Friday, November 2, 2018

FABRIC PARAMETERS, FABRIC SPECIFICATIONS

WOVEN FABRIC:

The woven fabric results after the interlacement of two series of yarn. The two different yarn are interlaced to each other at a right angle.  There two types of yarn lie in the fabric. The yarn running in longitudinal (vertical) direction or along with the direction of the length of the fabric is called warp. The yarn running in transverse (horizontal or along the width of the fabric) direction is called weft or filling.
 The warp and weft interlace to each other in the fabric according to design at always a right angle. The design pattern is referred to as weave.

FABRIC PARAMETERS:

The fabric parameters are the specifications of the fabric which are necessary to know before the start of weaving. If a weaver has all parameters of a fabric, he can start weaving without sample swatch of fabric. Fabric parameters are very important to a weaver. He can weave a fabric precisely if he knows all fabric parameters. A fabric consumer can place his order to weaver even he does not have sample swatch physically. Weaver can calculate the weight of the fabric and can calculate the raw material cost (yarn cost) with the help of these fabric parameters.
The main parameters of the fabric are given below:

·       Warp count

·       Weft count

·       Ends per unit length

·       Picks per unit length

·       Width of the fabric

·       Weight per square meter or yard

·       Warp crimp

·       Weft crimp

·       Weave

·       Denting order

·       Type of selvedge

·       Warp pattern

·       Weft pattern

·       Others special effect

Warp count:  

The yarn running in longitudinal or vertical direction is called warp. Yarn count using in the warp yarn is referred to as warp count.

Weft count: 

The transverse or horizontal yarn in the fabric is called weft or filling. The yarn count using in the weft yarn is referred to as weft count.

Ends per unit length:  

The individual (one) yarn of warp in the fabric is called end. The number of vertical or longitudinal yarns or threads per unit length in the fabric is referred to as ends per unit length. It is measured in ends per inch, ends per centimeter and ends per decimetre.

Picks per unit length: 

The individual (one) yarn or thread of the weft yarn is called a pick. the number of horizontal or transverse yarn or threads per unit length in the fabric is referred as picks per unit length. It is measured in picks per inch, picks per centimeter and picks per decimeter.

Fabric width: 

It is measured in inches, centimeters or meters etc. The distance between both the selvedge of the fabric is called fabric width.

Weight per square meter or yard: 

It is a very important parameter of the fabric. it is measured in grams, ounces, and pounds etc. This term is widely used to refer to the quality of the fabric. If the weight of one square meter of the fabric is measured in grams then it is called GSM of the fabric. If the weight of one square yard of the fabric is measured in grams then it is called GYM of the fabric. The weight of one square meter or yard is also measured in lbs. and ounces.

Warp crimp: 

It is expressed in the term of percentage. When the fabric is woven, the warp threads shrink because of interlacing of weft. If we weave one meter of fabric, more than one meter of warp length will be required to weave this one meter of the fabric.

Or

How much length of the fabric will a weaver get after weaving in one meter of warp length?
This is expressed in term of percentage.
There are two terms used to express the warp crimp:

1 – warp contraction

2 – warp regain

1 - warp contraction:  

The warp contraction % tell us how much length of warp will shrink after weaving. suppose a weaver make a warp beam of 1000 meter length after weaving he gets 950 meters of the fabric. Thus 50 meters warp contracted after weaving. The warp contraction in term of percentage will be:



Thus we can say that the ratio of warp crimp (the difference between warp length and fabric length woven)  to warp length in term of percentage is called warp contraction.
If we have the swatch of the fabric, we can determine the warp contraction %. The length of the swatch ( warp-wise) is measured first, then the warp end is taken out from the fabric swatch. This warp end is straightened and its length is measured. Now we can determine the warp contraction%:




2 - Warp regain: 

The warp regain tells us how much warp length will be required to weave one meter of the fabric.

Suppose a weaver has to weave 950 meters of the fabric and he consumes 1000 meters of warp length to weave this fabric. Weaver requires 50 meters extra warp length to weave 950 meters of the fabric length. The warp regain in term of percentage will be:


Thus we can say that warp regain is the ratio of warp crimp (the difference between warp length and fabric length) to fabric length in the term of % is called warp regain.

If we have the fabric swatch, we can determine the warp regain by using below formula:


Warp contraction and warp regain both very import parameters for a weaver. The warp regains percentage is used to determine the warp weight to be consumed to weave one meter of the fabric of given width. The weaver's beam length is also decided to weave a required length of the fabric.
The warp contraction percentage is helpful to determine the fabric length to be woven in certain weavers beam length. Weaver should always be careful when he determines these terms. Any negligence can cause financial loss to him. If Weaver has to weave yarn dyed fabric, he may come in very big trouble. The actual yarn requirement will change. It will be very difficult to arrange dyed yarn if yarn consumption increases due to incorrect determination of warp regain.

Weft crimp: 

It is expressed in the term of percentage. It is the ratio of difference (between straightened pick length and fabric width) to fabric width expressed in the term of percentage is called weft crimp. This term may also know as weft regain.

Suppose that a weaver needs 100 inches wide fabric.

Take out a full pick of fabric, make it straight completely. Now measure the length of a straightened pick in inches, say it is 105 inches. The weft crimp will be determined as follows:


By determining this term, a weaver decides the reed space to be used to weave a given fabric width. This term is very important. It is also used to determine the weft of the fabric. The weft crimp should always be determined carefully and precisely. Any types of negligence during the determination of weft crimp cause serious trouble to the weaver. The fabric width to be woven will directly be affected if this parameter does not determine correctly.
Note: the weft crimp plays a decisive role in the selection of reed count to be used on the loom.

Weave: 

The sequence of interlacement of warp and weft is referred to as weave. It is a very important parameter.

A weaver should always analyze the weave of the fabric swatch before accepting any weaving order.  A weaver knows his looms specifications. If weave of the fabric is within the range of his loom specifications, he can accept weaving order. The weave of the fabric also plays an important role in respect of the cost of production and loom productivity. If the number of heald shafts required to weave a fabric increases, the efficiency of loom decreases and the cost of production also go up.

Denting order: 

The sequence of passing the ends through the dents of the reed is called denting order.
It is a very important parameter of the fabric. Incorrect denting order changes the look of the resulted fabric. The denting order is always observed very carefully. Denting order plays a full role in the selection of reed count to be used on the loom.

Type of selvedge: 

In today’s weaving technology, three type of selvedge are possible ie. Conventional selvedge, tucking-in selvedge and leno selvedge. Therefore it is necessary to know the type of selvedge in the fabric before accepting the weaving order.  

Suppose that a buyer is asking to weave a fabric for the bed spread. He also wants to reduce his product cost, in this case, the selvedge of the fabric can play a very important role to reduce the product cost. A weaver can suggest to the buyer for tucking-in selvedge if Weaver is weaving the fabric on shuttle less loom. Thus the buyer can reduce the fabric consumption and can save stitching cost of two sides.

Warp pattern: 

When the multi-color (stipe or check fabric) warp is used to weave the fabric, the sequence of colors in the warp is determined.

Since a weaver knows his warping machine specification, therefore he can accept or reject the weaving order. If the warp pattern is beyond the limit of creel capacity of warping machine, it will not be possible to insert such type of warp pattern in weavers beam.

Weft pattern: 

In the multi-color weft fabric, the sequence of colors in the weft of the fabrics is referred to as weft pattern.

The sequence of weft pattern is determined before accepting the weaving order. If the number of colors used in the weft yarn is within the range of loom specifications, the weaver can accept the weaving order.

Other special effects:  

Many special effects can be created in the fabric by using different techniques. Pleated and sheer sucker fabrics are produced by using two different series of warp. Variable pick density can be used in the fabric also. Special effects can be produced by making take-up motion inoperative.

If the fabric has any special effect, it can be analyzed precisely before accepting the weaving order.

Suppose that there is a sheer sucker or pleated effect in the fabric, the loom should be equipped with double beams and programmable pick density (cramming motion). Variable pick density and variable denting order can create a check effect in the fabric. These special effects present in the fabric widely influence the cost of production in weaving.

You may also interested in following articles:

New English count ( Ne), an indirect yarn count system

Ring frame process and it's objectives

Fabric defects due to yarn faults

Handle of the fabric

Pilling in the fabric

You may also be interested in below sponsored links:

3 comments:

  1. EXCELLENT BASIC DATA FOR TEXTILE BEGINNERS..STILL NEED TO ADD BASIC DATA REGARDING KNITTED AND NON WOVEN TEXTILES..

    ReplyDelete

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