This document is actually based practical research That was completed during my internship in AMSONS textiles mills (pvt.) ltd Karachi, Sindhi, Pakistan. This document will really help you in your studies and will make it easy for you to understand about the process that are usually followed during printing and dyeing of fabric. In this document the quality control procedures of textile industry are also discussed.

1. Manufacturing Process of Textiles Mills
Muhammad Umair Akram#1
1#
Industrial & Manufacturing Engineering Department, NED University of Engineering and Technology
University Road, Karachi-75270., Sindh, Pakistan
1im079um@gmail.com
2umair.an@ymail.com
The flow chart of manufacturing process of AMSONS Textile Mill (Printing & Dying of Gary Fabric) that I observe
during my internship is as follow
After all these processes have done the finished fabric is sent to the market.
Grey Fabric
Inspection
Singeing & Desizing
Bleaching
Mercerizing
(If required)
Setting
(On Stenter)
Inspection
Dyeing OR Printing
Washing
(On PAD steam if dyed)
Inspection
Curing
(If printed)
Finish
(On Stenter)
Calendar
Sanforising
(If required)

2. I. INSPECTION OF GREY FABRIC
The manufacturing of anything requires raw material
AMSONS textile mill (Dying & Printing of Fabric) uses the
grey fabric as the raw material. This is usually collected by the
waving department or sometimes by the party.
The first step of manufacturing process is to inspect the raw
material that is as per required? Grey fabric is inspected as
1. Thread Counting i.e. (warp & weft)
In the fabric manufacturing process thread selection is
important to get the proper GSM of fabric it counted
by Pick glass.
2. Weight/sq. meter yarn
3. Yarn count
In this process we take the 10 threads of warp and ten
threads of weft and then they are weighted separately.
And then put in to this formula
Yarn count = number of threads*length of threads
(cm)*0.0059/weight of threads in (gm.)
Here the inspection of the grey fabric is completed.
II. SINGEING & DESIZING
The process of singeing is carried out for the purpose of
removing the loose hairy fibres protruding from the surface of
the cloth, thereby giving it a smooth, even and clean looking
face. Singeing is an essential process for the goods or textile
material which will be subjected to mercerizing, dyeing and
printing to obtain best results from these processes.
The fabric passes over brushes to raise the fibres, and then
passes over a plate heated by gas flames. When done to
fabrics containing cotton, this results in increased wettability,
better dyeing characteristics, improved reflection, no "frosty"
appearance, a smoother surface, better clarity in printing,
improved visibility of the fabric structure, less pilling and
decreased contamination through removal of fluff and lint.
Gas singeing is used in AMSONS textile industry. In gas
singeing, a flame comes into direct contact to the fabric and
burn the protruding fibre. Here, flame height and fabric speed
is the main concern to minimize the fabric damage. Singeing
is a mechanical process by which hairy, loose fibres are
removed from the surface of the textile material either by
heating or burning to make the material smoother and
lustrous.
Desizing is the process of removal of sizing material.
Different types of sizing materials are being used in industries.
The sizing material is of no use after the yarn is being woven
into fabric.
Desizing is the process of removing sizing materials from
the fabric, which is applied in order to increase the strength of
the yarn which can withstand with the friction of loom. Fabric
which has not been desized is very stiff and causes difficulty
in its treatment with different solution in subsequent
processes. After singeing operation the sizing material is
removed by making it water soluble and washing it with warm
water. Desizing is done by the oxidative method
(chlorine, chloride, bromite, hydrogen peroxide)
It is generally assumed that it is necessary to remove the
sizing material to achieve the satisfactory levelness of
bleaching, dyeing & printing process. Improper desizing
process may cause the faulty dyeing of fabric like un-even
dyeing and variation in shades and irregular printing.
After these steps, fabric is kept on rotation for 8 to 12 hours
continuously. The degree of proper desizing is determined by
extremely sensitive iodine test and the degree of sizing is
called Tigawa.
III. BLEACHING
Bleaching improves whiteness by removing natural
coloration and remaining trace impurities from the cotton; the
degree of bleaching necessary is determined by the required
whiteness and absorbency. Cotton being a vegetable fibre will
be bleached using an oxidizing agent, such as dilute sodium
hypochlorite or dilute hydrogen peroxide or caustic soda. If
the fabric is to be dyed a deep shade, then lower levels of
bleaching are acceptable. However, for white bed sheets and
medical applications, the highest levels of whiteness and
absorbency are essential. After scouring and bleaching, optical
brightening agents (OBA) are applied to make the textile
material appear whiter.
The bleaching process that is followed in AMSONS textile
is initially the desized fabric is washed/passed through the
tanks of bleaching agent whose recipe is (12gm/l caustic soda
+ 5gm/l weighting agent + 7gm/l stabilizer + 1gm/l sick ester)
then this fabric is steam heated at about 95⁰C for 30 to 40
mints then after fabric is passed through the water tanks and
washed. Thus the fabric is bleached.
IV. INSPECTION OF BLEACHED FABRIC
When the fabric is completely bleached its sample is than
send to the printing & dyeing lab where its inspection takes
place. The following three tests are done on the bleached
fabric.
1. Absorbency
2. Tigawa
3. PH
Absorbency test is carried out after bleaching. A scale is
stamped on the sample and dropped in to the liquid for 1 mint
the fabric absorbs the liquid. For the better quality level the
absorbency level must be higher or equal to 3.
Since the hydrogen per oxide is harm full to the human
body it is therefore, necessary to test the Tigawa according to
the scale defined the less the number of Tigawa the better the
quality it gains. This test is done by dropping iodine liquid on
the fabric, and then matches the colour with pre-defined scale.
For better quality level Tigawa must be less than 4.
PH
test is necessary to control the PH
of the dyeing bath
because it affects the exhaustion and fiction rate some dyeing
process are carried out in the alkaline medium and some are
done in acidic medium. It depends on the dye characteristic
and what type of dyes is used for which fibre. In general the
PH
level must be greater than 6.
V. MERCERIZING
Mercerization is a treatment for cotton fabric and thread
that gives fabric or yarns a lustrous appearance and
strengthens them. The process is applied to cellulosic
materials like cotton or hemp. A further possibility is
mercerizing during which the fabric is treated with sodium
hydroxide solution to cause swelling of the fibres. This results
in improved lustre, strength and dye affinity. Cotton is
mercerized under tension, and all alkali must be washed out
before the tension is released or shrinkage will take place.
Mercerizing can take place directly on grey cloth, or after
bleaching.
(This is an optional step, performed when party requires)
Note: During our whole internship mercerizing process was
not performed.
VI. SETTING

3. The setting of fabric is done on the Stenter machine.
Stenter is used for open form fabric. After passing the open
compactor fabric enters into the Stenter. Cotton fabric shrinks
width wise and weft distorted due to bleaching and dyeing
process. The main purpose of the fabric is to starch the fabric
width wise and recover the uniform width. The main purpose
of setting is to set the width of the fabric so that we are able to
print or dye the fabric according to requirement.
The function of Stenter is
1. Width of fabric is controlled by the Stenter.
2. Finishing chemicals are applied on fabric by Stenter.
3. Shrinkage property is controlled by the Stenter.
4. GSM of fabric is controlled by the Stenter.
5. Fabric is dried by the stentring process.
VII. DYEING & PRINTING
Dyeing is the process of adding colour to textile products
like fibres, yarns, and fabrics. Dyeing is normally done in a
special solution containing dyes and particular chemical
material. After dyeing, dye molecules have uncut chemical
bond with fibre molecules. The temperature and time
controlling are two key factors in dyeing.
Dyes are used for colouring the fabrics. Dyes are
molecules which absorb and reflect light at specific
wavelengths to give human eyes the sense of colour. There
are two major types of dyes - natural and synthetic dyes.
The natural dyes are extracted from natural substances such
as plants, animals, or minerals. Synthetic dyes are made in
a laboratory. Chemicals are synthesized for making
synthetic dyes. Some of the synthetic dyes contain metals
too.
Fabric dyeing, also known as piece dyeing, is dyeing
fabric after it has been constructed. It is economical and the
most common method of dyeing solid coloured fabrics. The
decision regarding colour can be made after the fabric has
been manufactured. Thus, it is suitable for quick response
orders. Dye penetration may not be good in thicker fabrics,
so yarn dyeing is sometimes used to dye thick fabrics in
solid colours. Various types of dyeing machines are used
for piece dyeing. The selection of the equipment is based
on factors such as dye and fabric characteristics, cost, and
the intended end use.
In AMSONS textile industry the dyes are made or tested
in the lab and then passed for the manufacturing process
and the machine used is Thermo-sol dyeing machine. The
process followed is continuous dyeing process in piece
dyeing, which is used primarily for fabrics that are to be a
solid colour; a continuous length of dry cloth is passed full-
width through a trough of hot dye solution. The cloth then
goes between padded rollers that squeeze in the colour
evenly and removes the excess liquid. In one variation of
this basic method, the fabric, in a rope-like coil, is
processed on a reel that passes in and out of a dye beck or
vat.
Textile printing is referred as localized dyeing. It is the
application of colour in the form of a paste or ink to the
surface of a fabric, in a predetermined pattern. Printing
designs onto already dyed fabric is also possible. In
properly printed fabrics the colour is bonded with the fibre,
so as to resist washing and friction. Textile printing is
related to dyeing but, whereas in dyeing proper the whole
fabric is uniformly covered with one colour, in printing one
or more colours are applied to it in certain parts only, and in
sharply defined patterns. In printing, wooden
blocks, stencils, engraved plates, rollers, or silkscreens can
be used to place colours on the fabric. Colorants used in
printing contain dyes thickened to prevent the colour from
spreading by capillary attraction beyond the limits of the
pattern or design.
Printing process used in AMSONS Textile industries uses
the digital printing mechanism. Digital textile printing is
described as any ink jet based method of printing colorants
onto fabric. Most notably, digital textile printing is referred to
when identifying either printing smaller designs or printing
larger designs onto large format rolls of textile. In AMSONS
Textile Industry Usually “Zimmer” machine is used for
printing of fabric which is based on jet ink technique. On the
machine equal to the equal to the number of colours used in
the design engraved rollers are placed on the machine so that
all colours are printed separately on the fabric thus at the end a
single design as obtained.
VIII. WASHING & CURING
Second step after dyeing is of drying of fabric which is
done on “PAD Steam” machine and then the fabrics goes to
the chemical pad at the third step and finely the dyestuff is
fixed on the fabric. Washing of Dyed fabric is done on the
PAD Steam. This process is performed with sulphur dye.
Fabric picks the chemical and goes to the steamer for fixation.
At the end the fabric goes through the washing pads to remove
the un-fixed dyestuff.
If the fabric is printed so it is needed to be cured. Curing is
the process of hardening the colour on to the fabric so that it
won’t remove after washing. The temperature must get hot
enough to firstly evaporate the water based medium, then set
the pigments - about 150°C [depending on the material to be
heat set], Hair driers & household tumble driers are not
suitable as they do not get hot enough to set the pigments.
IX.INSPECTION OF PRINTED FABRIC
After the printing/dyeing and curing the fabric’s sample is
send to the printing and dyeing laboratory for pilling and
staining i.e.(colour bleeding) tests are performed. Pilling is a
fabric surface characterized by little pills of entangled fiber
clinging to the cloth surface and giving the garment unsightly
appearance. The pills are formed during wear and washing by
the entanglement of loose fibers which protrude from the
fabric surface. Under the influence of the rubbing action these

4. loose fibers develop into small spherical bundles anchored to
the fabric by a few unbroken fibres.
The samples are given a multi directional movement and
rubbed against a standard fabric. After certain number of rubs,
the samples are examined and the number of pills counted.
This may be repeated say in stages of 500 cycles up to 3000 or
5000 and the rate of development of pills noted.
Colour bleeding test is performed on the dry and wet cotton
called “Percale cotton”. A piece of percale cotton is rubbed on
the printed fabric normally for 10 cycles and the degree of
colour bleeding is counted against predefined scale. This
number must be less than 3.
X. FINISHING
Textile finishing is the term used for a series of processes to
which all bleached, dyed, printed and certain grey fabrics are
subjected before they put on the market. The object of textile
finishing is to render textile goods fit for their purpose or end-
use and/or improve serviceability of the fabric. Finishing on
fabric is carried out for both aesthetic and functional purposes
to improve the quality and look of a fabric. Fabric may receive
considerable added value by applying one or more finishing
processes. The machines used for finishing process in
AMSONS Textile Industry are Stenter and calendar.
The purpose of the Stenter machine is to bringing the length
and width to pre determine dimensions and also for heat
setting and it is used for applying finishing chemicals and also
shade variation is adjusted. The main function of the Stenter is
to stretch the fabric widthwise and to recover the uniform
width. The fabric is collected from the batcher to the scary and
then it is passed through the pads where the finishes are
applied and sometimes shade variation is corrected. The fabric
is entered into the mahlo (weft straightener) the function of
the mahlo is to set the bow and also weave of the fabric is
gripped by the clips and pins are also provided but the pins
has a disadvantage that they pins make holes at the selvedge
but the stretching of the pins are greater than the clips. These
clips and pins are joined to endless chain. There are 8 to 10
chambers provided on the machine each chamber contains a
burner and filters are provided to separate dust from air. The
circulating fans blow air from the base to the upper side and
exhaust fans sucks all the hot air within the chambers.
Attraction rollers are provided to stretch the warp yarn.
XI. CALENDER
Calendering is an operation carried out on a fabric to improve
its aesthetics. The fabric passes through a series of calender
rollers by wrapping; the face in contact with a roller alternates
from one roller to the next. An ordinary calender consists of a
series of hard and soft (resilient) bowls (rollers) placed in a
definite order. The soft roller may be compressed with either
cotton or wool-paper, linen paper or flax paper. The hard
metal bowl is either of chilled iron or cast iron or steel. The
calender may consist of 3, 5, 6, 7 and 10 rollers. The sequence
of the rollers is that no two hard rollers are in contact with
each other. Pressure may be applied by compound levers and
weights, or hydraulic pressure may be used as an alternative.
The pressure and heat applied in Calendering depend on the
type of the finish required.
The purposes of Calendering are to upgrade the fabric hand
and to impart a smooth, silky touch to the fabric, to compress
the fabric and reduce its thickness, to improve the opacity of
the fabric, to reduce the air permeability of the fabric by
changing its porosity, to impart different degree of luster of
the fabric, and to reduce the yarn slippage.
XII. SANFORISING
“Sanforising allows preventing the cotton
from shrinking when washed. It is carried out by compressing
the cotton to reduce its shrinking capacity”.
Sanforising is the process of treatment used
for cotton fabrics mainly. It is a method of
stretching, shrinking and fixing the woven cloth in both length
and width before cutting and producing, to reduce the
shrinkage which would otherwise occur after washing.
The cloth is continually fed into the sanforising machine
and therein moistened with either water or steam. A rotating
cylinder presses a rubber sleeve against another, heated,
rotating cylinder. Thereby the sleeve briefly gets compressed
and laterally expanded, afterwards relaxing to its normal
thickness. The cloth to be treated is transported between
rubber sleeve and heated cylinder and is forced to follow this
brief compression and lateral expansion, and relaxation. It is
thus shrunk.
The greater the pressure applied to the rubber sleeve, the
less the shrinking afterwards. The process may be repeated.
The aim of the process is a cloth which does not shrink
significantly during clothes production by cutting, ironing,
sewing or, especially, by wearing and washing the finished
clothes. Cloth and articles made from it may be labeled to
have a specific shrink-proof value.
Note: During our whole internship sanforising process was
not performed.
Then at the end this finished fabric is sent to
the market for seal.