Denim fabric manufacturing process
S.M.Imtiazuddin (Popular Fabrics) and Anwer Tiki (AVM
The story of jeans begins in the mid 19th century
simultaneously in two European cities. Nimes in France, where
the fabric itself was created, the so-called “Serge de Nimes”
which led to the name denim. The color comes from Genoa in
Italy, as in French “Blue de Genes” which led to the Expression
“Blue Jeans”. The fiber and color come together to become the
Denim is a sturdy cotton warp-faced textile in which the weft
passes under two or more warp threads. This twill weaving
produces a diagonal ribbing that distinguishes it from cotton
Manufacturing of Denim
The term Denim has originated from the city of Nimes in
France where serge de Nimes was manufactured. Denim is made from
a vat dye, the Indigo dye, which is applied to the cotton fabric
in the loosely held form in layers. As far as manufacturing
process of denim is concerned, it is similar to that of Greige
fabric upto the process of weaving with the only difference that
in case of Denim Fabric, it is dyed at the stage of sizing
whereas, in the case of Greige Fabric, the decision regarding
the dyeing stage depends upon the finished product.
The initial stage of denim production is opening and
blending. Opening being with the bale of cotton fibre being
separated into small tufts. A blend of cotton fibres is made on
each opening line. These bales are selected using the USDA High
Volume Instrument (HVI) data, and PCCA’s unique computer
blending software produces optimal yarn strength.
Therefore, the cotton is delivered to Cards by air suction
from the Opening and Blending lines, through additional cleaning
and blending machines.
The major function of Carding is to remove foreign matter and
short fibers, from the cotton into a web and convert the web
into a rope-like form known as a sliver.
The drawing-in process produces a single, uniform sliver from
six card slivers. The additional blending, paralleling of fibers
and cleaning in this process produces a sliver for Open End and
Ring Spinning process. For Ring Spinning, however, the sliver
must pass through an additional process called Roving.
Cotton Fibers are formed into a yarn by centrifugal action in
Open-End Spinning. Individual fibers are spun into yarn, and
then the yarn is wound into a large package.
The open End Spinning machines have robots on each side which
automatically pieces (repairs broken ends).
On a different track, they have another robot that
automatically doffs (removes full packages) and starts up a new
package. The size and quality of each yarn end are monitored by
the Barco Profile System to ensure uniformity.
In Ring Spinning, the spinning frames receive Roving via a
transit system from the roving machines. The yarn is formed from
cotton fibres that are twisted together after being drafted by
passing between three steel rolls and three rubber rolls.
The yarn then is warped on a bobbin as it spins on a spindle
by use of a traveler. The relationship between roll speeds,
traveler speeds and spindle speeds controls the amount of twist
in the yarn. Ends down levels and production information are
gathered by the Uster Ring Expert System.
The spinning frames automatically doffs bobbin full of yarn
and send them to package winding ACG, which when needed one can
produce Amsler Open End yarn, also known as Faux Ring Spun yarn.
This technology enables ACG to impart various slub patterns into
an Open-End yarn. Denim made from this type of yarn character
and surface interest that cannot be achieved with traditional
(A) Greige yarn on cones: Normally yarn
received for weaving in cone form through ring spinning or from
open-end spinning in the single or double fold as required. For
weaving yarn is categorized into the following:
It is important to note that for yarn used for warp should be
sufficiently strong to withstand stress and strains exerted
during weaving operation. Hence they are having Count Strength
Product (CSP) and further sized to increase its strength. The
weft yarn is directly used on weaving machines and in some
cases, if required, is rewound also so as to enhance its
performance in weaving.
(B) Warping on Sectional/Direct Warping: The
warp yarn is required to be fed into a sheet form to the weaving
machines. At warping the individual cones are put into the creel
(the number of cones depends upon fabric construction) and yarn
from individual cones is pulled together in sheet form, wound on
a barrel called warping beams (for Direct warping) or on weaving
beams (for Sectional Warping). Normally if warp sheet is with
patterns of different colored yarns it is processed on the
sectional warping machine.
(C) Sizing of yarn in Set/ Beam to Beam Position:
The object of sizing is to improve the strength of yarn by
chemically binding the fibers with each other and also improve
upon its friction resistance capacity by chemically coating the
surface of yarn/fibers.
Furthermore, the number of threads in the warping beam sheet
is less than a number of threads required in the whole width of
the fabric. Hence multiplication of sheets by drawing yarn
together from many warp beams and again making one sheet is also
performed on sizing machine.
On sizing, normally 8 to 12% size material on warp thread is
applied. This improvement in strength and frictional resistance
characteristics of warp yarn is essential because, during
weaving, the yarn has to undergo serve strain and stress as well
as frictional issues.
(D) Drawing-in: Weaving is basically
interlacement of two sets i.e. warp and weft threads in desired
sequence and pattern. To obtain this interlacement, warp yarn
sheet is bifurcated and opened in the form of two layers/ sheet
and weft thread is inserted between so opened two warp sheets.
This operation is called shedding to perform shedding the warp
yarn needs to be passed through heald eyes of the heald shafts,
this operation is called as drawing-in.
(E) Beam Gaiting or Knotting on Loom: The beams
are fixed on weaving machines, threads are tied and heald shafts
are coupled. This operation is called Beam Gaiting. If undrawn
warp threads are directly knotted to the threads of finished
beams, it is called knotting. These operations are essential
because normally weavers beam can carry the only a certain
length of warp sheet on it and when so woven, the whole length
is converted to the fabric by weaving machine. Further warp
length is required to be fed which can be done by knotting or
Gaiting other beams on a weaving machine.
(F) Weaving: As stated earlier, weaving is
interlacing two sets of yarn and making fabric. One set is
called warp thread which is in sheet form, the other one is
called weft thread which is inserted between two layers of warp
sheet by means of a suitable carrier i.e. Shuttle, Projectile,
Rapier. Therefore, depending upon the type of the weaving
machine, the different types of technologies available for
weaving machine are briefly explained below:
- Conventional Shuttle Weaving System by Ordinary Loom or
- Shuttleless Weaving System by Air jet/Water
The shuttle loom is a conventional technology with much less
production on account of slow speed and excessive wear and tear
The above-mentioned shuttle loom technology has now become
obsolete. Denim is woven through shuttleless weaving systems
either on Air jet, Rapier or Projectile looms. These looms are
distinguished by their weft insertion methods.
Air jet Looms
These types of looms adopt the latest development in weaving
technology where weft insertion is done with the help of
compressed air. A very high weft insertion up to 2000
meters/minute is achieved. Compressed to rapier and projectile
looms, these looms are less versatile, but are economical and
are used in mass textile production unit like denim.
Water jet Looms
A water jet is a machine for weaving cloth (loom) which uses
a jet of water. The force of air to insert the weft (crosswise
threads) into the warp (lengthwise threads) water carriers the
yarn from one side to the other.
A rapier loom is a shuttleless weaving loom in which the
filling yarn is carried through the shed of warp yarns to the
other side of the loom by finger-like carriers called rapiers. A
stationary package of yarn is used to supply the weft yarns in
the rapier machine.
Dyeing and sizing of denim yarn
In denim fabric, warp yarns are indigo dyed. There are
various type of dyeing and sizing process which can be
classified into four types:
(i) Continuous indigo rope dyeing and sizing
The yarn which we get from the Ring frame is wound into
cheeses or cones and then placed on the ball warp on which 350
to 400 threads are formed into a rope. During this process, 12
to 24 ropes are dyed at a time based on the size of the rope
(ii) Continuous indigo dyeing and sizing
During this process, back beams are processed on the dyeing
and sizing machine instead of rope. The warp is dyed, oxidized,
dried and sized at the once.
(iii) Indigo back beam dyeing and sizing:
According to this process dyeing and sizing is done in two
stages. In the first stage, back beams are dyed, oxidized, dried
and wound on a batch roll. The batch roll is then sized, dried
and wound on a weavers beam.
(iv) Continuous Indigo Slasher dyeing & sizing
Contrary to the Indigo rope dyeing system, for the continuous
slasher dyeing and sizing back beams are used in this context.
That means that the total number of ends required for a weavers
beam are dyed, dried, sized and dried simultaneously.
Denim fabric dyeing
There are two types of dyeing processes of denim fabrics.
These are indigo dyeing and sulphur dyeing. The Indigo dyeing
produces conventional blue color and shade just like blue color.
Sulphur dyeing is used to produce a particular color like black,
grey, rust mustered and lime. Both are vat dyestuff. Both are
insoluble in water and have a very poor affinity to cellulose
fibers like cotton.
Finishing of denim fabrics
The final stage for denim fabrics means that the fabric is
wound on a cloth roll that comes from the weaving machine at a
particular interval and checked on the inspection machine. Here,
at the inspection machine any possible weaving fault can be
detected. Then, the fabric goes through various finishing
processes, such as brushing, singeing, washing, impregnation for
dressing and drying. Brushing and singeing remove impurities and
hairiness of the denim fabric. After completing all of the above
finishing processes, the fabric is sent to the garment
- Denim 1st Edition, Manufacture, Finishing and
Applications by Roshan Paul.
- The Denim Jeans Guide-Gentleman’s Gazette.
- Technical Bulletin. www.cottoninc.com.
- Mogahzy. Y.E (2009). Engineering Textile Integrating the
Design and Manufacture of Textile Products 1st Edition.
- Kadolph SJ. Textiles, 11th Edition. Upper Saddle River,
N.J.: Prentice Hall; 2010.
- Dinker Mahajan: Known All About Denim. Mahajan
Publishers Private Ltd. Ahmedabad.