This document provides an overview of textile testing. It defines quality and discusses different definitions and aspects of quality control, including testing and inspection. The document then defines textile testing as applying engineering and science to measure properties, characteristics, and conditions affecting textile materials. It lists common reasons for textile testing such as checking raw materials, monitoring production, assessing final products, and product development. Various types of textile testing are covered, including physical, chemical, biological, visual, physiological, and intelligence testing. The document also discusses topics like standardization of testing, sampling methods, types of samples, and measurement in textile testing.

1. Chapter 1
Introduction to Textile Testing
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2. QUALITY DEFINITION
Inspiring
product is superior to all competing products in every way possible.
Product based
In this definition quality is viewed as a quantifiable attribute ( measurable feature ) on
the product's performance in fields such as
Durability
 Reliability

3.  User based : That best satisfy the customer's preferences.
 Manufacturing based: with engineering and manufacturing practices based on
conformance to requirements or specifications.
Cont.….

4. Quality according to ISO, defined as:
 “Degree to which a set of inherent characteristics fulfils requirements”.
 Degree: refers to a level to which a product or service satisfies. So, depending
upon the level of satisfaction,
 a product may be termed as excellent, good or poor quality product.
Cont..

5. Inherent characteristics: those features that are a part of the product and are responsible to
achieve satisfaction.
Requirements:
 Refer to the needs of customer, needs of organization & those of other interested parties
(e.g. regulatory bodies, suppliers, employees, community & environment).
 The expectations that may be stated, generally implied or obligatory.
Cont..

6. Quality control
 Is a procedure or set of procedures intended to ensure that a manufactured product or
performed service
 adheres to a defined set of quality criteria or meets the requirements of the client or
customers

7. Two main Aspects of Quality Control
Testing
Testing is the analysis and evaluation of a material or product to asses its quality characteristics
or performance.
 Testing should be accomplished by some standard methods so that the test results can be
compared.
Inspection
 Is visual examination with respect to the specifications

8. What is textile testing?
Textile testing is the application of engineering knowledge & science to the
measurement
the properties & characteristics & conditions affecting textile materials.
It provides information about the physical or structural, chemical and
performance properties of the fabrics.
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9. Reasons for textile texting
1. Checking raw materials
2. Monitoring production
3. Assessing the final product
4. Investigation of faulty material
5. Product development and research
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10. 1. Checking raw material
• If the material is incorrect or substandard it is impossible to produce the required quality of
final product
• What is concerned to be raw material depends on the stage in processing at which the
testing takes place.
Fiber: spinner
Yarn: weaver
Finished fabric: garment maker
• Therefore the incoming material is checked for the required properties so that ,
unsuitable material can be rejected.
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11. 2. Assessing the final product
In this process the bulk production is examined before delivery to the customer
to see if it meets the specifications.
It is taken place after the material has been produced.
We can either check selected samples or we can check the entire material
produced.
Faulty material may be rectified & therefore grade will be given to the product
depending on the number of faults detected.
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12. 3. Investigation of faulty material
This enables steps to be taken to eliminate faulty production in future & so
provide a better quality product to the customers.
Investigation also involves the determination of which party is responsible in
the supply chain.
E.g. When finishing of the products are undertaken by outside companies
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13. 4. Product development & research
This is done because of the continual changing of textile technology for the
production of modified products.
The major functions of this process is to test the material to check that the
properties have been improved or have not been degraded by faster production
methods.
In this way an improved product or a low cost product with the same
properties can be provided fir the customers.
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14. Generally testing is done
1. Customer satisfaction
2. Controlling the manufacturing process and cost
3. Customer relation
4. Reputation
5. Employee satisfaction
6. Sales
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15. A Key issue in the modern testing is to understand the complexity of the
instruments & their working principles & finally to interpret the results in a
systematic and scientific way.
The chemical and physical structures of textile fabric determine how it will
perform and ultimately whether it is acceptable for a particular purpose.
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Cont.….

16. Scope of
textile
testing
Physical
testing
Chemical
testing
Biological
testing
Visual
examinatio
n
Physiological
testing
Intelligence
testing
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17. Physical Testing
The first broad classes of factors that affect the performance of fabrics are
physical agents and influences.
These may be further subdivided into mechanical deformation and degradation,
tactile and associated visual properties of fabrics after their use and
manufacture, and their response to heat, liquids and static charge.
They include tensile behavior, compression, bending or flexing, shrinkage,
abrasion resistance, frictional rubbing, torsion or twisting, and shear.
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18. Chemical Testing
• Textile fabrics have varying degrees of resistance to chemical agents such as
water and other solvents, to acids, bases and bleaches, to air pollutants and
to the photochemical action of ultraviolet light.
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19. Biological Testing
Textile fabrics may be adversely affected by various microorganisms and insects.
These tests would be useful for rapid screening of various modified and
unmodified fabrics for their ability to withstand biological attack.
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20. Visual Examination
Fabrics can be evaluated for a variety of attributes to assess their performance by
visual assessment either manually (subjective assessment) or by objective evaluation
techniques.
Visual examination of fabrics includes evaluating
the texture,
 surface characteristics,
dye shade variations,
design details;
weave patterns,
construction particulars,
pilling assessment, etc.
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21. Physiological testing
Fabric physiology deals with the physiological characteristics of fabrics that
are expressed in the well-being, performance and health of the wearer.
It covers the areas of physics, chemistry, medicine, physiology, psychology and
textile technology.
Three important physical parameters that are instrumental in the physiological
processes of fabrics are heat transmission, moisture transport and air
permeability.
The psychological properties include mainly the aesthetics of the fabric such as
color, fashion, prejudice, suitability for an occasion, garment style, fabric finish
etc.
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22. Intelligence Testing
• In the last decade, research and development in smart/intelligent materials
• structures have led to the birth of a wide range of novel smart products in
aerospace, transportation, telecommunications, homes, buildings and
infrastructures.
• The testing programs must include the testing of these fabrics to meet the ever
growing demand for hi-tech fabrics and garments.
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23. Standardization of testing
• A standardized test is a test that is administered and scored in a consistent or
standard manner.
• Requirements of results from a standardized test:
1. Explicit: on how they will perform or how they meet the specifications
2. Implicit: reproducibility of test results obtained either from time to time
,operator to operator or lab to lab
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24. The lack of reproducibility of results of materials may be due to :
1. Variation in the material
It can be solved through:
 Proper sampling
 Use of suitable statistical methods to analyze the results
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25. Cont.…
2. Variation due to test methods
-due to:
 operator care in handling specimen & adherence to the test procedure
 Specimen size
 Atmospheric conditions
 Type of test equipments
 Test conditions: speed ,pressure
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26. E.g. of standardized testing laboratories(organizations) world wide:
1. Bureau of Indian standards- India
2. British standards-Britain
3. American society for testing of materials(ASTM)-USA
4. Germany standards institute-Germany
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27. Sampling
Sample :it is a relatively small fraction which is selected to
represent a population
A sample is “a smaller (but hopefully representative) collection of
units from a population used to determine truths about that
population”
Sampling: a process of testing a small amount of something in order
to get information about the whole thing.
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28. Cont.…
3. factors that influence sample representative-ness
Sampling procedure
Sample size
Participation (response)
• When might you sample the entire population?
When your population is very small
When you have extensive resources
When you don’t expect a very high response
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29. Reasons for sampling:
To minimize time requirement for testing
Design nature of many of the tests
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30. Objectives of sampling
• To produce an unbiased sample in which the proportions of, for instance, the
different fibre lengths in the sample are the same as those in the bulk.
• to put it another way, each fibre in the bale should have an equal chance of
being chosen for the sample
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31. Sampling methods are governed by :
1. Form of the material (fiber/yarn/fabric)
2. Amount of material available
3. Nature of test
4. Type of testing instrument
5. Information required
6. Degree of accuracy required
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32. Types of sample
1. Random sample
 In this type of sample every individual in the population has an equal
chance of being including in it.
2. Numerical sample
 A sample in which the proportion by number of say long ,medium,& short
fibers would be the same in sample as in the population
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33. 3. Biased sample
When the selection of an individual is influenced by factors other than chance
A sample ceases to be truly representative of the bulk and a biased sample
results
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34. Types of Samples
34
 Probability (Random) Samples
Simple random sample
systematic random sample
Stratified random sample
Cluster sample
 Non-Probability Samples
 Convenience sample
 Purposive sample
 Quota

35. Simple random sample
In simple random sampling- all members of the population have equal and independent
chance of being included in the sample.
advantages
 Estimates are easy to calculate.
Disadvantages
 If sampling frame large, this method impracticable.
 Minority subgroups of interest in population may not be present in sample in sufficient
numbers for study.

36. Systematic sampling - is one in which every Kth subject on a list is selected for inclusion in
the sample.
The “K” refers to sampling interval, and may be 3rd (K=3) or 10th (K=10) subject.
The value of K is determined by dividing the population size by the sample size.
SYSTEMATIC SAMPLING

37. 37
ADVANTAGES:
 Sample easy to select
 Suitable sampling frame can be identified easily
 Sample evenly spread over entire reference population
DISADVANTAGES:
 Sample may be biased if hidden periodicity in population coincides with that of
selection.
 Difficult to assess precision of estimate from one survey.
Conti…d

38. Stratified sampling permits the tester to identify sub-groups within a population and create
a sample w/c mirrors these sub-groups by randomly choosing subjects from each section
Such a sample is more representative of the population across the sub-groups
Stratified sampling

39. Cont.….
Sub- groups in the sample can either be of equal size or proportional to the
population size
Equal size sample subgroups are formed by random selecting the same number
of subjects from each population subgroup
Proportional sub-groups are formed by selecting subjects so that the sub-group
percentages in the population.

40. Example 3: The following is a proportionally stratified sample:
i. population =9000 copes
ii. the desired sample size is = 3%=270
iii. recording and leveling all 9000 copes and classifying 9000 copes in yarn store say:
 65% -Ne 20 =5850
 20% -Ne10= 1800
 15 % -Ne 40 = 1350
 therefore 65 % of the sample = 176
20% of the sample = 54
15 % of the sample = 40
65*270/100

41. Therefore, a sample of 270( 176+ 54+ 40) copes, which is representative of the 9000 and
which reflects proportionally each size category of spinning copes
A non- proportionally stratified sample would randomly select 90 spinning copes from
each sub-groups .
Cont.…..

42. CLUSTER SAMPLING
42
Cluster Sampling - involves randomly selecting groups ,not individuals.
first a sample made up of clusters may be less representative than one selected through random
sampling.
Advantages :
Cuts down on the cost of preparing a sampling frame.
This can reduce travel and other administrative costs.
Disadvantages:
sampling error is higher for a simple random sample of same size.

43. Conti…
Two types of cluster sampling methods.
One-stage sampling- All of the elements within selected clusters are included in the sample.
Two-stage sampling-A subset of elements within selected clusters are randomly selected for inclusion
in the sample.

44. Non-Probability Samples
Convenience sample
Purposive sample
Quota
With non probability sampling, in contrast, population elements are selected on the basis
of their availability
because of the researcher's personal judgment that they are representative.
The consequence is that an unknown portion of the population is excluded.

45. Conti..d
 convenience sample – not because such samples are necessarily easy to recruit, but because
the researcher uses whatever individuals are available rather than selecting from the entire
population.
 Purposive sampling The researcher chooses the sample based on who they think
would be appropriate for the study.
 This is used primarily when there is a limited number of people that have
expertise in the area being researched

46. Cont…d
Quota sampling
 The population is first segmented into sub-groups, just as in stratified sampling.
 Then judgment used to select subjects or units from each segment based on a specified
proportion.

47. Measurement
The process of measurement can be defined as a quantitative comparison between a
predefined standard and the object being measured.
The definition shows that there two parts to the measuring process :
i. Comparison- as measurement
ii. Predefined standard – easily overlooked weighing an object using a single pan balance -the read its
weight- therefore, balance is the local standard -since it was calibrated with other standard.

48. Conti….d
It is also important that the calibration is carried out at regular intervals as instrument
reading can change over time because of wear of mechanical parts and ageing of electronic
circuits
Regular calibration being good laboratory practice it is specially demanded by ISO 9000.
The actual (process of measurement is always subjected to error ,which can be defined as
the difference b/n the measure value and the “true value”.

49. Fiber Sampling from Bulk
Zoning- is a method that is used for selecting samples from raw-cotton or wool or other
loose fiber where the properties may vary considerably from place to place.
A hand full of fibers is taken at random from each of at least 40 widely spaced places
(zones) throughout the bulk of the consignment and is treated as follows:

50.  Each handful is divided into two parts and one half it is again divided into
two and half it is discarded.
 This process is repeated until about required amount of fibers remain in the
handle eg 20 mg sample for fibre length test by comb sorter.
 Each handful is treated in a similar manner and the fibers that remain are
placed together to give a correctly sized test sample containing fibers

51. Sampling by zoning

52. Core sampling
Core sampling is a technique that is used for assessing the proportion of grease,
vegetable matter and moisture in samples taken from unopened bales of raw wool.
A tube with a sharpened tip is forced into the bale and a core of wool is withdrawn

53. Fiber Sampling from Combed Slivers, Roving & Yarn
Unless special precautions are taken , the longer fibers in the material being sampled are
more likely to be selected by sampling procedures leading to length biased sample.
This is particularly likely to happen in sampling material such as sliver, roving and yarns
,where fibers are approximately parallel.
The fiber extent as shown next rather than the fiber length as such which determines the
likelihood of the section.

54. The measuring of extent

55. CONT………
any bias in length also have effects on other properties such as fineness and strength.
There are two ways of dealing with this problems:
i. prepare a numerical sample
ii. prepare a length –biased sample – in such a way that the bias can be allowed for any
calculation

56. a) Numerical sample
In Fig . 1.1 A and B represent two places separated by a short distance in a sample
consisting parallel fibers.
If all the fibers whose left –hand ends shown as solid circles) lay between A & B where
selected by some means they would constitute a numerical sample
The truth of this can be seen from the fact that if all the fibers that start to the left of A were
removed then it would not alter the marked fibers

57. Selection of a numerical sample
If the length of one sample does not affect the composition of the
remaining sample ,then it can be considered to be numerical sample and
each segment is representative the whole.

58. Length-biased sample
 In a length-biased sample the percentage of fibres in any length group is
proportional to the product of the length and the percentage of fibres of that
length in the bulk. The removal of a length-biased sample changes the
composition of the remaining material as a higher proportion of the longer
fibres are removed from it

59. Fig.1.3Selection of a tuft sample

60.  By a similar line of reasoning if the sample is cut at the planes A and B
 The section between the planes will contain more pieces of the longer fibres
because they are more likely to cross that section.
 If there are equal numbers of fibres in each length group, the total length of the
group with the longest fibres will be greater than that of the other groups so
that there will be a greater number of those fibres in the sample.

61. The use of a length –biased sample is deliberate in the case so that the
measured mean fiber diameter is then that of the total fiber length of the
whole sample
If all the fibers in the sample are considered as being joined end to end
the mean fiber diameter is then the average thickness of the fiber .

62. This type of sample is also known as a tuft sample and a similar method is
used to prepare cotton fibers for length measurement by the fibro graph.
Fig.1.5 shows the fiber length histogram & mean fiber length from both a
numerical sample and a length biased sample prepared from the same
material.
By a similar line of reasoning if the sample is cut at the planes A and B, the
selection between the planes will contain more pieces of the longer fibers
,because they are more likely to cross that section.

63.  Sample for measurement of fiber diameter using the projections
microscope are prepared in this manner by selecting a bundle of fiber,
thus giving a length-biased sample
 If there are equal numbers of fibers in length group, the total length of the
group ,with longest fiber will be greater than that of the others groups so
that there will be a greater number of those fibers in the sample.

64. Fig.1.5 length group cm

65. Random Draw Method
The method is used for sampling sliver
The sliver to be sampled is parted carefully by hand so that end to be used has
no broken or cut fibers
The sliver placed over two velvet boards with the parted end near the front of
the first board.
The opposite end of the silver is weighted down with a glass plate to stop it
moving as shown below

67. This procedure is repeated, removing and discarding 2mm draws of fibre
until a distance equal to that of the longest fibre in the sliver has been
removed.
The sliver end has been normalized and any of succeeding draws can be used to
make up a sample as they will be representative all fiber length
This is because they represent a numerical sample as described earlier where all
fibers with ends between the two lines area taken as the sample. when any
measurement are made on such a sample all fibers must be measured.

68. Cut square method
The method is used for sampling the fibers in a yarn
A length of yarn being tested is cut off and the end untwisted by hand The end
is laid on a small velvet board and covered with a glass plate
The untwisted end of the yarn is then cut about 5 mm from the edge of the
plate as shown in Fig. 1.7.
All fibers that projected in front of the glass plate are removed one by one with
a pair of forceps and discarded.
By doing this all the cut fibers are removed leaving only fibers with their
natural length.

69. Cont.
The glass plate then moved back a few millimeters exposing more fiber ends
These are then removed one by one and measured
When these have all been measured the plate is removed back again until a total
of 50 fibers have been measured
In each case once the plate has been moved all projecting fiber ends must be
removed and measured .
Then whole process is then repeated on fresh lengths of yarn chosen at random
from the bulk until sufficient fibers have been measured

70. 1. Bias Due To Physical Characteristics
Longer fibers always have a greater chance of being selected
2. Position Relative To The Person
Lab assistant may pick bobbins from top layer of a case of yarn
3. Sub Conscious Bias
Person selecting cones will pick the best looking ones from ridges, cob webbed
ends.etc with out thinking about it.
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71. Measurement
• Measurement can be defined as a quantitative comparison between a predefined
standard and the object being measured.
• The actual process of measurement is always subject to errors which can be
defined as the difference between the measured value and the 'true' value.
• However, the 'true' value of any parameter can never be known because the
value can only be obtained through measurement and any measurement can only
be an estimation of the value, subject to unknown errors.
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72. Precision in measurement
• The term precision means the same as repeatability.
• It is defined as the quality that characterizes the ability of a measuring
instrument to give the same value of the quantity measured.
• In other words it is an indication of how well identically performed
measurements agree with each other.
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73. • Accuracy may be defined as conformity with or nearness to
the 'true‘ value of the quantity being measured.
• This can only be obtained by calibration of the measuring
system against the appropriate standards at suitable intervals.
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Accuracy in measurement

74. Sensitivity in measurement
• Sensitivity is defined as the least change in the measured
quantity that will cause an observable change in the instrument
reading.
• The sensitivity of a measuring instrument can be increased by
amplifying the output or by using a magnifying lens to read the
scale.
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75. 75
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