Introduction of Textile Testing and Quality Control

Testing : Testing is the process or procedure to determines the quality of a product.

Quality : The term quality refers the excellence of a product. When we say the quality of a product is good . We mean that the product is good for the purpose for which it has been made.

Control : To check or verify and hence to regulate.

Problems of Textile Dyes in the Environment

Dyes cause a lot of problems in the environment:

1. Depending on exposure time and dye concentration, dyes can have acute and/or

chronic effects on exposed organisms.

2. The presence of very small quantities of dyes in water (less then 1 ppm) is highly

visible due to their brilliance.

3. The greatest environmental concern with dyes is their absorption and reflection of

sunlight entering the water. Light absorption diminishes photosynthetic activity of

algae and seriously influence on the food chain.

Defination, Properties and Uses of Printing Thickeners

Thickener or Print pastes are traditionally made by weighing out and, if necessary, dissolving the
colorants and auxiliary chemicals and then stirring them into the required weight of
pre-prepared thickener. A thickener is a colourless, viscous paste made with one or
more thickening agents. The use of terms such as thickener, and thin, long or short, to
describe print pastes is of course descriptive rather than scientific, but is long
established and a useful reminder that the materials being handled possess complex
properties, not easily defined.The thickener must be stable and compatible with the dyes and auxiliaries to be used.

Combing Process of Cotton Spinning

The combing process is carried out in order to improve the quality of the sliver coming out of

the card. The process eliminates short fibres, it achieves better parallelisation of fibres, it

straightens curls, and it removes neps and residue impurities. It is clear from these functions that

the combing process is essentially aimed at obtaining excellent quality yarns and to fulfil this

objective raw materials with above average physical and mechanical features must be used from

the very beginning of the spinning process.

Working Process of Cotton Carding

Carding is one of the most important operations in the spinning process as it directly determines the final features of the yarn, above all as far as the content of neps and husks are concerned. There are many objectives of the carding process and these can be summarised as:

The basic knitting action of a needle

The basic knitting action of a needle

Figure A (1–7) illustrates the basic action of a needle. Except for the manner in
which the hook is closed (in this case by pressing the beard), the knitting action is
similar for all needles.The arrows indicate the relative movement of the loops along
the needles. (Whether the needle moves through the loops or the loops are moved
over the needle by some other elements depends upon the machine design.)

The knitting action of the latch needle

The knitting action of the latch needle
Figure A shows the position of a latch needle as it passes through the cam system,
completing one knitting cycle or course as it moves up and in its trick or slot.

1 The rest position. The head of the needle hook is level with the top of the verge
of the trick. The loop formed at the previous feeder is in the closed hook. It
is prevented from rising as the needle rises, by holding-down sinkers or web
holders that move forward between the needles to hold down the sinker loops.

The features of the latch needle

The features of the latch needle
The latch needle has nine main features (Fig. A):
1 The hook, which draws and retains the new loop.
2 The slot or saw cut, which receives the latch-blade (not illustrated).
3 The cheeks or slot walls, which are either punched or riveted to fulcrum the latchblade
(not illustrated).

The main parts of the bearded needle

The main parts of the bearded needle

There are five main parts of the bearded needle (Fig:A):


1 The stem, around which the needle loop is formed.
2 The head, where the stem is turned into a hook to draw the new loop through
the old loop.
3 The beard, which is the curved downwards continuation of the hook that is used
to separate the trapped new loop inside from the old loop as it slides off the
needle beard.

The advantages of the latch needle

The latch needle has the major advantage of being self-acting or loop-controlled,

so that individual movement and control of the needle enables stitch selection

to be achieved. It is ideally suited for use with computer-controlled electronic

selection devices. For that reason, it is the most widely used needle in weft knitting

and is sometimes termed the ‘automatic’ needle (provided there are loops on the

needle).

Fundamentals of Singeing

The verb ‘singe’ literally means ‘to burn superficially’. Technically, singeing refers to the burning-off of. Loose fibres not firmly bound into the yarn and/or fabric structure;

• Loose yarns not firmly bound into the fabric structure;

• Protruding fibre ends sticking out of the textile yarns and/or

fabrics.

Textiles materials are most commonly singed in woven or knitted fabric form or in yarn form.

Fundamentals of gas Singeing

In this type of singeing machine, the fabric passes over a burning gas flame at such a speed that only the protruding fibres burn and the main body of the fabric is not damaged by the flame. This is the most common type of machine used for singeing fabrics as well yarns.

Description of Basic Loom Mechanisms

The basic mechanisms in any type of loom can be classified as follows:

(a) Primary motions

(b) Secondary motions, and

(c) Auxiliary motions.

The primary motions can further be divided as shedding, picking and beat up motions. The shedding

opens the warp sheet into layers to facilitate passage of shuttle. The picking motion causes the shuttle

carrying weft to be propelled from one end of loom to another. The beat up motion lays the previously

laid weft to the fell of the cloth.

Definition, Characteristics and Classification of Twill Weave

Twill weaves are the weaves that find a wide range of application. They can be constructed in a variety

of ways. The main feature of these weaves that distinguishes from other types is the presence of

pronounced diagonal lines that run along the width of the fabric.

Definition, Characterestics and uses of honey comb

The honey comb weaves derive their name from their partial resemblance to the hexagonal honey comb

cells of wax in which bees store their honey. These weaves form ridges and hollows which give a cell

like appearance to the textures. Both warp and weft threads float somewhat on both sides, which coupled

with the rough structure, renders this class of fabric readily absorbent of moisture. The weaves are of

two classes, namely,

Definition and characteristics of Plain Weave

The plain weave is variously known as “calico” or “tabby” weave. It is the simplest of all weaves

having a repeat size of 2. The range of application of this weave is wide.

The plain weave has the following characteristics :

(i) It has the maximum number of binding points

(ii) The threads interlace on alternate order of 1 up and 1 down.

(iii) The thread density is limited

(iv) Cloth thickness and mass per unit area are limited.

(v) It produces a relatively stronger fabric that is obtained by any other simple combination of

threads, excepting that of “gauze”or “cross weaving”.