28 Introduction to Textile Testing

S. Sundaresan

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The industries involved in manufacturing a product need to produce quality product at optimum cost. It is very important that the product should have serviceability and durability. In textile industry the product manufacturing is done by using natural or manmade fibres or using natural and synthetic blends. The product produced from textile industry will have a range of commercial clothing to high end application namely space suits. Now days using high performance fibres highly functional textile products like bullet proof vests, fire fighter suits etc.. are also produced. In medical field the textile products play a very important role right from bandages, surgical cotton, theatre textiles, disposable materials, hygiene textile products, implantable and non implantable textiles etc… Textiles are an indispensable part of human life. Textiles are used for protection from wind, rain, heat and other natural adversaries. Textiles are being used from kitchen to automobiles to space and therefore, employed to satiate widely different human needs. Social, psychological, physical, economic parameters play a vital role in selection of textile products.


  • At the end of this lesson you will be able to
  • Know about the importance of textile testing Understand the outline of various test methods

The Important uses of textile include clothing, interior decoration, functional or industry–specific uses. Different end use fabrics have different quality/performance requirements. The different attributes of textile are quality, comfort characteristics, aesthetic characteristics, functional characteristics, safety characteristics. The quality and characteristics of textile material depends on mainly the raw material, type of manufacturing process involved and the type of finish given to the end product. The end product of textile materials are manufactured by using any one of the process called weaving, knitting, nonwoven, composites. Each process will have its unique features. For example for manufacturing a commercial shirting cloth, weaving process is used, but in case of producing  a “T” shirt we are using knitting process. In both the process the feed material is yarn, but of different characterises. For producing a cloth in knitting, the yarn should have low Twist multiplier compared to the yarn used in weaving process. Each and every process sequence in textile manufacture will vary depending on the end uses of the products and its functional requirements. For example in case of woven fabric the dimensional stability plays important role and in case of knitted cloth the elongation property is considered to be crucial one even though the yarn is made out of same raw material for both the process.


The quality of output product depends on raw material quality, process parameters, and finishes given to that product. The raw material selection depends on the end use requirement of the final product. In other words the raw material should be decided only based on the quality and functional requirement of the output product.



The definition for quality can be given by “Degree to which a set of inherent characteristics fulfils requirements. It is always the result of high intention, sincere efforts, intelligent directions and skilful execution. As per the ISO – 9001: 2000 quality is the degree to which a set of inherent characteristics that fulfils the requirements. Quality is inversely proportional to (unwanted) variability”


During 1970’s the quality and its control were mainly concentrated on product specification and emphasis on final inspection. In 1980’s it aimed at process oriented system, ensuring quality through preventive measures and finally aimed at customer satisfaction and this process is termed as quality assurance. From 1990’s the term quality management introduced in the textile industry stressed on quality cost effectiveness through quality planning and continual improvement. From the year 2010 onwards the total quality management concepts introduced in textile industry develops into a zero defect system and meets the requirement of the society.


To obtain good quality and consistency in delivering the product, the textile industry follows stringent testing methods and procedure right from the raw material to finished product. The testing methods used to assess the extent to which the products meet the specifications and the control Involves assessing product quality, assessing process deviations.


Quality of the product in textile sector can be checked by two methods namely visual inspection and testing using testing instruments. In other words it can be stated as objective evaluation and subjective evaluation. The testing may be done by using qualitative techniques or by using quantitative techniques. The reason for testing isthat, it leads to quality process control, product development and research, regulatory requirements. It involves Checking raw materials, Monitoring production, assessing the final product, investigation of faulty material, minimising the variations, avoiding buyer – seller disputes in test results, whether the quality is acceptable or not, (how will be the yarn performance in weaving? etc).


Investigation of faulty materials (analysis of customer complaint, identification of fault in machine etc.), Specification testing to prove whether they fall within the limits allowed in the specification (e.g. specified by a customer)


Visual Inspection is the activity such as measuring, examining, gauging one or more characteristics of a product and comparing the results with specified requirements in order to establish whether conformity is achieved for each characteristic. Visual inspection is carried out mainly to appraise the quality of products and other requirements. Normally, visual inspection is carried out on the textile products to examine the occurrence of yarn defects, fabric defects, fabrication defects, design/colours besides specification particulars.


The testing of textile materials is also used to assess the performance characteristics, for example a garment is considered to be serviceable when it is fit for its particular end use. After being used for a certain length of time the garment ceases to be serviceable when it can no longer fulfill its intended purpose in the way that it did when it was new.The particular factors that reduce the service life of a garment are heavily dependent on its end use are analysed and tested.


By testing we come to know the characteristics, performance and process suitability of the raw material. Since all the material cannot be tested we follow the sampling technique. The following are some of the terms used in sampling

  • Lot: A specific quantity of material or a collection of units offered for inspection and acceptance at one time.
  • Lot size: No. of units/quantity in the lot.
  • Sample: A portion of the material or a group of units, taken from a lot which serves to provide information for reaching a decision regarding acceptance.
  • Sampling plan: A specific plan which states the sample size, the criteria for accepting, rejecting the lot.
  • Sample size: The no. of units/quantity in the sample.
  • AQL: The maximum percent defective or maximum number defects per 100 units which can be considered satisfactorily as process average is termed as Acceptance Quality Limit.

In textile industry the raw material which is a fibre plays an important role in deciding the quality of the end product. The important fibre properties that plays vital role in deciding the quality and performance of the end product are listed below

  • Fiber fineness
  • Micronaire
  • Span length
  • Fiber strength
  • Fiber elongation
  • Short Fiber index
  • Degree of Maturity
  • Colour
  • Neps
  • Cross sectional appearance

The finesses of fibre influences Twist, Drape, Spinning limit. The finer the fiber greater is the total surface area of the fiber available for inter fiber contact and consequently less twist is required. Fiber Length will decide the spinnabilty of the fibre. Fiber Strength denotes the maximum tension the fiber sustains before it breaks. It can be expressed as breaking Strength, Tenacity (Breaking load per unit fineness) etc. Fiber elongation is a measurement of the elastic behaviour of the fibers in the bundle. . Fiber elongation improves yarn strength, enhances blending compatibility, reduces yarn break in processing, increase fabric durability and reduces strength losses in finishing. Short fiber index is the weight of fibers whose length is less than 0.5 inch expressed in %. Presence of short fibers leads to higher yarn imperfections like Thin, Thick and Neps. The degree of fiber wall development of cotton fiber is called maturity. The cotton with high number of immature fibers causes fiber damages during processing and effects yarn quality and fabric quality by producing higher neps and irregular absorption of dyes. Immature fibers have less cellulose in the cell wall and the result is lower dye absorption. Neps with large portion of immature fibers cause white specs in the fabric. Moisture is the percentage of water present in the sample being tested. Colour of cotton ranges from white to yellowish and is classed into the groups “White”, “Light Spotted”, “Spotted Tinged” and “Yellow Stained”, in descending order of quality. Trash content is a typical problem of cotton fibers. While picking cotton, leaves, broken branches, dirt and dust comes along with cotton balls. In ginning the seeds get broken and some of the seed coat fragments with small fibers stuck to cotton. These foreign materials affect the appearance of yarn and fabric badly. The values of the above said properties were combined together and it is represented as fibre quality index which will give the idea about the quality of the raw material.


Similarly the important yarn properties which play a vital role in deciding the fabric quality can be listed below

  • Count or linear density of yarn Twist per unit length ( TPI)
  • Evenness (U%)
  • Strength (LBS): lea strength or single yarn strength CSP – count strength product
  • Yarn appearance by grading Hairiness index

   Count of the yarn decides the yarn diameter and weight per unit length of the yarn. In the textile industry the count is expressed in English system (Ne), tex, or denier system. Based on the count the yarn can be broadly classified as coarse, medium and fine count. The twist inserted in the yarn decides the strength of the yarn. The twist in the yarn is measured as Twist per Inch ((TPI). Coarser yarn has got lesser TPI than the finer yarn. The strength of the yarn is expressed as lea strength in pounds or single yarn strength in gms/tex. The strength of yarn decides the weavabilty or knitability of yarn. The strength of yarn and yarn count is combined and expressed as count strength product(CSP). The evenness of the yarn gives an idea about how the yarn diameter varies throughout its length. It is expressed in terms of number of thick places, thin places and neps present per unit length of yarn. The evenness value is expressed as U%. It influences the fabric performance. The appearance of the yarn is a subjective evaluation which is not practised now in the industry. Based on the appearance of yarn which is wound on the black board the yarn is graded using the standard ASTM board in terms of grade ( A to D).


In case of fabric the following are the essential tests carried out in the textile industry to assess the quality.

  • Grams per square meterDimensions of the fabric
  • Threads per unit length ( ends/inch, Picks/inch, wales/inch, Coarse/inch)
  • Cover factor or tightness factor
  • Tensile strength Tearing strength
  • Dimemensional stability : Bending length, Flexural rigidity,
  • Bending modulus Abrasion resistance
  • Air permeability Bursting strength Ballistic strength Drape
  • Crease recovery Pilling

   During use, the textiles product is subjected to different process like Stretching, Twisting, Bending, Shearing and Compression. The stretch in the fabric is related to resistance to the applied force. This resistance is determined by incrementally loading the material and recording the relation between the load or stretch and the amount of specimen stretch expressed as tensile strength. Bursting strength is an alternative method of measuring strength in which the material is stressed in all directions at the same time and is therefore more suitable for such materials. The air permeability of a fabric is a measure of how well it allows the passage of air through it. The ease or otherwise of passage of air is of importance for a number of fabric end uses such as industrial filters, tents. Water absorption test is important for some textile end uses such as towels, tea towels, cleaning cloths, nappies (diapers) and incontinence pads which require the material to absorb water. Water repellency also an important test for the fabric end uses, particularly those where fabric is used out of doors;&require the material to be more or less impermeable to rain. These include outerwear such as anoraks, cagoules and raincoats and also industrial fabrics such as tents and tarpaulins.


A waterproof fabric is one that is coated or impregnated to form a continuous barrier to the passage of water using for example rubber, polyurethane, PVC or wax coatings.Showerproof fabrics are ones that have been treated in a a way as to delay the  absorption and penetration of water. Drape is the term used to describe the way a fabric hangs under its own weight. It has an important bearing on how good agarment looks in use. The draping qualities required from a fabric will differ completely depending on its end use; therefore a given value for drape cannot be classified as either good or bad. Knitted fabrics are relatively floppy and garments made from them will tend to follow the body contours. Woven fabrics are relatively stiff when compared with knitted fabrics so that they are used in tailored clothing where the fabric hangs away from the body and disguises its contours. Measurement of a fabric s drape is meant to assess its ability to do this and also its ability to hang in graceful curves. Creasing of a fabric during wear is not a change in appearance that is generally desired. The ability of a fabric to resist creasing is in the first instance dependent on the type of fibre used in its construction. The magnitude of this crease recovery angle is an indication of the ability of a fabric to recover from accidental creasing. Pilling is a condition that arises in wear due to the formation of little ‘pills’ of entangled fibre clinging to the fabric surface giving it an unsightly appearance. Pills are formed by a rubbing action on loose fibres which are present on the fabric surface. “Abrasion resistance” is expressed as the number of rubs required to cause a breakdown in the test specimens or to lead to an unacceptable visual change.


In case of textile materials which is undergone wet processing the following tests are important Colour fastness test: light, rubbing, washing fastness Colour matching Colour fastness test is very important test which will reveal the fastness of dye on the fabric. It denotes the loss of colour in the material due to prolonged use. It is a subjective evaluation process in which the sample specimen is compared with a grey scale for rating.Colour fastness describes the tendency of a material to change or lose its colour when subjected to some external agent. Colour of the fabric may get faded due to sunlight, due to rubbing, washing and also due to perspiration. So the colour fastness test done separately for


The final garment is inspected visually for any defects. Then it is checked for its dimension (Size, length, width) as per the specification and also checked for correctness of care labels. The garment is also tested for dimensional stability by using shrinkage test to assess the fabric shrinkage due to washing. The Seam Slippage test is done to assess the failure of seam. The failure of seam makes a garment unusable even though the fabric may be in good condition. The packing of garment is also checked whether it is done as per the specification.


Apart from the routine methods used in testing some of the special test methods required to evaluate the fabrics meant for high performance. For example the fabric made for bullet proof vest, tent cloth, space suit etc.., requires special test to assure the quality. For this purpose special testing like ballistic test, moisture vapour transmission test (MVTR), Thermal comfort test etc.., are used. The fabric comfort test which is used to test the low stress mechanical property of the fabric is done by using Kawabata evaluation system (KWES) or by using FAST system. The comfort test gives the tailorability of a fabric. The use of high volume instrument (HVI) will gives combined test results of fibre characteristics.


In the textile industry the testing is a continuous process to evaluate the product quality. The test results are intercepted with reference to standard test results or by using statistical techniques. The analysis of with and between sample variation is an important parameter to check the product quality & is also practised in the textile industry. The coefficient of variation (CV%) is a statistical tool used in most of the textile testing evaluation. Apart from the routine tests some significance tests like “t” test, F test etc.., are some of the statistical tools used to assess the quality of the textile product.


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