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Wednesday, August 19, 2015

A Fresh Approach to Fabric Quality Assessment

A Fresh Approach to Fabric Quality Assessment



Abstract

At present there is no unanimity in the assessment of fabric quality among various groups- Manufacturers, Traders, Standards Organizations, Government Departments, Research Organizations, Technologists, Engineers, Educationists, Students, etc., even though all are interested in assisting the ultimate beneficiary-the customer to select the best quality fabric at affordable price. This leads us to ponder over the question, “What is Quality?” A fresh approach is made here to assess the Fabric Quality, based on fabric texture, irrespective of material used, fabric structure, fabric condition, end use and country of manufacture, evaluate the fabric in terms of total score and thereafter assign Fabric Quality Grade (FQG).

Introduction

When a customer goes to a show room or a shop to choose a fabric to meet his/her requirement, he/she is flabbergasted by the different varieties of fabrics displayed on the table or in the shelves, and is totally confused as to which one he/she should select. A sales man/girl further adds to the confusion, stating every one of the goods is of good quality and inferior quality goods are not stocked in the stores. Ultimately the customer purchases a fabric to suit his/her purse rather than the need, irrespective of the quality of the fabric he/she has purchased.

What is Quality?                          

When a customer wants to purchase a fabric, what does he/she expect to find in it? Is it the material, look, colour, design, luster, smoothness, thickness, weight, fineness, flexibility, drape, durability, brand, labeling, or cost? Some of these are measurable characteristics, while others are aesthetic. As the saying goes “quality is what the customer wants and it is duty of the manufacturer to build into the fabric what the customer is looking for and to satisfy his/her needs. This has resulted in the production of innumerable varieties of the same type of fabric and their flooding the market. Who should assess the quality of the fabric and how can the customer be assisted in the selection of the fabric by properly grading the fabric for quality?



Assessment of Fabric Quality

Way back in September 1949 W.A. Graham Clark1, former Chief, Textile Division; U.S. Tariff Commission suggested the adoption of BYT (effective yards of yarn per pound of cloth) value as the basis of classification of fabrics into 14 groups. F.T. Peirce2 in his classic paper published in March 1937 introduced the concept of cover factors (on the lines of the twist factors for yarns) to assess fabric quality. John B. Dickson3  introduced in 1954 the concept of weight factors to produce the fabrics of

similar quality.

By choosing easily measurable characteristics of fabrics, based on fabric texture, irrespective of fabric structure, fabric condition, material used and the end use of the fabric, it is possible to assess the fabric quality. The characteristics identified for such assessment are (1). Average Count, (2) Fabric Weight, (3) Cover Factors, (4) Weight Factors, (5) Fabric Thickness and (6) Fabric Condition.


Classification of Fabrics

Fabrics are classified as follows:



1. Average Count as Coarse, Medium, Medium Fine, Fine, Extra Fine


Average Count
Coarse

Medium
Medium Fine
Fine
Extra Fine

Na
≤17.857

17.858~
35.715~
59.525~
95.239~







35.714
59.524
95.238
190.476
2. Fabric Weight as Light, Medium, Heavy.





















Weight

Light
Medium

Heavy





W(oz/Sq.Yd)

<4 span="">

4~<8 span="">

≥8





W1 (gsm)

<135 .624="" span="">
135.624~<271 .249="" span="">

≥271.249

3. Cover Factors: as too openly Set, Openly Set, Closely Set, Too Closely Set















Too Openly Set
K
<5 span="">
K1+K2

<10 span="">






Openly Set
K 5<11 span="">
K1+K2

10<22 span="">






Closely Set
K 11<18 span="">
K1+K2

22<36 span="">






Too Closely Set
K
>18
K1+K2

>36


























4. Weight Factor Ratio: as Weft-Faced, Approximately Equal –Faced, Warp-Faced.


Weft-Faced

w1/w2

<0 .7656="" span="">


Approximately Equal-Faced
w1/w2

0.7656~1.2656

Warp-Faced

w1/w2

>1.2656

5. Fabric Thickness: as Thin, Medium Thick, Thick, Too Thick










G (mils)

G (mm)



Thin
<9 .57="" span="">


<0 .24="" span="">



Medium Thick
9.57~ <17 .37="" span="">

0.24~<0 .44="" span="">



Thick
17.37~<39 .37="" span="">

0.44~<1 .00="" span="">



Too Thick
≥39.37

≥1.00


6. Fabric Condition: as Grey (loomstate) or Finished in any way





Assessment of Fabrics for Quality

The six parameter chosen for assessment of Fabric Quality are as follows:




1. Average Count ( Na)
Coarse
Medium
Medium Fine
Fine
Extra Fine
Score




2.5


4.5



5.5
6.5
8.5
2. Fabric Weight (W or W1)

Light

Medium
Heavy


Score







2.0

4.0


6.5


3. Some of Cover Factors (K1+K2)








K1+K2 value
<10 span="">

10~<22 span="">

22~36

>36






Score
2.0

4.5

8.0

12.0





4. Weight Factor Ratio: (w1/w2)








w1/w2 Ratio
<0 .7626="" span="">
0.7626~1.2656

>1.2656




Score
3.0




2.0


3.0


























5. Fabric Thickness (G)









G value (mils)
<9 .57="" span="">

9.57~<17 .37="" span="">

17.37~<39 .37="" span="">
≥39.37


G value (mm)
<0 .24="" span="">

0.24~<0 .44="" span="">

0.44~<1 .00="" span="">
≥1


Score
4.0


3.0

2.0

1.0


6. Fabric Condition










Grey (Loom state)
Finished




















Score
1.0




2.0









Fabric Quality Grading








Total Score of all the six parameters = 36.0
















Fabric Quality Grade (FQG)
Total Score





Below Average (Grade IV)
<10 .5="" span="">





Average (Grade III)


10.5~<19 .0="" span="">





Good (Grade II)


19.0~<27 .5="" span="">





Very Good (Grade I)


≥27.5~36.0
















Applications

The following example illustrates how the Fabric Quality Grade (FQG) is arrived at.

Variety No 1: Dress
Classification
Score
Material


N1× N2 68s × 60s


Na
63.8s
Fine count
6.5
n1×n2 75.5 × 75.5


W (oz/Sq.Yd) 1.7259)
Light weight
2.0
W1 (gsm)
58.5 )


K1×K2 9.16×9.75


K1+K2   18.91
Openly Set
4.5
w1×w2 1.11×1.26


w1/w2 Ratio 0.88
Equal-Faced
2.0
d1×d2 (mils) 4.34×4.62


d1×d2 (mm) 0.11×0.12


G (mils) 8.96)
Thin
4.0
G (mm) 0.23)


Fabric condition
Grey
1.0


Total Score
20.0


Fabric Quality
Good


FQG
Grade II

Recommendation

The proposed method of Fabric Quality Assessment, including assigning total score for various parameters and categorizing it according to Fabric Quality Grading (FQG) is   
universally applicable to all types of woven fabrics, irrespective of material used, fabric construction, weave or design, nature of weaving, fabric condition and country of origin. If need be, minor modifications or further subdivisions may be made in the method to meet specific requirements.











Courtesy  Prof. D.V. Muniswamy
                                                                                  


































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