Yarn to Fabric Manufacturing

QUALITY ASSURANCE

TEXTILE TESTING

Textile testing is checking the quality and suitability of raw material and the selection of material. It is an important part of textile production, distribution, and consumption. Though it is an expensive business but essential too. There are some reasons for textile testing; such as, checking raw materials, monitoring production, assessing the Final Product, investigation of faulty material, product development, and research.

TESTING: Testing means checking, examine and verification of some items. On the other way, we can define testing as; it is the process or procedure to determine the quality of a product.

OBJECT OF TESTING

• Research
• Selection of raw material
• Process control
• Process development
• Product testing
• Specification test
• Testing is governed by 5M, which are: Man, Machine, Material, Method, and Measurement.

QUALITY CONTROL

Quality control is the synthetic and regular control of the variable which affects the quality of a product. It is the checking, verification, and regulation of the degree of excellence of an attribute or property of something.

It is the operational techniques and activities that sustain the quality of a product or service in order to satisfy given requirements. It consists of quality planning, data collection, data analysis, and implementation and is applicable to all phases of the product life cycle; design, manufacturing, delivery and installation, operation, and maintenance.

• Objects of Quality Control: To produce a required quality products.
• To fulfill the customer’s demand.
• To reduce the production cost.
• To reduce wastage.
• To earn maximum profit at minimum cost.

IMPORTANCE OF TEXTILE TESTING

The primary objective of textile testing is to assess the product’s properties and predict its performance during use. The information obtained may be used for the following:

1. Research and development
2. Selection of raw materials/inputs
3. Process development
4. Process control
5. Quality control
6. Product testing
7. Product failure analysis
8. Comparative testing and benchmarking
9. Conformity with government regulations and specifications

TYPES OF TESTING

PHYSICAL TESTING

FABRIC CONSTRUCTION TEST

DEFINITION:

EPI: EPI means “Ends per Inch”. A number of yarn in the warp direction is measured by EPI. Normally, ends per Inch are the number of warp threads. It represents a vertical thread of the fabric. It is called warp yarn.

PPI: PPI means “Picks per Inch”. The number of Weft yarn in the fabric is measured by PPI. Picks per inch are the number of weft threads of the fabric. It represents the horizontal threads. It is called weft yarn.

PURPOSE:

To calculate the EPI and PPI of the given sample.

PROCEDURE:

• Collect the fabric swatch.
• Put the fabric swatch on the plain table.
• And also marks the wrap & weft direction of the fabric.
• Mark 1X1 inch on the fabric sample and place pick glass over it
• Count vertical or wrap yarn one by one and find out the number of warp yarns.
• Count horizontal or weft yarn one by one and find out the number of weft yarns.

TESTOMETRIC TENSILE TESTING MACHINE

TENSILE STRENGTH:

• Tensile testing is the most commonly applied test method for analyzing the mechanical properties of fabric materials.
• Tensile strength is the ability of a material to withstand a longitudinal pulling (tensile) force and refers to the breaking strength of a material when applying a force capable of breaking many strands of the material simultaneously, at a constant rate extension/load.

PURPOSE:

• Tensile testing of textiles provides the strength and elongation properties for both natural and manmade materials, such as cotton, carbon, polyester, nylon, glass, and graphite.
• This test method is used as an indication of the tendency of yarns to slip at a seam. Such slippage results in garment failure at a seam, which is not readily repairable by re-seaming.

APPLICATION

Textile Tensile Testing Machine can test tension, bursting, tear, elongation, elastic, thread slip, peeling, and other mechanical properties of textile, this tensile equipment talks directly with a PC running a data analysis software package in English, via a high-speed RS232.

GRAB TEST

• A grab test is a tensile test in which the center part of the specimen width is gripped in the tensile grip jaws.
• Due to the way the sample is gripped, edge effects, which may cause inaccurate data for fabrics, are eliminated.

TESTING METHOD – ASTM D5034

The ASTM D5034 (Grab Test) is a test method of the American Society of Testing and Materials (ASTM).

PREPARATORY PROCESS

To measure a fabric’s ability to resist grab test, fabric is cut to the following specifications:

• Length: 14
• Breadth: 10

PROCEDURE

• To evaluate, the fabric being tested is put into a machine that grips the fabric with two clamps.
• One clamp is stationary and the other moves away applying tension until the fabric breaks or ruptures.
• This test is performed in both the warp and weft directions.
• The number of pounds required causing a fabric to break or rupture determines the rating.

SEAM SLIPPAGE TEST

• This test method is used to determine the resistance to slippage of filling yarns over warp yarns, or warp yarns over filling yarns, using a standard seam.

TESTING METHOD- ASTM D434

The ASTM D434 is a test method of the American Society of Testing and Materials (ASTM).

PREPARATORY PROCESS

To measure a fabric’s ability to resist seam slippage, a seam is constructed to the following specifications:

• Length: 35cm
• Breadth: 10cm
• Seam Type: 301 Lockstitch
• Stitches per Inch: 13 to 14

PROCEDURE

• To evaluate, the fabric being tested is put into a machine that grips the fabric with two clamps.
• One clamp is moved away from the other applying tension at the sewn seam. This test is performed in both the warp and filling directions.
• The tension is increased until the seam separates to a specific distance.
• The number of pounds required to cause separation due to yarn slippage determines the rating.
• A seam slippage of a maximum of 6mm is acceptable for woven fabrics.

ELMENDROF TEAR TESTING

TEAR STRENGTH

Tearing strength is the resistance of a fabric to withstand a tearing force required to propagate a tear after its initiation.

SCOPE

This test method covers the determination of the force required to propagate a single-rip tear starting from a cut in fabric and using a falling-pendulum (Elmendorf-Type) apparatus.

PURPOSE

This test for the determination of tear strength is used extensively throughout the trade and applies to most fabric types. This test is suited for the machine direction of warp knit fabrics and not suited for either direction of other types of knit fabric.

SAMPLE PREPARATION

• Cotton fabric was taken.
• Warp and weft direction of the fabric was identified.
• Two strips were cut from the fabric of the dimensions of the tear tester template.

PROCEDURE

• The pendulum is positioned to the starting position.
• The sides of the specimen are placed centrally in the clamps with the bottom edge carefully set against the stops and the upper edge parallel to the top of the clamps.
• The specimen should lie free with its upper area directed toward the pendulum to ensure a shearing action.

• Using the built-in knife blade a 20mm slit is centrally cut in a test specimen held between two clamps and a force is applied which propagates the slit as a tear through the specimen.
• The resistance to tearing is factored into the equipment scale using the pendulum capacity.
• For weft direction, we get the value of warp and for warp direction, we get the value of weft.
• The resistance is recorded as the tearing strength of the specimen.

 

EQUIPMENT USED

Falling pendulum tester

• Weight of the blade – 6400 gms

• Size of the cut – 2mm

 

PILLING TEST

Pilling is a fabric surface characterized by little pills of entangled fiber clinging to the cloth surface and giving the garment an unsightly appearance. The pills are formed during wear and washing by the entanglement of loose fibers which protrude from the fabric surface.

 

TESTING METHOD – ISO12945-1

 

PURPOSE

This method is used to assess fabric surface pilling and fuzzing by tumbling randomly.

 

PROCEDURE

• A specimen (12 cm x 12 cm) is cut from fabric (2 for warp 2 for weft).
• Both ends of the fabric sample were fixed on the polyurethane rubber tube.
• All the four samples are then tumbled together in a cork-lined box 9” x 9” x 9” and allowed for the required 360 revolutions per cycle.
• The specimens are taken out and removed from the rubber tube and rated.
• These samples are put into pilling boxes as per the conditions. The conditions or standards involves:

1. All wool samples which contain 50% more wool are kept in rotation under the pilling box for 5 hrs.
2. Terry wool samples which contain more % of polyester are kept in rotation under pilling box for 10hrs

 

ABRASION TEST

Abrasion is one aspect of wear and is the rubbing away of the component fibers and yarns of the fabric.

PURPOSE

• Martindale Abrasion & Pilling Tester is to determine the abrasion and pilling resistance of all kinds of textile structures.
• Samples are rubbed against known abrasives at low pressures and in continuously changing directions. The amount of abrasion or pilling is compared against standard parameters.

 

PROCEDURE

• The sample to be tested is conditioned first.
• Then the test specimen is prepared.
• The abrading cloth is mounted on the machine which is called woven felt having GSM around 600, diameter 140mm.
• Then the sample whose abrasion is to be measured is placed in the sample holder then it is put on the abrading cloth in between plates.
• Before going to start the actual process first the Lissajous of the figure is found which confirms the proper working of the machine.
• Then the 200kg weight of sample holder and 595kg weight of a whole specimen.
• Total 9kpa force is applied and the machine is started after 20000 rotations the testing of the sample is done for thread break, min 2 thread breaks are observed.
• Then it is considered an endpoint. 20min are required for 1000 revolutions.
• Then in terms of the number of rubs the abrasion reading is given.

 

INSTRUMENT USED

Martindale abrasion cum pilling tester

 

GSM (GRAM PER SQUARE METER)

GSM is a metric measurement meaning grams per square meter- it is how much 1 square meter of fabric weighs and the higher the GSM number the denser the fabric will be.

 

PURPOSE: To measure and calculate the GSM accurately.

 

TEST METHOD – ASTMD3776

 

PROCEDURE

• The sample is conditioned first with the standard atmospheric conditions.
• The sample is cut accurately of size 30cm by using a template then the weight of the sample is taken and by using the following formula the GSM is calculated.
• GSM=WEIGHT/AREA

INSTRUMENT USED: Paramount template30cm/30cmandWeight Balance

 

CHEMICAL TESTING

SHRINKAGE TEST

Shrinkage is “width wise or lengthwise contraction of textiles material usually after wetting or drying or to an exposure to evaluated temperature.”

 

PURPOSE

This test method is intended for the determination of dimensional (length and width) changes of fabrics when subjected to home laundering procedures.

 

TESTING METHOD – AATCC135

PROCEDURE

• The fabric to be tested is conditioned first.
• Then the shrinkage marking on the sample is done by using a template.
• Then the sample is taken for a normal wash if it is all wool sample. The container is used which is filled with water and a few drops of TFO are added for better shrinkage analysis.
• The samples are dipped into water at 27Degree Celsius kept for 2 hrs.
• Then rinsing & drying is done.
• For another sample except for all wool samples, the process is the samples are kept in a washer at 41degree Celsius and then it is taken out.
• Shrinkage can be measured by using the following formula,

% shrinkage=Initial length –final

Length /Initial length *100

 

MACHINE USED

Whirlpool washing machine, container, Template 25cm&whirlpool Tumble Dryer

 

COLORFASTNESS TO WASHING

• Colorfastness is the resistance of a fabric to change in its color characteristics or to transfer its colorant(s) to adjacent materials.

PURPOSE

• This part of ISO 105 specifies methods intended for determining the resistance of the color of textiles of all kinds and in all forms to domestic or commercial laundering procedures used for normal household articles using a reference detergent.

 

METHOD USED – ISO105C06

 

PROCEDURE

• First, the test specimen is prepared of a standard method of sample size 10/4cm.
• The sample to be tested is sandwiched between the fabric samples as per standards.
• For Top Specimen Adjacent fabric Terry wool = polyester, cotton, wool All wool = cotton, wool.
• For yarn and fabric Terry viscose = polyester, cotton
• For testing first, the sample stitching is done with the help of a stitching machine.
• The specimen is properly stitched. The launderometer temp set at 60 degrees Celsius.

Process of washing

• For Top Samples are washed using ISO 3 Solution of washing involves Standard soap without OBA 5gpl + sodium carbonate 2gpl.
• The above solution is taken in test beaker and then the sample is inserted into the solution and then the pots or beakers are put into launderometer and the switch is turned ON and the process is continued for 30min.

For yarn and Fabric

• This ISO 2 method is followed which contains a Solution of washing AATCC standard reference detergent without OBA
• These samples are kept in launderometer at 50 degrees Celsius for 45min.
• Then the samples are washed and kept in the oven for drying.
• Then after drying the washing fastness is measured by using greyscale for change in color and staining.

 

INSTRUMENT USED: Launderometer

 

 

COLORFASTNESS TO CROCKING

PURPOSE

A crock test is used to determine the amount of color that may be transferred from a sample fabric to another fabric by rubbing.

TEST METHOD –AATCC8

PROCEDURE

• For this testing first, the sample strip is taken whose rubbing fastness is measured. Then the backside of the sample is taken into consideration for testing.
•  The sample is mounted in the crock meter properly whose rubbing is tested.
• Then a small sample of polyester is taken for testing.
• Dry rubbing and wet rubbing are two parts of rubbing.
•  First, the dry rubbing is carried out by covering the rubbing surface of an instrument having a diameter of 16mm with the help of a sample holder and then turning the switch ON or it is also called resetting the machine.
• Then in 10 seconds. 10 cycles are completed and the machine will automatically stop after the sample is removed.
• For wet rubbing, the polyester sample used is wetted with slight water and rinsed by pressing with paper and the same procedure is followed for wet rubbing by changing the surface of rubbing fabric or by changing the position of rubbing.
• Then after drying of sample the greyscale rating is given which includes rubbing fastness of the sample.
• Colorfastness to crocking/rubbing is categorized from 1-5. The higher the number the better is the fastness.

 

COLORFASTNESS TO SUBLIMATION

• Sublimation is the process of phase change from solid to gas, without going into the liquid phase.
• Fastness to sublimation is probably the most important requirement of dyed polyester, apart from fastness to light. The migration behavior and wet fastness of dispersed dyes on polyester are closely involved with their response to heat treatments.

PROCEDURE

• The test is only carried out for top &yarns.
• The sample is taken and sandwiched between polyester samples like adjacent fabric and then the test specimen is kept on the plates of sublimation fastness tester at 180 degrees Celsius for 30 seconds then the samples are taken out and by using greyscale the ratings are given to it.
• For all wool samples, this test is not applicable because wool damage at this higher temp

 

INSTRUMENT USED:

Precision press or sublimation fastness test.

 

Sample Tests