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In-house testing lab

The only way to ensure your future in garment exports!

Manjit Singh Saini

Gone are the days when packed shipments, without inspection and quality control, used to leave our shores and the money used to flow in our bank account. What would happen with, the so-called un-inspected merchandise used to be the sole responsibility of the buyer. Today the times have changed drastically. The buyer is altogether different, knowledgeable and well versed. He really demands complete satisfaction on the quality front, before he even proceeds to place an order with any exporter.

The buyer will demand reports from a third party (a professional lab like, SGS or MTL or ITS etc) along with the shipment so that he is assured of the quality of the merchandise, which he is purchasing. The present times have even gone far beyond the third party inspection. The buyer demands each of his supplier to be totally quality conscious with strict quality control norms with an in-house testing laboratory. He wants to see that the organisation from which he is procuring has the quality mindset. In addition to getting the testing certificate from a professional lab, the fast growing exporters have realised the importance of having an in-house testing lab in their organisation. This is the sole reason of why the big exporters are progressing very fast and the small exporters are withering away. The big difference is the Q-factor. In-house quality control lab and quality assurance tools confirms the buyers of the quality mindset. The question which is frequently asked is why to have an in-house testing laboratory ? We shall try to answer this question.

An in-house testing laboratory ensures quality at two important levels:

Level 1: In-process quality control

Level 2: Quality assured final product.

Level 1: An in-house testing laboratory saves money during the in-process quality control in the following ways:

1. Speeds up the production as you do not need to wait for the result from the professional lab. (Mind it, TIME is the most crucial factor in exports!) 2. It helps in the development of processes and systems that are reliable and repeatable.

3. Minimises the possibility that the final product will be rejected.

4. Minimises the possibility that expensive re-processing will be required.

5. Reduces the need to use expensive transport to deliver the late foods due to reprocessing.

6. Builds the confidence of the Exporter, as every lot can be tested as against only one or just few lots, the testing facilities being in-house.

Level 2: The testing laboratory saves money at the end process where the quality assurance is a vital part of the relationship with the customer. When you deliver the goods, which meet the requirement of the buyer, you save money in the following ways:

1. Reduces the cost of claims from the customer.

2. Reduces the possibility of the wastage due to fabric problems.

3. Keep the exporters reputation and goodwill unharmed.

4. Strengthens possibility of getting repeat orders.

5. Keeps the relationship with the buyer happy and guarantees long and cordial relationship.

A properly equipped and managed testing laboratory that uses good laboratory practices is the key to making the above savings and taking advantages of a secured future thru confirmed quality assurance and control. An in-house testing lab has become an integral part of the success of a garment export house. When the QC lab has attained such high importance, it is necessary that every garment exporter should have the basic knowledge of the important tests, carried out in an in-house testing lab.

Depending upon the type of garment and its intended usage, various types of tests are conducted on the fabric/garment. The major types of tests conducted are as below:

1. Colour fastness testing (Washing, rubbing, light, perspiration etc.) 2. Physical properties testing (GSM, count, length, construction etc.)

3. Durability performance testing (Tensile, bursting, abrasion etc.)

4. Comfort & safety performance testing (Spray, flammability etc.)

5. Aesthetic performance testing (Stiffness, drape, crease, pilling etc.)

We will explain and cover the colour fastness testing in this article.

COLOUR FASTNESS TESTING

The colour fastness properties of the textile material are of considerable significance. A fabric/garment is purchased for its colour and other aesthetic properties. The fabric should retain such properties for a considerable period of time. The durability of the colour is dependent on factors like fiber content, class of dyes, method of dyeing and printing, type of finishing treatments as well as action of washing and detergents used. The most common tests in the colour fastness testing are as below:

a. Colour fastness against rubbing (dry/wet)

b. Colour fastness against washing

c. Colour fastness against perspiration

d. Colour fastness against light.

Two other Important Tools/Equipment for the colour fastness testing are the : e. Grey scales for assessing the colour fastness results.

f. Colour matching cabinet for assessment.

a. Colour fastness against rubbing (dry/wet) or crocking

It is one of the most important and preliminary test in colour fastness of textiles. This test is designed to determine the amount of colour transferred from the surface of coloured textile material to other surfaces by rubbing. It is applicable to textile made from all fibers in the form of yarn or fabric whether dyed, printed or otherwise coloured.

Equipment : The instrument used to ascertain the rubbing fastness of any type fabric or even the garment is called Crockmeter. As per the standard the operator needs to move the meter handle 10 complete turns at the rate of one turn per second. This is the Crockmeter.

New: The Manual Crockmeter. To ensure that the test is conducted in the right procedure and to eliminate the dependence on the competency of the operator an automatic version of the Crockmeter is available : digiCROCK (motorised crockmeter).

Principle of the test: A coloured test specimen is rubbed with white crock test cloth (either dry or wet) under controlled conditions. The colour transferred to the white crock cloth is assessed by a comparison with the grey scale for staining.

b. Colour fastness against washing

Another important test in an in-house laboratory. This test is intended for determination of colour fastness of textile material (cotton, linen, silk, manmade fibers, wool), in any form (fibre, yarn or fabric) against washing. Equipment: The instrument used to ascertain the washing fastness is called digiWASH (normally called Launderometer). The digiWASH (ISO) is a washing fastness tester, which is completely made of stainless steel, to undertake the testing as per ISO/British/European standards. Whereas the digiWASH - II adheres to both ISO as well as AATCC standards. The digiWASH can also be used to ascertain colour fastness against bleaching and dry-cleaning.

Principle of the test: A specimen of textile in contact with pieces of specified adjacent fabrics (or multi-fiber fabric) is mechanically agitated tin soap solution, rinsed and dried. The Change in colour of the specimen and the staining of the adjacent fabrics are assessed with the grey scales. The specimens are tested under appropriate condition so temperature, detergent solution, bleaching and abrasive action such that the colour change is similar to that occurring in five hand, hone or commercial launderings.

c. Colour fastness against perspiration

An important test for sportswear fabric and garments. This test is intended for determination of colour fastness of textile material of all kinds and in all forms (fibre, yarn or fabric) to the action of human perspiration. As the human perspiration can be either acidic or alkaline so the perspiration test is conducted making both the solutions.

Equipment: The instrument used to ascertain the perspiration fastness is called Perspirometer. There are two models of Perspirometer available for perspiration test.

1. Perspirometer Package SS (ISO): As per ISO/BS/European standard.

2. Perspirometer Package SS (AATCC): As per AATCC standards.

The Perspirometer SS Package (whether ISO or AATCC) consists of two unit of Perspirometer units with one dead weight. The AATCC Perspirometer dead weight exerts the pressure of 4.54 kg, whereas the ISO Dead Weight exerts a pressure of 5.00 kg. The two units with one dead weight is supplied to ensure the accuracy of the test. As human perspiration can be either acidic or alkaline hence two units are used separately one for acidic and other for alkaline to avoid contamination of the samples during testing.

Principle of the test: Specimens of textile in contact with pieces of specified adjacent fabrics (or multi-fiber fabric) are treated in two different solution (acidic and alkaline). These specimens are than drained and placed between the two plates under a specified pressure in the Perspirometer. The Perspirometer units are than kept in an Incubator to provide body temperature for a certain time. The specimens and the adjacent fabric are dried separately. The change in colour of each specimen and the staining of the adjacent fabrics are assessed with the grey scales.

d. Colour fastness to light

Colour fastness to light refers to the ability of the fabric to withstand colour change when exposed to sunlight. The resistance to degradation (or fading) of fabric dyes and prints due to light is an important requirement of a garment because without such resistance, the garment may change colour and such colour may not be acceptable to the client. This method covers the scope for determining of the colour fastness of textile material of all kinds and in all forms to the action of daylight or artificial light.

Equipment: The instrument used to ascertain the colour fastness to light are as below:

1. Colour fastness of textile material to daylight (equipment used : Exposure rack)

2. Colour fastness of textile material to artificial light (Carbon-arc lamp) (Equipment used : digiLIGHT)

3. Colour fastness of textile material to artificial light (Xenon lamp) (Equipment used : XenoLIGHT)

4. Colour fastness of textile material to artificial light (Advanced xenon lamp apparatus in which the temperature, humidity, rain, light exposure etc. can be controlled) (Equipment used: Advanced Weather-O-meters).

Principle of the test: Specimen of the textile material to be tested and THE light fastness standards are exposed simultaneously to a light source under specified conditions. The colour fastness to light of the specimen is evaluated by comparison of the colour change of the exposed portion and the unexposed portion by using a grey scale. The light fastness classification is determined by comparing the change in colour of the specimen with that of the simultaneously exposed light fastness standards.

e. Grey scales for assessing colour fastness results

Once the tests have been conducted on the colour fastness instruments, we need to get the result in a universally acceptable output so that anyone can understand the end result. There are two types of grey scales:

i. Grey scale for assessing staining.

ii. Grey scale for assessing change in colour.

i. Grey scale for assessing staining: The grey scale for staining consists of nine pairs of nominally white and gray colour chips, each representing a difference in colour or contrast (shade and strength) corresponding to a numerical rating for staining. The result of staining from a colourfastness test is rated by visually comparing the difference in colour or the contrast between the stained and unstained specimens with the difference represented by the scale. The colour fastness grade is equal to the grey scale step which is judged to have the same colour or contrast difference.

ii. Grey scale for assessing change in colour: The grey scale for colour change consists of nine pairs of standard gray colour chips, each representing a difference in colour or contrast (shade and strength) corresponding to a numerical fastness rating. The result of a colour fastness test is rated by visually comparing the difference in colour or the contrast between the untreated and treated specimen with the differences represented by the scale. The colour fastness grade is equal to the grey scale step which is judged to have the same colour or contrast difference. While doing analysis with any of the above grey scale, as per standards, the surface area needs to be illuminated with an artificial daylight/north sky daylight source with illumination of 538 lux (50 lumens per square foot) or more. The light should be incident upon the surfaces at 45ø 5? and the direction of viewing 90 ? 5? to the plane of the surface. This is where the need for a colour matching cabinet comes, as this condition is satisfied by a colour matching booth having a 45ø angle stand.

f. SpectraLUX II (colour matching cabinet)

A colour matching cabinet makes an integral part of the colour fastness analysis and colour matching process. It provides standardised and controlled environment for visual assessment of colours and to undertake the analysis of results of the colour fastness testing instruments (i.e. digiCROCK, DigiWASH, digiLIGHT, XenoLIGHT, etc.). The SpectraLUX II along with a 45ø angle stand completely meets the standard requirement of the light which should be incident upon the surfaces at 45 ? 5? and the direction of viewing 90 ? 5? to the plane of the surface. SpectraLUX II is the latest colour matching booth specially designed to meet the requirement of American buyers and major US retail stores. It is a foldable type cabinet with high quality construction having six light sources:

1. Artificial Daylight (D65)

2. Cool White Light (CWF)

3. U-30 Light (American store light matching)

4. TL-84 Light (European store light matching)

5. Inc A Light (Domestic light matching)

6. UV Black Light (For whites and florescent dyes).

(The author is the CEO and executive director of Paramount group)