QUALITY CONTROL IN TEXTILE

DEFINITION

QUALITY CONTROL:

"The systems required for programming and coordinating the efforts of the various groups in an organization to maintain the requisite quality”.

OBJECTIVES:

To maximize the production of goods within the specified tolerances correctly the first time.

To achieve a satisfactory design of the fabric or garment in relation to the level of choice in design, styles, colours, suitability of components and fitness of product for the market.

QUALITY CONTROL IN TEXTILE

Every operation under wet processing such as pre-treatment, dyeing, printing or finishing irrespective to its specific aim in desired product finds its basis in:

Maintenance of high quality Cost effectiveness Improved functionality Lower generation of waste Minimum use or reuse of water and chemicals Overall environment friendliness Application of appropriate machinery and technology

ON-LINE QUALITY CONTROL SYSTEM

This type of quality control is carried out without stopping the production process. During the running of production process a set up automatically performs and detect the fault and also takes corrective action.

Raw Material Controlo Best quality raw materials with economical considerationo The fabric must be without fault, with proper absorbency,

whiteness as per requirement of the subsequent process.

Process Controlo Process with accurate parameters

OFF-LINE QUALITY CONTROL SYSTEM

Performed in the laboratory and other production area by stopping the production process consisting of fabric inspection and laboratory and other test. Correction steps are taken according to the test result.

All the Off-Line tests for finished fabrics can be grouped as follows:

o Physical tests o Chemical tests

Specified test methods of AATCC, ISO, ASTMD, M&S, DIN, JIS etc.

PHYSICAL TESTS

• Identification of fiber physically• Count & construction of fabric•  Blend Ratio•  Abrasion, Pilling & snagging • Strength (Tear, strip, seam slippage, cyclic and

bursting) • Dimensional stability • Appearance test • Crease recovery • Air permeability/down proof  test

FASTNESS TESTING

• Light fastness• Washing fastness• Dry Cleaning• Perspiration• Cold Water and Sea Water• Yellowing • Dry heat and hot pressing • Sublimation•   Rubbing Fastness (Crocking) 

CHEMICAL TESTS

• Determination of Formaldehyde content• Percentage Purity of Acids & Alkalis• Auxiliaries for application of wet processing• Viscosity• pH• Tests for variety of Functional Finishing • Flammability • Water & Oil repellency test • Soil/Stain release test

TENSILE STRENGTH

A test piece is held in two or more places and extended until it breaks. The tensile properties measured are generally considered arbitrary rather than absolute. Results depend on specimen geometry, the fiber type and arrangement, as well as the fabric structure.

Standards commonly used for tensile strength tests are as follows:

o ISO 13934-1:1999o ASTM DS 034-95

TENSILE STRENGTH

FABRIC ABRASION RESISTANCE:

To abrade the sample until a predetermined end-point is reached, such as the breaking of two threads or the generation of a hole, while recording the time or number of cycles to achieve this

Many different standards are used worldwide for abrasion resistance tests, including:

o ISO 12947-1-1998o ASTM D 3884

FABRIC ABRASION RESISTANCE:

o A four-inch diameter specimen normally less than 12.5mm thickness is mounted on a rotating turntable.

o Abrasive wheels are applied to the sample using a fixed weight.

oFor a specified number of cycles, the abrasive wheels wear away the sample.

oThe result is calculated by measuring the weight loss per thousand cycles of abrasion.

CROCKING RESISTANCE

To measure for colorfastness to crocking, the fabric to be tested is rubbed with squares of white cotton fabric (wet and dry) under controlled pressure for a specified number of times. The amount of color transferred to the white test squares is matched to a control chart and a rating is established.

Standard commonly used for Crocking resistance test is as follows,

o AATCC 8

CROCKING RESISTANCE

ULTRA-VIOLET LIGHT RESISTANCE

To measure for colorfastness to light, the fabric to be tested is exposed under specific conditions to a controlled light source which simulates the sun’s rays. At timed intervals, the test swatch is compared to a gray scale and the degree of fading is rated.

Standard commonly used for Crocking resistance test is as follows

o AATCC 16A

DETECTION OF FORMALDEHYDE IN TEXTILES

 A weighed fabric specimen is suspended over water in sealed jar.  The jar is placed in an oven at a controlled temperature for a specified length of time.

  The amount of formaldehyde absorbed by the water is then determined colorimetrically.

Test methodo AATCC 112-2008

FLAME RESISTANCE

VERTICAL FLAME TEST:o Fabric is mounted in a vertical holder and exposed to an open

flame for a specified amount of time. Once the flame is removed, the after flame and char length of the test sample are measured against various code standards to establish a classification.

o ASTM D6413

TUNNEL TEST:o Fabric is clamped or glued to a substrate, which is placed on

the ceiling of test chamber and ignited by a flame below. Fabric is then evaluated for the density of the smoke formed, the amount of fuel contributed and the extent of the flame spread. Rating is established based on these factors.

o ASTM E84 

FLAME RESISTANCE

OILY STAIN/SOIL RELEASE TEST

A stain is applied to a test specimen. An amount of the staining substance is forced into the fabric by using a specified weight. 

The stained fabric is then laundered in a prescribed  manner and the residual stain rated on a scale from 5 to 1 by comparison with a stain release replica showing a graduated series of stains.

Standard methodo AATCC 130-2010