industrial training on amber denim mills limited
TRANSCRIPT
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Department of Textile Engineering
Industrial Attachment
AMBER DENIM MILLS LTD. Banglabazar, Gazipur, Bangladesh
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AMBER DENIM MILLS LTD. Banglabazar, Gazipur
View of Amber Denim Mills Limited
Prepared by:
Rakibul Hasan ID: 113-088-041
Batch: 24th(WET) Cell: 01930492011
Online published by:
Md. Israfil Alam Rana Sr. Engineer
R&D Cell: 01717123339
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Supervising Faculty:
Dr. A.B.M. Abdullah
Professor Department of Textile Engineering
Primeasia University Banani, Dhaka
Industrial Supervisor:
Engr. Md. Kamruzzaman
D.G.M (Plant) Amber Denim Mills Limited
Banglabazar, Joydevpur, Gazipur
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ACKNOWLEDGEMENT
“In the name of Allah, the most Merciful and Beneficent"
At first my gratefulness goes to Almighty Allah to give me strength and ability to complete this industrial
attachment. You have made my life more bountiful. May you name be exalted. honored and glorified.
Now, we wish to take this excellent opportunity to thank a lot of people who have assisted inspired us in
the completion of our training period.
We fell grateful to and wish our profound our indebtedness to Professor M.A. Khaleq.Dean&
Head,Department of Textile Engineering, Primeasia University for his kind approval of the thesis topic and
guidance during my study.
We would like to express our deepest sense of gratitude to our supervisor Professor Dr. A.B.M. Abdullah.
Professor, Department of Textile Engineering for his continuous advice, encouragement and guide to
make the industrial attachment.
We would like to express our deepest sense of gratitude to our Co-supervisor Sr.Lecturer Nayon Chandra
Ghosh, Department of Textile Engineering for his continuous advice, encouragement and guide to make
the industrial attachment.
We are thankful to our Md. Anwar Hossain, Assistant Professor, Department of Textile Engineering. For
his continuous advice, encouragement and co-operation to make the industrial attachment.
We would like to thank the management of the Amber Denim Mills Ltd. for giving our opportunity to
work on the different sections and helping our in every possible way. Our deepest appreciation goes to
Engr. Md Kamruzzamam, DGM, Amber Denim Mills Ltd. For his permission to conduct my industrial
training without which it would be uncompleted.
We are also thankful to Md. Shazzadul Islam, AGM(Dyeing), Amber Denim Mills Ltd. for providing the
required data and also for guiding in a profound way to complete our industrial attachment.
After him I would like to thank Mr. Rafat Bin Hasan and Mohammad Israfil Alam for their continuous
advice, encouragement and co-operation to make the industrial attachment.
We would like to thank our entire course mate in Primeasia University, who took part in this ,discuss
while completing the course work.
Finally , we must acknowledge with due respect the constant support and patients of my parents.
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CONTENTS
Table of Contents
ACKNOWLEDGEMENT ................................................................................................................................... 4
INTRODUCTION ............................................................................................................................................. 9
COMPANY PROFILE .............................................................................................................................................. 11
1.1 ABOUT AMBER GROUP ............................................................................................................................................ 11
1.2 ENTERPRISES OF AMBER GROUP ................................................................................................................................ 12
1.3 AMBER DENIM MILLS LTD. ....................................................................................................................................... 13
1.4 COMPANY PROFILE ................................................................................................................................................. 15
1.5 WORK-TIME SCHEDULE OF THE FACTORY .................................................................................................................... 16
1.6 TYPE OF MACHINE USED .......................................................................................................................................... 17
1.7 FACTORY LOCATION MAP ........................................................................................................................................ 18
1.10 PRODUCTION PROCESS FLOW CHART ....................................................................................................................... 20
DENIM FABRIC ..................................................................................................................................................... 21
2.1 WHAT IS FABRIC? ................................................................................................................................................... 22
2.2 DENIM FABRIC ....................................................................................................................................................... 22
2.3 WHERE DID THE NAME “DENIM” COMES FROM? .......................................................................................................... 22
2.4 WHAT EXACTLY IS DENIM AND HOW IS IT MADE? ......................................................................................................... 23
2.5 WHAT WAS DENIM FIRST USED FOR? ......................................................................................................................... 23
2.6 DENIM PROCESS FLOW ............................................................................................................................................ 24
YARN ................................................................................................................................................................... 25
3.1 YARN QUALITY ....................................................................................................................................................... 26
3.2 SPECIALTY OF YARNS ............................................................................................................................................... 27
3.3 TYPES OF YARN USED ............................................................................................................................................... 29
3.4 YARN COUNT USED ................................................................................................................................................. 29
3.5 SUPPLIER OF THE YARN ............................................................................................................................................ 29
WARPING ............................................................................................................................................................ 30
4.1 WARPING ............................................................................................................................................................. 31
4.2 IMPORTANCE OF WARPING ...................................................................................................................................... 31
4.3 IMPORTANT REQUIREMENTS OF WARPING................................................................................................................... 31
4.4 WARPING PROCESS INVOLVES ................................................................................................................................... 31
4.5 TYPES OF WARPING ................................................................................................................................................ 32
4.5.1 Direct warping ............................................................................................................................................ 32
4.5.2 Indirect warping ........................................................................................................................................ 33
4.5.3 Ball Warping .............................................................................................................................................. 33
4.6 DEFECTS & REMEDIES OF WARPING ......................................................................................................................... 34
4.7 DIFFERENCE BETWEEN HIGH SPEED WARPING AND SECTIONAL WARPING ........................................................................... 37
4.8 WARPING IN AMBER DENIM MILLS LTD. ..................................................................................................................... 37
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4.8.1 Machine Specifications .............................................................................................................................. 38
4.8.2 Warping Section Layout ............................................................................................................................. 40
4.8.3 Machine Main Parts .................................................................................................................................. 41
4.8.4 Briefly Description of Different Parts ......................................................................................................... 41
4.8.5 Essential Features ...................................................................................................................................... 49
4.8.6 Calculations ................................................................................................................................................ 50
DYEING ................................................................................................................................................................ 52
5.1 DYEING ................................................................................................................................................................ 53
5.2 OBJECTS OF DYEING ................................................................................................................................................ 53
5.3 THEORY OF DYEING ................................................................................................................................................. 53
5.4 DENIM DYEING ...................................................................................................................................................... 54
5.5 DYES USE FOR DENIM : ............................................................................................................................................ 54
5.5.1 Vat Dyes ..................................................................................................................................................... 55
5.5.2 Sulphur Dyes............................................................................................................................................... 57
5.6 DENIM DYEING PROCESS ......................................................................................................................................... 58
5.7 ROPE DYEING ........................................................................................................................................................ 59
5.8 PROCESS SEQUENCE IN INDIGO ROPE DYEING IN DENIM .................................................................................................. 61
5.9 PROCESS CONTROL OF INDIGO ROPE DYEING ............................................................................................................... 64
5.10 SLASHER DYEING .................................................................................................................................................. 66
5.11 LOOP DYEING ...................................................................................................................................................... 67
5.12 DIFFERENCE BETWEEN SLASHER AND ROPE DYEING ..................................................................................................... 67
5.13 RELATIVE MERITS AND DEMERITS ............................................................................................................................. 68
5.14 DYEING IN AMBER DENIM MILLS LTD...................................................................................................................... 69
5.14.1 Machine Specification ............................................................................................................................. 69
5.14.2 Dyeing ...................................................................................................................................................... 70
5.14.3 Pure Indigo ............................................................................................................................................... 70
5.14.4 Topping .................................................................................................................................................... 72
5.14.5 Bottoming ................................................................................................................................................ 74
5.14.6 Regular Dyeing Recipe ............................................................................................................................. 76
5.14.7 Equipments used in dyeing lab ................................................................................................................. 78
LONG CHAIN BEAMING ........................................................................................................................................ 79
6.1 LONG CHAIN BEAMER ............................................................................................................................................. 80
6.2 PROCESS FLOWCHART FOR LONG CHAIN BEAMER ........................................................................................................ 81
6.3 LONG CHAIN BEAMING IN AMBER DENIM MILLS LTD. .................................................................................................. 82
6.3.1 Machine Specification ................................................................................................................................ 82
6.3.2 Essential Features ...................................................................................................................................... 83
6.4 BRIEFLY DESCRIPTION OF DIFFERENT PARTS ................................................................................................................ 83
SIZING .................................................................................................................................................................. 86
7.1 DEFINITION ........................................................................................................................................................... 87
7.2 OBJECTS OF SIZING ................................................................................................................................................. 87
7.3 CHANGES IN YARN DUE TO SIZING .............................................................................................................................. 87
7.4 TYPES OF SIZING ACCORDING TO APPLICATION .............................................................................................................. 87
7.5 SIZE INGREDIENTS AND THEIR FUNCTION ..................................................................................................................... 88
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7.6 CONTROLLING POINT OF SIZING ................................................................................................................................ 90
7.7 SIZING IN AMBER DENIM MILLS LTD. ......................................................................................................................... 91
7.7.1 Machine Specification ................................................................................................................................ 91
7.7.2 Process Flow Chart .................................................................................................................................... 93
7.7.3 Regular Sizing Recipe ................................................................................................................................. 93
7.8 SIZING ................................................................................................................................................................. 95
7.9 BRIEFLY DESCRIPTION OF DIFFERENT PARTS ................................................................................................................. 96
WEAVING........................................................................................................................................................... 100
8.1 WEAVING ........................................................................................................................................................... 101
8.2 FLOW CHART ....................................................................................................................................................... 101
8.3 BASIC WEAVE DESIGNS ......................................................................................................................................... 102
8.4 CLASSIFICATION OF MODERN WEAVING MACHINES .................................................................................................... 103
8.4.1 Air-Jet Weaving ........................................................................................................................................ 103
8.4.2 Projectile Weaving ................................................................................................................................... 104
8.4.3 Rapier Weaving ........................................................................................................................................ 105
8.4.4 Water-Jet Weaving .................................................................................................................................. 106
8.5 WEAVING IN AMBER DENIM MILLS LTD. ................................................................................................................... 107
8.5.1 Machine Specification .............................................................................................................................. 107
8.5.2 Looming................................................................................................................................................... 109
8.5.3 Basic Motion ............................................................................................................................................ 109
FINISHING .......................................................................................................................................................... 117
9.1 DEFINITION ......................................................................................................................................................... 118
9.2 OBJECTS OF FINISHING .......................................................................................................................................... 118
9.3 TYPES OF FINISHING .............................................................................................................................................. 118
9.4 FINISHING IN AMBER DENIM MILLS LTD. .................................................................................................................. 119
9.4.1 Finishing ................................................................................................................................................... 120
9.4.2 Mercerization ........................................................................................................................................... 129
9.4.3 Desizing .................................................................................................................................................... 132
9.5 REGULAR FINISHING & MERCERIZING RECIPE ............................................................................................................. 134
DENIM WASH .................................................................................................................................................... 135
10.1 DENIM WASHING ............................................................................................................................................... 136
10.2 TYPES OF DENIM WASH ....................................................................................................................................... 136
10.2.1 Mechanical wash ................................................................................................................................... 136
10.2.2 Chemical wash ....................................................................................................................................... 136
10.3 DENIM WASHING IN AMBER DENIM MILLS LTD. ...................................................................................................... 137
10.3.1 Regular Recipe ....................................................................................................................................... 137
10.3.2 Machine Specification ............................................................................................................................ 139
10.4 MOST COMMON DENIM WASHES ........................................................................................................................ 143
INSPECTION ....................................................................................................................................................... 148
11.1 INSPECTION IN AMBER DENIM MILLS LTD. .............................................................................................................. 149
11.2 INSPECTION PROCESS .......................................................................................................................................... 149
11.3 FABRIC DEFECTS ................................................................................................................................................. 150
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11.4 DEPARTMENT WISE DEFECTS AND CODES NO ............................................................................................................ 152
11.5 QUALITY ASSURANCE PROCEDURE ......................................................................................................................... 152
QUALITY ASSURANCE ........................................................................................................................................ 154
12.1 QUALITY ASSURANCE IN DENIM ............................................................................................................................ 155
12.2 HANDLING OF RAW MATERIALS IN GODOWN ........................................................................................................... 155
12.3 APPROVAL OF RAW MATERIAL ............................................................................................................................... 156
12.4 WARPING ......................................................................................................................................................... 156
12.5 DYEING & SIZING ............................................................................................................................................... 156
12.6 WEAVING ......................................................................................................................................................... 157
12.7 SINGEING .......................................................................................................................................................... 157
12.8 FINISHING ......................................................................................................................................................... 158
12.9 INSPECTION & PACKING ....................................................................................................................................... 158
12.10 WASHING AND SHADE GROUPING ........................................................................................................................ 159
12.11 DISPATCH ....................................................................................................................................................... 159
RESEARCH & DEVELOPMENT (R&D) ................................................................................................................... 160
13.1 R & D DEPARTMENT IN AMBER DENIM MILLS LTD. .................................................................................................. 161
13.2 DEVELOPED SAMPLES .......................................................................................................................................... 162
13.3 NAME OF SOME BUYERS ...................................................................................................................................... 163
TESTING LAB ...................................................................................................................................................... 164
14.1 QUALITY ........................................................................................................................................................... 165
14.2 DENIM QUALITY ................................................................................................................................................ 166
14.3 QUALITY TESTING ............................................................................................................................................... 166
14.4 INTERNATIONAL STANDARDS ................................................................................................................................ 167
14.5 AQL – ACCEPTED QUALITY LEVEL .......................................................................................................................... 167
14.6 TEXTILE TESTING & QUALITY CONTROL ................................................................................................................... 168
14.7 SCOPE OF FABRIC TESTING ................................................................................................................................... 168
14.8 LAB TEST CAPABILITY .......................................................................................................................................... 171
14.9 MACHINE USED IN TESTING LAB............................................................................................................................ 175
STORE & INVENTORY CONTROL ........................................................................................................................... 180
15.1 STORE AND INVENTORY CONTROL .......................................................................................................................... 181
15.2 SCOPE OF INVENTORY CONTROL ............................................................................................................................. 181
15.3 INVENTORY SYSTEM FOR RAW MATERIAL ................................................................................................................ 181
15.4 INVENTORY SYSTEM OF SPARE PARTS ..................................................................................................................... 182
15.5 INVENTORY CONTROL OF FINISHED GOODS.............................................................................................................. 182
15.6 OTHER INVENTORIES ........................................................................................................................................... 182
MARKETING ACTIVITIES ....................................................................................................................................... 183
16.1 MARKETING ACTIVITIES ....................................................................................................................................... 184
16.2 PROCEDURE OF EXPORT BUSINESS BY AMBER DENIM MILLS LTD. ................................................................................ 184
UTILITIES ............................................................................................................................................................ 186
17.1 DEFINITION ....................................................................................................................................................... 187
17.2 UTILITY DEPARTMENT OF AMBER DENIM MILLS LTD. IS RELATED TO THE FOLLOWING THINGS ............................................ 187
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17.3 WATER SUPPLY .................................................................................................................................................. 187
17.4 BOILER ............................................................................................................................................................ 187
17.5 GENERATOR ...................................................................................................................................................... 189
17.6 AIR COMPRESSOR ............................................................................................................................................... 190
17.7 DRYER ............................................................................................................................................................. 191
17.8 CHILLER ............................................................................................................................................................ 193
17.9 HUMIDIFICATION PLANT ...................................................................................................................................... 194
EFFLUENT TREATMENT PLANT (ETP) .................................................................................................................. 195
18.1 INTRODUCTION .................................................................................................................................................. 196
18.2 ETP IN AMBER DENIM MILLS LTD ......................................................................................................................... 196
18.3 OUTLET EFFLUENT PARAMETERS (BANGLADESH STANDARD) ....................................................................................... 197
18.4 PROCESS FLOW CHART ........................................................................................................................................ 198
18.5 DESCRIBE THE PROCESS FLOW CHART .................................................................................................................... 198
SECURITY ........................................................................................................................................................... 201
19.1 SECURITY SECTION .............................................................................................................................................. 202
19.2 SECURITY MAIN GATE ......................................................................................................................................... 202
DISCUSSION ............................................................................................................................................... 203
SOME SUGGESTIONS: ................................................................................................................................ 203
LIMITATIONS OF THE REPORT: .................................................................................................................. 204
CONCLUSION ............................................................................................................................................. 204
REFERENCES .............................................................................................................................................. 205
INTRODUCTION
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If the theoretical knowledge is a prescription of medicine then the practical knowledge
would be taking of medicine.
It is always very easy to make a man understand about a firebox by showing and lighting
practically
Rather than describing theoretically who has not ever seen a firebox. So, for any technical
education the practical experience is the most important as well as the theoretical
knowledge.
As we are studying in a technical line, it is always important for us to gather the practical
knowledge.
Through our study life the only biggest chance for us to combine the theoretical
knowledge with the Practical knowledge is the “Industrial Attachment Period” that comes
only once in the education life when completing under graduate education.
So we can easily realize the importance of Industrial Attachment. And in addition the
knowledge we gathered from the industrial training reflects in the report of industrial
attachment note book.
So industrial attachment is the process where a trainee can blend his theoretical
knowledge with practical knowledge which increased the ability of work, skills,
performance and attitude and so on.
It also provides sufficient knowledge about production management, productivity
evaluation, work study & efficiency, industrial management, production planning and
control, production cost analysis, inventory management, utility, maintenance and so on.
Industrial attachment makes us reliable to be accustomed with the industrial atmosphere
and also improve courage and inspiration to take self responsibility.
I have tried to my best to prepare this note book applying our best efforts. I have tried to
gather all the necessary information to make it a valuable for me as well as for everyone.
I think it will help me a lot in future practical life.
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Chapter One
Company Profile
1.1 About Amber Group :
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Mr. Showkat Aziz Russell
Chairman of Amber Group
Amber Group was established in 1996 and began its journey with Amber Cotton Mills
Limited. The group flourished with its gradual demand in the market. Apart from cotton,
other successful areas where the group operates include denim, board and doors,
Internet gateway, radio, lifestyle shopping outlet and leisure resort etc. The process of
establishing a television channel in ongoing. Backed by a high density of advanced
technology and sophisticated manufacturing facilities, Amber group is being managed by
highly qualified technical and management professionals. The excellence of the
technology and blooming genius of its personnel are the strength of the organization.
Amber Group with its various interests is rolling ahead with drive and determination to
be the best in all the areas it operates.
1.2 Enterprises of Amber Group :
Amber Cotton Mills Limited
Amber Denim Limited
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Amber Denim Mills Limited
Partex Rotor Spinning Mills Limited
Partex Rotor Mills Limited
Amber Board Ltd.
Amber Lifestyle
Amber Radio
Amber IT
Bhawaal Resort
1.3 Amber Denim Mills Ltd. :
Amber Denim Mills Ltd. is one of the major concerns of Amber Group. It is a premium
denim fabric producing company. It has started its journey in 2012 with the best and latest
machinery available in the world. The current capacity is two million yards of finished
fabric per month.
Figure: Front View of Amber Denim Mills Ltd.
On the fabric side, product range of ADML includes weights from 4.5 oz. up to 14.5 oz.
using multi count, multi-twist ring, open-end yarn using CAIPO technology. It has a world’s
best MORRISON Indigo dye range from USA, which is capable of doing color like
bottoming, topping, reactive colored denim, Sandwich and very deep indigo shades.
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Figure: Weaving Section Figure: Dyeing Section Most modern
Weaving is done on machines from Picanol from Belgium. ADML uses the most modern
weaving machine in air-jet version to get good productivity and to make trouble free
fabric even if it is made with coarser slub or spandex. The loom shed is totally humidified
and temperature controlled with enough air circulation and sufficient pressure to help
machine and yarn to make better fabric and always make the shed clean.
On the finishing side, ADML has machine from MORRISON textile co. of USA, which is the
most modern finishing range introduced in Bangladesh for the first time by Amber.
Sufficient brushing, singeing in both side, high quality skew device, bigger padder,
sanforizer and compacting device to make the fabric more clean and maintain shrinkage
properly.
Amber was the pioneer of starting Flat finish fabric commercially in Bangladesh and is
capable of doing a variation in flat quality as per the buyer’s requirement. They can make
Soft Finish, Flat Finish, and Super Flat as well. This machine was specially designed as per
Amber‘s requirement. Amber gives importance to inspection machines also. To control
proper tension and easy handling Amber uses most modern machines with conveyer belt
with auto wrapping and packing.
On the quality side, Amber uses most modern and efficient lab instruments from Atlas UK
which is operated by trained technicians. The verivide Light box, Spectrophotometer,
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Rubbing tester, Washing Fastness, Tensile strength etc. gives accurate results and helps
to keep quality good and more consistent.
The R&D department is independent and equipped to promptly invent new designs for
new fashion and develop buyer‘s requirement timely. This department keeps all
documents from dyeing recipe to fabric construction and keeps master roll to keep shade
in same consistent even over a longer discontinuity. Amber always researches to develop
new fashion as per the world requirement as well as to maintain comfort & durability.
Amber is manufacturing all kinds of denim fabrics in rigid and stretch in the following
versions: Non flat, Flat Super Flat, Resin coated, Pigment Coated, Over Dyed, PU Coated,
Ash Coloured, Reactive Coloured, ECRU & RFD Denim.
Amber always researches to develop new fashion as per the world requirement as well as
to maintain comfort & durability. Amber is manufacturing all kinds of denim fabrics in
rigid and stretch in the following versions:
Non flat Flat Super Flat Resin coated Pigment Coated Over Dyed PU Coated ECRU Denim RFD Denim Ash Colored Denim Reactive Colored Denim Color Denim
Amber is manufacturing bi-stretch commercially for the first time in Bangladesh. There is
no end in fashion. They are also in the process of making Linen Denim, Viscose denim,
and so on.
On the environment side, Amber maintains a state of the art Water and Effluent
Treatment Plant meeting toughest international standards, and always looks to make the
working environment greener. It has plenty of lush trees surrounding the plant premises.
Amber maintains labour laws, gives all facilities like medical, housing, leave, festival bonus
etc. to their employees.
1.4 Company Profile :
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Company Name AMBER DENIM MILLS LTD Company Status Private Limited Company
Owner Md. M.A.Hashem
Managing Director Md. Showkat Aziz Russell
Factory Location Jangaliapara (Banglabazar), Mirjapur,
Joydevpur, Gazipur-1700.
Corporate Office House: 02, Road: 09, Block: G, Banani,
Dhaka
Type of Factory Fabric Manufacturing
Product Denim Fabric
Capacity 2.1 million yards per month
Project Cost 31.6 million US dollar
Total Area 323000 sft
Production Area 270000 sft
Structure Steel structure surrounded by brick wall
Total Manpower 1144
1.5 Work-Time Schedule of the Factory:
The factory runs 24 hours a day. It maintains a tight work schedule. It follows mainly 3
schedules. i.e. A-shift: 6 a.m. - 2 p.m., B-shift: 2 p.m. - 10 p.m. & C-shift: 10 p.m. - 6 a.m.
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Section Number ofShift Duration
Warping 2 12 hours each
Dyeing 3 8 hours each
LCB 2 12 hours each
Sizing 3 8 hours each
Weaving 3 8 hours each
Finishing 2 12 hours each
Utility 3 8 hours each
Security 3 8 hours each
Stuff &Commercial General Shift 9 a.m. – 5p.m.
Top Management General Shift 9 a.m. – 5p.m.
It is to be noted that 35% workers are working here in 3 shifts and 65% workers are
working in 2 shifts.
1.6 Type of Machine Used :
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Section Machine
Name
Brand Name Origin Model Qua
ntity
Warping Ball Warping
Sectional Warping
Morrision
KARL MAYER
USA
Germany
450 BW
N/A
04
01
Dyeing Rope Dyeing Morrision American N/A 01
LCB Long Chain
Beaming
Morrision USA MDS-RB 550 12
Sizing UKL Sizing m/c
Karl Mayer Sizing
m.c
UKIL Mechinery
KARL MAYER
Korea
Italy
GSSM-100
BM 2600/1000
02
01
Weaving Air jet m/c PICANOL Belgium OMNI Plus 800 180
Finishing Finishing m/c
Mercerize m/c
Morrision
N/A
USA
China
N/A
N/A
02
01
Washing
Washing m/c
Dewater m/c
Laundery Sryer
m/c
YILMAK
N/A
N/A
Turkey
China
N/A
HBM 250S
KZ-20A
GDZZ-25
01
01
01
1.7 Factory Location Map:
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1.10 Production Process Flow Chart:
Ball Warping
Rope dyeing
Long Chain Beamer
Sizing
Drawing-In
Weaving
Finishing
Inspection
Packing
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Chapter Two
Denim Fabric
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2.1 What is Fabric?
The word "textile" comes from the Latin "texere", "to weave." It originally meant a fabric
made from woven fibers. Today, the word "textile" includes fabrics produced by felting,
weaving, knitting, and knotting fibers. It also refers to man-made fabrics which may be
produced by other methods.
2.2 Denim Fabric :
Denim is a cotton or cotton/polyester blend, durable heavy weight twill weave yarn dyed
fabric. Usually the warp is colored and weft is white. It is often right-hand twill with a blue
(indigo) warp and white weft for use in apparel in a variety of weights. Since it is a warp-
faced twill, the colored warp yarns predominate on the face and the white weft yarns on
the back. It is available in several weights, ranging from 4.00 oz/yd2 to 16.0 oz/yd2 in a
2/1 or 3/1 interlacing pattern basically. Its long term popularity has made it a fashion
fabric in casual wear. It may be napped, printed, made with spandex or other stretch yarns
or otherwise modified for fashion. Even today, classic denim is still dyed with indigo dye.
2.3 Where did the name “Denim” comes from?
Denim (French town of Nîmes, from which 'denim' (de Nîmes) gets its name) is a rugged
cotton twill textile, in which the weft passes under two (twi-"double") or more warp
threads. This produces the familiar diagonal ribbing identifiable on the reverse of the
fabric, which distinguishes denim from cotton duck. Denim has been in American usage
since the late 18th century. The word comes from the name of a sturdy fabric called serge,
originally made in Nîmes, France, by the André family. Originally called serge de Nîmes,
the name was soon shortened to denim. Denim was traditionally colored blue with indigo
dye to make blue "jeans", though "jean" then denoted a different, lighter cotton textile;
the contemporary use of jean comes from the French word for Genoa, Italy (Gênes),
where the first denim trousers were made.
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Figure: Classic Denim (indigo dyed)
2.4 What exactly is Denim and how is it made?
Denim is a rugged cotton twill textile, in which the weft passes under two or more warp
fibers. This produces the familiar diagonal ribbing identifiable on the reverse of the fabric,
which distinguishes denim from cotton duck. It is a twill-weave woven fabric that uses
different colors for the warp and weft. One color is predominant on the fabric surface.
Because of this twill weave, it means the fabric is very strong. But today, denim is
diversified in many ways according to customer satisfaction and fashions.
2.5 What was Denim first used for? Denim was originally used by workers. They wore denim clothes because of its durability,
it was extremely strong and perfect for their daily jobs, and it didn’t wear out easily
making it a good fabric for the long run.
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2.6 Denim Process Flow :
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Chapter Three
Yarn
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3.1 Yarn Quality :
In order to produce good quality denim, the yarn quality used for denim production
should be optimal. In rope and slasher dyeing machine the passage of yarn is very
long. Hence it is necessary to control the lapping of yarn in the passage of yarn, otherwise
bands of high and low densities will be formed in the yarn, which ultimately cause shade
variation in the fabric. This leads huge loss of fabric. Therefore the TM of the yarn is to be
appropriate to avoid any snarling of yarn during running through the passage.
The yarn should be free of weak place, to avoid any breakages during dyeing. Long slub,
thick and thin places in the yarn may leads to prominent fabric defects in the fabric, as
denim is a contrast fabric made of indigo blue warp and grey weft yarn. The weft yarn
hairiness should be low, otherwise high yarn hairiness and major variation in yarn
hairiness shown weft bands which is a major fabric defects. Higher yarn neps may also
cause serious fabric defects.
The quality criteria of carded OE or ring spun yarns used for denim production are as
follows:
Minimum staple length:2.7cm
Short fibers proportion (less than 12 mm long) should beunder 40%,
Micronaire value should be 4.0 -4.5,
Twist factor : 4.5 to 5.0, for warp yarns, 4.2 for filling yarn,
Low yarn hairiness, low neppiness
Good yarn strength and uniformity.
In the early 1990s, the majority of yarns used in denim production
were OE yarns. However, recently, there is a strong demand of using
more carded ring spun yarns in both warp and weft, which gives the
fabric a softer handle.
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Warp yarns for bottom weight jeans typically range from Ne 4.0 to Ne 12.5/1 or as per
requirement of finished denim fabric. Finer yarns are used for lighter weight jeans, vests,
dresses, and skirts and the yarns range may be from Ne 12.5 to Ne 30.0.
3.2 Specialty of Yarns :
Modern ring-spinning frames and open-end machines can be installed with devices that
can manufacture predetermined yarn effects. These effects can vary from slubs (thick
places) with different lengths, different spacing between slubs, or variations in the yarn
count.
Fig: Yarn Winding Cones
Elastic Denim Yarns:
Core-spun yarns are produced conventionally on ring-spinning machines by introducing a
spandex filament at the back of the front drafting roll of the machine. The drafted cotton
fibers twist around the spandex core to produce an elastic ring-spun type yarn. There are
also open-end and air-jet spinning machines that have been adapted to produce core-
spun yarns. The core filament yarn (normally spandex) is inserted through the rotor shaft
on OE frame or the spindle of the air-jet frame, and the cotton fiber wraps around the
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spandex filament during the process of spinning. The yarn is somewhat similar to the ring
core-spun yarns in term of yarn and fabric characteristics. Open-end and air-jet core-spun
yarns have fewer knots and splices as compared to ring core-spun yarn.
Lycra Yarn :
The picture shows that how the lycra yarn are stretched among the fibre and by force too.
That the dia reduces or decreases by the applied force that’s the speciality of lycra yarn.
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3.3 Types of yarn used :
Rotor yarn
Ring yarn
Slub yarn
Polyester
Lycra yarn
3.4 Yarn count used :
For warp : 6, 7, 8, 9, 10, 12, 14, 16, 20, 30 (Slub +Normal)
For weft : 6, 7, 8, 9, 10, 12, 14, 16, 20, 30 (Slub +Normal)
Polyester : 300D,600D
Lycra : 10L40D, 16L40D, 200L40D,300DL40D
3.5 Supplier of the Yarn :
Partex Rotor Mills Ltd.
Partex Rotor Spinning Mills Ltd.
Amber Cotton Mills Ltd.
Sapphire Textile Mills Ltd.
Mahamud Denim Ltd.
Nishat Mills Ltd.
Shaoxing Xingji Import & Export Co. Ltd.
Square Textile Ltd.
Kader Synthetic
Ashik Composite Textile Ltd.
Purbani Rotor Mills
Ashik Composite Textile Ltd.
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Chapter Four
Warping
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4.1 Warping :
The parallel winding of warp ends from many winding packages (cone, cheese) on to a common package (warp beam) is called warping.
4.2 Importance of Warping :
Construction of a beam of warp yarn.
Construction of a parallel yarn sheet.
Modifying the faults of yarn like thick or thin place.
Winding the pre- determined length of yarn.
Combination of small packages.
Accelerating the next process.
4.3 Important requirements of Warping :.
The tension of all wound ends must be uniform and possibly constant during all the time of with drawl from the supply package.
Warping should not impair the physical and mechanical properties of yarn.
The tension should be moderate to allow the yarn complete retain its elastic properties.
Predetermined length should be observed.
Production rate should be high as possible.
The surface of warping package must be cylindrical.
4.4 Warping process involves :
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4.5 Types of Warping :
Beam/Direct warping
(Grey/Mono colour fabric)
Sectional/Indirect warping (Warp patterns: Stripe sand Checks)
Ball warping (Denim fabric)
4.5.1 Direct warping :
In direct warping, the yarns are withdrawn from the single-end yarn packages on the creel
and directly wound on a beam.
Direct warping can be used to directly produce the weaver’s beam in a single operation.
This is suitable for strong yarns that do not require sizing and when the number of warps
on the warp beam is relatively small. This is also called direct beaming. It can also be used
to make smaller, intermediate beams called warper’s beams. These smaller beams are
combined later at the slashing stage to produce the weaver’s beam. This process is called
beaming.
Figure: High speed/Direct warping
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4.5.2 Indirect warping :
In Indirect warping, a section beam is produce first. It is also called band warping or drum
warping. The section beam is tapered at one end. Warp yarn is wound on the beam in
sections, starting with the tapered end of the beam. Each section has multiple ends that
are traversed together slowly during winding along the length of the section to form the
angle. Due to the geometry of the yarn sections, the last section on the beam will have a
tapered end that will make the whole yarn on the beam stable. It is important that each
layer on the beam contain the same number of yarns. The same length of yarn is wound
on each section. After all the sections on the beam are wound completely, then the yarn
on the beam is wound on to a regular beam with flanges, before slashing. This process is
called re-beaming.
Figure: Indirect warping
4.5.3 Ball Warping :
Ball Warping is mainly used in manufacturing of denim fabrics. The warp yarns are
wound on a ball beam in the form of a tow for indigo dyeing. After the dyeing process,
the tow is separated and wound on a beam. This stage is also called long chain beaming
or re-beaming.
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Figure: Ball warping
4.6 Defects & Remedies of Warping :
1. Lapped end
Cause:
The broken end of yarn is not tied to the end on the warp beam & overlaps the
adjoining yarn. The beam is not properly brake & the signal hook fails to operate.
Remedies:
Tying the broken end to the end on the warp beam.
Proper signal hook.
2. Piecing
Cause: One broken end is pieced to another yarn end on the warping beam.
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Remedies:
By proper joining.
3. Soft ends on the warping beam
Cause: Breakage of a group of ends & piecing them in bundle or by lapping. This defect is
caused by the careless of the operator.
Remedies:
Careful operation.
Broken end should be piece up properly.
4. Incorrect form of build
Cause: Caused by non uniform spreading of ends in the guide reed & its improper setting &
conical winding in case of non uniform pressure of the warping beam.
Remedies:
Uniform spreading of ends.
Appropriate setting.
5. Slacks & irregular yarn tension
Cause:
It happens due to any one of these reasons- improper threading of the yarn into the tension devices, ejection of yarn from under the disc of the yarn tensioning device, or yarn tension devices of poor quality.
Remedies:
Proper threading of tension device.
Good quality of tension device.
6. Broken ends on the beam
Cause: A group of ends is broken & tied as a brunch or worked-in with overlapping.
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Remedies:
Broken ends should be removed.
7. Conical winding on the beam
Cause: It occurs due to incorrect load applied by the pressure roller.
Remedies:
Correct load applied.
8. Improper length of warping
Cause: It is due to malfunction of the counter & the brakes of the measuring device & warp
beams.
Remedies:
Good measuring device.
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4.7 Difference between High speed warping and Sectional warping :
High speed warping Sectional warping
To produce common fabric To produce fancy fabric
High production Low production
Large no of yarn are required Small amount of yarn are required
Weavers beam is produced after
sizing
Weavers beam is produced before sizing
Creel capacity is greater than1200 Creel capacity is greater than 300 to400
Cone, cheese winding are used Flanged bobbin is used
Single yarn is used Twist yarn is used
Cheap process Costly process
Uniform tension Not uniform tension
Used very much Not used
4.8 Warping in Amber Denim Mills Ltd. :
The warping section of the Amber Denim Mills Ltd. is working under the A.G.M. of
Preparatory Section. MDS-BW 450 warping machine with Custom Magazine Creelis used
here. The department is connected with dyeing section directly and working 24 hrs. R&D
department inspects the cones which is converted in beams of required length and
forwarded to dyeing section.
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4.8.1 Machine Specifications :
NAME : MORRISION BALL WARPINGMACHINE
Total Machine :04
Model : MDS BW 450
Origin :USA
Year of Installation :2012
Creel capacity : 456
Winding Speed : 250-300m/min
M/c Speed r.p.m 450 BW
Line Speed 290 (mpm)
Lease Interval Max 1000 & Min 500 m
Maximum Beam Diameter : 1200mm
Air Pressure Required : Max 34 & Min 29.9 PSI
Maximum Length of Yarn Can Wind : Around 12000m
Yarn Count : Both Ring & Open End yarn
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NAME KARL MAYER SECTIONAL WARPINGMACHINE Total Machine 01
Type ERGOTEC-M 2000/1000
Origin Germany
Year of Installation 2014
Creel capacity 720
Winding Speed 400m/min
M/c Speed r.p.m 450 m/mim
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4.8.2 Warping Section Layout :
Total Area = 20000 sft
A= Exit
B1,B2,B3,B4= Morrision Bal Warping Machine
C=Wall
D=Sectional Warping Machine
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4.8.3 Machine Main Parts :
Creel Section :
Bobbin Stand/ Package Stand Holder
Plastic Disk
Post
Post Controller
Sensior
Ciramix Guide
Reed : Control Box
Pulley Stand
Head Stock : Motor Counter Roller Traverse Hook Pressure Roller
4.8.4 Briefly Description of Different Parts :
Creel
In ball warping, all the packages are loaded into the adapters of the creel of ball warping
machine. The creel is normally designed to accommodate about 330 to 430 packages.
The creel may be of different types, such as Magazine Creels and Traveling Package
Creels. The passage of yarn in ball warping are shown in Fig. 1
Fig.1 : Passage of yarn in ball warping
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Fig. 2: Ball Warping Machine
The Magazine creels are straight-line creels having a reserve yarn package placed beside
the running packages (Fig. 3). The tail end of the running package is knotted with the start
end of the reserve package. When the running package is depleted, the warper continues
to run with the from the reserve package.
Fig. 3: Magazine Creels
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The traveling package creels are V-shaped creels. The running yarn packages are kept on the
outside of the V and the full yarn packages are loaded on the inside of the V. When the
running packages are emptied, the yarn spindles on the creel are rotated so that the full
packages move to the outside of the creel and the empty packages move towards the inside
of the V-creel for replenishment. The warping machine is start with the new yarn ends. The
empty packages are unloaded and replaced with new full packages.
Fig : Ball Warping Logs
Tensioners
The individual yarn from each package loaded in the warping creel are passes through a
tensioner. There are different types of tensioners available for ball warping machines. The
different types of tensioners are as below:
Fig.: Typical Yarn delivery to the warp preparation machines
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Post and disk tensioners: This type of tensioner unit two or three posts fitted onto a flat
base. Two round disks are placed onto each post. The yarn is passes between the disks and
wrapped around the posts. Out of the two or three post, one is movable. This varies the
angle of wrap, which apply different levels of tensions to the yarn. The tension on the yarn
can be increased by adding weights onto the op weights. This type of tensioners is
inexpensive, simple to thread up, require less maintenance. However the yarn has a
tendency to jump up out from between the disk, it is very labour intensive to change the
tension levels to the yarn.
Driven disk tensioners: This type of tensioners has a twin-disk arrangement. The disks are
supported from below and the tension is applied from above the disk through weights or a
spring loaded device. A gear under each pair of disk is matched to another gear. This gear is
mounted on a continuous shaft which is connected to a motor to rotate the disk. In some
latest machinery manufacturer incorporates 4 RPM motor per post for disk drive. The
rotation of the disk prevents thread cutting and dampens due to ballooning of the yarn. This
type of tensioners requires less effort to change tension levels. However it requires more
maintenance due to maintenance of the electric motor.
Fig.:Typicaldrivendisktensioner,TensionRange:10-150grams,OperatingSpeed:
0- 1,500 MPM, 4 RMP Gear Motor per post
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OZ Tensioner: The OZ tensioners is very simple and popular in different denim production.
The tensioners consist of a cylindrical housing which is fitted with small ceramic eyelet at
the top and bottom. There are two steel balls inside the housing. The yarn is threaded up
through the bottom eyelet, around the steel balls and out through the top eyelet. The
tension is applied to the yarn as it passes around the steel balls. The tension on the yarn is
higher at the rear of the creel due to distance of the yarn travel and lower at the front of
the creel due to the same reason. At the rear of the creel, the balls are prevented for giving
much tension to the yarn, as the yarn already has higher tension. However, at the front of
the creel, the yarn tension is less. The balls exert higher pressure to the yarn as it passes
between them. Hence the tension across the yarn sheet remains equal.
The advantages of this type of tensioners are minimum maintenance required and no
adjustments required in this system. However, there is a limit of how much tension can be
applied to the yarn. It is difficult for threading and it is relatively expensive.
Electronic Tensioner: The electronic tensioners are of two types, such as: Capastan Type
and Rotating Disc Type.
In the Capastan type of tensioner, a round capastan fitted on a precision shaft. The capastan
is fitted onto the bearings located inside of a round DC coil. The yarn is wrapped around the
outer surface of the capastan and when the yarn is pulled out, the capastan rotates. An EM
field is created under the capastan if no voltage is applied to the DC coil. A hysterisis ring
attached to the inside of the capastan, reacts with the EM field and a resistance is created
against the free rotation of the capastan. This resistance incorporates tension to the yarn.
In order to achieve equal tension to each yarn, varying levels of DC voltages are applied to
each tensioner. The advantages of this type of the tensioners are less maintenance
required, no use of electric motor.
In the Rotating Disc type on the same principle, but it applies tension in different way. Two
disks are fitted in the vertical position onto a ceramic shaft. Inside disk, there is a DC coil.
An electromagnetic field is generated when voltage is applied to the DC coil. The outside
disk is attached to the magnetic field and pulls tightly against inner disk. It applied tension
to the yarn threaded between the two disks. The amount of tension depends upon the
strength of the EM field created by the DC coil. A 4 RPM AC motor fitted on each tensioiner
turn the disks to avoid thread cutting.
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Stop motion devices
A stop motion device is fitted in the creel to stop the machine at the event of any end
breakages. There are different types of stop motion devices available. However each of
them having their own advantages and disadvantages. Some of stop motion devices are as
below:
Drop wire stop motion : It is fitted on each vertical row at the front of the creel bands.
This is the simplest type of stop motions. A drop wire is placed onto each yarn end. There
is an exposed electric contact bar beneath the drop wires. An open electric circuit is
maintaining in the electric contact bar in normal running condition. However at the time
of any end breakages, the drop wire falls onto the contact bar and shorts out the circuit.
This system is very inexpensive and very fast reacting. However, the system is exposed to
dust, lint and short fibers. If the contact bar is accumulated with fluff, the drop wire will
not be in contact with the bar and the system remains open.
Photoelectric stop motion : This type of stop motion works on almost in same principle as
the drop wire type, but there is some difference. The photoelectric system uses a faller
which is attached to a shutter inside of an airtight housing of the housing. Inside the
housing, there is a photocell having a transmitter at one end and a receiver at the other
end of the housing. A light beam is emitted to the receiver which maintains an open
electric circuit. At the time of an end breaks, the faller drops. This causes the attached
shutter passes through the light beam, which ultimately initiating the stop signal to the
warper. The system is reliable, inexpensive as compared to drop wire. It is easy to thread
and maintenance free. However, the system having disadvantages of residual tension on
the yarn which preventing the shutter to drop.
Electric Motion Sensor : In this system an electric motion sensor is fitted in the balloon
shield at the yarn cone. The system measures the motion of the yarn when it exits from
the cone. The yarn balloons housed in the balloon shield through a light beam. The system
remains open as long as the light beam is broken by the ballooning motion. At the event of
end breakages, the ballooning action immediately stops and the sensor signals the warper
to stop. This system is reliable, fast acting and self cleaning. But the system is expensive.
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Lease Stand
After leaving the creel, the yarn passes through the reed of a lease stand. The lease stand
having two reed / comb, out of which one reed is movable up and down, which allows each
adjacent yarn end to raise or lowered to form a shed of yarn sheet. Each alternate yarn
threaded through alternate reed.
A lease string is inserted across the shed formed by the reed, at a specified intervals, may
be 1000 m. At this interval, the machines is automatically stops for lea insertions. However,
the intervals of lease may be varied within the rope, as per requirement of the technologist.
The lease helps in maintain proper leasing in subsequent process, i.e. in long chain beamer.
Any cross ends in the rope can be cleared at the lease portions. The operator in long chain
beamer can check whether there is any cross end at lease portions. Any broken end, missing
end can be properly mended at lease portions. Hence lease is an important consideration
in denim productions. Most of the denim technologist use cotton or synthetic filament yarn
for lease. The lease strand should not be of coarse count, or thick at any rope, which may
cause unusual end breakages in rope dyeing by touching in fingers.
Next the yarn passes through a counter stand or combination of counter stand and
condenser tube assembly. Here the yarn sheet is condensed into a bundle. From the counter
stand the yarn passing it through a funnel-shaped trumpet. It is located at the rear of the
ball warper. Here the total ends of the yarn sheet is collected in a rope form. This rope is
wound on a “log”.
In the ball warper, there are two motor driven drive rolls which are geared together. The
ball warping log is placed between these two drive rolls and held against the surface of the
drive rolls with pneumatic pressure. The log turns as the two drive roll runs. A pneumatic
brake attached to the drive rolls stops the rotation of the rolls as and when required or at
the time of any end breakages.
Ball warping machine normally uses a chain and dual sprockets in order to give side-by-side
motion of the rope during winding onto the log. This side-by-side movement of the chain is
provided through mechanical gear in the traverse to the drive roll motor. The traverse
movement of the chain is synchronized to the drive roll rotation speed. However, there is a
problem of ribbon formation in the log at certain diameter, as it is not possible to vary the
speed of rotation of the rope onto the log. The ribboning causes the machine to vibrate
until the rope achieve a somewhat more uniform surface across the log.
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McCoy Ellison provides a separate AC Inverter controlled motors for the traverse and for
drive the rolls. Both are controlled by Programmable Logic Controller (PLC) so that the speed
of the traverse is not depends upon the speed of the drive rolls.
Ball Warper Gear-in speed
The maximum gear-in speed of the ball warper depends upon the desired production of a
mill. A typical speed is 360 to 400 m/min.
Ball windup
In the ball warping, the yarn passes through the traversing trumpet, which distributes the
rope onto the log. The ball warping machine should be such that, there is a minimum of
“dwell time” at the end of each traverse stroke. This prevents hanging of the yarn over the
ends of the ball and formation of any loops.
Ball dimension
The relationship between the ball dimensions and the corresponding length of yarn is an
important consideration during purchasing of ball warper. The ball length can be calculated
with the following formula by assuming a typical yarn density 59 cubic inches per pound.
Ball length in yards = {11.8 x yarn count x ball width x (D2 – d2)} / Endsper rope Where D=
Ball diameter in inches,
D= Log diameter in inches
Braking and start-up
At the time of any end breakage, the ball warping brakes are immediately activated by stop
motions. This sudden stoppage of the machine may leads to risk of scuffing the ball on the
driving drums, unless the brakes are synchronized properly. In the event of rapid start of
the machine, there is a chance of yarn scuffed. Some manufacturer incorporates synthetic
covered driven drums to minimize yarn scuffing and slipping.
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Control Panel
Through the control panel the variation of speed and the panel are controlled through the control panel.
4.8.5 Essential Features :
The essential features are:
Heavy frame construction with polyurethane covered bed rolls ensures high speed winding,
The Smart Stop Technology™ activates brakes only on critical stops which maximizing brake life,
Controlled deceleration and Smart Lease Technology™ with creep speed avoids rope (kinking) knotting during stops,
Belt driven traverse system with speeds up to 10m/second and accelerations up to 40m/second
Automatic speed profile of traverse servo drive is programmable for infinite speed adjustment allowing variable ball patterns
Full width Turn Around Stand allows even yarn tension and less lost ends
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4.8.6 Calculations :
Some examples are given below to show the concept of warping plans.
Problem : 01
If Weight of Bag: 50Kg
Total Number of Cone: 24 Count: 7OE
Then find out the length of yarn in one cone.
Solution :
Per cone weight = total weight of cone /total no of cone
=50/24
=2.08333
Length of yarn in one cone = weight ×count
=2.08333×2.20462×840 × 7/1.0936M
=24695.1307M
Answer: Length of 7 OE = 24695M
Problem : 02
If Set length: 21000m
Count: 7 9 12
Ratios:4:4:4
Find out average
count.
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Solution :
Average Yarn Count= 12 × 7 × 9 × 12 /4 × 9 × 12 + 4 × 7 × 12 + 4 × 7 ×9
=9072/432+336+252
=9072/1020
=8.894
Answer: Average Count =8.89
Problem : 03
If, Set length: 24695m
Total ends: 4464 Ends/beam:446
Total beam:10 Count: 7OE
Find out the weight of yarn
required.
Solution:
Weight of yarn in one beam =Set Length × Total Ends × 1.0936/840 × 2.2046 ×count
= 24695 × 446 × 1.0936/840 × 2.20462 ×7
=12044877.592/12963.1656
=929.16Kg
Total yarn required = Weight of yarn in one beam× Totalbeam
=929.16×10
=9291.61Kg
Answer: Total Yarn Required = 9291.61Kg
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Chapter Five
Dyeing
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5.1 Dyeing :
The process by which a textile material is to be changed physically or chemically, so that it
looks mono uniform colored is called dyeing. All commercial textile dyeing processes take
place by the application of a solution or a dispersion of the dyes to the textile material
followed by some type of fixation process. The dye solution or dispersion is almost always
in an aqueous medium. A major objective of the fixation step is normally to ensure that the
coloured textile exhibits satisfactory fastness to subsequent treatment in aqueous wash
liquors. Dyeing is mainly depends on the type of fabric, structure of fabric and the properties
of dyes.
5.2 Objects of Dyeing :
The textile goods are dyed uniformly with single color.
To increase the attractiveness of the textile goods.
To make the fabric suitable for various usage.
To make the textile goods suitable for decorative purposes.
5.3 Theory of Dyeing :
The procedure by which dye stuff enters into the textile goods is called theory of dyeing. It
is essential to have certain degree of fastness properties when a dye particle is applied on
textile goods. The whole process of dyeing is completed by four steps as follows:
Dye molecules come to the fabric surface from the dye bath.
Fibre absorbs the dye molecule from the outer surface of the fibre to the internal surface of the cellulose.
Migrates the dye molecules everywhere of the fibre molecules.
Anchoring or fixing the dye molecules to the fibre molecules by hydrogen or covalent bond.
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5.4 Denim Dyeing :
The classical jeans were produced out of indigo-dyed Denim fabric. The special character of
this fabric – only the warp thread is dyed makes it necessary to carry out dyeing in yarn
form. The yarns applied for Denim were exclusively produced on ring spinning machines in
former times. The development of OE yarns by applying smaller rotors with a spinning speed
of up to 200 m/min has led to the application of OE rotor yarns both for warp and weft. The
yarns applied for weaving must be of high quality, a high fiber for strength, regularity as well
as a small part of short-stapled cotton fibres belongs to the basic features of the denim yarn.
For regular jeans qualities the warp yarns are spun in a fineness of 50 to 90 tex, for the weft
yarn the fineness ranges are mainly 75 to 120 tex. If Denim is made out of Tencel or Modal
especially for jeans shirts the finenesses are up to 25 tex. Indigo, sulphur and indanthrene
are mainly used in the dyeing process. Two methods are applicable for continuous dyeing
with indanthrene dyes: rapid dyeing and vat dyeing. While processing the basic colored
denim, reactive dyes are used and fixed with hot caustic soda solution. The dyeing process
is mainly influenced by the dyestuff characteristics, dyeing temperature and necessary
chemicals used in the process. Indigo dye is the most popular choice as it has good depth of
shade and suitable rubbing and washing fastness.
When cotton yarn is dyed with indigo, it leaves a ring-dyeing effect, because of which the
outer layer of warp yarn is coated with indigo, and the core of the yarn remains undyed.
This gives the denim garment a unique ‘faded look’ and a rich blue shade after repeated use
and wash. Originally, the warp yarns or ends were put through the dye bath side by side to
form a sheet of yarn, which passed continuously through several dye baths, squeeze rollers
or airing sequences. Specially two types of dyes are commonly used in factory. Vat dye and
sulphur dye. These two types of dyes are described below.
5.5 Dyes use for Denim :
Vat Dyes
Sulphur Dyes
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5.5.1 Vat Dyes :
The name vat was derived from the large wooden vessel from which vat dyes were first
applied. Vat dyes provide textile materials with the best colour fastness of all the dyes in
common use. The fibres most readily coloured with vat dyes are the natural and man-made
cellulosic fibres. Vat dyes are more expensive and difficult to apply than other classes for
cellulose such as directs, sulphurs, and reactive. Indigo is a special case in the vat dye class.
Indigo is attractive for its pleasing blue colour and for the unique fading characteristics of
garment dyed with it. Vat dyes are characterized by the presence of a keto group. Vat dyes
in keto form are water insoluble pigments.
5.5.1.1 Why So Called Vat Dye? The word vat means, ‘Vessel’. The dyes take their name from vatting. The vat dyes are
naturally coloring matter and kept in wooden vat and make solubilise vat dyes by the
process of formantation – so it is called vat dyes. They are applied in a special kind of a dye
bath in which the dye is reduced to a soluble form by means of a strong reducing agent,
such as hydrosulphite. The vat dyes are insoluble and cannot be used directly and requires
vatting. Among all the dyes, it has the best fastness properties.
5.5.1.2 Dyeing with vat dyes :
The application of vat dyes to cellulosic materials occurs in five stages.
Aqueous Dispersion:
The insoluble vat dye is dispersed in water.
Vatting:
This step involves the chemical reduction of the vat dye to produce the soluble, reduced or
leuco form of the dye. This is achieved by Sodium Hydro sulphite, Sodium Hydroxide and
water. The sodium hydrosulphite chemically reduces the vat dye in the alkaline conditions
created by the presence of sodium hydroxide.
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Absorption of dye molecules by the fibre :
The vatted dye molecules are substantive to the cellulosic material when this is introduced
into the dye liquor. To achieve adequate exhaustion, an electrolyte is added to the dye
liquor and the temperature may be increased depending on the specific vat dye. The
application of the dye molecule to the fibre occurs at temperatures specific to a particular
vat dye and occurs in a range from 200 C to 600 C. The addition of the electrolyte alters the
equilibrium of the dye liquor so as to increase the substantivity of the dye molecules for the
fibre. During this stage of dye application the textile material must be kept immersed in the
dye liquor to prevent premature oxidation of the leuco compound.
Figure: Water soluble leuco form of indigo
Re-oxidation of dye molecules within the fibre:
Once within the polymer system of the fibre the leuco form of the vat dye has to be oxidized
and converted to its original colour and the insoluble form of the dye. Oxidation of the leuco
compound can be achieved by atmospheric oxygen although this is somewhat slow. In
practice, a mild oxidizing reagent such as sodium per borate is used to convert the soluble
leuco compound into the original insoluble vat dye.
Soaping-off vat dyes:
During the previous stage some insoluble vat dye may be deposited on the surface of the
textile material. This has to be removed to prevent poor rub-fastness as well as a possible
change of shade due to the subsequent removal of this surface deposit. Soaping-off, which
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is the boiling of the dyed material in a liquor containing some suitable detergent, removes
this surface dye. The term soaping-off was derived from the fact that before the
development of detergents, soap was used to remove the surface dye.
5.5.2 Sulphur Dyes :
These dyes are so called because they contain sulphur atoms in their molecules. The fibres
most readily coloured with sulphur dyes are the natural and man-made cellulosic fibres.
5.5.2.1 Chemistry of dyeing with Sulpher Dye :
The Sulpher dyes contain Sulpher linkage within their molecules. They are insoluble in
water but can be made soluble in water by treating them with reducing agents. This also
makes them substantive towards cellulosic fibres. Na2S acts as reducing agent that breaks
the Sulpher linkage and break down the longer molecules in to simple components which
can penetrate the material (fiber/fabric) surface easily.
5.5.2.2 Dyeing with Sulphur Dyes :
Initially the goods are wet out in the bath. Since the dyeing liquor contains appreciable
amounts of sulphide, copper fittings must be avoided. If wetting or penetrating agents are
used these should be of the anionic type since non-ionic surfactants form stable, non-
substantive complexes with the leuco thiols. An anionic product such as phosphated 2-
ethylhexanol is suitable. The bath may then be set at 40°C with some sodium polysulphide.
Polysulphides in the leuco dyebath prevent premature oxidation of the dye and reduce the
tendency to bronziness of deep dyeing of blues, navies and blacks. An addition of a
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sequestrant such as EDTA avoids precipitation of the leuco thiolate by calcium and
magnesium ions. The leuco dye is then added slowly and, since the leuco dyes only have low
to moderate substantivity for cellulose, some salt may be added initially, or in portions
during dyeing, to promote exhaustion. After dyeing the goods are rinsed, the leuco dye
oxidised and the dyeing is soaped as for a conventional vat dye.
Sulphur dyes usually have acceptable substantivity, particularly in the presence of salts, so
that stripping in a fresh reducing bath is not easy. Dyeing is often conducted at the boil but
this decreases the degree of exhaustion. Sulphur dyes require less salt than reactive dyes
and usually have reasonable exhaustion. Low sulphide leuco dyes require more salt and no
polysulphide. They do not give good exhaustion in heavy shades and the use of a low liquor
ratio is recommended. For popular shades such as black, it has long been common practice
to use a standing bath. This is a dye bath that is re-used for subsequent dyeings after
addition of more reduced dye. Any free sulphur that tends to accumulate is dissolved by
addition of sodium sulphite to give thiosulphate. This prevents it sticking to the goods. The
actual dyeing temperature can vary. At higher temperatures around the boil, the bath
exhaustion is less but penetration of the leuco dye into the fibres is better than at lower
temperatures.
5.6 Denim Dyeing Process :
There are three processes in the practice for continuous denim dyeing:
1. Rope Dyeing 2. Slasher or Sheet Dyeing 3. Loop Dyeing
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5.7 Rope Dyeing :
The indigo Rope dyeing technology for denim production is considered a superior dyeing
technology, where better uniformity of dyeing is achieved than other Indigo dyeing
technologies like slasher dyeing. Indigo rope dyeing was started in USA.
Today rope dyeing accounts for a large percentage of warp yarn dyed for denim production.
The system offers highest production, due to continuous process, as there is no stoppages
for set changes. In this dyeing method, maximum continuity of shades and minimum danger
of center to selvedge shade variation can be achieved. Flow diagram of rope dyeing is shown
in Fig. . During dyeing process, it forms a coating in the outer layers of the cotton yarn and
fiber. This produces a ring of color around the cotton yarn, with the core remains white core.
This dyeing effect is known as ring dyeing.
Fig. : Rope dyeing and subsequent sizing, Step 1: Ball Warper, Step 2:Rope Dyeing, Step 3: Long Chain
Beamer, Step 4: Sizing
Indigo dye is a vat dyestuff. It is insoluble in water and has a very poor affinity to cellulose
fibers like cotton fiber. In normal stage, indigo will not dye cotton fiber. For dyeing of cotton
yarn, indigo should be converted into water-soluble “leuco” form in chemical reduction
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process. Reducing agents such as sodium hydrosulfite with sodium hydroxide are used to
convert the indigo dye to its soluble form. The reducing agent also initially changes the color
of the dye from its blue color to a very pale greenish yellow color. The leuco form of indigo
forms a coating on the outer layer of the cotton yarn. The yarn is then exposed to the air,
where the indigo become insoluble by oxidation. The oxygen in air converts the soluble
indigo dye to its original insoluble form and back to its original blue color. The chemical
reaction is shown in Fig. .
Fig. : Simplified description of the reduction/oxidation of Indigo
When the indigo dye oxidized, it becomes trapped into the outer layers of the cotton yarn.
In a single passage of indigo dye, a small amount of dye being deposited on the yarn surface
which causes light blue shade. In order to obtain deep indigo blue shades, the cotton yarn
should be subjected to repeatedly dye with indigo dye. The indigo dye is layered by dyeing
in a multiple passes of the rope into the soluble indigo dye and then subsequently exposing
it to the oxygen in the air for oxidation. This multiple passing of yarn into dye bath is known
as dipping. Normally, the cotton yarns are dyed with indigo dye in at least 4 to 8 passages
of the dye bath. After every passage of dye bath the yarns are exposed to air and followed
by further dipping in soluble indigo dye bath. After every passage of the dye bath all the
oxidized indigo dyestuff fixed on the surface of the cotton fiber/ yarn, only a small portion
of indigo is replaced by fresh indigo. This results in the increase in the depth of shades.
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In some cases a sulfur black or blue dye can be applied to the yarn before indigo dyeing in
order to achieve darker shades. This is known as a sulfur bottom. If the sulfur dye is applied
after the yarn has been indigo dyed, it is known as sulfur top.
5.8 Process sequence in Indigo rope dyeing in denim :
In rope dyeing, 12-36 ball warping ropes of yarn are fed side-by-side simultaneously into the rope dyeing range for application of the indigo dyeing. The process sequence is as below:
Fig. : The passage of yarn in rope dyeing
Pre-scouring
In the rope dyeing range the ropes are first passed through one or more scouring baths. It
consist of wetting agents, detergents and caustic. The objectives of pre-scouring is to
remove the wax content from cotton, naturally occurring impurities in cotton fiber yarn such
as dirt, minerals, ash, pectin, and naturally occurring waxes, removal of trapped air from
cotton yarns through wetting the yarn at temperature of 90 to 95ºC. Removal of these
materials is very important in order to achieve uniform wetting and uniform dyeing. The
trapped air is essential to be removed as it may cause uneven dyeing. There is approx. 2
liters of air in 1 kg of yarn. One liter of air decomposes 2 liters of Sodium hydroxide which
also increase consumption of sodium hydroxide.
The following agents normally used in pre-scouring.
Caustic Soda: In pre-scouring, 3–5% sodium hydroxide (depends upon
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the quantity of cotton fibers) is used, which removes the wax by the action of soapanification.
Wetting agent: Anionic wetting agent are normally used.
Sequestering agent: It is used to make the water soft, as it is very difficult to find the desired softness in water (about 1-3 ppm) even with the use of soft water.
The ropes are subsequently fed into one or more water rinsing baths.
Hot wash
The ropes is hot washed 80 – 90ºC to remove the sodium hydroxide left in the yarn after
pre-scouring, otherwise it will change the pH values of dye – bath.
Cold wash
After hot wash, the yarn ropes is fed through a cold wash bath to brought back to its room
temperature.
Dyeing
The ropes of yarn are then fed into the indigo dye baths and skyed after each dip. As the
constant of substantivty for indigo it is only 2.7, where as for other color, it is 3.0. Hence
there is a need of repeated dipping of 5 to 6 dye baths with multi – dip and multi –nip facility
to increase the penetration.
As indigo belongs to IK class of vat dyes, the dyeing is done on room temperature, and
oxidation is done by air. Sodium hydrosulphide is used to reduce the indigo, as Indigo is not
soluble in water. Then caustic soda is also used to make sodium salt of vat color to make it
soluble.
The pH of the indigo dye bath should be maintained between 10.5 to 11.5, as at this level,
the dye affinity is very high. This is because at this pH, sodium salt of indigo is mono phenolic
form. pH is maintained by the addition of caustic soda.
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Washing
After the dyeing process, the ropes of yarn are rinsed in several water baths to remove any
unfixed dye. Rubbing fastness of indigo, which is a very important parameter, can be
improved through washing. In a typical indigo dyeing range, there are four wash bath after
the dye bath. The typical washing process are in Fig.
Fig. : Typical washing Process
The softener treatment at the last was box is very important in rope dyeing. The dyed rope
is to be opened at the next operation, Long Chain Beamer. The softener helps easy opening
of the rope, hence less end breakages.
Cationic softener is generally used with 1.2% of the weight of the yarn and pH in the range
of 4 to 5.5. Softening treatment is done at room temperature, as high temperature may
cause tendering of yarn.
Drying and Coiling
After the washing, the ropes are dried by hot cylinder and coiled incan.
Fig. : Rope cans
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5.9 Process Control of indigo rope dyeing
Concentration of Hydrosulphite
Hydrosulphite is measured by vatometer. It should be from 1.5 gpl to 2.5gpl. It can also be
measured by Redox potential of dye bath which should be from -730 mV to -860 mV.
Relatively high conc. of hydrosulphite gives a clear shades with minimum reddish streaks.
The indigo dye stuff in the dye bath should be kept in soluble stage. Indigo dye has a
tendency to react with the oxygen in the air and get oxidized and transferred into their
original insoluble stage. Hence an extra quantity of hydrosulphite is maintained in the dye
bath to keep the indigo dyestuff in soluble stage.With lack of hydrosulphite, the leuco indigo
is less dissolved and goes to insoluble stage and thereby adheres to a greater extent to the
fibers. Further lack of hydrosulphite may cause higher unreduced dyestuff in the liquor. This
results unfixed dyestuff onto the yarn. Under these circumstances a reddish bronze like
shade is developed in the yarn.
Caustic Soda or pH value
The pH of the dye bath should be around 10.5 - 11.5, as at this pH range, there will be
formation of more monophenolate ions, which lead to higher color yield and good wash
down effect. At higher pH, dye penetration is less and leads to poor wash down effect.
The pH influence the shades in the following way:
High pH or Caustic Concentration --> Redder and lighter
Low pH or caustic concentration --> greener and darker
Dye concentration in Dye bath
Dye concentration is an important parameter in indigo dyeing. Generally the concentration
of dye influence the shades as below:
High Indigo Concentration --> Shade is greener and lighter
Low Indigo Concentration --> Shade is dull and Red.
Dipping Time
The dipping time of the ropes in the dye bath plays an important role in indigo dyeing.
Dipping time varies from 15-22 seconds. Longer the dipping time, better will be the
penetration. However, too long dipping time may dissolve the previously oxidized indigo. At
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very short dipping time, the liquor exchange, i.e. the amount of chemicals consumed and
replaced by fresh addition of reduced indigo, will not be adequate. This may leads to poor
dyeing and depth of dye penetration. However the time available for diffusion of dyestuff
until oxidation commences is too short.
Squeeze Pressure
The squeezing pressure should be optimum. High squeezing pressure may leads to low pick
up of color and better penetration. At rope dyeing, squeeze pressure may be between 5-10
tones. Squeeze roller hardness should be about 70-75 deg. shores
Airing Time
Airing time is an important consideration in rope dyeing for proper oxidation. The airing
time should be 60- 75 seconds. Longer airing time leads to high tension on the yarn, whereas
low airing time leads to poor oxidation.
Drying
The dyed and washed rope should be properly dried with proper moister content.
Insufficient or uneven, over or less dried yarns will result in poor opening and high
end breakages in re-beaming.
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5.10 Slasher Dyeing :
In continuous slasher/sheet dyeing and sizing machine, direct warping beams are used,
instead of ball warping logs in case of Indigo rope dyeing system. The Slasher Dyeing
machine is capable of handling Ne count form 9/s to 30/s (OE and Slub both). Typical
schematic sheet dyeing range is shown in Figure. At the back end of the slasher/sheet dyeing
range, the direct warping beams are creeled. The yarns sheet from each beam is pulled over
and combined with the yarns from the other beams so that multiple sheets of yarns can be
made. When dyeing according to the sheet dyeing method, instead of cables the warp
threads are fed to the machine parallel next to each other. These are much smaller
compared to the rope dyeing machines. Another advantage is that the cables don’t need to
be open after dyeing.
Moreover, each yarn wets much faster and in this way reduces the dipping and wetting
times during dyeing. All in all, each thread has a larger surface compared to a dyeing cable
and this requires somewhat more hydrosulphite to prevent a premature oxidation of the
indigo.
Figure: Sheet Dyeing Range
P
age4
9
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5.11 Loop Dyeing :
In the loop dyeing process, the yarn is dyed in a single bath instead of several. The desired
depth of color is attained by passing the yarn through the vat several times. Subsequently,
as a part of the same process, the yarn is sized. The advantages and disadvantages of loop
dyeing are the same as with sheet dyeing.
Figure : Loop Dyeing
5.12 Difference between Slasher and Rope Dyeing :
Comparison On Slasher Dyeing Rope Dyeing
Required Space Less More
Mercerizing Easy Difficult
Manpower Less More
Dye bath Less capacity More
Broken end repairing
Not Possible
In rope dyeing there is
apossibility to repair broken end
in LCB(Long ChainBeamer) Flexibility Flexibility to produce denim in different
colors and small quantities
Less flexible. Difficult to change
colors.
Set change
Machines should start and stop at the
time of set change. Hence shade
matching is not easier until hundreds of
meters of yarn run.
No need to start and stop the
machine at the time of set
change. Hence shade matching is
easier.
Extra ends Extra ends Required. No extra ends.
Different colour mixing
Not possible
Possible to mix ends of different
colours. One can get stripe
design at re-beaming.
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Count range
Advantages for lighter yarn. Can use Ne
1-30 without major change.
Large numbers of yarns are
difficult to open at re-beaming.
Hence it is not suitable for fine
yarn. CanuseNe1-16 without
major change. In latest machines
even higher yarn count can
bedyed. Rear view characteristics
offabric
Less thin / thick & knot points High thin / thick & knot points
Dye dipping time for
effective dye result
< = 14s ( standard 10 – 14sregulated by
speed)
< = 21s ( standard 15 –21s
regulated by speed)
Production capacity
Approx. 9 to 11 mill. Mt. in case of
normal capacity. Approx. 10 to22 mill.
Mt. in case of double capacity.
12 ropes = 9 to 11.5 mill. Mt.,
24 ropes = 18 to 23 mill. Mt.,
36 ropes = 27 to 34.5 mill.Mt. Cost Cost of production is lesser compared
to RopeDyeing
Cost of production is more
compared to sheetDyeing
5.13 Relative merits and demerits :
Generally rope dyeing denim range produces better quality of denim than slasher dyeing.
Rope dyeing means for higher production and long runs. Ropes dyeing can more lots without any stoppages at set change. In case of sheet dyeing, the machine remains stop at set change.
In rope dyeing better dry and wet fastness properties in denim fabric can be achieved, than sheet dyeing.
In sheet dyeing good quality yarn is required, as mending of broken ends is very difficult in sheet dyeing. This problem is less in rope dyeing.
Sheet dyeing produces more waste than rope dyeing.
Lot to lot, set to set shade consistency is better in rope dyeing,
In sheet dyeing, there is a problem of center to selvedge shade variation. This can be caused due to uneven nip pressure, non-uniform chemical and colour content in dye boxes. This problem can also occur in rope dyeing as well. But proper rotation of the dried yarn cans at spreading and winding and even distribution of warp yarns over the full width of the fabric minimize the problem.
The wetting and immersion time, oxidation time of dyed yarn are less in sheet dyeing due to parallel warp threads.
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5.14 Dyeing in Amber Denim Mills Ltd. :
5.14.1 Machine Specification :
Brand name Morrision Rope Dyeing
Model Nill
Year of construction 2012
Country of origin American
Creel capacity 37
Speed 30-35 m/min
Number of dye bath 8
Total no of box 15
No of dry cylinder 36
Year of construction 2012
Air Pressure required 5.4(Depend on Count)
Steam pressure required 5kg
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Dry Cylinder Temp. 1st 5 bar-2nd 2.3 bar
production/day 70000 m/day
5.14.2 Dyeing :
There are several types of dyeing available in denim. But in Bangladesh 4(four) types of
dyeing processes are used:
Pure Indigo
Topping or Indigo Bottoming Sulphur Topping (IBST)
Bottoming or Sulphur Bottoming Indigo Topping (SBIT)
Pure Black/Sulphur
5.14.3 Pure Indigo :
Indigo dye is an important dyestuff with a distinctive blue color (see indigo). The natural dye
comes from several species of plant, but nearly all indigo produced today is synthetic.
Among other uses, it is used in the production of denim cloth for blue jeans. The form of
indigo used in food is called "indigotine", and is listed as FD&C Blue No. 2.
Flowchart for Pure Indigo:-
Creeling
Scouring/Mercerizing
Cold Washing Bath
Cold Washing Bath
Indigo Color Bath-1
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Oxidation
Indigo Color Bath-2
Oxidation
Indigo Color Bath-3
Oxidation
Indigo Color Bath-4
Oxidation
Indigo Color Bath-5
Oxidation
Indigo Color Bath-6
Oxidation
Indigo Color Bath-7
Oxidation
Indigo Color Bath-8
Hot Washing Bath-1
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Hot Washing Bath -2
Hot Washing Bath -3
Softener
Dryer
Can
5.14.4 Topping :-
In this method two type dyes are used for developing the required shed. In the topping
method the Indigo dyes are used to develop the blue in the bottom part of the yarn whereas
the Sulphur dyes are used to develop the black color shed in the top part of the yarn.
Flowchart for Topping:
Creeling
Scouring/Mercerizing
Cold Washing Bath
Cold Washing Bath
Indigo Color Bath-1
Oxidation
Indigo Color Bath-2
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Oxidation
Indigo Color Bath-3
Oxidation
Indigo Color Bath-4
Oxidation
Indigo Color Bath-5 (Off)
Oxidation
Indigo Color Bath-6 (Off)
Oxidation
Normal Wash Bath-7
Oxidation (Nill)
Black Color Bath-8
Hot Washing Bath-1
Hot Washing Bath -2
Hot Washing Bath -3
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Softener
Dryer
Can
5.14.5 Bottoming :-
In this method two type dyes are used for developing the required shed. Here Sulphur dyes
are used to develop the black color shed in the bottom part of the yarn whereas the Indigo
dyes used to develop the blue in the top part of the yarn.
Flowchart for Bottoming:
Creeling
Scouring/Mercerizing (Off)
Cold Washing Bath
Cold Washing Bath
Black Color Bath-1
Oxidation
Normal Wash Bath-2
Oxidation (Nill)
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Normal Wash Bath-3
Oxidation (Nill)
Indigo Color Bath-4
Oxidation
Indigo Color Bath-5
Oxidation
Indigo Color Bath-6
Oxidation
Indigo Color Bath-7
Oxidation
Black Color Bath-8
Hot Washing Bath-1
Hot Washing Bath -2
Hot Washing Bath -3
Softener
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Dryer
Can
5.14.6 Regular Dyeing Recipe :
Recipe for Indigo
Indigo 100 gpl
Coustic 75 gpl
RD-999 6 gpl
Hydro 100 gpl
Lediquest 6 gpl
Total Volume 3000 L
Recipe for Botoming
Sulfotex 30 gpl
Coustic 15 gpl
RD-999 6 gpl
Secho 2 gpl
Reducing Agent 10 gpl
Total Volume 2700 L
Recipe for Topping
Sulfotex 60 gpl
Coustic 61 gpl
RD-999 5 gpl
Reducing Agent 25 gpl
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Total Volume 600 L
Recipe for Scouring
Secho 2 gpl
Coustic 30gpl
RD-999 6 gpl
Total Volume 2700 L
Recipe for Scouring
Softener 14 gpl
Total Volume 1700 L
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5.14.7 Equipments used in dyeing lab :
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Chapter Six
Long Chain Beaming
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6.1 Long Chain Beamer :
After the rope dyeing of warp yarn in denim production, the next operation is the Long Chain
Beamer (LCB). When the rope has been dyed and dried in the rope dyeing range, it is taken
in large cans in coiler section. In rope dyeing range, if the machine has a capacity 24 ropes,
then there will be 24 separate coilers which delivers 24 ropes in separate cans. These cans
are transferred to the Long Chain Beaming area. The basic purpose of long chain beamer is
to open the rope into a sheet form of yarn and wind onto a warper beam which in turn
transferred to the sizing machine.
In Long Chain Beamer, the yarn alignment in the dyed rope is change from a rope form to a
sheet form. In the Long Chain Beamer the rope pull from the can ( Fig. 2) by moving them
upward to a guiding device. The guiding device is mounted above the can, probably in the
ceiling. The upward movement of the rope allows the ropes to untangle before nearing the
beamer head and allow the rope to shake loose form from the rest of the rope in the can.
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6.2 Process Flowchart For Long Chain Beamer :
Can
Accumulator
Tension Stand
Tension Control Dancer
Reed
Counting Roller
Beam
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6.3 Long Chain Beaming In Amber Denim Mills Ltd. :
6.3.1 Machine Specification :
Fig. : Morrison MDS-RB 550 Long Chain Beamer
Brand Name Morrision
Machine No 12
Model No MDS-RB 550
Year of construction 2013
M/c Speed 550 mpm
Gross weight 3500 kg
Rated Current 37 A
Air Pressure 4-6 bar
Ampere Interrupter Capacity 13 KA
Production Per Day 70000 m/day
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6.3.2 Essential Features :
The essential features are:
Flange diameter of 1 meter at the highest speeds can be achieved. Head is equipped with either beams with journals or gear type heads.
The machines are equipped with Semi Automatic Beam Doffing system which facilitates for easy removal of LCB beams.
Various functions like stop / jog / run, beam doffing, accumulator device, tension control system are incorporated.
The machine is equipped with pneumatic / hydraulic double end Disc Brakes for immediate stops to minimize any missing ends in the beam.
The Sheet strummer at comb helps in the web opening with variable speed AC motor. This also automatically lifts and lowers during machine stop /start.
Optional features are Press Roll with kick back to prevent scuffing of yarn and Elevated Back Up Accumulator
Fig. : Passage of Rope in Morrison MDS-RB 550 Long Chain Beamer
6.4 Briefly Description of Different Parts :
Accumulator
An accumulator is a device which allows the rope to be accumulated in a controlled manner
at the time of unwind the section beam on the Long Chain Beamer in order to find out and
to repair a broken end. The accumulator is an important component on a Long Chain
Beamer, as there is no stop motion device in the re-beamer and the operator observes the
yarn sheet whether there is any broken end. Accumulator may be of different types, such
as:
Open Sheet Accumulator
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Offset Roll Rope Accumulator
Deep Groove Pulley Rope Accumulator
Beater Bar and Comb
After the Accumulator the rope returns to the Tension Stand. There is a Beater Bar located
at the top of the Tension Stand which is round four or five sided in shape. It is at this point
where the yarn rope begins to be opened into a yarn sheet. The function of the Beater Bar
is to apply sufficient tension, friction to the rope, assisting in the opening or spreading the
yarn and to separate the ends without any damage to the yarn. After the Beater Bar the
rope passes through a comb located on the Long Chain Beamer, which separates individual
yarn ends and keeps them parallel to one another. From the comb, the warp yarns are
guided onto a flanged section beam.
In the Long Chain Beamer, the section beam is supported and driven by an electric motor.
The electric motor may be of either DC motor or AC inverter type drives spindles spindles
which support the section beams. The section beam wind the yarn sheet onto it. Generally,
the operator run the machines by depressing a Foot Pedal. As long as the Foot Pedal is
depressed, the machines continues to run and whenever the Foot Pedal is released, the
machines stops.
Tension Stand
When the ropes come down from the guiding device, it passes through tensioning Stand
rollers (Fig.). The purpose of the Tension rollers is to established necessary warp tension to
the rope and help in further separation of the ropes before going through a comb. If no
tension is applied to the rope, then the rope have a tendency to resist opening up into the
sheet form. Ultimately each in the rope will start separating directly at the comb located at
the Long Chain Beamer. This may leads to rope damage.
The Tension Stand is approximately 4-feet high and consists of two tension drums, each
approximately 14-inches in diameter and 14 inches face length. These rolls are fitted one
over the other.
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Fig. : Tension Stand
Some machinery manufacturer incorporates an AC Vector motor and drive is used to create
tension in the rope instead of a pneumatic or EDDY current brake. This provides
considerable energy saving. As the motor is operated in a regeneration mode, it providing
power that can be consumed in the beamer head.
The rope from the tension stand passes through an Accumulator.
Fig. : Passage of dyed yarn rope in a Typical Long Chain Beamer
Stop Motions
In most of the LCB machines not incorporated with any automatic stop machines. The eyes
of the operator work to detect the end breakages. However it depends on the skills of the
operators.
This manual system of detection of end breakages is not a reliable system of detection of
end breakages in any Beaming operations. Some machinery manufacturer incorporated
various stop motions in re-beaming process in order to detect the end breakages in LCB.
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Chapter Seven
Sizing
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7.1 Definition :
The process of applying a protective adhesive coating upon the yarn surface is called
sizing. This is the most important operation to attain maximum weaving efficiency
specially for blended and filament yarns.
7.2 Objects of Sizing :
To improve the weave ability of warp yarn.
To increase the tensile or breaking strength for cellulose yarn.
To maintain good quality fabric.
To reduce hairiness, weakness of textile materials.
To remove electrolytic formation for synthetic or blended yarn. To increase elasticity.
7.3 Changes in Yarn due to Sizing :
Breaking strength: Increase
Abrasion Resistance: Increase
Stiffness: Increase
Elasticity: Increase
Frictional Resistance: Increase
Yarn Diameter: Increase
Extension: Decrease
Electrostatic Charger: Decrease Hairiness: Decrease
7.4 Types of sizing according to application :
Pure sizing: When sizing is done in yarn which produces unbleached fabric is
called pure sizing. So, ingredients are on the weight of yarn 7 to10%.
Light sizing: This is used for dyeing and printing. 11 to 15% sizing ingredients
are used on the weight of yarn.
Medium sizing: For increase of strength and weight of the yarn 16 to
40%sizingingredients are used on the weight of yarn.
Heavy sizing: It is used to increase the weight of yarn. Above 40% sizing
ingredients are used on the weight of yarn.
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7.5 Size Ingredients and their function :
Starch or Adhesive: The carbohydrate component extracted from certain plates is
called starch. Example: Starch not maize, corn, potato etc.
Function:
To improve the strength
To increase smoothness
To increase elasticity
To increase stiffness To impart adhesion
Softening Agents: The agent which is used to give fabrics a soft handle and frequently
smooth appearance is called softening or lubricating agent. Example: Japan wax, tallow,
lin seed oil, coconut oil, animal fats, mineral oil, T.R.O., soap etc.
Function:
To make the yarn soft and slippery
To smoothen the yarn
To reduce the stiffness To reduce flexibility and friction
Antiseptic or Anti mildew Agent: The substances which prevent the mildew
formation is called anti-mildew agent. Example: Carboxylic acid, salicylic acid, Zinc
chloride, phenol etc.
Function:
To prevent mildew formation
To prevent size material for a longtime
To help to store the size yarn To protect yarn from bacteria or fungi.
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Hygroscopic Agents: The agents who are used to moisture yarn and to prevent
excessive drying of yarn is called hygroscopic agent. Example: MgCl2, CaCl2, Glycerin etc.
Function:
To moisture the yarn To prevent excessive prevent of yarn
Weighting Agents: The agent which is used to increase weight of yarn and to impart
the fullness and feel to the fabric is called weighting agents. Example: China clay, Sodium
Sulphate, French chalk etc.
Functions:
To increase the weight of yarn during finishing
To impart fullness and to fell the fabric To prevent opening of the cloth.
Tinting Agents: The agent which is used for the temporary coloration of textile
materials is called tinting agents.
Example: Blue, Tinapol, Optical brightener etc.
Function:
To increase the brightness and to remove the yellowish color of yarn
To prevent dusting off To form a particular shade
Wetting Agents: The agents which are used for uniform distribution of the sizing
solution is called wetting agent.
Example: Sulphanol, soap, MgCl2 etc.
Function:
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To increase size exhaust To obtain a distribution of the sizing solution
Antifoaming Agents: The substrates which prevent the foam formation is called
antifoaming agent. Example: Pyridine, Benzene etc.
Function:
To prevent foam formation To give uniform size pickup
Neutralizing Agents: This type of agent is used to neutralize the sizing solution.
7.6 Controlling Point of Sizing :
Viscosity of the size solution
Sizing machine speed
Size add-on levels
Concentration of the size mixture
Volume of the size box (both quantity and size level)
Threading arrangements
Volume of the size box (both quantity and size level)
Condition of squeeze rollers
Squeezing pressure
Hardness of squeeze rollers
Diameter of squeeze rollers
Yarn count and size box warp density per unit space.
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7.7 Sizing in Amber Denim Mills Ltd. :
7.7.1 Machine Specification :
Brand Name UKIL MACHINERY
Origin Korea
Total Machine 02
Const. Year 2012
M/c speed 35 mpm
Creel Capacity 16
No of Squeeze Roller 6
No of Emersion Roller 2
No of Size Box 2
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No of Size Dryer 14
Size Box Temp. 88-92ᵒc
Preparation Tank Temp. 90-92ᵒc
Reserved Tank Temp. 92ᵒc
Production per day 60000 m/day
Brand Name KARL MAYER
Origin Italy
Total Machine 01
Const. Year 2014
M/c speed 35 mpm
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Creel Capacity 16
No of Squeeze Roller 4
No of Emersion Roller 4
No of Size Box 2
No of Size Dryer 18
Size Box Temp. 90ᵒc
Preparation Tank Temp. 90-92ᵒc
Reserved Tank Temp. 92ᵒc
Production per Day 30000 m/day
7.7.2 Process Flow Chart :
Creeling
Size Box
Dryer
Head Stock
7.7.3 Regular Sizing Recipe :
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Recipe of UKIL Sizing Machine
Water 500 L
K2000 15.83 kg
T20 41.66 g
Master 1.66 kg
Wax/B60 2.09 kg
Ecosize .87 kg
Recipe of KARL MAYER Sizing Machine
Water 1000 L
K2000 46 kg
B120 58 kg
CMS60 8 kg
UEXD12 24 kg
Wax 5.6 kg
Ecosize 2.4 kg
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7.8 Sizing :
The purpose of sizing is to increase the strength of yarn through chemically binding the
fibers with each other. The main object of sizing warp yarns is also to encapsulate the
yarn with a protective coating which reduces yarn abrasion that takes place during the
weaving operation and reduces yarn hairiness preventing adjacent yarns from entangling
with one another at the weaving machine. Also, this size protective coating also prevents
the indigo dye from rubbing off during the weaving. Sizing operations also involves
multiplication of warp sheet from long chain beamer sheets by collecting the yarns
together and making one weaver’s beam. Normally, 8-12% size is applied in sizing.
The performance of weaving largely depends upon the quality of the sized beam. In order
to achieve good performance in weaving, the sized warp beams should have certain
characteristics, such as:
The sized beam should have minimum number of yarn breakages, no crossed yarns, low hairiness with no clinging.
The size add-on should be uniform through the length of yarn sheet,
Equal residual yarn moisture content,
No over-dried yarn.
No stickiness in the yarn
Equal yarn tension/elongation
high residual elongation in the yarn,
perfectly wound edges
For a long time, sizing of denim yarn normally carried out with starches or slightly
modified starches and binders. However, with the advent of different garment washed
techniques and the softness of the fabric required by the customer has led to new sizing
recipes.
The components of a sizing machine are:
Creel, Size Box, Drying Section, and Headstock
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7.9 Briefly Description of Different Parts :
Creels :
At the back end of a sizing machine, the section beams from the Long Chain Beaming
process are creeled. The yarn sheet from each section beam is pulled over and combined
with the yarns from the other beams.
There are various types of creels available today for denim sizing; each has its own
advantages and disadvantages. The common design of creels is as below:
Cluster Creels : In the cluster creel arrangement of a sizing range, the crosswalks
are placed between each cluster of 4 beams (Fig.). It allows passage for easy
supervision and access to the operator. In the long chain beamer beam, there is more
chances of broken ends and lappers. Hence it is more important to access the sizing
back beam.
Fig. : Cluster Creel
Magazine Creel : In the magazine creel, there are two creel sections; one creel in the
storage position can be used for loading of re-beamer beam, while the other creel is in
running condition. The advantages of the creeling are higher productivity due to saving
time in the set change. There are different types of magazine creel available. The most
common types are the side-to-side and front-to-back/side-to-side. However magazine
creel takes more space.
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Another creel design is the rotating or carousel creel. In this creel design, two creel
sections are tied together and turn on a central pivot point. Rubber wheels ate fitted at
the four corners of the creel which allow the creel to turn. The back of the creel becomes
the front of the creel in the run position.
In the carousel creel design, the creel is rise up on a cushion of air and is motorized to
rotate. The creel can be loaded in remote locations, may be near long chain beaming and
then pulled on a cushion of air into the position behind the back of a sizing machine.
Fig. : Beam creel with tension controller
Creel Braking
Creel braking is very important in denim sizing. The main object of brakes in a creel is to impart a constant unwinding tension. The tension should be remain same from full to empty of the back beam as well as during acceleration and deceleration. The primary guide roll going into the size box is fitted on load cells. The tension of a single sheet or a number of sheet is measured by means of a load cell. The tension controllers then control the tension by sending pneumatic signals to each brake, if there is any difference between the actual tension and the desired tension.
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Size Boxes
Size box is one of the most critical component of a denim sizing machine. The application of size on the yarn should be uniform to provide necessary protection during subsequent process, in weaving. The number of size boxes is also an important
criteria of efficient sizing. The number of size box depends on the space occupied by the yarn in a given sheet width.
The number of size boxes is also depends on the type of weaving machines used in the plant. If the sized yarn is woven on a high speed air jet loom, then the uniformity and the quality requirement of the sized beam is higher than on a projectile looms. Hence for air jet looms, two size boxes is recommended. When the yarn sheet enters the size box, the yarns are guided downward and passed through the size paste in the size box. Then the yarn sheet passed through a set of squeeze rolls. The squeeze rolls control the wet pick-up, and influences the size add-on onto the yarn.
After the size boxes the yarn sheets are dried by passing over steam- heated, Teflon coated cylinders. Different capacity of cylinder in sizing is shown in Fig.
After the drying zone, the yarns pass through a set of stainless steel split rods. The function of the split rods is to separate the yarns into individual sheets, equivalent to the number of section beams in the creel. The yarn sheets then collected into one single sheet and passed through a expansion comb, which separates individual yarns. The yarn sheet then wound onto the loom beam.
Cylinder dryer
The dryers having an important role in efficient sizing and to avoid yarn abrasion and fibre and yarn
hairiness which occur as the warp yarns rub against each other and during opening of the warp yarns
that are clinging together. The Teflon-coated cylinders reduce yarn hairiness and clinging. The Karl
Mayer sizing machine dryer may be of multiple configurations, Teflon coated and equipped with
temperature control devices. The automatic moisture control configured either as a floor layout or
overhead version of drier.
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Fig. : Cylinder Driers
Leasing Zone
Due to the nature of sizing, the yarns in the sheet may be stuck together at the exit
of dryer section. Therefore they are separated into individual ends using leasing rods.
The individual sheets of yarns from each section beam are separated.
Beaming
The yarns are wound on to weaver’s beam at the headstock. A pressing roller is
pressing the warp yarn for uniform tension winding. A guide roller guides the yarns to
the weaver’s beam.
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Chapter Eight
Weaving
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8.1 Weaving :
The process of producing a fabric by interlacing warp and weft threads is known as
weaving.
The machine used for weaving is known as weaving machine or loom. Weaving is an art
that has been practiced for thousands of years. The earliest application of weaving dates
back to the Egyptian civilization. Over the years, both the process as well as the machine
has undergone phenomenal changes. As of today, there is a wide range of looms being
used, right from the simplest handloom to the most sophisticated loom.
8.2 Flow Chart :
Weavers beam
Drawing/Knotting
Denting
Shedding
Picking
Beat up
Fabric Take up
Fabric Let off
Rolling
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8.3 Basic Weave Designs :
Plain weave
Twill weave
Zigzag twill
Herringbone twill
Broken twill
Mostoftheotherweavesarederivedfromthesebasicweaves.Theimmediatederivativesof
thesestructures are warp rib, filling rib, and basket weave.
Plain Weave:
Plain weave is the simplest of all weaves. It has one-over one-under interlacing for both
warp and filing yarns, therefore the plain weave formula repeats on two warp and two
filling yarns. Plain weave requires only two harnesses. In Denim manufacturing this
weave is called Chambray.
Figure: 1/1 plain weave
Twill Weave:
TwillWeaveisproducedinastepwiseprogressionofthewarpyarninterlacingpattern.Theint
erlacing pattern of each warp yarn starts on a different filling yarn and follows the same
formula. These result sin the appearance of a diagonal line called twill line in the fabric,
which is then characteristic of this design. Depending on the direction of the twill line,
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the twill weaves are called right-hand or left-hand twills.
The sum of the digits in the formula determines the unit cell of the design, which also
gives the minimum number of harnesses, requires weaving the design; at least three
harnesses are required for a twill weave.
Common twill, Steep twill, Reclining twill and broken twill are the different variations of the twill weave.
Figure: 3/1 Twill weave
8.4 Classification of Modern Weaving Machines :
Modern Weaving machines are classified according to their filling insertion mechanism.
The classification is as follows:
Air-Jet
Projectile Rapier Water-Jet
8.4.1 Air-Jet Weaving :
Air-jet weaving is a type of weaving in which the filling yarn is inserted into the warp shed
with Compressed air. Air-jet system utilizes a multiple nozzle systems and a profiled reed.
Yarn is drawn from a filing supply package by the filing feeder and each pick is measured
for the filling insertion by means of a stopper. Upon release of the filling yarn by the
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stopper, the filling is fed into the reed tunnel via tandem and main nozzles, which provide
the initial acceleration.
Fig.: Operation principle of air jet loom
8.4.2 Projectile Weaving :
Projectile weaving machines use a projectile equipped with a gripper to insert the filling
yarn across the machine. The gripper projectile draws the filling yarn into the shed. The
Projectile glides through the shed in a rake- shaped guide. Braked in the receiving unit,
the Projectile is then conveyed to its original position by a transport device installed
under the shed.
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Fig.: Operation principle of Projectile
8.4.3 Rapier Weaving :
In Rapier weaving, a flexible or rigid solid element, called rapier, is used to insert the
filling yarn across the shed. The rapier head picks up the filling yarn and carries it
through the shed. After reaching the destination, the rapier head returns empty to pick
up the next filling yarn, which completes the cycle. A rapier performs a reciprocating
motion.
Fig.: Rapier Weaving Machine
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Rapier weaving machines can be of two types:
Single Rapier Machines: A single, rigid rapier is used in these machines. The rigid rapier
is a metal or composite bar usually with a circular cross section. The rapier enters the
shed from one side, picks up the tip of the filling yarn on the other side and passes it
across the loom width while retracting. Therefore, a single rapier carries the yarn in
one way only and half of the rapier movement is wasted. Also there is no yarn transfer
since there is only one rapier. The single rapier’s length is equal to the width of the
loom.
Double Rapier Machines : Two rapiers are used in these machines. One rapier, called
the giver, takes the filling yarn from the yarn accumulator on one side of the loom,
brings it to the center of the machine and transfers it to the second rapier which is
called the taker. The taker retards and brings the filling yarn to the other side. Similar to
the single rapier machines, only half of the rapier movements is used for filling insertion.
8.4.4 Water-Jet Weaving :
A water-jet weaving machine inserts the filling yarn by highly pressurized water. The
relative velocity between the filling yarn and the water jet provides the attractive force.
If there is no velocity difference, then there would be no tension on the yarn results in
curling and snarling of the yarn. Water-jet weaving machine can only be used for
hydrophobic fibers.
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Fig.: Water Jet Weaving Machine
8.5 Weaving in Amber Denim Mills Ltd. :
In Amber Denim Mills Ltd. weaving is air Jet. There are 180 airjet machines. The
department is working under the good supervision of Mr. Paul who is weaving manager
and very much dedicated to his work. He is working with all his technical, management
hardworking staff. Like some other departments weaving department is running 24
hours a day and meeting the sales requirements. Weaving department is playing a
leading role in denim manufacturing at of denim at Amber Denim Mills Ltd..
8.5.1 Machine Specification :
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Brand Name PICANOL
Model No OMNI-Plus 800
Origin Belgium
M/C Speed 850 rpm
Heald Frame 16
Dope Wire 6
Total Relay Valve 2
Air Pressure Required 6 bar Min
Number of Cutter 2
Let Off Motion Electrical
Take up Motion Electrical
Shading Cam
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8.5.2 Looming :
Looming covers the process involved in warp preparation after sizing up to setting
them to loom. The process can be shown as follows:
Drawing-in → Warp Tying → Loom
Drawing-In: The process of drawing every warp end through its drop wire, heddle eye and reed dent
can be performed manually or by means of automatic machines. In both case, a
length of warp yarn, just enough to reach to the other side of the frame, is unwound.
Leasing (i.e. selecting warp) of the warp at this stage simplifies the separation of the
yarns. Then they are threaded through drop wires heddle eyes and reed dents. The
automatic drawing machine can handle the leasing-in and drawing -in process in one
single operation.
Tying-In: When fabric of a particular type is being mass-produced, the new warp beams will be
identical with the exhausted beams on the looms. Therefore, if every end on the new
beam is tied to its corresponding end on the old beam, the drawing-in process can be
omitted. Tying-in may be done by means of a small portable machine on the loom or as
a separate operation away from the loom.
8.5.3 Basic Motion :
In order to interlace wrap and weft threads to produce a fabric, the following motions are
necessary on any type of loom:
Primary motions Secondary motions Tertiary motions
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8.5.3.1 Primary Motions :
These are fundamental or essential motion. Without these motions, it is practically
impossible to produce a fabric. It is for this reason that these mechanisms are called
primary motion.
Shedding Mechanism :
The shedding mechanism separates the warp threads into two layers or divisions to
form a tunnel known as ‘shed’. The shed provides room for passage of the shuttle. A
shed may be formed by means of tappets, dobby and jacquard.
Shedding Components: There are two main shedding components:
Heald frame
Cam
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The Heald or Heddle: Alternate vertical movements according to the evolution of the
warp yarn and the passage of the picks drive the heddles. Healed frame or heddles
consists of a wooden frame, which consist of healed wires.
To provide straight path for the passing of the warp. These are twisted and metallic wires,
which slides on flat bars within the frame.
Cam / Tappet: The purpose of the cam is to control the motion of harness frames, the lift
of reed and the weave pattern. Possible weave patterns of fabric are 1/1, 2/1, 3/1 and
4/1. There are 4 cams in the air jet loom and a single cam is double plated. The cam
acquires special curved shape.
Healed Shaft: A healed shaft consists of a wooden or metal frame carrying healed wires.
The width of a healed shaft is slightly greater than that of the warp sheet and is usually
36 to 48 cm deep.
The functions of a healed shaft are:
To carry healed wires and maintain warp yarns in their correct positions
To form a shed line.
Picking Mechanism :
The picking mechanism passes weft thread from one selvedge of the fabric to
theotherthroughtheshedbymeansofashuttle,aprojectile,arapier,aneedle,anair-jetora
water-jet. The inserted weft thread is known as “pick”.
Components of Picking Mechanism:
Cone Stand Cone holder Disc Tensioner
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Warp Yarn Path Diagram(Air jet) :
Weft Yarn Path Diagram(Air jet):
Cone Break Detector: Cone break detector detects filling yarn breaks that occur
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between the cone and pre winder. The cone break detector stops the weaving machine
before the pre winder is empty. Cone break detector between the cone and the pre
winder prevents starts up marks.
The Filling Tensioner: Filling tensioner are necessary to ensure a most uniform yarn
tension between the cones and pre winder drum, therefore ensuring an absolute
uniform tension under filling yarn winding without any loop formation.
Weft Accumulator or Prewinder: The pre winder draw filling yarn from a cone,
winding it on the winder drum which in turn, makes for gentle pick insertion. The
weft yarn is drawn off the package and wound on to measuring bands and fingers by
the rotating motion of thread guiding tube. The diameter of the measuring band
can be adjusted according to the width of the loom. Adjusting the measuring bands
and the number of coils sets the pick length. The electro magnetically controlled
stopper pin releases the weft yarn at the machine angle set.
Storage Control: As it takes time to rise the motor rpm to the standard rpm at starting
required weft yarn for next insertion is wound in advance to secure smooth weft
insertion. While the loom is running, corresponding length weft yarn to one insertion
is supplied to the pre winder, and storage is controlled in the pre winder.
Measuring Control: One pick length of weft yarn is measured by releasing or hooking
solenoid FDP pin electrically. There are two timings;
One is for the first pick at starting and the other is preceding pick at normal operation.
These timings secure accurate measuring, storage, measuring and weft insertion are
controlled by output of signal command.
Balloon Breaker: The balloon breaker reduces the balloon dimensions when drawing
yarn from the pre winder. The closer the pre winder to the balloon breaker, the
smaller the yarn balloons. When weaving heavy filling yarns, there is the potential to
increase the rate of insertion when using a balloon breaker.
Main Nozzle: Nozzle is a duct of smooth varying cross section in which air is used to
accelerate weft yarn through the shed across the width of fabric. On air jet weaving
machines in each channel there are two main nozzles, one is fixed and other is movable.
Relay Nozzles: Relay nozzle mounted in sley are connected in groups to
electromagnetic valves. The electromagnetic relay nozzle valve starts the air jet.
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The length of time the valve is opened depends on the reed width and relay valve
spacing as well as on the yarn. The compressed air is distributed from the compressed
air tank via the valves to the nozzles. Relay nozzles are arranged over the entire length
of the reed, the relay nozzles assists the movable main
Filling Cutter: The function of cutter cuts the filling at the left hand and right hand
side of an insertion. The cutter is driven by the motor and is completely independent
of the machine drive. The position, the movement of cutting and the condition of the
filling cutter are very important for the insertion. Cutter is mounted on both ends of
the fabric. On yarn supply side, yarn is securely cut every time reed is beaten. On
driving side preceding yarn is cut between the temple and the space roll. The motion
of the cutter cam attached to the main shaft is transmitted through cutter cam lever
and cutter rod to cutter edge.
Filling Detectors: The filling detectors or sometimes called feelers mounted at the
reed holder on the loom and the end of the driving side photo electrically monitors
whether there is weft yarn arrive or not.
Beat Up Mechanism :
The beat-up mechanism beats or pushes the newly inserted length of weft thread(pick)
into the already woven fabric at a point known as “fell of the cloth”. These three
mechanisms namely shedding, picking and then beat-up are done in sequence.
Beating Components:
Sley: The sley is a metal frame. In case of air jet contains profile reed, relay nozzles, filling
detector, stretch nozzle and side detector. At its forward motion the last pick is beaten
up to the fell of the cloth, and at its forward motion the weft is allowed to insert through
relay nozzles through the open shed. The heavy reciprocating sley with the help of a reed
firmly beats up the last pick to the fell with the sufficient velocity.
Reed: The reed is an arrangement if vertical steel wires spaced a given distance apart a
securely fastened at the top and bottom by the bindings. The spaced between two wires
is known as "dent". Reeds are made with any desire number of dents per inch, according
to the requirements of the cloth that is to be woven. A reed contains a definite number
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of dents on a given length; this is termed as the count, the pitch, or the number of reed.
The reeds are named differently. Reeds are named from the number of dents contained
in one inch. The shape and thickness of the metal wires used in the reed is important.
Reed selection depends on several considerations including fabric appearance, fabric
weight (ends per unit width), beat up force, air space requirements and weave design.
8.5.3.2 Secondary Mechanisms :
These mechanisms are next in importance to the primary mechanisms. If weaving is to be
continuous, these mechanisms are essential. So they are called the “secondary
mechanisms”. The yare:
Take-up motion Let-off motion.
Take-up motion: The take-up motion withdraws the cloth from the weaving area
at a constant rate so as to give the required pick-spacing (in picks/inch or picks/cm) and
then winds it on to a cloth roller. The main part of the mechanism is the take up
rollers, which draws the cloth at the regular rate, and the number of picks per inch
decides this rate. The take up roller is covered with emery cloth or hard rubber
depending upon the type of cloth woven. The drive to the take up roller is by a train
of gear wheels put into motion directly from the main shaft.
Let-off motion: The let-off motion delivers the warp to the weaving area at
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the required rate and at constant tension by unwinding it from the weaver’s beam. The
secondary motions are carried out simultaneously. The speed of the servo motor is
transmitted to warp beam gear via reduction gear, thus driving beam.
8.5.3.3 Tertiary Mechanisms :
To get high productivity and good quality of fabric, additional mechanisms, called auxiliary
mechanisms, are added to a loom. The auxiliary mechanisms are useful but not absolutely
essential. This is why they are called the “auxiliary mechanisms”. These are listed below.
Weft stop motion
Temples
Brake
Warp stop motion
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Chapter Nine
Finishing
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9.1 Definition :
In general, before marketing, all the process which is applied on the fabric after weaving
is called finishing.
In short sense, finishing is the process by which the fibers, yarns and fabrics are made as
presentable to the customer and these processes are implemented after coloration.
The term finishing covers all those treatments that serve to impart to the textile the
desired end-use properties. These can include properties relating to visual effect, handle
and special characteristics such as waterproofing and non-flammability.
9.2 Objects of Finishing :
To increase the attractiveness of fabric.
To increase the serviceability.
To increase the beauty and glitterness of fabric.
To increase the fineness and to ensure smoothness.
To ensure the softness of the fabric.
To free from hairiness of the fabric.
9.3 Types of finishing :
Physical/Mechanical Finishing:
The finishing process which is performed by machines but not using of chemicals is
called physical/mechanical finishing.
Example: Calendaring, embossing, raising, sanforizing etc.
Chemical Finishing:
The finishing process which is performed by application of chemicals which reacts with
fibres is termed as chemical finishing.
Example: Starching, Mercerizing, resin finishing, Desizing, Water Repellent Treatment, Flame Retardant
Treatment, etc.
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9.4 Finishing In Amber Denim Mills Ltd. :
Amber Denim Mills finishing department is a well-established modern section with a
suitable range of the finishing processes required for denim.
Proper finishing process is necessary otherwise the fabric will be rejected by the buyer. In
case of denim mainly controlling of the shrinkage and the skew of the fabric is done.
Besides, finishing process finishing section of Amber Denim Mills have to do a lot of others
job like fabric storing, inspection, sample processing etc. So a finishing section in a denim
industry plays a vital role. Finishing section of Amber Denim Mills Ltd is responsible for
the following:
Finishing process
Quality control
Inspection
Sample processing and preservation
Finished fabric storing and delivery
The following types of finishes are applied to the denim fabric at Amber Denim Mills.
Singeing
Softening
Skew control
Desizing
Mercerizing
Sanforizing
Calendering
Resin finishing
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9.4.1 Finishing :
9.4.1.1 Machine Specification :
Brand Name Morrision
Origin USA
Const. Year 2012
M/C Speed 30-38 mpm
No of Dryer 20
No of Bath 1
Required Steam 0.56 bar
Squeeze roller Tension 10-10.5 psi
Chemical Box Temp. Room Temp.-60ᵒc
Rubber Belt 16.5 Shrinkage
Water 45 LPM
Production per Shift 35000 m/1 shift
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9.4.1.2 Flow Chart :
Fabric Unwinding
J-box
Brusher
Singeing
Chemical Box
Squeeze Roller
Dryer
Sanforizing/Rubber Belt
Calendering/Pulmer
9.4.1.3 Bricuefly Describe The Process Sequence of Denim Finish Line :
J-Box: Store the fabric for some while during the process. This unit is important when
change of batcher. Stored fabric supports the continuous operation.
Brushing: In the brushing stage, the grey fabric is brushed to remove the loose lint and
loose fluff from the fabric surface. It also raised the protruding fibers on the fabric
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surface which are removed in the next stage of singeing process.
Singeing: The fabric is then singed in both or only faces side which burn off the
protruding fibers from the fabric surface. Normally denim fabric is singed twice in
a single passage of a singeing machine. The denim finished fabric must have soft
and pleasant handle.
Before Singeing After Singeing
Types of Singeing:
Singeing can be classified into two types: 1. Direct singeing 2. Indirect singeing
1. Direct singeing is the most popular procedure. The fabric passes either glowing
metal with contact (mainly for pile fabric) or a direct gas flame. Important for both techniques: when the machine stops, the fabric is moved from the metal and the flame stops, too.
2. The indirect singeing works with highly heated ceramic modules. Infrared beams are burning the loose fibres. Speed controls the singeing effect.
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Softening: After the singing range, the fabric is subjected to a chemical pad treatment.
Softeners are often used in the chemical treatment in order to impart soft feeling of
the fabric.
Skewness Control: The skewness in denim fabric, particularly in twill weave creates a
serious problem in subsequent garment manufacturing and its washing. Leg twist is a
major problem in denim manufacturing. Due to this problem the leg is rotated in the
opposite direction of the twill of the fabric after laundering. Leg twist is assumed to be
happen due to the directional yarn stresses. These are inherent in regular twill weave
fabrics and developed during weaving. During washing the yarn stresses is relaxed which
change the regular position of interlacement between warp and filling yarns. Due to this
reason the legs are twisted. Normally leg twist not shown on garment stage. It only
observed after laundering of the garment. Although leg twist appears after first
laundering and it increases progressively with repeated launderings.
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Figure: Fabric with skew Figure: Fabric without skew
Ideally warp and weft should be at right angle to each other in normal fabric. Skew in the
fabric occurs when the warps are displaced from their vertical position or when the weft
is displaced from their horizontal position.
The leg twist is created due to tensions in the fabrics. It is related to the twill direction.
Normally a right hand twill fabric twists in the counter clockwise direction. Similarly a left-
hand twill fabric twists in the clockwise direction. These leg twist problem can be
eliminated through compensating the tensions by deliberately skewing the fabric in the
counter clockwise direction for right-hand twills (RHT) and in the clockwise direction for
left-hand twill(LHT).
Hence the RHT denim fabric should be skewed by advancing the right selvage with respect
to the left selvage in the fabric of face up. This results in counter clock wise skew. Similarly
a LHT fabric should be skewed by advancing the left selvage when run face up. The
amount of the skew to be applied depends upon many factors, such as the type of twill
weave, the weight of the fabric, the yarn sizes, and the twist of the yarns. The twill angle
is also an important factor.
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The movement of yarn in a plain fabric the movement of yarn in a twill fabric In case of
plain weave fabric, the free spaces in warp and weft direction is equal. Hence the forces
acting on all sides of each float are equal, which makes the fabric more stable. However
in case of twill weave fabric, at the portion of a float; there is a gap or free space equal to
the actual diameter of the yarn. Due to this free space, there may be possible that the
floating yarn push away the crossing yarn.
The floating yarn to push away the crossing yarn at the interlacing point
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The two forces acting opposite to each other in the floats makes them like an in-plain
lever (Fig. A). The position of the free spaces on either side of the float determine the
direction in which the float to be skewed. For a right hand 2/2 twill fabric, the location of
the free spaces, as shown in Fig. A will skewed clockwise shown in Fig. B. For a left- hand
2/2 twill fabric, as shown in Fig. C, the floats will be skewed anticlockwise.
Herringbone or any other types of zigzag twill, there is no risk of the fabric becoming
skewed, as in such weaves, floats (in-plane levers) act oppose to each other. The degree
of skew movement depends upon yarn characteristics, weaving tensions, and the fabric
structures.
Dryer: Wet fabric is dried in this section. Steam produced by boiler heating the cylinder
drum. It increase the inside temperature of the drum. The temperature can be adjusted by changing steam pressure. There are 20 drums for drying.
Sanforizing: Sanforizing is a mechanical finishing process of treating textile fabrics to
prevent the normal dimensional alternation of warp & weft. After sanforizing the
residual shrinkage of woven fabric may be zero. The sole objective of sanforizing is to
control the length wise shrinkage of fabric.
Shrinkage phenomenon: During spinning, weaving, bleaching, dyeing and the various
finishing processes, yarns and cloth are under a continuous tension. Yarns and/or fabrics
are not fixed materials. They consist of separate, stretchable fibres which submit to the
tension. In other words, fabrics do stretch in length and width. The tension within the
yarns, which is caused by this stretching, can be eliminated when the friction within the
fabric is reduced. This reduction in friction occurs during laundering where both water
and soap act as a lubricant. The lubricant, along with the mechanical action of the washer,
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helps the fibres relax and contract to their original length before the elongation takes
place. This means that the fabric shrinks and recaptures its original equilibrium.
Controlled Compressive Shrinkage Process :
The internationally well known and most important shrinking process today dates back
more than 70 years. Though the correct expression for this process is Controlled
Compressive Shrinkage, the average person knows it as SANFORIZED. The process is a
purely mechanical treatment without any addition of chemicals.
The purpose of the process is to shrink fabrics in such a way that textiles made up of these
fabrics do not shrink during washing. The amount of potential wash shrinkage must be
determined prior to shrinking. A full width sample is wash-tested according to the test
method. After the lengthwise and widthwise shrinkage has been determined, the
compressive shrinkage machine can be adjusted accordingly.
Principle of Mechanical Shrinking :
Figure: Shrinking process
The shrinking process takes place between the rubber belt and the heated shrinking
drum. The pressure roller presses the rubber belt against the shrinking drum and the belt
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is stretched. When the pressure of the roller is relieved the belt shrinks again. The fabric
inserted between the rubber belt and the drum has to follow the shrinking of the belt
and is itself shrunk. The fabric shrinkage can be varied by varying the pressure of the roller
on the rubber belt. The greater the roller pressure, the greater the shrinking. The fabric
is fed on the convex part of a drying cylinder and when the blanket retracts to the concave
section of the blanket, the cloth is physically forced to comply with the curvature and
shrinks according to the thickness of the blanket. The cylinder serves to hold the fabric on
to the blanket and does not let it slip back.
The excessive heat of the shrinking cylinder can cause damage to rubber belt. In order to
prevent this, perforated water pipes spray water on the belt as it leaves the fabric. This
has two advantages;
The rubber belt is cooled down and prevented from surface hardening.
Very little water remains on the grainy surface of the rubber belt and absorbed by the fabric. This results in good and easy shrinking process.
Calendaring
After grey fabric is subjected to singeing, softening, skewness, sanforizing etc. it is finally
dried to retain its true shape and dimensions. But in this state the fabric becomes least
lustrous. Because for those operations the threads in fabric become weave and crimped.
But if a fabric is to appear highly lustrous then its surface should be parallel to each other
and all should lie in the length direction.
Objects of Calendaring :
To cause a closing together of the threads of the fabric by flattening them and thus tending to fill up the interstices between warp and weft.
To produce a smooth, glossy and highly lustrous appearance on the surface of the cloth.
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To reduce fabric thickness.
To reduce air permeability and water permeability of fabric by changing its porosity.
Essential elements of calendaring :
The following three elements should be controlled during calendaring.
High pressure
High temperature
Suitable degree of dampness
Besides these the number, composition & arrangements of pressure bowls and speed of
running cloth are also should be controlled carefully.
9.4.2 Mercerization:
Mercerization is a physio-chemical process where yarn (cotton) is treated with 15-25%
caustic soda solution at a temperature of 200-300C. It is necessary to hold the fabric under
tension and wash thoroughly.
9.4.2.1 Machine Specification :
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Machine Name Mercerizing Machine
Origin China
M/C Speed 25-40 mpm
No of Dryer 20
Wash Box 6
Coustic Box 2
Cylinder 20
Steam 120ᵒc
Production Per Day 32000-36000 m/day
9.4.2.2 Flow Process Chart for Mercerization:
Fabric Unwinding
Cold Wash Box
Hot Wash Box
Hot Wash Box
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Chemical Box
Cylinder
Chemical Box
Cylinder
Cold Wash Box
Chain Up
Hot Wash Box
Hot Wash Box
Acid Wash Box
Normal Wash Box
Dryer
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9.4.2.3 Advantages of mercerization:
Increase tensile strength
Improve hygroscopicity
Improve dye affinity
Improve smoothness
Improve luster
Improve dimensional stability and physical compactness 20-30% dye and chemical save while dyeing after mercerization.
9.4.3 Desizing:
Desizing is the process of removing size materials from fabric. This is done
simplypassingthefabricthroughsomehotwaterbathforseveraltimes.Sometimessoftenerca
n be used for better removing of size materials and also for better soft handfeeling
9.4.3.1 Flow Process Chart for Desizing:
Fabric Unwinding
Cold Wash Box
Hot Wash Box
Hot Wash Box
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Chemical Box
Cylinder
Chemical Box
Cylinder
Cold Wash Box
Chain Up
Hot Wash Box
Hot Wash Box
Hot Wash Box
Dryer
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9.5 Regular Finishing & Mercerizing Recipe :
Recipe for Finishing
Belfasin 5 gpl
Adasil 20 gpl
Recipe for Mecerizing
Coustic Box
Coustic 7.5 gpl
Acid Box
Acetic Acid 3 gpl
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Chapter Ten
Denim Wash
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10.1 Denim Washing:
Washing treatment on denim garments offers an aesthetic finish, enhanced the appeal
and increases the fabric strength. Different types of denim washing is available in order
the meet the requirements of today’s denim fashion trend. However each of the washing
techniques having their own advantages and limitations.
10.2 Types of Denim Wash:
Denim washing are of two different types.
1. Mechanical wash 2. Chemical wash
10.2.1 Mechanical wash:
Mechanical denim washes are stone washing and micro sanding. During stone washing,
stones are used in order to achieve typical wash down effect. There are three types of
micro sanding, such as:
Sand blasting
Machine sanding
Hand sanding
Whiskering
Shot gun denim
Water jet fading
Super stone wash
Ice wash
Thermo denim
Laser technology finish
10.2.2 Chemical wash :
Chemical washes of denim fabric may be of different types. Such as :
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Denim Bleaching
Enzyme washing
Acid washing
Rinse wash
Cellulose wash
Ozone fading
Snow wash
Salt water denim
Flat finish
Over dye
Sun washing
Super dark stone
10.3 Denim Washing in Amber Denim Mills Ltd. :
When an order comes from buyer in form of washed sample the technical person
determine the shade percentage, amount and type of washing to that fabric to get the
appearance like the sample. So it is very important to wash the sample fabric to justify his
assumption. Amber denim mills only gives washed sample recipe so that buyer can get
his desired design but does not run mass production.
10.3.1 Regular Recipe :
A typical recipe for above three types of washing is given below:
Desizing
Chemicals Temperature
Time Rinse Extracting
Drying
Anti-stainAgent Desizing Agent
60ᵒC 20minutes
2 Times 3 Time 25 min
Enzyme washes
Chemicals Temperature
Time Rinse Extracting
Drying
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Anti-stainAgent Eurozyme AceticAcid
45ᵒC pH:4.5-5
25 minutes
2 Times 3Time 25 min
Bleach Wash
Chemicals Temperature
Time Rinse Extracting
Drying
Bleaching powder
60ᵒC Asrequired
2 Times 3Time 25 min
Chemicals Temperature
Time Rinse Extracting
Drying
Sodium Sulphaite
60ᵒC Asrequired
2 Times 3Time 25 min
PeroxideWash
Chemicals Temperature Time Rinse Extracting Drying
Anti-stainAgent Causticsoda Hydrogenperoxide
60ᵒC 10min 2 Times 3 Time 25 min
Neutralization
Chemicals Temperature
Time Rinse Extracting
Drying
Neutral Enzyme Anti Staining Agent
48ᵒC 25minutes
2 Times 3 Time 25 min
Softening
Chemicals Temperature
Time Rinse Extracting
Drying
Softener Silicon
35ᵒC 5minutes Nill 3 Time 25 min
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10.3.2 Machine Specification :
Machine Name YILMAK
Origin Turkey
Model HBM 250 S
Const. Year 2013
Drum Volume 250 Lt
Drum Speed 0-40 rpm
Electric Installation 1.5 kw
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Voltage 400 V
HZ 50 HZ
Ampere 3.2 A
Max. Temp . 95ᵒC
Weight 346 kg
Protection Catagory iP 54
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Machine Name Dewater Machine
Origin China
Model KZ-20 A
Rotery Cage Diameter ɸ 510 mm
Load Wet Weight 20 kg
Rotery Cage Weight 270 mm
Rated Frequency 50 HZ
Product Standart QB/2324-1997
Main Axis Speed 1310 r/min
Sape Size 1200*800*700 mm
Motor 1.5 KW
Weight 450 kg
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Machine Name Laundery Sryer Machine
Model GDZZ-25
Origin Nill
Weight 330 kg
Stream Pressure 0.4˜0.5 MPa
Wattage input rating 1.5 kw
Voltage 3.0 V
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10.4 Most Common Denim Washes :
Washing Type &Features Application
Over-dyed / Tinted Denim:
Over-dyeing / tinting of denim is an additional dyeing treatment which is normally carried out on jeans after sewn. This add another tone of color to the jeans. Normally denim garments is over-dyed with yellowish dye for appearing dirty look. Tinted/ over-dyed denim garments shows a used / vintage& muddy look to the garments. During tinting, a little amount of tint or color is added to the garment in order to change the hue/cast/tone of indigo shade.
Torn Jeans:
Some jeans are teared at some places in order to get natural tearing look. The fabrics have actual rips, holes, tears and/or lacerations.
Vintage Denim:
It is a type of denim washing in which the denim garments is subjected to heavy stonewashing or a cellulose enzyme wash, with or without bleach for showing an old and worn outlook.
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Washing Type &Features Application
Destroyed/damaged/used/whiskers:
Whiskering, also known as 'Cat's Whiskers', are the crease lines around the crotch. Whiskering can be done on the sides of knee and crease marks on the back of the knee. During natural wear, in the portion of a crease, Pigment is removed. Denim garments can be made of old, worn and /or used look by several different ways, such as with the help of laser, sandblasting, machine sanding, hand sanding or abrading by some kind of power tool. With the help of a grinder, whiskering can be produced around the hip to crotch area of the pant. Damaged look of a denim pant can be made by cutting the edges at different areas before washing, such as at bottom, pockets, fly and knee area.
Flat Finish:
Flat finish of denim fabric involves mercerization plus calendaring processes to achieve the flat surface. It imparts an even wash down effect and clean surface. The mercerization process swells up the cotton fibers which is pressed in calendaring to achieved a flat surface.
Ozone Fading:
In this technique of denim washing, the garment is bleached with ozone dissolved in water in a washing machine. However this technique can also be carried out in a closed chamber by using ozone gas. The advantages of these methods are: There is minimum loss of strength It is a simple method and environmentally friendly. The ozonized water after laundering can easily be deozonized by UV radiation.
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Washing Type &Features Application
Super Dark Stone Wash:
This type of denim wash offers an extra dark indigo color which is obtained from a double-dyeing technique.
Super Stonewash:
It is type of wash treatment of denim garments in which the denim garments is subjected to prolonged stonewash treatment for more than six hours. Soda ash and soap are used for hard wash. Steam is used
up to 60-80 0C for one hour to finish the washing process. It is followed by acetic acid wash treatment, then the garments are neutralized and rinsed.
Dirty wash:
In this washing process, after stone-washing treatment, the denim garments are dyed with special chemicals. This shows a dirty looks to the garments.
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Washing Type &Features Application
Laser marking/Spray painting: Laser marking/Spray painting:
Laser marking/Spray painting is a computer controlled technique through which different patterns or designs, such pictures, images, lines, text etc. can be developed on denim garments. It is also called spray painting in denims. In this technique chemicals or pigments is sprayed on the fabric in order to get different pattern on the garments. This is followed by curing of the garment. The advantages of the systems are: It is a water free process. Hence it is an It is an
ecological and economical process. There is zero effluent discharge.
As this process in computer controlled, the chances of human error is negligible.
This system having excellent reproducibility and higher productivity.
The machine requires less maintenance and cleaning.
Consuming less time. This technique having no adverse effect on
fabric strength.fabricstrength.
Ice Wash:
Ice washing is a type of denim washing in which almost half the dye is removed during washing.
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Water-jet fading: In this method of water jet fading, one or both surfaces of the denim garment are exposed through hydro jet nozzles. This hydro jet treatment gives a patterning effect to the garments and /or improves the surface finish, texture and durability of denim garment. This process is not involved with any chemical, hence it is environmental friendly and more economical. The required colour fading is achieved without affecting the fabric strength or or durability, or warp shrinkage.
Washing Type &Features Application
Quick Wash Denim:
In normal indigo dyed denim is associated with various problems during washing. The denim fabric manufacturers are in search to develop a new dyeing method in which the wash cycle can be minimizes. In this regard, Quick wash denim has been introduced in which the fabric is dyed with modified technique of dyeing, so that during wash cycle, indigo dye can be removed easily during a shorter washing cycle. Quick wash treatment procedure consumes less water and chemicals and required less time for washing, retaining fabric strength. By controlling the ionic form of indigo and cellulose in the dye- bath, the uniformity of indigo dyeing can be achieved. The alkalis used and pH conditions of indigo dye-bath produce stable color yield.
Advantages of quick wash denim: Quick wash denim requires less indigo dye. The washing
treatment also requires less enzymes and oxidizing agent. Hence it is an economical and environment friendly process.
The development of streaks in garments after washing has been avoided by using a modified alkali-ph controlled system giving uniformity of shade.
The washing time is 20-30% less than conventional denim.
Snow Wash:
This type of washing treatment for denim is a variation of acid wash. It gives bright white highlights.
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Sun Washing:
Sub washing of denim fabric imparts a sun faded appearance to denim garments. It is carried out by bleaching and stoning of the denim garments.
Soft feel denim:
Soft feel denim can be made with the addition of softener at the garment stage.
Chapter Eleven
Inspection
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11.1 Inspection in Amber Denim Mills Ltd. :
Quality is ultimate concern; every single yard of the denim goes through inspection
department and rated by a point count system to ensure that quality is up to standard
before packing. Defective fabric pieces are rejected and sold as seconds and relatively
minor defective points are marked clearly using stickers to alert cutters.
11.2 Inspection Process:
Fabric batcher is set at the back side of machine equipped with rollers which provides
fabric unwinding. Inspection table is laminated white to enhance the defect identification.
Four tube lights are provided to optimize the lighting. Measuring counter is provided in
front of the inspection table for controlling length. It has forward, reverse, start and stop
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button controls. Inspection is carried out on white board table. The cloth is pulled over
the white board table by a variable speed motor and different cloth defects are recorded
for quality control purpose. They inspect the fabric according to 4 point system. After
inspection fabric is wound on roller.
Four (4) Point System:
This is issued by the American Society for Testing and Materials with reference to the
designation: ASTM D5430-93. Faults are scored with penalty points of 1, 2, 3 and 4
according to their size and significance.
Size Of Defect (Length in Inches) Penalty Points
3 inches or less 1
Over 3 inches but less than 6inches 2
Over 6 inches but less than 9inches 3
Over 9inches 4
11.3 Fabric Defects :
Fabric Defects are divided into two types:
Removable defects
Non removable defects
Major Fabric Defects:
Starting mark:
Causes: Main cause is loom stoppage.
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Remedy: This cannot be avoided but can be controlled by starting mark setting.
Reed mark:
Causes: If any fault occur at reed Faulty denting in the reed.
Remedy: Right selection of the reed and right denting.
Snarl:
Causes: Excess main nozzle pressure Low filling tension
Remedy: Main nozzle air pressure control Correct setting of the PFT finger value
Double pick:
Causes: Cutting problem of the cutter. Faulty setting of the air pressure.
Remedy: Cutter position is to be set correctly. Air pressure should be reset.
Miss pick/ broken pick:
Causes: Excess air pressure of main nozzle
Remedy: Main nozzle air pressure should be reduced
Warp breakage:
Causes: Bad sizing Low strength of the yarn Crossing of the warp yarn
Remedy: Re knotting Proper sizing
Loose or Tight (sizing Fault):
Causes: knotting is given, when breaks yarn, the yarn tension does not match with other yarn as a result Loose or tight occurs.
Filling Stop:
Causes: If weft is failed to reach FD1 If weft is too long & reach FD2
Remedy: Correct setting of the weft length Correct setting of main nozzle Correct setting of relay nozzle Proper setting of air pressure Proper setting of pre-winder Proper setting of creel position
Oil Mark or Crease, Hole:
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When fabric gets spots of oil lubrication from any part.
Contamination:
It is a yarn fault, Plastic Others are mixed with yarn.
Patti:
It is the dark color or thick weft lines in the fabric.
Crease Mark:
Creases occur due to improper finishing.
11.4 Department wise defects and codes no:
11.5 Quality Assurance Procedure:
At first grey fabric is inspected thoroughly with the help of the inspection machine if any
defect is present there then the fault code number is written in inspection sheet.
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When 100 yards fabric inspections is completed then stop the operation & fabric is cut by
scissor. Next, types & no. of fault is converted into point system as mentioned below. This
point is expressed as percentage by using the following formula:
Inspection Calculation Formula = Total Point × 36 × 100/ Fabric length × Fabric width
Point Range Class Class Name
Up to 20 Points / 100m. Class A Elite
Up to 20 – 30 Points / 100m.
Class B Zenith
Up to 30 – 40 Points / 100m.
Class C Insta
More than 40 Points / 100m.
Rejected Rejected
After calculation, the operator place the ‘Identification sticker’ on the fabric roll with
mentioning details of the fabric as Order no, Usable width, Fault grade, Roll length, Total
point, set, style etc.
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Chapter Twelve
Quality Assurance
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12.1 Quality Assurance in Denim :
Denim has gained much popularity that if you look around, you will surely notice
somebody wearing denim in your nearby. Now, more than just complementing a
rugged style, the denim has become suitable for any occasion. Denim is being worn
irrespective of demographic differences. The material denim is synonymous with
familiar blue jeans and is denoted by a rugged twill textile that produces the familiar
diagonal ribbing. Today, there are around twenty Denim manufacturers in
Bangladesh alone catering to the domestic and export markets. The manufacturing
facilities are fast catching up at India, Pakistan and Vietnam. Denim today is now
available in various shades of blue, black and brown within each there are different
effects generated by washing.
Quality Assurance in Denim mill can thus significantly help in achieving the above
objectives. Academically, Quality Assurance may be defined as "the planned and
systematic activities implemented in a system for fulfilling the quality
requirements of a product or service." The current paper highlights in brief various
check points employed in Denim mill for arresting the non conformities so as to
reduce the production losses and quality down gradations.
12.2 Handling of Raw materials in Godown:
Basic raw material for denim fabric is yarn. The same is either produced internally or
is procured from outside. Following care should be taken for avoiding the damage of
packages in go down:
In case of yarns purchased from outside, yarn should be unloaded from truck
gently and location of god own should be as near to warping. This will ensure
minimum yarn damage due to impact and significantly improve the warping
performance due to reduction in cut ends.
In case of In-house yarn, plastic packages are used generally. Car needs to be
taken to use undamaged plastic packages only so as to minimize breaks at
warping due to worn out packages.
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12.3 Approval of raw material:
The raw material for composite Denim mill is fibre while for non composite mill it is yarn
only. The raw material should be approved first before consuming for production.
Following raw material parameters affect the yarn properties and running performance.
For any new supplier/yarn sample it is always better to test the same by running the yarn
as weft in the running looms for assessing its performance. Slub yarn approval should be
given only after assessing the appearance either on yarn appearance board or by
producing the fabric by running the same on the loom along with standard Slub yarn.
12.4 Warping:
Warping serves as the acid test for the assessing the yarn quality. Warping performance
is considered to be satisfactory if breaks/million metre at 1200 mpm is as under:
Following points should be taken care while warping for getting the lower end breakage
rate:
Damaged package found while mounting should not be creeled. Tension in the yarn should be adjusted so that yarn sheet is neither slack nor very
tight (Norm is 10% of the yarn breaking strength). High speed provides necessary tension to the yarn sheet. In case of higher breaks
speeds can be reduced to some extent. Drum pressure should be selected based on the hardness required of the warpers beam.
The warpers beam rims (flanges) should be checked periodically for damage and eccentricity.
The breakages should be recorded along with the reason like cut ends, breakage from Slub, opening of splice portion so as to take corrective action for next supply.
12.5 Dyeing & Sizing:
It has been found that yarn performing very good at warping sometimes create problem
at dyeing range due to greater liveliness leading to grouping of yarn. Sometimes yarn
performing poorly at warping leads to good running at dyeing. This may be due to
elimination of all weak points at warping itself. In addition to performance concerns,
shade consistency and centre side variation is also one of the challenges for mills having
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sheet dyeing ranges. These challenges make dyeing and sizing as very important
operations in the Denim manufacturing. Following points should be taken care while
dyeing & sizing:
Alignment of warpers beam in creel should be perfect.
In India most of the milis are using indigo in powder form only. Thus purity, moisture content and tone (reddish/greenish) of indigo powder must be checked before taking in bulk production.
The parameters like pH & mV of the dye liquor needs to be checked every 30 to 45 minutes. Generally it is kept around 11.5 to 12.0 and 750 ± 30 respectively. In many advanced machines, online checking & display of these parameters is also available.
For shade consistency, yarn should be drawn from every beam for shade evaluation manually as well as by spectrophotometer.
Mills facing Center Side Variation should draw yarns from both the sides and centre from front of the dyeing machine and check for any variation Size add on is generally kept around 8 to 12% depending on yarn count.
12.6 Weaving:
Weaving is an operation where first image of denim fabric is realized. On getting perfect
beams, the weaving efficiencies generally reaches Y6 to 98% per shift. In general the
performance is considered satisfactory till Warp and Weft break level is less than 1.5
breaks/ cmpx. Following points should be taken care while weaving so as to supply
defect free material to the next operation.
Weft yarn should be kept covered with plastics / cardboards so that no fly gets deposited on the packages.
Care should be taken while beam knotting so as to avoid any crossed ends.
High speed air jet looms are commonly used for weaving denim fabrics. Air pressure should be adjusted perfectly depending on the weft so that weft passes smoothly through the shed without creating defect like furkey.
12.7 Singeing:
Singeing is an important operation as it burns the protruding fibres from the fabric
surface. Following care needs to be taken while singeing:
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Flame quality should be perfect (singeing should be done in blue flame only).
Flame height should be uniform (4 to 5 inches) and should not vary throughout the width else it will lead to bands in the fabric.
Speed should be optimum (around 70 to 80 mpm) so that effective singeing action is performed.
12.8 Finishing:
In denims two types of finishing machines (Foam finish/Wet finish) are found. Both have
it's own advantages and disadvantages. Irrespective of the type of finishing machines,
following points should be taken care while finishing operation:
The greige fabric must be tested for knowing the shrinkage & skew potential.
Based on the shrinkage & skew potential, shrinkage & skew is applied so that residual shrinkage in fabric is less than 3.0% and skew movement less than 2.0%.
The fabric entering Sanforiser should be moist (around 12 to 1 5%) in order to get good body. I n absence of moist fabric, the fabric feel is very limpy. Nowadays online moisture meter are also installed in the region for monitoring of same.
The draft between sanforiser and palmer cylinder should be less than 1.0% so that shrinkage applied is not lost due to stretching.
12.9 Inspection & Packing:
Inspection provides the true picture of the fabric quality by informing the main defects
for down gradation. Action can be taken in particular department for reducing the
value losses. Following steps to be taken in inspection and packing department for
getting the right quality product:
Inspection to be done for 100% fabric by any accepted inspection system. In
general 4point inspection system is commonly followed.
Full width fabric sample of 10" length from every roll is collected for pick
checking and shade grouping.
Full width sample after every 4000m should be sent to laboratory for parameter
testing like weight, shrinkage, skew, stiffness, tensile and tear strength.
Papertubelength&qualityshouldbeperfectsothatfabricdoesn'thangfromtheedge
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s and paper tube doesn't get collapsed during storage or transit.
Each fabric roll is weighed and packed using HOPE woven cloth, shrink
wrapping or stretch wrapping Fabric weight (OSY) should be checked from length
and weight of the roll before dispatching so as to segregate lower weight rolls if
any.
12.10 Washing and shade grouping:
Washing and shade grouping is very important activity in Denim mill. Export buyers
or very reputed domestic buyers ask for the taper/sequencing report along with the
dispatches. Generally buyers ask for the washed swatches along with
taper/sequencing reports. The important point is as under:
The collected 10" sample from every roll is cut into five equal pieces. One piece
from all the rolls of the particular order are stitched as blanket along with standard
swatch and washed as per the customer recipe or own developed recipe. After
washing the swatches are measured on spectrophotometer for shade values and off
shade rolls are removed from the dispatches. In case of major shade off, recipe of
washing can be changed (if acceptable to customer) and same should be
communicated to customer for getting the desired shade as required.
10 Storing of Rolls Storing in godown is all together a specialized activity. If not
done properly all the good work done so far will be no use. In general, care should
be taken for following points;
Rolls should be stacked horizontally and not vertically. Vertical stacking lead
to waviness problem on opening.
Rolls should be stacked in such a way that it is easy to locate any roll at the time of dispatch
12.11 Dispatch:
Dispatch is last activity but certainly but very important. Following care needs to be
taken during dispatch operation:
CareshouldbetakentheapprovedrolllistgivenbyQAisonlyloadedLoadingshouldbe
gentle enough so that there are no damage to the packing.
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Chapter Thirteen
Research & Development (R&D)
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13.1 R & D Department in Amber Denim Mills Ltd. :
Research & Product development department is an important department for any textile
industry. This plays a direct role on developing a product.
Amber Denim Mills Ltd. has also a Research & Development (R&D) department with
modern amenities which correlates very well with the upcoming new product.
Continuous research programmed is carried-on here, which is completed by product
development. The R&D department is independent and equipped to promptly invent new
designs for new fashion and develop buyer’s requirements timely. This department keeps
all documents from dyeing recipe to fabric construction and keeps master roll to keep
shade in same consistent even over a longer discontinuity. Amber always researches to
develop new fashion as per the world requirement as well as to maintain comfort &
durability. Most often this department creates new product on the basis of new design &
structure by their own creativity according to the current market demand and then give
it to the buyer. If this design is approved by the buyer then it is stored. They already
developed over 5000 samples.
When an order comes from buyer in form of washed sample. The technical person
determines the shade percentage, amount and type of washing to that fabric to get the
appearance like the sample. So it is very important to wash the sample fabric to justify his
assumption. For this purpose a small washing unit is established in the factory.
Every order firstly comes into R&D department via marketing peoples by mail or swatch.
The R&D experts analyze these samples and match it with their developed samples. If
they find similar samples then this is sent to buyers for approve. If buyers approve it then
the R&D section goes for production.
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13.2 Developed Samples:
Samples according to Weave 3/1 (both RHT &
LHT) 2/1 (both RHT
& LHT)
2/2 RHT, 3/2 RHT
4/1 RHT, 1/1 chambrey
Broken Twill, Herringbone Twill,
Zigzag Twill, Fancy Design
Samples according to Count Samples according to Count
Samples according to Weight Samples according to Weight
Samples according to Color Samples according to Color
Samples according to Finish Samples according to Finish
The R&D department also performs different testing solutions. Most modern and efficient
lab
Instruments from Atlas, UK which is operated by trained technicians. The variable light
box,
Spectrophotometer, rubbing tester, Washing Fastness, Tensile strength tester etc. gives
accurate results and helps to keep quality good and more consistent.
Lab reports of a running lot are constantly maintained. After each process a sample for
testing is sent by the production staff usually after many meters of run. Lab reports
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contain information about various tests performed according to buyer requirements and
their results with remarks of responsible staff about the fabric.
13.3 Name of some Buyers:
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Chapter Fourteen
Testing Lab
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14.1 Quality :
According to the standard ISO 9004-2, quality is the essential nature of something, an
inherent or distinguishing characteristic or property, superiority, excellence, or perceived
level of value. Exact characteristics experienced as quality features vary between people.
Each person has their own references of quality, some people find good durability and
functionality as good quality, for others, attractive design and brand status is good quality.
Costumers rely on a wide variety of aspects to decide if the product meets their quality
references. The quality characteristics of a product have to be incorporated so that the
customers desire and will to purchase the product can be cost-effective .
The broad concept of quality can be divided into three subcategories:
Intrinsic
Extrinsic
Perceived
Intrinsic quality is created during product development and production and is depending
on materials, methods and processes.
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Extrinsic quality is not a part of the specific product; it is everything around the product
like brand, shop, price, merchandising, marketing and reply of retailers.
Perceived quality is the intrinsic and extrinsic quality together .
14.2 Denim Quality :
The intrinsic qualities of jeans are affected by two main groups: material and production.
By dividing into these two groups when researching quality, it will be easier to analyse
possible improvements.
The material category holds fibre, yarn and fabric structure whilst production consists of
the production phase with pre-treatment, making (cutting, sewing, trimming) and
finishing. Several different finishes or washes can be applied to jeans to achieve different
looks. Many of the washes aim to give the jeans a worn and torn look.
FIGURE . Main groups and subcategories of factors affecting intrinsic quality of denim jeans.
Fibre, fabric and garment properties are tested with the purpose to ensure both high
durability and quality. Durability properties can be tested in laboratories, but test results
from the laboratories do not always accurately predict how the garment will perform
when used by consumers. The test results will only indicate how the fabric may perform,
it is also possible to notice fabrics or garments that do not stand the quality tests.
14.3 Quality Testing :
Denim fabrics were tested considering five durability aspects: abrasion resistance, tear
strength, colour fastness to rubbing, colour fastness to washing and dimension stability.
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The tests resulted in quantified data that was put together and analysed. On four out of
five tests; abrasion resistance, colour fastness to rubbing, colour fastness to washing and
dimension stability the result are subjective judged by the authors.
The selection of tests to perform and what denim styles to tested were based on the claim
statistics of the company. The chosen denim styles were some of the most frequent styles
in the claim statistics, and some of the styles were available on the market at the moment.
14.4 International Standards :
The International Organization of Standardization (ISO) is an international institution with
an aim to simplify and improve the quality management of companies and organisations.
By establishing standards, routines can be simplified, money saved and quality improved.
Most of the 16 000 standards of today are international. The benefit of international
standards is that the common base of information will simplify trade and production
across the world. The standards make it easier to compare and to assess capacity,
quantity, content, extent, value and quality. Standards are optional, but by deciding to
follow them there are certain rules to meet. Many standards are used as regulations and
also to guide or define properties that may secure material and products to be sufficient
for its end use .
14.5 AQL – Accepted Quality Level :
Accepted Quality Level (AQL) is a quality control tool for inspection of products. As earlier
mentioned, products (in this case jeans) can be inspected in several different ways. For
evaluations, tests or other types of comparisons, AQL is a good tool to control how well
the products stand in relation to the quality requirements. The AQL will tell the amount
of products that should be inspected and how many defects that are accepted, rather
than dictating what tests should be made. Based on the AQL, randomised inspections are
made, which gives the company a result that indicates the status for a majority of the
products.
The amount of products that will get inspected and how many faults that are accepted
are determined by a combination of the AQL-level, the inspection level and the size of the
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order. Each company chooses what levels they want to work with. An AQL of 1,5 will not
accept faults in more than 1,5 % of the inspected lot. There are three inspection levels; I,
II and III. Inspection level II is most commonly used, but at less comprehensive inspections
level I is used, and at more comprehensive inspections level III is used.
Defects are classified by their severity; minor, major or critical. Three minor defects are
equal to one major defect. If the amount of defected products in the inspected lot
exceeds the AQL, the order should be rejected, otherwise it can be accepted .
14.6 Textile Testing & Quality Control:
Textile Testing & Quality Control (TTQC) is very important work or process in each
department of export oriented industry. Buyers want quality but not quantity. In every
department of textile industry quality maintained of each material. Because one
material’s quality depend on another’s quality. For example, if qualified fiber is inputted
then out put will be good yarn.
14.7 Scope of Fabric Testing:
The performance of a fabric is ultimately related to the end-use conditions of a material.
The physical, chemical, physiological and biological influences on fabrics affect their end-
use performance. Although all agents affect textile performance at the fiber, yarn and
fabric levels, emphasis is generally given to fabrics since they represent the largest class
of textile structures in a variety of applications.
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Thus, a fabric is usually the most complex and representative form of a textile structure
that is subjected to these agents and influences in most end uses. Testing of fabrics and
quality control is broad in its scope. It can include, for instance, the means for
determining and controlling the quality of a manufactured product. It can be used to
measure the outside factors that influence the test results. Testing of fabrics to the
above influences of a physical, chemical and biological nature would be of great help to
manufacturers in adjusting their process control parameters to produce the right
material.
Physical Testing :
The first broad class of factors that affect the performance of fabrics are factors that
influence the test results. Testing of fabrics to the above influphysical agents and
influences. These may be further subdivided into mechanical deformation and
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degradation, tactile and associated visual properties of fabrics (such as wrinkling,
buckling, drape and hand) after their use and manufacture, and their response to heat,
liquids and static charge. The testing of fabrics to mechanical deformation is very
important and refers to fabrics that are subjected to variable and complex modes
of deformation. They include tensile behavior, compression, bending or flexing,
shrinkage, abrasion resistance, frictional rubbing, torsion or twisting, and shear.
Chemical Testing :
Chemical and photochemical exposure of textiles may lead to yellowing or discolouration
of undyed fabrics, to fading of dyed fabrics, and/or to degradation of dyed and undyed
fabrics. These adverse results are due to depolymerization of the polymer chain in the
fibre that may occur by hydrolysis, oxidative processes and/or crosslinking. Textile fabrics
have varying degrees of resistance to chemical agents such as water and other solvents,
to acids, bases and bleaches, to air pollutants and to the photochemical action of
ultraviolet light. Resistance to chemical agents is dependent on fibre type chemical nature
of the dyes, additives, impurities, finishes present in the fiber, and to a lesser extent on
the construction and geometry of the fabric.
Biological testing :
Textile fabrics may be adversely affected by various microorganisms and insects. The
effect of biological agents on textile fabrics is important for enhancing their end-use
performance in many areas. Testing of fabrics and evolution of specific test methods for
the above biological influences would help manufacturers, retailers and users of fabrics
to develop strategic ways to maintain and protect their fabrics in storage and
transportation. These tests would be useful for rapid screening of various modified and
unmodified fabrics for their ability to withstand biological attack.
Visual Examination :
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Visual examination of fabrics includes evaluating the texture, surface characteristics,
dye shade variations, design details, weave patterns, construction
particulars, pilling assessment, etc. Defect analysis is another major area today and is
widely discussed in the textile industry. Defects are bound to occur in fabric during
manufacture for a number of reasons.
The complex problem of fabric quality control through defect analysis may be solved by
means of computer vision using advanced digital signal and image processing tools.
Many of these image processing applications aim at detecting textural characteristics
and textural defects of fabrics, including color detection and dye shade variations.
Intelligence Testing :
In the last decade, research and development in smart/intelligent materials and
structures have led to the birth of a wide range of novel smart products in aerospace,
transportation, telecommunications, homes, buildings and infrastructures.
Intelligent textiles are fibers and fabrics with a significant and reproducible automatic
change of properties due to defined environmental influences.
Physiological testing :
Three important physical parameters that are instrumental in the physiological
processes of fabrics are heat transmission, moisture transport and air permeability. The
physiological properties of fabrics relate to what the fabric or garment feels like when it
is worn next to the skin, such as too warm, too cold, sweaty, allergic, prickly, etc.
Therefore, in the assessment of a fabric or garment for a particular end use, the comfort
of that product is considered to be very important. Fabric testing therefore needs to
address the comfort properties of fabrics.
14.8 Lab Test Capability :
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Physical :
SL
No
Test Name US Method EU Method
1 Tensile Strength ASTM D5034
ASTM D5035
ENISO/ISO 13934-1
ENISO/ISO 13934-1
2 Tearing Strength ASTM D1424
ASTM D2261
BSENISO/ISO 13936-1
BSENISO/ISO 13936-2
BS 3320
3 Seam slippage ASTM D434 BSENISO 13936-1
BSENISO 13936-2
BS 3320
4 Seam Strength ASTM D1683 BSENISO 13935-2
5 Pilling Resistance(Martindale) ASTM D4970 BSENISO 12945-2
ISO 12945-2
6 Pilling Resistance(ICI) BSENISO 12945-1
ISO 12945-1
7 Abrasion
Resistance(Martindale)
ASTM D4966 BSENISO 12947(2-4)
ISO 12947(2-4)
8 Fabric Weight(GSM) ASTM D3776 ISO 3801
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BSEN 12127
9 Fabric Count ASTM D3775 ISO 7211-2
10 Stitch Density ASTM D3887 BS 5441
11 Stretch & Recovery ASTM
D2594(knit)
ASTM
D3107(Woven)
Chemical :
SL
No
Test Name US Method EU Method Others
1 C/F to Washing
C/F to
Washing(Oxidation
Bleach)
AATCC 61
ISO 105 C01-
C05
EN ISO 105 C06
ISO 105 C08
BS EN ISO 105
EN ISO 105 C09
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2 C/F to
Crocking/Rubbing
AATCC 8 BS EN ISO 105
X 12
3 C/F to Perspiration AATCC 15 BS EN ISO 105
E04
4 C/F to Water AATCC 107 BS EN ISO 105
E01
5 C/F to Sea Water AATCC 106 BS EN ISO 105
E02
6 C/F to Non-Chlorine
Bleach(Spot Test)
TS-001
7 C/F to Chlorine
Bleach(Spot Test)
TS-001
8 C/F to Saliva &
Perspiration
DIN 53160
9 C/F to Saliva GB/T
18886
64LFGB B
82.10-1
10 Dimensional Stability AATCC 135 ISO 6330
11 Skewness/Spirality AATCC 179 ISO 16322
12 Skew & Bow ASTM D3882
13 Spirality After
Laundering
ISO 16322-2&3
14 pH AATCC 81 ISO 3071
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14.9 Machine Used In Testing Lab :
Name Model Picture
Crock Meter ICI Pilling
Tester
M238AA
Pilling Tester M227
Quartz Precision
Thermo-Hygrograph
TH-27R
Electronic Balance N/A
Tinious Olsen
Universal Strength
Tester
M250
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Electronic Elmendorf
Tearing Tester
M008HE
ICI Pilling Tester M227
GSM N/A
Analytical Balance ME204E
Shaker SK-300
Hot Plate JSHS-180
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pH Meter S220
Laboratory Wringer GT-D19B
Millipore N/A
Whirpool Washer N/A
Electrolux Wascator FOM71CLS
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Rota wash M228
Launder O Meter 131520 GYROWASH
Whirpool Dryer N/A
Electrolux Dryer T5130
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Quick Wash Plus N/A
Electric Woven G209A
Electric Incubator IB-05G
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Chapter Fifteen
Store & Inventory Control
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15.1 Store and Inventory Control:
Inventory control of raw materials, semi-finished goods, finished goods and other
miscellaneous goods lead smooth production. As Amber Denim Mills Ltd. follow the
correct way of inventory control system, it can have a good and huge production as it
demands.
There are two room for storing and inventory control.
15.2 Scope of inventory control:
Raw materials
Yarns
Dyes store
Others chemicals store
Finished fabric
Spare parts
General store
Capital equipment
Accessories
Stationary
Maintenance parts.
15.3 Inventory System for Raw Material:
The main raw material of denim fabric is yarn, which is stored in two stages such s-
1. Long time storage 2. Storage before production
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Long time storage : Amount of yarns which are required for the production of several
months as prerequisite.
Storage before production : The amounts of yarn, which are loaded in the store, room
concern with the production section for continuous speed of production.
15.4 Inventory System of Spare Parts:
The spare parts of different section such as preparatory & dyeing, weaving section,
finishing section are stored. If a machine is innovated its slightly effected parts will be
stored as spare after repairing needed. In addition, these parts are used in conjunction
with new parts.
15.5 Inventory Control of Finished Goods:
After the completion of finishing, the finished fabric is stored from where the finished
fabric is delivered to the buyer.
15.6 Other Inventories:
Other inventories like empty packages or packages with few yarns & cartoons are stored
in wastage room. From this, packages with few yarns are used for sample production.
Mechanical equipments for maintenance are stored in mechanical room, lubricants are
stored in lubricant room & a drum is kept in the shed as stand by requirement.
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Chapter Sixteen
Marketing Activities
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16.1 Marketing Activities:
The commercial section of Amber Denim Mills Limited performs the following functions:
Official dealing with buyer
Communicate with factory in charge for issuing delivery date
Dealing with bank
Preparing different necessary documents
16.2 Procedure of Export Business by Amber Denim Mills Ltd. :
To get order:
Like any other factory, Amber do not need to any kind of product marketing to get order.
It is so much renowned denim factory in Bangladesh that they do not knock the buyer's
door for order. Buyers come here with query for definite sample or style for their own
interest.
Sample preparation:
Amber denim already prepared over five thousand types of fabric sample. So they have
huge number of fabric sample collection. If buyer's requirement match with any of earlier
fabric then a sample from stock is send to them, otherwise a new sample is prepared and
sends to buyer.
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Issuing of P.I (Performa invoice):
If the buyer approves the sample, then Amber issues Performa invoice to the buyer.
What is P.I. (Performa Invoice)?
Performa invoice is a paper where all the terms and condition of that business dealing is
write down. Amber mainly notice the following points in their PI:
Description of the product.
Price
Last date of L.C open 'by the buyer
Date of delivery
Date for bill payment after delivery
Some other official terms and condition
(Letter of credit) opens by the buyer:
If the buyer agrees with the terms and condition on the P.I then the buyer open L.C
against that order.
What is L.C (Letter of Credit)?
L/C (Letter of Credit) is credit contract whereby the buyer's bank is committed (on
behalf of buyer) to place an agreed amount of money at solicits disposal under some
agreed condition.
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Chapter Seventeen
Utilities
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17.1 Definition:
The definition of utilities can be expressed in many ways.
A Company that generates transmits and/or distributes electricity, water and/or gas from
facilities that it owns and/or operates.
A utility system used in industrial facilities. This area includes boilers, chillers, cooling
towers, air compressors, and their associated fluid distribution systems.
17.2 Utility department of Amber Denim Mills Ltd. is related to the
following things:
Electricity: Gas Generator, Rural electrification Board (REB)
Water: Deep Tube well
Gas: TITAS
Steam: Boiler
Compressed air: Air compressor
Chiller
Humidification plant
Effluent Treatment Plant (ETP)
Water Treatment Plant (WTP)
17.3 Water Supply:
Water is supplied by deep tube well. There are two tank main & reserve tank for water
storage. The level of water is monitoring continuously and reading is taken in every hour.
A daily report is prepared for that and this water is supplied to many sections like dying,
boiler, generator, compressor etc
17.4 Boiler:
A steam generator or boiler is usually a closed vessel made of steel for supplying steam.
Boiler function is to therefore the heat produced by the combustion of fuel (here gas is
used) to water and ultimately to generate steam. The steam produced in the boiler
section supplied to different section of mill.
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Supplied sections for steam:
Sizing
Finishing
Dyeing unit
Washing unit
Chiller
Machine Specification :
Figure: Boiler
Name MecHMar
Origin Malyasia
Model AS2400/150
Const. Year 2012
Working Pressure 1050/50 n/mm2/psi
Design Pressure 1069/155 n/mm2/psi
Test Pressure 1604/233 n/mm2/psi
INSR Authority LLOYD’S REGISTER
Steam Capacity 7.5 kg
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17.5 Generator:
An electrical generator is a machine, which converts mechanical energy into electrical
energy. The energy conversion is based on the principle of the production of dynamically
induced e.m.f.
Features:
12 cylinders turbocharged and intercooled Fully integrated engine diagnostic and control system including:
Spark timing control
Turbocharger control
Speed governing
Individual cylinder knock detection
Air/Fuel ratio control Fuel tolerance High altitude capability Low Btu option
Machine Specification :
Figure: Generator
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Name Jenbacher Gas Engines
Origin Waukesha
Model J320GS LEANOX
Const. Year 2012
Total Machine 04
Capacity 1060 Meg
Fual Gas
17.6 Air Compressor:
Compressed air along with gas, electricity and water is essential to most modern industrial
and commercial operations. It runs tools and machinery, provides power for material
handling system and ensures clean breathable air in contaminated environment. In
Amber Denims rotary screw compressor is used.
Features:
With one-to-one drive, the air end is directly connected to the motor via a maintenance-free coupling that eliminates transmission losses.
Direct drive screw compressors deliver outstanding performance and increase energy savings.
It uses oversized air ends specifically selected to produce the required output in flow and pressure.
Compared to compressors using small, high-speed, gear-driven air ends, the one-to- one drive provides significant savings.
No-loss power transmission.
Lower power consumption.
Reduced maintenance and related downtime costs.
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Machine Specification :
Brand Name BOGE
Origin German
Model S271
Const. Year 2012
Rate of Flow 3050 m3/min
Max Service Pressure 10 bar
Motor Speed 1500 min
Motor Power 200+750 KW
17.7 Dryer:
The atmospheric air drawn into a compressor is a mixture of gases that always contains
water vapors.
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However, the amount of water vapor that air can carry depends on the temperature. As
air temperature rises – which occurs during compression – the air's ability to hold
moisture increases also. When the air is cooled its capacity to hold moisture reduces
which causes the water vapor to condense. Removing the moisture from the compressed
air not only prevents costly breakdowns and production downtime, but also keeps
maintenance and repair costs to a minimum. Refrigeration drying is usually the most
efficient solution for the majority of compressed air applications
Features:
Low pressure drop, non-fouling heat exchanger.
Low pressure drop filtered separator with microprocessor controlled filter monitor removes liquids and particulates to 3 microns.
"No-loss" electronic Eco-Drain for reliable condensate removal.
On/off load digital scroll refrigeration compressor (Dual Control models only).
Hot gas bypass control (Demand Manager models only).
Optional cold coalescing oil removal filter eliminates oil aerosols to 0.008 ppm.
Machine Specification :
Brand Name BOGE
Model DS460
Capacity 46
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17.8 Chiller: A chiller can be generally classified as a refrigeration system that cools water. Similar to
an air conditioner, a chiller uses either a vapor compression or absorption cycle to cool.
Once cooled, chilled water has a verity of application from space cooling to process use.
Chiller Tower Specification:
Name Absorption Chiller
Origin Korean
Model WCS-S036
Const. Year 2012
Cooling Capacity 325 USRT
Chilled Water Flow Rate 19.6 m3/h
Chilled Water Temp. 13-8 ͦ c
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Cooling Water Flow Rate 358 m3/h
Cooling Water Temp 32-37 ͦ c
Heating Source Type Steam
Steam Pressure 8 kg/cm2
Heating Source Temp. N/A
Electric Power 3.0-400 V-50 Hz
17.9 Humidification Plant:
Humidifier is a system to provide proper humidity and temperature in a working space.
To maintain the proper humidity and temperature in a weaving mill is very important.
Different electrical circuit board of weaving machine cannot work for a long period
without proper temperature and humidity. Proper humidity helps to remove the
producing static electricity due to friction of different machine parts.
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Chapter Eighteen
Effluent Treatment Plant (ETP)
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18.1 Introduction:
In this industrialized age, environmental pollution is a matter of great concern. Surface
water pollution is one of the elements of environmental pollution. Chemical processing
industries especially textile processing industries are claimed to produce huge effluent
to discharge in our rivers. A complex mixture of hazardous chemicals both organic and
inorganic is discharged into the water bodies from all these industries, usually without
treatment. It is well known that textile mills consume large volume of water for various
processes such as sizing, desizing, scouring, bleaching, mercerizing, dyeing, printing,
finishing and washing. Due to the nature of various chemical processing of textiles, large
volumes of wastewater with numerous pollutants are discharged every day.
In Bangladesh most of the industrial units are located along the banks of the rivers and
they do not use Effluent Treatment Plant (ETP) for wastewater. As a consequence,
industrial units drain effluent directly into the rivers without consideration of the
environment. Setup an effluent treatment plant is mandatory for a factory today.
Authority gives no permission of electricity and gas connection to a new factory without
ETP.
18.2 ETP in Amber Denim Mills Ltd:
Effluent Treatment Plant (ETP) of Amber Denim Ltd. has successfully established in the
beginning and running continuously 24 hours a day. They are maintaining all the
discharged parameters according to environmental law.
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Figure: Effluent Treatment Plant(ETP)
Quantity: The quantity of effluent to be treated shall be of the order of = 840 m3/day.
Capacity of the effluent treatment plant:
The effluent treatment plant has been designed on the basis of the following:
Denim fabrics manufacturing plant. Contaminated effluent is100% Less contaminated is nil Operated continuously for 24 hours a day Flow rate of treatment envisaged is 35 m3/hr.
18.3 Outlet Effluent Parameters (Bangladesh Standard) :
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18.4 Process Flow Chart:
18.5 Describe The Process Flow Chart:
Pre-Treatment
Screening:
The raw waste water (Raw Effluent) from the process of the plant would be first screened
through a manual bar screen strainer channel, where all particles with dia. > 5mm as well
as small pieces of the fibre and floating suspended matters like polythene paper,
polythene bags, rags and others materials removed by bar screen net. The bar screen
consists of parallel rods or bars and is also called a bar rack. These devices are used to
protect downstream equipment such as pumps, lines, valves etc. from damage and
clogging by rags and other large objects. The bar screen is cleaned manually by means of
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rakes. The screening is disposed off suitably after they are de-watering. The screened
clean effluent flows by gravity to an equalization tank.
Primary-Treatment
Coagulation & Flocculation:
The homogenized effluent is than pumped to a flash mixing tank followed by a
flocculation tank. Where added coagulants like lime (Calcium Hydroxide) and Ferrous
Sulfate (FeSO4) for coagulation of the total dye particles. The basic idea of adding
coagulant is to bring together all the suspended and dye particles so that they can
precipitate out in a flash mixing and coagulation mechanism. Adequate quantity of poly
electrolyte polymer solution are dosed to enhance the process of color removal by the
flocculation process.
Precipitation and Sedimentations Tube Settler-1:
The flocculated effluent is taken by natural gravity in to the tube settler-1 from
flocculation tank for precipitation of dyes and suspended particles. The flocs formed are
removed in the downstream tube settler-1 by the help of tube settler media. The effluent
will further flow by overflow system to a pH correction tank where requisite quantity of
acid will be dosed and pH will be adjusted as per the requirement.
pH Correction:
The overflow effluent from tube settler-1 tank is than taken by gravity in to the pH
correction channel for neutralization. 33% HCl acid is dosed for neutralizing the pH from
around 10 to 7. The pH correction channel is designed for hydraulic retention time of
around 10 minutes and is provided with slow speed agitator for thoroughly mixing of
waste with acid. A pH indicator is installed in the tank for measuring the pH (optional).
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Secondary-Treatment
Biological Reactor 1 & 2:
The neutralized effluent is taken by gravity in to the biological treatment aeration tank
for treatment of organic matter to reduce BOD/COD aerobically. The biological reactor is
designed on extended aeration principle. The aeration is provided with fixed type surface
aerator for providing the required oxygen for the biological degradation of BOD and COD.
The air is supplied by means of the bubble diffusion.
Figure: Biological Reactor
Tube Sattler- 2:
After aerobically treatment effluent flows by gravity to the tube settler – 2, the biological
solids generated are removed from the tube settler – 2 by the help of tube settler media.
Filter Feed Pump:
The effluent from tube settler – 2 overflow in to the pressure sand filter and activated
carbon filter feed pump. From here the disinfected effluent is pumped by means of the
pressure sand filter feed pump to the pressure sand filter. The pump is normally operated
in automatically with interlock to the level switch in the filter pump.
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Chapter Nineteen
Security
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19.1 Security Section:
The main objective of the security is to safe handling of the goods from/to the mill
premises. For the achievement of such objective a team of security guards has been
employed by the Company. All the keys relating to the mills office, labor colony, (quarters)
are lying into the responsibility of the security officer.
No outside visitor can come into the mills premises without the permission of the security
guards or administration department.
19.2 Security Main Gate:
This office has been made to keep the record of each and every thing coming into and going out of the mills gate.
This office keeps and maintains the time record of all the workers on time cards and pay register for the final costing of the workers’ salaries.
It keeps the attendance records, which is then used to calculate the salary to be paid to the Workers on monthly basis.
It keeps the records of the overtime, leaves; number of days worked of all the workers and then calculates their overtime on the basis of the basic salary of each worker.
For 24 hours close attention to the production floor and also the outside, there are several
close circuit camera all over the factory. This operation is done by the administration
department from administration office.
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Discussion
Amber Denim Mills Ltd. is the largest and most versatile business conglomerate in the
private denim sector in Bangladesh. Amber Denim Mills Ltd. is committed to the best
human workplace practices. Their goal is to continuously improve their Human resource
policies and procedures through education, training, communication and employees
involvement. Right from inception the policy of the company has been to provide total
customer satisfaction by offering quality denim fabric in time. To meet the manufacturing
to quality and promote delivery Amber Denim Mills Ltd. decided to integrate the
manufacturing process in a planned manner. Over the year the entire process has been
integrated by importing sophisticated machinery from world renowned manufacturers.
According to their capacity they have an enriched production team which is very rare in
other factories of Bangladesh. The working environment of Amber Denim Mills Ltd. is very
cordially & friendly. All of the executives & employees of Amber Denim Mills Ltd. are very
much cordial & they always appreciate the learners.
The goal of Amber Denim Mills Ltd. is to get high production & to maintain the quality of
the product at a minimum cost.
Some suggestions:
The Finishing floor is dirty most of the time though it is cleaning every day. The warping floor is dirty most of the time though it is cleaning every day. Fly dist
removed from yarn surface create this problem. Some machine are stop for Steam problem. This Problems are recovery early. The temperature of the sizing shed is higher than others though it has ventilation
system. We think blower fan’s speed should increase for better suction of hot air. There is no overhauling maintenance for few machines. We think overhauling
maintenance should carry on by maintenance department for continuous production of machines.
Unnecessary lighting should remove for less power consumption.
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Limitations of the report:
I had a very limited time. In spite of our willing to study more details it was not possible to do so.
Some of the points in different chapter are not described as these were not available.
The whole process is not possible to bind in such a small frame as this report, hence our effort spent on summarizing them.
Conclusion
I have completed our industrial attachment successfully by the grace of Allah. Industrial
attachment sends me to the expected destiny of practical life. Though it was established
only a few years ago, it has earned “very good reputations” for its best performance over
many other export oriented textile mills.
I am enough fortunate that I have got an opportunity of having a training in this mill.
During the training period I have received co-operation and association from the authority
full & found all man, machines & materials on appreciable working condition. All stuffs &
officers were very sincere & devoted their duties to achieve their goal.
Finally I would like to wish Amber Denim Mills Ltd. to have a blast & thanks to
administration of Amber Denim Mills Ltd. for their cordial attitude to me.
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References
1. http://amber.com.bd/
2. http://morrisontexmach.com/welcome.cfm
3. http://textilelearner.blogspot.com/
4. http://www.denimsandjeans.com/
5. http://articles.fibre2fashion.com/
6. http://www.picanol.be/PICBESITE/EN/
7. http://www.mechmar.com.my/products_as.htm
8. http://www.dresserwaukesha.com/index.cfm/go/list-
prodsubline/productline/gas-compression-engine/
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The End