To confirm the particular quality of any fabric, fabric testing has great importance. sorts of tests required for the material are confirmed by the customer . it's going to vary from one buyer to a different . As its importance, this text has shown an in depth discussion on fabric testing.
Fabric Testing.
Normally garment is produced from fabric. the material are often woven or knitted or knit fabric, solid color dyed, printed, check, or stripe that's finished fabric. Before making garments from those fabrics especially for giant quantities. It should be kept in mind that the garment could also be rejected by the customer thanks to some quality problem of the material although the material could also be fresh . To avoid such sorts of problems, fabrics need to test to spot their actual quality before making the clothes and it's called fabrics testing.
Objects of materials Testing:
The reasons for completing tests on fabrics are numerous and a few common ones are acknowledged below:
To check that the material conforms to fabric specification.
To note the effect of changes in structural details.
To note the effect of physical and chemical treatment, exposure to weather or laundering or washing, etc.
To obtain some identification of probable performance in use.
To investigate the causes of failure and customers complain.
To help in designing a cloth for a selected purpose.
To study the interaction of fiber, yarn, and fabric properties.
List of Some Common Fabric Tests:
There are differing types of cloth tests have done by using different fabric testing machines before cutting the material to verify the proper quality of the material . Among those, some common fabric tests have presented within the following:
Abrasion resistance,
Stiffness test,
Drape test,
Crease recovery test,
Pilling test,
Colorfastness test,
Shrinkage test,
Special property test etc.
Abrasion and Abrasion Resistance Test
Abrasion:
Abrasion is one aspect of wear and tear and is that the rubbing away of the component fibers and yarns of the material .
Abrasion could also be classified as follows-
Plane or flat abrasion-A flat area of fabric is abraded.
Edge abrasion-This quite abrasion occurs at collars and folds.
Flex abrasion-In this case, rubbing is amid flexing and bending.
Abrasion Resistance:
The resistance power against damage thanks to abrasion of a cloth referred to as abrasion resistance.
Factors affecting abrasion resistance:
Fibre type:
Nylon is usually considered to possess the simplest abrasion resistance. Polyester and polypropylene even have good abrasion resistance. Blending either nylon or polyester with wool and cotton is found to extend their abrasion resistance. Viscose and acetates have rock bottom abrasion resistance.
Fibre properties:
A fabric made up with longer fibres gives better abrasion resistance than short fibres because they're harder to get rid of from the yarn. For an equivalent reason filament yarns are more abrasion resistant than staple yarns made up of an equivalent fibre. Increasing fibre diameter up to a limit improves abrasion resistance.
Yarn twist:
An optimum amount of twist during a yarn gives the simplest abrasion resistance. At low-twist factors, fibres can easily be faraway from the yarn in order that it's gradually reduced in diameter. At high twist levels, the fibres are held more tightly but the yarn is stiffer so it's hard abrade struggling
Fabric structure:
Fabrics with the crimp evenly distributed between warp and weft give the simplest wear because the damage is spread evenly between them.
Martindale Abrasion Tester:
Detailing of the machine:
This apparatus gives a controlled amount of abrasion between fabric surfaces.
Abrasion is given at comparatively low pressures in continuously changing directions.
In this test, circular specimens are abraded under known pressure.
This abrasion is given by a motion that's the resultant of two simple harmonic motions at right angles to at least one another.
The fabric is abraded against a typical fabric called abradant.
Abrasion resistance is estimated by visual appearance or by loss in mass of the specimen.
METHOD :
Four specimens, each of 38mm in diameter are cut by using the acceptable cutter.
Then they're mounted within the specimen holders with a circle of ordinary foam backing behind the material . The specimens must be placed flat against the mounting block.
The test specimen holders with the specimens are placed on the abradant.
A spindle is inserted through the highest plate and therefore the correct weight (usually of a size to offer a pressure of 12kPa but a lower pressure of 9kPa could also be used if specified) is placed on top of this.
The standard abradant should get replaced at the beginning of every test and also replaced after each 50,000 cycles if the test is sustained beyond this number.
While the abradant is replaced it's held flat by a weight and therefore the retaining ring is tightened.
Behind the abradant, there's a typical backing felt which is replaced at longer intervals.
After appropriate clamping of specimen on the holders, required numbers of cycles of abrasion is applied.
Several methods are wont to judge the quantity of injury . Some are mentioned below:
The difference in appearance between an abraded and unabridged specimen.
The number of cycles required to supply a hole, broken threads or broken strip.
Loss in weight often plotted against the amount of cycle. Change in thickness e.g. loss of pile height.
Loss in strength. tensile, bursting or tearing strength, expressed in percentage of unabridged strength.
Change in another properties like luster, air permeability etc.
Microscopic examination of injury of yarns and fibers.
The specimen is examined at suitable intervals without removing it from its holder. within the Table, the time intervals between examinations are shown.
All four specimens should be judged individually. The individual values of cycles to breakdown of all four specimens are reported and also the typical of those .
Things to be consider before abrasion testing / Factors affecting abrasion tests:
Condition of specimen: the material should be conditioned and tested during a standard testing atmosphere.
Choice of testing instrument: the selection of testing instrument could also be dependent upon the character of the testing desired, e .g-flat abrasion, flexing abrasion, etc.
Choice of abrasive motion: The rubbing movement could also be reciprocating, rotary or multidirectional.
Direction of abrasion: The direction of abrasion are often at angles to the warp and weft directions.
Choice of abradant: The severity of the abrasion will vary with the character of abradant. For example: steel and carbide give constant abrasive qualities. a typical worsted or canvas fabric, abrasive of varied grade also are used as abradant.
Backing the specimen: The hardness of the backing of the specimen may affect the results. In some testes a tough backing is employed , in others a felt or rubber .
Cleanliness of the specimen and instrument: The region to be abraded should be handled as little as possible and be free from foreign matter like graphite of pencils. The accessories of the instrument which can rub the material must be spotlessly clean and free from grease.
Tension on the specimen: Standard method of mounting the specimen should be wont to avoid errors thanks to variation within the tension used.
The pressure between abradant and specimen: The severity of the abrasion are going to be suffering from the pressure applied. So suitable standard must be found out .