Overall process of Denim

1. Welcome to the presentation
of
overall process of denim
Presented to
Shamsuzzaman Sheikh
Assistant professor
&
Abu Yousuf Mohammad
Anwarul Azim, CSCA
Lecturer,
Textile Engineering Department,
DUET.
Presented by
Abdul Kader
Id: 135049
TE-4/2

2. Introduction
• Now a day’s Denim is a most popular and demanding fabric around the world
because of the unique features of denim fabric. Denim came from the French
word “Serge de Nimes”. “Jeans” produced by denim is preferable to the
teenagers because it can be worn as a fashionable or casual dress in different
conditions. The production of denim is more than 50 percent of the world’s
production is done by the South Asian countries whereas China and Bangladesh
are one of the larger contributors.
• Denims are produced from 4 oz. to 16 oz./ sq. yds in weight. Technically Denim is
defined as a 3/1 warp faced twill but also produced from weaves like: Left hand
twill, right hand twill, broken twill, cross hatches, cords, dobby's, structures, etc.
• Denims are made from yarn dyed warp and undyed weft. Traditionally, denim
was dyed with various shades of indigo, yarn-dyed, different costs, and over-
dyed with various types finishes at fabric as well as garments state. Denims are
manufactured different types of after treatments or washes like stone wash,
bleach wash, hand wash, acid wash, over dyed, printed denims and even
embossed.

3. Features of denim fabric:
• Denim is one of the highly demanding international commercial fabric.
• Produce by 100% cotton yarn but you may find there are a few denim fabric
blended with spandex and polyester.
• Manufactured by Twill weave.
• Warp yarn dyed by indigo/blue eye.
• Weft yarn remain white/grey as its natural color.
• Denim jeans is very strong and does not tear easily that’s why it is long lasting.
• Denim can be ironed at a high temperature.
• Denim is very long lasting fabric but after a certain period it becomes fade.
• Denim is durable, drape and flexible in nature.
• Denim is a woven fabric made by interlacing warp and weft yarn.
• To control shrinkage, wrinkling commonly blended with spandex.
• Blended denim fabric has a very good stretch ability, comfortable wear for a
slim figure.
• Use of denim: Jacket, jeans, shirts, skirts, swimsuit, belts, handbags etc.

4. Some denim types
Raw denim selvedge denim Organic denim stretch denim
Poly denim Colored denim
Denim from fox
fibre
Crushed denim

5. Some denim types
Vintage denim Ecru denim Marble denim Reverse denim
Bull denim Printed denim Slub denim
Cotton serge
denim

6. Fibre criteria
Most of the denims are produced with 100% cotton and cotton-based blends with Lycra®,
Polyester, Tencel®, Bamboo, Jute, Nylon, and Linen etc. An ideal cotton mix for denim
should have the following quality parameters.
2.5% span length > 25mm
Strength (g/tex) >18
Micronaire > 4.5 to 5.0
Maturity Coefficient >0.75
Uniformity Ratio> 49%
Trash> 4.9%
In Bangladeshi mills, in most cases substantial quantity of waste yarns are used. This is
mainly done to reduce the cost of production. A well established mix for denim yarns are as
follows;
i. 80% waste, which consists of
(i) Dropping-1,
(ii) Dropping-2,
(iii) Flat strip,
(iv) Comber noil.
ii. 20% Fresh Cotton

7. Yarn criteria
(i) Rotor yams are the best and most widely used yarns in Denim production.
Because of their very high speed rotor yams are much cheaper than ring spun
yams. Off course rotor can only produce yarns of up to 30Ne. Though cheap
rotor yarns are associated with greater imperfections than corresponding ring
yarns therefore knit goods are produced from ring yarns.
(ii) Count range from 6 to 16 Ne but most widely used range is 7 to 12 Ne. For
slub yarn the range is 9 to 20 Ne.
(iii) Quality- Counf CV-<1.2, Single yarn strength> 12.8 gm/tex, Elongation>
6.0,U% <9.5.
(iv)As huge amount of slub yarns are used today the idea of too much strict U%
is not considered.

8. Warping section
Ball Warping process:
• In ball warping, 350 to 500 yarn ends are
pulled from the creel. The yarns then pass
through a comb-like device (reed), which
keeps each warp yarn separate and
parallel to its neighboring ends.
• At intervals of every 1000 or 2000 yards,
a lease string is placed across the sheet of
warp yarns to aid yarn separation.
• The yarns then go through a funnel-
shaped device called a trumpet or
condenser, which collapses and
condenses the sheet of yarn into rope
form.
• The rope is wound onto a long cylinder
called a log on a machine called as a ball
warper.
• Indigo dyeing will take place at rope form.

9. Dyeing section
Pre Scouring
↓
Hot Wash
↓
Cold Wash
↓
Dye baths
↓
Hot Wash
↓
Cold Wash
↓
Softener
Application
Process sequence
Dyeing sequence

10. Long chain beaming section
• Once the warp yarns are rope dyed, it is then necessary to change the yarn
alignment from a rope form to a sheet form before entering the next
process, sizing. Re-beaming involves pulling the ropes of yarn out of
storage tubs and moving them upward to a guiding device (sometimes
called a satellite). This upward travel allows the ropes to untangle.
• Once the ropes come down from the guiding device, they go through
tensioning rollers to help further the separation of the ropes before going
through a comb at the warper
• Warper separates individual yarn ends and keeps them parallel to one
another. From the comb, the warp yarns are guided onto a flanged section
beam.
• After sizing, it is ready for weaving.

11. Figure: Long chain beamer.
Can
Accumulator
Tension Stand
Reed
Counting Roller
Beam
Main parts
Cont..

12. Sizing unit
Accomulator
Size box
Dryer
Accomulator
Leaser
Beaming unit
Main parts
Sizing sequence

13. Types of sizing
Surface sizing
Mantle sizing
Core sizing

14. Weaving section
The weaving process interlaces the warp, which are the length-wise
indigo dyed yarn and the filling, which are the natural-colored cross-
wise yarn. The warp thread is in the form of sheet. The weft thread is
inserted between two layers of warp sheets by means of a suitable
carrier, such as Shuttle, Projectile, Rapier, Air current, Water current,
etc. The selection of carrier depends upon the type of weaving
machinery used. The two different technologies available for weaving
machines are –Conventional Shuttle Weaving System which is done by
Ordinary Looms or Automatic Looms; and the Shuttleless Weaving
System which is done by Airjet, Waterjet, Rapier, or a Projectile
weaving machine. The Conventional Shuttle loom results in lesser
production due to slow speed and excessive wear and tear of machinery.
As such, now denim is generally woven through Shuttle less Weaving
System namely, Airjet looms, rapier looms or projectile looms.

15. Finishing section
Denim Finishing The final woven fabric, wound on a cloth roll, is taken out
from weaving machines at particular intervals and checked on inspection
machines so that any possible weaving fault can be detected. In this quality
control exercise, wherever any fault is seen, corrective measures are taken then
and there only. The woven Denim Fabrics then goes through various finishing
processes, such as brushing, singeing, washing, impregnation for dressing and
drying. Brushing and singeing eliminate impurities and help to even the surface
of denim fabric. Dressing regulates the hand and rigidity of the fabric while
compressive shrinking manages its dimensional stability. The standard width
denim fabrics is then sent for making up. In this process, the fabric is cut into
the desired width according to the size required. The made- up denim fabric is
then thoroughly checked for defects such as weaving defects, uneven dyeing,
bleaching and dyeing defects, oil stains, or patches. After inspection, the final
product is categorized quality-wise. The fault less fabrics are sent to the
packaging department while the defective ones are sent for further corrections.

16. Thanks to all