Fabric Club Of BD: Oct 29, 2010

Plain Weave

Labels: Weaving Manufacturing Technology | at 10/29/2010 01:52:00 PM

Structure

It plain weave, each weft thread (filling) passes alternatively over and under each ways 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 healed shafts.

Manufacturing

On the loom, plain weave requires only two harnesses. 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 colors or thicknesses.

Properties

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

Other Names

Tabby, Calico, alpaca and taffeta

Variations of Plain weave

1. Square plain weave

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 weave

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.

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 CLOTH

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 sodaor 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.

Voilers are used in lightweight, semi-opaque fabrics for= dress saris and light filters. Crepes are used dress, blouses and support bandages. Samples of some of the plain weaves.

PLAIN WEAVE DERIVATIVES

This group of structure comprise 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 lives in horizontal direction like =á whereas cord refers to the lines running in vertical direction ¦L¦L¦LThere 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 twocounts 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 proporation 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 interveaving 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.

Summary plain weave Rib variation

1. Structuring process

– Variation of plain weave

– Plain weave loomset up

– Different from plain weave due to warp/filling fabric yarn count unbalanced by process of packing of yarn in one direction, or by combining large and small yarns in the weave. Large yarns produce a rib or bump which may run along the warp or filling directions.

2. Identifying the weave

– Look for lengthwise cords or cross-wise ribs

– Scratch the fabric surface with finger nails to detect ridges.

3. Performance Characteristics compared to plain weave

fabrics

– More subject to yarn slippage and raveling.

– Less abrasion resistant.

– Softer.

– Crisper – if crisper yarn is used.

4. Common fibres characterized by Identifying

characteristics

· Light weight fabrics that are opaque with filament yarns tissue-faille, taffetta.

· Light weight fabrics that are translucent with spun yarns-dimity.

· Medium – to-heavy weight fabrics that are opaque with filament warp and filament or spun filling : taffeta, faille, repp, ottoman, silk broad cloth.

· Medium weight fabrics that are opaque with spun warp and filling yarns: cotton/wool broad cloth, poplin, gross grain, ottoman, Bedford cord.

MAT 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 chequred or dice effect as represented in designs below:

The simplest of there weaves is known as two-and-two and four-end matt weaves as indicated in figure, in which warp threads and picks interweave in pairs throughout the fabric, on the principle of plain weaves. Variegated or irregular matt weaves are developed by combining irregular groups of warp and weft threads on indicated in Figures P,Q, R, S and T

P = 5/3 matt irregular

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

R = Centre stiched Hopsack Derivative

S = Barley corn Hopsack.

T = Stitched Hoprack-stitching is done every where except centre.