Quality Evaluation of Textile
Ramandeep Singh
B.Tech, Dept. of Textile Engineering
Giani Zail Singh Punjab Technical University Campus,
Bathinda, Punjab, India
Email: rmnsandhu3335@gmail.com
Why textile testing is important?
Textile measuring and testing processes are used to characterize fibers, rovings, yarns, textile structures, clothing, and carpets. Tests on fiber and textile-reinforced composites are in a special field. These textile properties are important for trade and allow a comparison of the product quality of different companies (for example, USTER-Statistics). In textile testing processes, many influencing factors must be considered: testing chamber climate, testing method and procedure, and number of tests and evaluation method. So quality evaluation is very important in textile trade.
Textile testing is necessary to achieve one or more of the following objectives:
- Assessment of performance during actual use.
- Comparison between norms and actual.
- Fitness for purpose or end use suitability.
- Minimization of trade disputes.
- Facilitation of exports and imports.
For quality evaluation of textile following testing process are done in textile industry:
Fiber testing:
Testing of fibers is required for determining their quality and to control the quality of the finished product.
We can broadly divide the fiber testing in two categories-
- Cotton fiber testing
- Man-made fiber testing
1. Cotton fiber testing:
Following are the main properties of cotton fiber:
- Fiber Length
- Fiber Fineness
- Fiber Strength
- Maturity and Color of cotton
- Trash%
Fiber Length: It is determined by Digital Fibrograph and is expressed as ‘span length’.
Fiber Fineness: It is measured by Air Flow method with the help of ‘Fineness Meter’. It is expressed in microgram/inch (micronaire).
Fiber Strength: It is measured by testing a bundle of fibers with the help of ‘Stealometer’. It is expressed as gm/tex.
In modern textile mills these properties are tested with the help of HVI (High Volume Instrument) which is an automatic version of the above facilities.
Maturity and color of cotton: The HVI instrument can also have a module for measuring ‘Maturity Ratio’ and the ‘Colour Index’ of cotton.
Trash %: It is not a fiber property. However, its determination is necessary from commercial as well as quality point of view. Trash% is measured by an instrument called ‘Trash Analyzer’ which works on the principle of ‘separation’. Normally 100-200 gms of cotton is tested for determining the trash%.
2. Man-made fiber testing:
Following are the main properties of Man-made fiber:
- Mean Length
- Denier
- Tenacity and Elongation
- Crimp
Mean Length: It is determined by measurement of single fiber on a ruler or measuring tape.
Denier: It can be measured by cutting and weighing method or by using resonance principle on ‘Vibroskop’ instrument.
Tenacity and Elongation: Tenacity and elongation is measured by breaking single fiber on a tensile testing machine. This is expressed as gm/denier and % respectively.
Crimp: Crimp properties of the fibers are important for converting them into yarn. It is expressing the extent of crimpiness in the fiber denoted as crimp%.
Humidity:
Humidity is the amount of moisture present in the atmosphere.
Absolute humidity: It is the weight of water present in a unit volume of moist air. The unit is grams/ cubic meter.
Relative humidity: It is the ratio of actual vapour pressure to the saturated vapor pressure at the same temperature expressed as percentage.
…………………..Actual vapour pressure
R.H % = ——————————————————- x 100
………………….Saturated vapour pressure
Moisture regain: It is an important parameter which effects the behavior of fibers. Moisture regain is determined by difference in weight of fibers at standard condition and after oven drying.
…………………….Weight of sample at 65% R.H – Oven dry weight
M.R % = ——————————————————————————————– x 100
……………………………………………Oven dry weight
Standard Atmospheric Conditions :
- H – 65 %
- Temp – 27oC
Yarn testing:
Testing of yarns is required for determining their quality and to control the quality of the finished product.
The main yarn quality parameters are given below:
- Yarn Count
- Lea Strength
- Single yarn strength
- Unevenness
- Imperfections
- Classimat Faults
- Hairiness
Yarn Count: The term yarn count or yarn number is commonly used to define fineness of yarn. The yarn count is determined by measuring yarn length accurately and weighing it on electronic balance.
Lea Strength: Lea yarn strength is determined by testing lea of 120 yards on pendulum type ‘Lea strength tester’. Strength is expressed in lb or kg depending upon the requirement. Yarn strength is important from processing and fabric strength point of view.
Single yarn strength: Single yarn strength is a better indicator of yarn performance in knitting and weaving. This is tested on Single yarn strength tester working at constant rate of traverse (CRT) or constant rate of extension (CRE). Values are expressed as gm/tex or RKM.
Twist: Twist is an important property of yarns as it gives strength to yarn and feel in fabric. Depending upon the direction of twist (S or Z type), twist is measured by untwisting the yarn in case of plied yarn and by twist – re twist method in case of single yarn. It is expressed as TPI (Twist per Inch) or TPM (Twist per Meter).
Classimat faults: The yarns also have seldom occurring faults, besides Uster imperfections which are known as objectionable faults.These faults are classified as A,B,C,D,E,F,G,H,I by Uster Classimat system and are generally expressed in terms of no. of faults/lacs meters .
Advantage of classimate:
Origin of yarn faults can be identified:
- Optimization of clearer gauge settings.
- Customer requirement could be fulfilled.
Hairiness: All the fibers are not bound in core of yarn and lots of them protrude from the surface. These are termed as ‘hairs’. Hairs are varying in length ranging from 0.5 mm to 10 mm. These hairs are measured by optical scanning or by CCD camera technique by Uster hairiness tester.
You may also like:
- Classification of Textile Testing: Fiber Testing, Yarn Testing, Fabric Testing
- Different Types of Textile Testing Methods
- Reasons for Textile Testing and Different Fabric Test
- List of Chemical Testing Equipments for Dyeing Lab
- Different Types of Testing Equipments Used in Textile Lab
- Spinning Testing Lab Equipments, Their Specifications and Functions
- List of Physical Testing Machines in Dyeing Lab
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
