersection is moved one outward and one upward as

In next pick again the point of intersection is moved one outward and one up ward as

The three steps in construction twill are as follows:

Right Hand Twills and Left Hand Twills

The twills can be produced from Right to left (also called as left hand twill) as shown in fig.

Or from left to right as ( also called as right hand twills)

The Twills can be

1. Warp faced Twill: In which quantity of warp is more on the face of the fabric eg 3/1 twill.

2. Weft faced twill: In which quantity of weft is more on the face of the fabric (e.g 1/3 twill)

3. Warp and Weft faced twill: In which warp and weft are in equal quantity on the face of the fabric (eg. 2/2 twill).

Angle of Twill

The angle formed in the cloth by a twill weave depends upon:

(a) The relative ratio of ends and picks per cm.
(b) The rate of advancement of interlacing

If the EPI and PPI are equal, a regular twill runs at an angle of 45º as shown:

In fact the angle of the twill with the horizontal can be calculated by the formula:

Tangent ( Angle) = ((Rate of Advancement of twill upwards x ends per cm)/(Rate of advancement of twill outwards x pics per cm))

Thus if
Step upward = 2
Step onward = 1
Ends/cm = 42
Picks/cm = 21
Then tan(angle of twill) = ((2 x 42)/(1x21)) thus the angle would be = 76º

As in the following twill

Factors influencing the prominence of twills

The relative prominence of twills is chiefly determined by:

(a) The character of weave
(b) The character of yarn
(c) The number of warp and weft threads per inch
(d) The direction of twill in relation to the direction of twist imparted to the yarn.

(a) The Character of Weave

A twill weaves will be relatively more pronounced if developed from longer than from shorter floats of yarn.

(b) Character of yarn

A more pronounced twill will result either from coarse spun of soft spun yarn than from fine spun or hand spun yarns; also from folded yarn than from single yarn.

(c) Number of Threads per inch

A twill will be relatively more or less pronounced in proportion to the number of warp threads and picks of weft per inch.

(d) Direction of twill with relation to the direction of twill in the yarn

If twills are produced in the reverse direction to that of the twist in the yarns, they will be more pronounced and if twills are produced in the same direction as that of the twist in the yarn, they will be less pronounced.

 

Matt, Hopsack or Basket Weaves

MATT, HOPSACK OR BASKET WEAVES


Simple matt weaves are those in which groups of two or more adjacent warp threads and picks interlace with each others so as to produce a chequered or dice effect.

Regular Matt Weaves

The simplest of these weaves is known as two-and-two and four-end matt weaves as indicated in figure above, in which warp threads and picks interweave in pairs throughout the fabric, on the principle of plain weaves.

Irregular Matt Weaves

Variegated or irregular matt weaves are developed by combining irregular groups of warp and weft threads.

P = 5/3 matt irregular

Q = Fancy basket which in combination of warp and weft Rib. 3/1, 1/3 fancy basket

R = Centre Stitched Hopsack Derivative

S = Barley corn Hopsack.

T = Stitched Hopsack-stitching is done everywhere except centre.

Further extension of Hopsack Weaves (Variegated Hopsack)

The purpose of modifying Hopsack Weaves is to make the surface more firm and to get more variety of patterns.

Self Stitched hopsack weaves.

In this weave one end is (or pair of ends) stitched down to give fancy appearance to fabric.

How to make a self stitched Hopsack

Let us take a 3-and-3 hopsack. It is represented as

We see that it is divided into four parts. To make it self-stitched , reverse the working of the centre of each small square , that is where weft is up, make it down and where warp is up make it weft up as shown in the given figure:

We can also modify the hopsack by another method. Again we take the same weave as A and reverse the float at one corner of each small square to get the required weave as shown below:

Barley Corn Weaves

The Barley Corn weaves are modified hopsack weaves which employ cross twill in their designs. The cross-twill in the designs gives a considerable degree of firmness to a cloth as compared with ordinary hopsacks of similar sizes.

Stitched Hopsacks

Stitched Hopsacks are used to impart firmness to large weaves by the introduction of plain stitching threads. In Design below the plain threads are introduced only in the warp , so that the float in the weft sections of the design are broken. This is known as Hopsack with Single Line Stitch.

Similarly we can make Hopsack with Double line Stitch in which certain threads of both series interweave plain to produce similar warp and weft sections as given below

Compared to plan weave, hopsack fabrics tend to have a softer drape and hand. They are more wrinkle resistance and permit more air to pass through them. They however, shrink more, have more yarn slippage and less abrasion resistance.

Common Fabrics classified by Identifying characteristics

• Light weight, transparent, sheer, unbalanced: dimity (also ribweave)

• Medium weight, opaque, balanced look, soft hand-oxford cloth, chambray, sail cloth.

• Heavy weight, operque, balanced look, soft hand: Hopsack, monk’s cloth.

• Heavy weight, opaque, balanced look, crisp hand: duck and canvas.
 

Plain Weave Variations- Ribs and Chords

PLAIN WEAVE VARIATIONS- Ribs and Chords

This group of structure comprises of different simple weaves which are all extensions of the plain weave and can be produced on two heald shafts.

RIB AND CORD EFFECT PRODUCED IN PLAIN WEAVE

Ribs refer to the lines in horizontal direction like ≡ whereas cord refers to the lines running in vertical direction │││There are many ways to produce rib and cords, some of these methods are as follows:

(1) By using different counts of warp and wefts

By using different counts of threads, ribbed or corded effects can be produced throughout the fabric.

The ribs or cords will be is the direction of coarsest threads. The figure illustrates an example of cloth woven from comparatively fine warp and coarse weft which develop a series of ribs lying in the direction of weft and known as warp ribs.

If we take coarse warp and fine weft, the ribs would be called the weft ribs.

(2) By using tension difference within warps and wefts

Rib formation can be also be done by taking two series of warp threads. One series of warp threads is at higher tension than the other. Only one system of coarse and soft weft is used. During weaving the warp thread from higher tension beams are held taut. Thus during weaving they are prevented from bending, as shown: This causes weft to form prominent ribs on both sides of the cloth. The slack warp threads freely bend over and under picks of weft to bind these firmly in position.

(3) By using two series of both warp and weft

In this the warp series comprise two counts of yarn, one fine and strong, which is held at greater tension during weaving, and the other coarse and soft, which is held at a lesser degree of tension. The weft series also comprise two counts of yarn one fine and strong and the other very coarse and strong.

When coarse picks are inserted, all medium warp threads only are raised to form ribs, and when fine picks are inserted, all fine warp threads only are raised, it causes deep furrows (dents) as shown in figure:

(4) By Using Normal Warp and Weft

Here we make use of the principle of fabric structure which says that “The relative prominence of threads diminishes in proportion to the amount of bending performed by them in the cloth.”

Here the ribs or cords may be formed by causing two or more threads of one series (i.e. either warp or weft) to lie closely side by side, so as to virtually constitute a coarse thread composed of several strands not twisted together, and interweaving such groups of threads with separate threads of other side.

Ribs

Simple ribs in the direction of weft may be formed by separating alternate warp threads (as in calico plain weave) and inserting two or more picks of the weft in the same warp shed. Figures shown below are designs for this class of rib weaves containing two, there, four and six picks respectively in each warp shed:

Cords

Similarly simple cords in the direction of warp may be formed by raising warp threads in uniform group of two or more threads. Figure given below are the designs for chords in which three, four and six warp threads respectively are grouped together.

As the horizontal and vertical lines produced in the above two cases are regular in size so these are known as regular warp and weft ribs respectively Figures given below represent irregular or variegated chords which are unequal in size. Similarly irregular ribs can be produced by turning these figures to sides.

Performance Characteristics of Ribs and Cords compared to plain weave fabrics

Ribs are more subject to yarn slippage and raveling. They are less abrasion resistant, softer and crisper if crisper yarn is used.

 

Plain Weave for beginners-1

In this series I would like to share with you my notes on various woven textile structure. We start from the plain weave

Structure of Plain Weave

In plain weave, each weft thread (filling) passes alternatively over and under each warp yarn in a square pattern.

Alternative names

It is also known as tabby, homespun or taffeta weave.

Manufacture

On the loom, the plain weave requires only two heald shafts.

Each weft yarn goes alternately under and over the warp yarns across the width of the fabric.

Appearance

It has a flat appearance. There are no distinct designs. However these may be produced if yarns have contrasting colours or thicknesses. The various color and weave effects that can be produced will be dealt with in another blog.

Properties

It is easily produced. This is the most made weave in the world. It is relatively inexpensive.

Variations of Plain weave

1. Square plain weaves

In such weaves, warp and weft are present in equal amounts, or in other words, warp cover factor is equal to the weft cover factor.

These are used as surgical dressings, dairy cloths, muslin dress fabrics, parachute fabrics, handkerchief fabrics, fabrics for shoes and tents, sheeting fabrics; canvas for transport covers and fabric for use as ribbons in type writers or computers.

2. Warp-faced plain weaves

In these fabrics, warp cover factor is greater than that of weft cover factor. This is normally achieved by having more ends than picks per cm. the warp crimp is also high in these fabrics, while weft crimp is low. Thus very faint lines across the width of the fabrics are produced.

A typical fabric in this group is poplin. A typical construction for a polyester/ cotton poplin shirtings is 50x25; 16 tex x 16 tex; 14% x 93% giving a weight of 130g/m2 and a cover factor of 20.0+9.7 = 29.7.

3. Weft-faced plain weaves

This is not a popular group of fabrics as it is normally produced with more than ends per cm, the rate of production in the loom will be greatly reduced. The most popular fabric in this group is the limbric, which is used for dress prints.

ORNAMENTATION OF PLAIN WEAVE

The appearance of a plain fabric can be changed in many ways.

1. The use of colour

In the warp direction, colour stripes are produced along the length of the fabric. In the filling direction, colour stripes are produced across the width of the fabric. When used in both warp and weft directions, a check effect is produced.

2. Changing yarn court

Stripes and check effects can be produced by using different yarn count in one or both directions.

3. Changing the yarn twist

Using combinations of different twist levels and directions in the warp or weft, different effects can be produced is the fabric due to the changes in the orientations of the fibers as shown.

4. Different Finishing treatment

Treatments such as dyeing mercerizing with caustic soda or coating can change the characteristics of plain fabric.

5. Any combination of the above

VOILE AND CREPE FABRICS

These are specialized types of plain weave fabrics. These fabrics are produced using highly twisted two fold yarns. with the doubling twist in the same direction as that of single yarn.

For voile yarn the tex twist factor is generally between 5000 and 7000, while for crepe yarn, it is nearer to 9000.

Voiles are used in lightweight, semi-opaque fabrics for dress saris and light filters.

Crepes are used dress, blouses and support bandages.

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Drafting and Denting Plan in Weaving Design

Systems of drafting

Apart from straight draft there are other systems of drafting which are in vogue. Some of the common ones are given as follows:

1. Skip drafts

This systems is particularly useful is weaving very densely set fabrics. Normally a small number of heald shafts is required, but to avoid overcrowding of heald eyes and to reduce friction and rubbing, more than minimum heald shafts are used.

For example, the plain weaves indicated at A may be drawn on two heald shafts as shown in B. But this works only when cloth is coarse. If the cloth is of medium fineness then plain weave may be drawn on four heald shafts as shown in C. If the cloth in very fine, the plain weave may be drawn on six heald shafts, as indicated in D.

Sateen draft

The purpose of sateen draft is similar to skip draft. It is also used to reduce friction between adjacent warp ends and to prevent overcrowding of heald eyes. But here the number of heald shaft is not increased rather the ends are staggered and placed randomly.

For example the following design employs straight draft.

However, the same design can be made using sateen draft

Notice that peg-plan is also changed.

Point draft

Point drafts are used for weaves which are symmetrical about the centre. They are frequently employed to produce waved or diamond effects.

The main advantage of the system is that is allows the production of a large number of effects with lesser number of heald shafts than those used in straight draft.

Example – Consider a design employing pointed draft as in this figure given below:

Denting plans

Denting plans describe the arrangement of the warp ends in the reed (dents are the gaps between the metal reed wires).

Denting plans depend on the number of ends per inch and the number of dents per inch in the reed.

Denting plans indicate how many inch to be put in one end of the dent.

It we place those ends which work alike in the same dent of the reed, there will be same rubbing of ends.

The prevent this, the ends which work alike are drawn through different dents.For Example, The figures A show a design and B its denting order.