Indian Journal of Fibre & Textile Research
Vol. 19, September 1994, pp. 168-171
Fabric quality evaluation by objective measurement
B K Behera & P K Hari
Department of Textile Technology, Indian Institute of Technology, New Delhi 110 016, India
The objective measurement of hand and related attributes offabrics which determine their value to the
consumer, has been well recognized by the manufacturing industries and consumers. This paper describes in
brief the concept of fabric objective measurement and its potential in today's advanced, quality conscious and
competitive market. The measurement principle and the various profitable application areas of objective
evaluation offabrics are also described. In addition, a brief outline of the instruments developed under the
trade name of KES and FAST systems for measuring fabric performance characteristics is given.
Keywords: Aesthetic property, Comfort property, Fabric formability, Low-stress mechanical properties,_
Objective measurement, Primary hand, Tailorabilitv
1 Introduction
Quality has become the prime requirement in all
spheres of life in today's competitive environment
and can broadly be assessed from the perforrftance of
the product. The performance of clothing materials
can be classified as:
(i) Utility performance, e.g. strength, durability, etc.
(ii) Comfort performance: mechanical fitting to hu·
man body; and physical
(iii) FabriC performance during clothing manufacture.
The advent of new fibres and different processing
technologies have led to the production of fabrics
covering a wide spectrum of quality characteristics.
This, coupled with the development of quality
awareness in the consumer, has given rise to the need
for ensuring aesthetic and comfort properties of
fabrics besides durability. Moreover, for international trade, quality is certainly the most important
feature.
In yarn p,oduction, international quality
standards controllable by electronic equipment are
acceptable. In weaving, there is still some individual
quality judgement, e.g. about the number of
acceptable faults per 100 metres.
Traditional fabric quality evaluation comprises
measurement of (i) durability characteristics like
strength and elasticity, and (ii) comfort and aesthetic
characteristics. While the importance of durability is
well recognized by the industry and consumers,
aesthetic and comfort qualities, which are quite
subjective in nature, are yet to receive the emphasis
demanded by the consumer. Textile and clothing
industries have traditionally used subjective
assessments, by individual judgement, of these fabric
qualities as the basis of fabric quality evaluation.
However, in view of the ever increasing diversity of
fabrics and clothing, rapidly increasing automation
in textile and clothing manufacture, and retirement
and non-replacement of experts with extensive
experience in textiles and clothing, a critical need for
quick response in the textile and clothing industries
has become imperative to minimize the increasing
difficulties in subjective assessment of fabric quality
attributes.
Although the aesthetic and comfort qualities have
been considered traditionally as subjective feelings, it
has been demonstrated in recent years that these are
quantifiable in terms of physical measures. In fact, the
attributes which influence these qualities are difficult
to be characterized objectively. These are a set of
mechanical properties which influence the aesthetic
reaction to both the tactile sensations of handle and
feel and the visual impressions of drape and hang.
They link into comfort through skin contact, to
appearance retention through wrinkling and
creasing, and to durability through the damaging
consequences of sharp folds. They also influence the
behaviour offabrics in many of the operations in an
apparel factory and, for technical textiles, they
determine conformability.
2 Historical Background of Fabric Objective
Evaluation
The objective measurement of fabric mechanical
properties can be traced back to the work reported by
Pierce in 1930 in a classic paper "The Handle of Cloth
as a Measurable Quantity". The pioneering research
BEHERA & HARI: FABRIC QUALITY EVALUATION
work was, however, carried out at TEFO in the late
1950s and I 960s, involving evaluation of low-stress
mechanical properties such as bending, buckling,
tensile, shear and compression for the tailorability
and formability of the fabrics into garments.
Subsequently, Lindberg et al. were the first to apply
the theory of buckling to textile fabrics in garment
technology. Longitudinal fabric compression is a
fabric mechanical property that is particularly
important in tailoring, i.e. the forming and sewing of
flat pieces of fabrics into three-dimensional shaped
garments. This property was related to fabric
formability by Lindberg. Tatsuki Matsuo in the
Toyobo Research Center developed test methods,
identified useful parameters, and built-up a
remarkable collection of fabric samples, which
provides an 'Atlas' of fabric hand combining
subjective feel and objective characterization.
In 1972, the Hand Evaluation and Standardization
Committee (HESC) was formed by the efforts of
Prof. Sueo Kawabata of Kyoto University and his
associates, with the support of the Textile Machinery
Society of Japan, for the purpose ofslandardization
of hand evaluation. Based on the standardization of
the primary hand values and development of the
numerical expression of items, the research on the
interaction between these hand values and the
mechanical properties of fabrics was started by
Kawabata and Niwa in the mid 70's. Finally, these
work, along with the vision and technical skill of
Kawabata, led to the development of KES-F
instruments in 1972 which were subsequently
upgraded to KES-FB and used in the wide spread
fabric assessment first in the Japanese industry and
then in the rest of the world.
To make the Kawabata's system more simple and
cheap, the CSIRO Division of Wool Technology,
Australia, developed the FAST (Fabric Assurance by
Simple Testing) system which is commercially
available and also widely used for the objective
evaluation of fabric.
3 Basic Concept of Objective Evaluation
Aesthetics and comfort are generally understood
to be the subjective feelings. While categorizing the
fabric performance, the performance relating to the
aesthetic appearance can also be included in the
category of fabric comfort performance because it is
closely related with the fitness to the human body.
Leaving apart the aesthetic appearance, the comfort
performance may be divided into two components,
viz. mechanical comfort and thermal comfort. The
fabrics which have superior mechanical and thermal
comfort performance are usually called high quality
169
fabrics. While the thermal comfort is assessed from
the permeability of the fabric to air, water and heat,
the mechanical comfort has been evaluated by the
subjective method called 'handle', which is
traditionally assessed on the basis of visual and
tactual impressions. When the professional experts
judged the handle, they express the feeling, perceived
from the hand touch, by several expressions which are
commonly used by the experts. However, the
researchers, in recent years, have attempted to
express fabric handle in terms of physical properties
such as shear and flexural rigidity, hysteresis of
deformations, compressibility and surface smoothness, and also the comfort characteristics in terms of
air permeability, thermal iru;ulation capacity, water
repellem;y, water vapour transmission, etc.
The basic concept underlying the fabric objective
measurement technology is that necessary and
sufficient instrumental measurements should be
made on the fabrics to specify and control the quality,
tailorability and ultimate performance of an apparel
fabric. This approach has become feasible due to the
development of suitable instruments for measuring
fabric low-stress mechanical and physical properties
and also due to the development of analytical
methods for interpretation of data through
computers. The objective measurement of the fabrics
has now been proved as a potentially powerful tool
for modern industry.
4 Principles of Measurement
Experimental techniques for the measurement of
low-stress mechanical properties have been evolved
over a number of years and a variety of equipment and
test methods are available. However, in recent years,
KES-FB and FASTsystems have been receiving the
maximum attention. The KES-system has retained
the basic design of Kawabata 's four instruments for
the investigation of six characteristic aspects related
to fabric hand. The KES-system instruments and the
fabric properties measured by them are given below:
KES-FBI
KES-FB2
KES-FB3
KES-FB4
Tensile and shear properties
Pure bending
Compression
Surface friction and surface roughness
In KES-system, the quality of fabrics, their
tailorability and the subsequent apperance and
performance of garments can be related to six basic
fabric mechanical properties. The fabric mechanical
properties and their corresponding performance
characteristics are shown in Table I. The principles
used in the measurement of fabric mechanical
properties by the KES-FB instruments are shown in
170
INDIAN J. FIBRE TEXT. RES., SEPTEMBER 1994
Fig. I. It is worth mentioning here that these
instruments are designed to take the measurements at
low stress levels, i.e. they do not test to break the
specimen. The instruments allow data on a wide range
of parameters, including both deformation and
recovery, for each mechanical property to be
measured. Fig. 2 shows the typical deformation
recovery curves for fabric extension or lateral
compression, and fabric bending or shear. The
shaded area in the curves shows the energy loss during
a complete cycle. During the testing of materials, it is
important to select the maximum tension/com pression/bending/shear value for the recovery part of the
cycle that is likely to reflect the values experienced in
the performance of the garment. Taking measurements for the above parameters over many years,
Kawabata has chosen 16 different parameters (Table
2) as the objective features influencing fabric hand.
All or only some of these parameters can be used to
define the behaviour of a fabric as it affects the
appearance and/or performance of a garment or the
processability of the fabric.
Table 2--Kawabata's list of objective features
Tensile
LT
WT
RT
EM
B
Bending
2HB
Shearing
G
2HG
2HGS
Compression LC
WC
RC
Surface
MU
MMD
SMD
Thickness
T
Weight
W
Linearity of load/extension curve
Tensile energy, gf.cm/cm 2
Tensile resilience, %
Extensibility at 500 gf/cm
Bending rigidIty, gf. cm 2 (cm
Hysteresis of bending moment
Shear stiffness, gf. cm/deg
Hysteresis of shear force at OS shear angle
Hysteresis of shear force at S- shear angle
Linearity of compressionlthickness curve
Compressional energy, gf. cm/cm 2
Compressional resilience. %
Coefficient of friction
Mean deviation of MIU
Geometrical roughness. m
Fabric thickness, mm
Fabric weight. mgjcm 2
Table 3-Primary hand values
Koshi (Stiffness)
-
a measure of crispness. bending
and flexural rigidity
Numeri (Smoothness)
-
a measure of smooth, supple and
soft feel
5 Primary and Total Hand
Kawabata and Niwa, from the visual and tactual
judgement of the fabric by the HESC experts,
recognized three attributes as primary hand values
and named them as Koshi, Numeri and Fukurami
(Table 3). Kawabata and associates, in an experiment
with 500 samples of winter suiting fabrics, asked
seventeen experts to rank these fabrics, in order, from
10 (with strongest impression) to 0 (with no feeling).
The experts were also asked to provide an overall
evaluation and to place the fabrics in order of
preference on a scale of 0-5 from unacceptable to
excellent. They tenned this ranking as the total hand.
Elaborate statistical correlations then led t{)
equations relating (i) the total hand ranking to the
Fukurami (Fullness
and softness)
-
a measure of bulk with springiness in compression, rich and wann
Shari (Crispness)
- a measure of crisp ridged fabric
surface with a cool feel
Hari (Anti-drape)
- a measure of flare. the opposite of
limp conformllbility
Table I-Fabric mechanical properties and their corresponding
perfonnance characteristics
1//777177//777A
TENSILE
LOAI)
I
Perfonnance characteristics
Fabric handle and drape
Fabric fonnability and tailoring
Gannent appearance and seam
pucker
Mechanical stability and shape rePure bending
tention
Relaxation shrinkage, dimensional
Lateral compression
stability and hygral expansion
Longitudinal compression Wrinkle recovery and crease retenand buckling
tion
Surface roughness and
Mechanical and physiological
friction
comfort
Uniaxial tension
Biaxial tension
Shear under tension
St€.~
r[Jtc[
I
TDlSD<
COMPRESSION
SURfACE FRICTlCJ-j
t
SURF ACE ROUGHII£SS
_ _ f"lIAC[
rlR:[
j
Property
St€,.,R
AfQ.[
~-
Fig. I-Principles used ill the KES-F instruments for the
objective measurement of fabric me40hanical and surface
properties
[l€lIIir
IDIDING
I04£NT
SHEAR
STIIESS
.::frCtnCi . .
SHCNI RltilDITY
LOSS
<ca)
Fig. 2-Typical defonnation curve: (a) fabric extension or lateral
compression, and (b) fabric bending or shear
171
BEHERA & HARI: FABRIC QUALITY EVALUATION
three primary hand rankings; and (ii) the primary
hand values to the set of objective measurements from
the KES-system. Thus, this method provides an
estimate of both the features assessed in primary hand
and the market preference as denoted by total hand.
Subsequently, they extended the study to men's
summer suiting and women's fabrics. These proved
more complex and, therefore, they added some more
attributes (Table 3).
The FAST system, developed by CSIRO,
comprises four operations. In this sys.tem, the
extension meter measures tensile properties in warp
and weft directions and, in contrast to KES, it
measures shear behaviour through extension in the
bias direction. The compression meter measures
fabric thickness at different loads. The bending meter
operates on the simpler principle of measuring the
bending length instead of obtaining the full bending
response as given by KES. All these test results.are
recorded automatically and can enter the data in a PC
through the FAST data acquisition and analysis
program. The measurement of surface friction and
roughness, as in the case of KES system, is not
included in the FAST system. However, an
additional FAST manual test indicates the
dimensional stability of the fabric to heat and
moisture.
6 Various Applications of Fabric Objective
Measurements
BeSIdes the assessment offabric quality attributes,
objective measurement can also be used in the
following areas:
6.1 Production Control in Apparel Manufacture
The various areas in apparel industry where fabric
objective measurement is being profitably applied
are:
- Objective evaluation of fabric tailorability,
finished garment appearance and quality.
Objective specifications by tailoring companies
for fabric selection, production planning,
process control and quality assurance usmg
fabric mechanical and dimensional properties.
- Measurement and control of the comfort,
performance and stability of fabrics and
clothing during use, including laundering and
dry-cleaning.
6.2 Production Control and Product Development in Textile
Manufacture
The advantage of objective measurement as a
scientific basis for fabric engineering and production
control has been realized in textile manufacturing.
The production control in textile manufacture
requires a scientific basis for the engineering/design
of apparel fabrics to meet the demands of quality
conscious consumers and clothing manufacturers.
Fabric manufacturers have also realized that the
low-stress fabric mechanical and physical properties
are the basic engineering properties of apparel
fabrics. Moreover, the fabric objective measurements provide a common language for communication between fibre producers, yarn manufacturers,
fabric manufacturers and processors and also
between clothing manufacturers and traders. Thus,
the fabric objective measurement permits the rational
application of engineering principles to product
specification, quality control and assurance, process
control, product development, and process improvement in textile manufacture.
Objective measurement provides requisite fabric
specifications suitable for specific end uses based on
the measurement of fabric mechanical, surface and
other physical properties. Optimization of these
properties enables the fabric manufacturers to
develop new fabrics for specific end uses.
7 Conclusion
The quality and performance characteristics of
fabric and clothing are closely related to their basic
engineering properties and can, therefore, be
controlled through fabric objective measurements.
These measurements provide objective communication between various sectors of the textile and
clothing industries, thus facilitating fabric
specification for quality and performance requirements and transactions based on these specifications. The development and application of fabric
objective measurement technology is consistent and
compatible with continuing trends to high technology in the textile and clothing industries.
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