MPROVING WORKING ENVIRONMENT AND PRODUCTIVITY OF A SEWING FLOOR IN RMG INDUSTRY
THE REpORT.both name_N (2)
1. Bangladesh University of Textiles
Report on
Industrial Attachment
From May 20, 2015 to July 20, 2015
At
Hamid Fabrics Ltd
Academic Supervisor
Kazi Sowrov
Asst. professor
Department of Fabric Engineering
Faculty of Textile Engineering
Bangladesh University of Textiles
Prepared by
Sohel Rana (ID: 2011-1-135)
Hasibul Islam Bappi (ID: 2011-1-162)
1
2. Foreword
Industrial attachment is the part and parcel of the engineering education. Higher studies
in any discipline of engineering doesn’t end without Industrial experience in firsthand
perspective. Textile is the most demanded product by human on earth after food, the
higher study of textile engineering needs the experience of industrial field even the
mechanical points are taught academically.
The students of Bangladesh University of Textiles are assigned to perform the task of
experiencing textile industries in the final semester of Undergraduate study. We are
concentrated on the field of weaving. For the industrial attachment we applied to Hamid
Fabrics Ltd., because this is country’s one of the leading woven textile factories. After
getting permitted through the proper authorities we got the fortunate chance to experience
the industry. As we went through our endeavor the operations and day to day activities in
the industry as well as machine operation and maintenance including manpower
management, it was quite clear how this was a leading textile factory in our country and
how our country is one of the world’s top textile product manufacturer and exporter.
We received the invaluable education from the university faculty that has no alternative.
For which are indebted to our teachers for life. Here we are expressing our special
gratitude to,
Kazi Sowrov (Asst. prof, Dept. of Fabric Engineering)
Dr. Shah Alimuzzaman, (Head, Dept. of Fabric Engineering)
We are grateful to administration and management personnel that we could perform the
attachment program in Hamid Fabrics Ltd.
Our gratitude goes to::
Mr. Abdullah al Mahmud (Managing Director)
Mr. Mir Azharul Islam (Executive director)
Mr. K. K. Ghose (G.M., Admin)
We were immensely helped by the management of Weaving section of Hamid Fabrics
Ltd. We are grateful to::
Mr. Kalyana Sundaram (A.G.M., Weaving)
Mr. Abdullah al Baki Akanda (Sr. Manger, Weaving)
2
5. Project Description
Name:
Hamid Fabrics Limited; A Sister concern of Mahin Group
Type:
Hamid Fabrics Limited is a 100% Export oriented textile manufacturing Company. The
Company needs Export Registration Certificate (ERC) for exporting finished goods and
Import Registration Certificate (IRC) for import of raw materials from abroad. HFL has
obtained both registration certifications from the Chief Controller of Import and Export
(CCI&E) division of the Government of the People’s Republic of Bangladesh. Both
certificates are issued for one year and need to be renewed every year.
Hamid Fabrics Limited procures yarn, gray fabrics, dyes and chemical from abroad under
duty free bonded category and it maintains stocks of such raw materials in its storage at
any given time to maintain smooth operation. Therefore, the Company needed to obtain
Bonded Warehouse License from the Customs Bond Commissionerate of the
Government of the People’s Republic of Bangladesh. Hamid Fabrics Limited obtained
Bonded Warehouse license since commencement of production. The license for ‘deem
exporter’ is given for a year and needs renewal after year end to recalculate the capability
of import volume for the current year.
Year of Establishment:
Hamid Fabrics Ltd.: Established in 1996
Hamid Fabrics Ltd. Unit 2: Established in 2003
Hamid Weaving Mills Ltd.: Established in 2008
Tazrian Weaving Mills Ltd.: Established in 2013
Address:
Head Office:
Hamid Tower, 5th & 6th Floor,
24 Gulshan C/A, Circle 2,
Dhaka 1212, Bangladesh.
Phone: (+8802) 8834564, 8834565, 8834104, 9894589, 8814775, 8833549
Fax: (+8802) 8813077
Email: info@mahingroup.com
5
6. Factory:
Shilmandi, Narsingdi.
Factory Location:
Factories are located in Shilmandi, Narsingdi, in the close vicinity of Dhaka‐Sylhet
highway (only about 50 yards inside).
Figure 1.1: Satellite view of the location
History of the project development:
DESCRIPTION OF BUSINESS:
Hamid Fabrics Ltd. is the flagship Company of Mahin Group. It is a Public Limited
Company registered in Bangladesh and incorporated under the Companies Act, 1994. It is
engaged in the manufacturing of ‘solid’ dyed fabrics for the 100% export oriented Ready
Made Garment (RMG) industry of Bangladesh. After the planned expansion, the
Company will step into a more value adding segment by introducing ‘yarn dyed fabrics’
to its product line. HFL was formed as a Private Company limited by shares with the
name and style of Siddique Fabrics Limited on 27 April 1995. Subsequently on 23rd
May, 2000 the Company name was changed to Hamid Fabrics Limited. Later, the
Company was converted into a Public Limited Company vide a resolution passed in the
Extraordinary General Meeting held on 25 February 2010. The relevant Certificate from
the Registrar of Joint Stock Companies (RJSC) was received.
The weaving unit is a state of the art facility that incorporates 104 high speed Toyota
JAT710 airjet looms in Hamid weaving mills ltd. And 78 airjet looms in Tazrian weaving
6
7. mills ltd. The dyeing and finishing unit incorporates German and Japanese machinery of
Kusters, Bruckner, Kyoto, Monforts etc. The factory in house modern lab testing
facilities assist the production of quality products. As a result, with supreme commitment
to quality it has established itself as a major role-player in textile manufacturing industry.
HFL produces high quality fabrics that are sold to RMG manufacturers in Bangladesh
which are in turn exported as finished products. Therefore, HFL is a “deemed exporter”
and qualifies for all export incentives and benefits.
HFL is one of the leading manufacturers of high quality textiles in Bangladesh. Due to
superior quality, HFL’s products are nominated by globally renowned buyers such as
GAP, Zara, C&A, Marks & Spencer, UniQlo, BHS, Tesco, Wal‐Mart, Tommy Hilfiger,
George, Levi’s, H&M, S.Oliver, Nike, Dickies, Charles Vogele, Carrefour, Miles and
Lcwaikiki (Tema) for sourcing textile to RMG manufacturers in Bangladesh.
HFL has been assigned a credit rating of AA₃ by Credit Rating Agency of Bangladesh
Limited (CRAB). This is one of the highest credit ratings achieved by a textile Company
in Bangladesh. Entities rated in the ‘AA' category are considered to have strong capacity
to meet their financial commitments. It differs from the highest‐rated entities only to a
small degree. AA is judged to be of very high quality and is subject to low credit risk.
Reputed international lending agencies viz. Deutsche Institutions ‐ UND
Entwicklungsgesellschaft MBII (DEG) and The OPEC Fund for International
Development (OFID) had extended credit facilities to HFL at the inception of the
Dyeing & Finishing Unit.
The Company provides the highest priority to maintain global benchmarks for quality
throughout the value chain commencing from raw material sourcing, manufacturing,
finishing and delivery. HFL achieved OEKO‐Tex Association Certificate in recognition
of its continuous efforts towards quality.
HFL is a member of Bangladesh Textile Mills Association.
7
8. Expansion Project:
The Company has decided to set up an expansion project such as yarn dyeing project to
maximize its profitability as the yarn dyed fabrics has a high demand in the global market
as well as its return is also high. Total investment in the project has been estimated at
Tk.1, 059,437,850.00 of which Tk.722, 000,000 will be financed from IPO fund. Detailed
calculation and planning has been shown in the feasibility report.
Nature of business
Hamid Fabrics Ltd is a “deemed exporter” that is engaged in weaving, solid‐dyeing and
finishing of woven fabrics for 100% export oriented RMG units. It is planning to set up a
yarn‐dyeing facility under the proposed expansion plan. Under solid dyeing, woven
fabrics go through a single color dyeing process whereas yarn dyeing allows multicolored
dyeing of woven fabrics with a maximum range of 8 colors.
Distribution of Products/Services:
Hamid Fabrics Ltd. sells its products directly to the country’s RMG units. The Company
usually offers to deliver the products to the premises of RMG Units. Most of the sales go
to RMG units situated within the range of greater Dhaka region as well as Chittagong
who are nominated by the ultimate foreign buyers.
Competitive condition in the Business:
There is a range of external and internal competitive conditions affecting the business of
Hamid Fabrics Ltd. Critical external competitive conditions influencing the business of
HFL include demand‐supply gap of fabrics in the local market, future outlook for RMG
industry, low cost labor, government policy and availability of GSP facility. Given the
comparative cost advantage of Bangladesh together with stimulating government policy,
the textile and apparel industry has attractive growth opportunities. The main (internal)
competitive advantage of HFL lies in its ‘robust production process’ that encompasses
state of the art machineries, preventive maintenance, quality control, motivated
workforce, visionary entrepreneurship and expert management leading to superior
product quality and established track record. The Company has already placed itself as
one of the leading manufacturers of solid dyed fabrics in Bangladesh. The proposed
expansion plan would open up a new avenue of growth for the Company. The
8
9. manufacturers of solid dyeing fabrics are scattered around with small scale production
facilities with the exception of a few large‐scale renowned players.
Environment Clearance Certificate:
Hamid Fabrics Ltd is one of the pioneers in taking effective measures on environmental
issues. It set up a large scale Effluent Treatment Plant with a capacity of 50 cubic meters
per hour following World Bank guidelines to reduce environmental hazard since
commencement of operation. At the same time, the Company also has established two
water treatment plants to keep its water supply into production at more neutralized level,
which allows less injection of heavy neutralizing chemical into production. The Company
is also in the process to start its Caustic recovery plant to reduce the caustic consumption
and enable more efficiency in chemical usage.
HFL has obtained Environmental Clearance Certificate from the Department of
Environment, Government of The People’s Republic of Bangladesh for its factory
situated at Shilmandi, Narshingdi. The Company obtained this Certificate from the very
beginning of the production and keeps renewing it every year.
The company has been certified as Oeko‐Tex Standard 100 or Öko‐Tex Standard 100
since 2007. Oeko‐Tex Standard 100 is an international testing and certification system for
textiles, limiting the use of certain chemicals. It was developed in 1992. This certification
for companies requires, among other things, compliance with specified criteria for
avoiding or limiting the use of harmful substances in production.
The other licenses are also obtained from the respective authorities, namely Registration
from Board of Investment of Bangladesh (BOI), Fire License from Department of Fire,
Labor License from Ministry of Labor and also has the membership of Bangladesh
Textile Mills Association (BTMA).
9
10. Sponsors:
Hamid Fabrics Limited does not own any subsidiary, associate or related holding
company. However, HFL is a part of Mahin Group sponsored by HFL’s main
shareholders/directors.
The directors are following:
Name Designation
Mr A.H.M. Mozammel Haque Chairman
Mr. Abdullah Al Mahmud Managing Director
Mrs. Salina Mahmud Director
Ms. Nusrat Mahmud Director
Ms. Nabila Mahmud Director
Syed Anisul Haque Independent Director
Mrs. Farhana Danish Director
Chaklader Mansurul Alam, FCA Independent Director
The shareholders are following:
1. Mr. Abdullah Al
Mahmud
2. Mr. A. H. Md.
Mozammel
Hoque
3. Ms. Salina
Mahmud
4. Ms. Nusrat
Mahmud
5. Ms. Nabila
Mahmud
6. Kazi Nasim
Uddin Ahmed
7. Ms. Farhana
Danish
8. ICB Capital
Management
9. Bangladesh Fund
10. ICB AMCL First
NRB Mutual
Fund
11. ICB AMCL
Second NRB
Mutual Fund
12. ICB AMCL
Pension Holders
Unit Fund
13. ICB AMCL Unit
Fund
14. ICB Asset
Management
Company ltd.
15. ICB Unit Fund
16. Janata Capital
and Investment
Ltd.
17. Crystal
Insurance
Company Ltd.
18. Mr. Mir Md
Amin Hasan
19. Mr. Rezaur
Rahman Khan
10
11. 20. Mr. Mohammad
Amjad Hussain
Chowdhury
21. Mrs. Riaz Ur
Rahman
22. Mr. Md. Anis ur
Rahman
23. Mr. Mrinal Kanti
Sarker
24. Mr. Tariq Uddin
Ahmed
25. Engr. Abdullah
Hasan
26. Mr. Md.
Shahabuddin
Khan
27. Mr. Mahmudul
Alam Jewel
28. Mr. Mir Azharul
Islam
29. Mrs. Samira
Khatun
30. Ms. Farhana
Parvin
31. Mr. Nuruzzaman
Khan
32. Mr. Sharif
Mohammad
Kibria
33. Mercantile
Securities Ltd.
34. Ms. Sabrina Ali
35. Md. Sarwar
Alom
Product Mix
The products of Hamid Fabrics Ltd can be categorized in terms of raw material mix,
weight range, design and finishing features.
The product range offers 100% cotton fabrics as well as blended fabrics such as
1. Cotton/polyester,
2. Cotton/viscose,
3. Nylon/cotton and
4. Cotton/lycra.
The weaving unit produces gray fabrics in various design and constructions such as
Twill,
Blended,
Canvas,
Calico,
Oxford,
poplin,
Rib stop,
Broken Twill,
Rib cord,
Matt,
Ottoman,
Stretch,
Herringbone,
Cotton
Linen
And various dobby designs with weight range of 100‐450 GSM. The finishing mix of
Hamid Fabrics Limited comprises water repellent, fire proof, wrinkle free, Teflon
coating, aero finish and chintz finish etc. The major markets for HFL’s products are the
United States of America and the European Union.
11
12. Annual production capacity:
Hamid Fabrics Ltd has two production units: 1.Weaving, 2.Dyeing and Finishing.
The weaving unit has an annual capacity of 6.85 million yards of gray fabrics. Dyeing
and finishing unit has a capacity of producing 21.60 million yards of finished dyed fabric.
The following table illustrates the production capacity of grey and finished fabrics and its
utilization: (in 2013-14)
Particulars Unit Installed
Capacity
Utilization during
the period
Utilization
Grey Fabric (Weaving) Yards 6,853,000 5,246,972 76.56%
Woven Fabric (Dyeing
& Finishing)
Yards 21,600,000 17,193,211 79.60%
Project Cost:
particulars As at 30 June, 2013
Land and Development 705,584,000
Building and Construction 246,397,141
Plant and Machinery 567,567,225
Vehicles 6,929,366
Electrical Installation 17,137,061
Gas line installation 22,431,509
Office equipment 8,503,002
Furniture and Fixtures 4,331,845
Total 1,578,881,148
Departments:
Administration
Human Resource
and
Development
Planning
department
Weaving
preparatory
Woven dyeing
and Finishing
Inspection
Store
Utility and
Maintenance
QC and Lab
Accounts
Power
generation
12
13. Physical Infrastructure:
Hamid Fabrics Limited has its own factory land at Shilmandi, Narshingdi; about 40 km
from Dhaka City measuring 1178.65 decimals and total land area is in the name of Hamid
Fabrics Limited. The buildings of Weaving Unit of HFL include factory building (35,000
sq.ft.), 3‐storeyed raw material go‐down (6,969 sq.ft.), 3‐storeyed staff accommodation
(9,288 sq.ft.) and fabric go‐down building (7,650 sq.ft.) and 3‐storeyed office building
(4,000 sq.ft.). The other civil works include generator and substation room (1,037 sq.ft.),
boiler room (765 sq.ft.) and a workshop (680 sq.ft.).
Fig 1.2: Dyeing Section Fig 1.3: Tazrian Weaving mill
Dyeing & finishing unit consist of state of the art pre‐fabricated structure of 134,000 sft
including 20,000 sft floor office rooms and laboratory with modern furniture and fixtures.
Apart from that another 10,000 sft floor space three storied building also has been
completed including installation of utility facilities like boiler, generator, substation etc.
and finally structure for pump house and gas / electricity meter.
The Company’s head office is situated in its registered address on rent, Hamid Tower
(5th & 6th Floor) 24, Gulshan C/A, Circle‐2, Dhaka‐1212, Bangladesh. Company owns
the following operating fixed assets and they are situated at Company’s office and factory
premise. Hamid Fabrics Ltd. owns factory land measuring 9.54 acres. A land area of 7.10
acres is allocated between the two units of Weaving and Dyeing & Finishing, while the
remainder is to be utilized for the proposed expansion project.
13
14. Sources of, and requirement for, power, gas & water:
Power:
The Company has 800 KW load electricity connections taken from the Rural
Electrification Board (REB). In addition, HFL has 3 Gas Generators (2 X 800 KW and 1
X 510 KW) totaling to 2.10 MW of Germany and USA origin to support its expanded
facilities and two sub‐stations of 2230 KVA to ensure the backup power supply. The
proposed project would require connected load of 2300 KVA. The maximum demand for
the expansion project has been estimated at 1900 KW. HFL will install 2 dual fuel
(gas/furnace oil) generators each having capacity of 1 MW, which would be used for the
expanded capacity. The electricity connection from Rural Electrification Board will
remain as back‐up support.
Gas:
Gas is supplied from the Titas Gas Transmission & Distribution Company Ltd. Gas
would be needed to run generators and boilers. The present gas connection has a capacity
of 72.96 million cft per year. The annual consumption of natural gas for the expansion
project is estimated to be 309.29 million cft at 100% capacity utilization. Usually the gas
supply in the region, by Titas Gas Transmission and Distribution Company Ltd, is stable
and satisfactory.
Water:
The Company owns two deep tube‐wells and two water treatment plants. The proposed
project will require water for various civil works during implementation as well as
regular operations. The proposed project will have water supply from the existing
facilities (deep tube‐well). Another deep tube‐well will also be installed to meet
additional water requirements. A soft water treatment plant will be set up to meet the
requirements.
14
15. The Company has Plant & Machineries (including electrical and gas installation) as per
the following schedule:
Weaving Plant (With Brand Origin)
Machine No. of
machine
Brand
1. Sizing Machine 2 Karl Mayer Italy
2. Warping Machine 2 Karl Mayer Italy
3. Doubling Machine 2 Blower India
4. Gas Generator 1 CAT USA
5. Gas Generator 1 MWN Germany
6. Boiler (Gas Fired) 2 Cochran UK
7. Cooling Tower 1 India
8. Humidifier 4 Japan
9. Hydraulic Beam Lifter 1 Germany
10. Electric Beam Lifter
Overhead Crane
1 Germany
11. Cloth Inspection Machine 10 Shiaw Tai
Tong
Taiwan
Dyeing and Finishing plant:
Machine No of machine Brand Origin
ETp plant 1 Bangladesh
Water Treatment Plant 1 India
Singeing & Desizing 1 Kusters and osthoff Germany
Bleaching Range 1 Kusters Germany
Mercerizing Range 1 Kusters Japan
Washing Range 1 Kusters Germany
Pad steam Range 1 Kusters Germany
Thermosol Dyeing 1 Kusters and
Bruckner
Germany
CPB 1 Kusters Germany
15
16. Emerizing Range 1 Lamperti Italy
Stentering Range 1 Bruckner Germany
Sanforizing Range 1 Monforts monfortex Germany
Twister 2 Volkmann Germany
Remarks:
The factory is equipped with the latest and modern machine from famous and
international brands and also holds very skilled workers to work with these amenities.
The position among the top textile manufacturers is obtained through the perfect
combination of the work and talented use of the machines. The best quality is maintained
always and it is not compromised with at any cost. This brings the fame among the
international buyers for this factory.
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21. 13. Store and Inventory
Manager
Officer
Helper
Worker
14. Accounts
Manager
Accounts officer
Cashier
15. Security
Manager
Officer
Guard
Shift Change:
There are two types of shift system, one type is for the workers and executives and the
other shift system is followed by the managers.
Shift Duration
A 06:00 am to 02:00 pm
B 02:00 pm to 10:00 pm
C 10:00 pm to 06:00 am
General Shift 09:00 am to 05:00 pm
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22. Responsibilities:
Production officer:
Production officer looks after the production process in first hand and deals with the
machines directly and also handles the workers involving. He takes every problems in
account and solves it with consultation of senior production officer and managers. He
directly reports everything going on in the production to the senior production officer.
Some of duties include:
Checking the machines continuously for finding faults or problems.
Take data of production parameters and submit it to the server.
Deals with the workers and their problems.
Informing the authority the overall conditions in regular periods.
Checking any scope of increasing productivity.
Guiding the production process from beginning to end.
Manager:
Manager is in charge of individual section. He has to be observant and careful of the
production process going on. Anything that can be a problem must be solved with
precision otherwise the manager will be responsible. So there must be pre made strategies
and procedures of solving the types of problems that occur regularly.
Executive:
Executives are in charge of specific tasks. Executives are responsible for the perfect and
day to day performance of doing and controlling the quality of the task. He informs upper
levels about any kind of problems.
Remarks:
The manpower management is the major part in the production and manufacturing
industry. The proper utilization of the manpower can bring the highest quantity and
highest quality of product. The personnel on all levels must be in satisfaction for the work
they do which also depend on the top level management and the working environment of
the workplace.
22
24. Machines:
The machines are listed following:
Section Machine Name
Twisting Section 1. Yarn Doubling Machine.
2. Yarn Twisting Machine.
Weaving preparatory
section
1. High Speed warping Machine (Total 3 machines in Unit 1
and unit 2).
2. Sizing Machine (Total 2 machines in unit 1 and unit 2).
Loom preparatory
section
1. Auto leasing machine.
2. Auto Knotting Machines (Total 2 machines).
Weaving section Air Jet Loom (104 looms in Hamid Weaving mills ltd. & 78
Looms in Tazrian Weaving mills Ltd).
Pretreatment section 1. Singeing and Desizing Machine.
2. Scouring &Bleaching Machine.
3. Mercerizing Machine.
Dyeing section 1. Cold pad batch dyeing machine.
2. Pad dry Thermosol Dyeing machine.
3. Pad steam machine.
4. Washing machine.
Finishing Section 1. Stenter machine.
2. Sanforizing machine.
3. Emerizing machine.
4. Carbon brush Machine.
Factory Sectional Layouts:
In Hamid weaving mills, there are 104 Toyota JAT710 air jet looms. The looms can be
divided according to their shedding mechanisms. There are Dobby shedding, positive
cams, and crank shedding mechanisms in the looms. 10 looms run their shedding by
dobby mechanism, 20 looms run by crank shedding mechanism & the rest of the looms
run by positive cam shedding mechanism.
The layout plans of weaving preparatory section, looms section and the dyeing sections
are following.
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27. Twisting
capacity: Same
count and only
30Ne with 40Ne
Operation rpm:
20000 to 22000
Machine parts:
1. Monitor display
2. Cradle
3. Disk
4. Drum
5. Capacitor
6. Tail in gear
7. Flyer
8. Tensioning
device
9. Pre take up roller
10. Multi tensioning
device
11. Balloon meter
12. Stop motion
feeler
3. High speed Warping Machine:
Machine Specification:
Brand: Karl
Mayer
Origin: Germany
Type (brand
model): ZM SP
1800/1000 DNC
Year of model:
2007
Creel: V shaped
Creel Capacity:
Total 720 cone
holder
Speed: Highest
1200 m/min
Warp Beam
capacity: Around
600 g/dm3
(Depending on
the yarn count)
Single Yarn
length on the
warp beam:
Around 25000 m
(Depending on
the yarn count)
Yarn package:
Cone
Count of
warping yarn: 7
to 120Ne
Production
capacity: 20 to
25 warp beams
per 24 hours
(Number of
beam production
depends on
machine
downtime)
Machine parts:
Headstock:
1. Variable v reed
2. Yarn speed
controlling
device
3. Pneumatic
pressure unit
4. Break assembly
5. Driving drum
6. Display
7. Motor
8. Brake shoe
9. Brush
27
28. Creel:
1. Cone holder
2. Tensioner
3. Sensor
4. Break indicating
light
5. Yarn separator
6. Cutter
7. Yarn guide
8. Blower
4. Sizing Machine:
Machine Specification:
Brand: Karl
Mayer Rotal
SRL
Origin: Germany
Model:
BM260011250
Year of model:
2007
Avg. completion
period : Around
1 hour for one
sized beam
Time for
installing new
warp beams: 1 to
1 ½ hour
No. of warp
beams: Highest
16
Pre wetting unit:
2
Sizing unit: 2
Size stock no.: 2
Cooking tank
capacity: 1250
liters
Reserve tank
capacity: 1500
liters
Length of each
yarn: variable
(around) ~25000
m
Speed of warp
beam: ~50
m/min
Machine parts:
1. Beam creel
2. Rewinding frame
3. Water box
4. Size box
5. Cylinder dryer
6. Teflon coated
cylinder
7. Load cell roller
8. Machine display
9. Reed
10. Press roller
11. Feed roller
12. Pendulum roller
13. Weavers beam
14. Mahlo reader
15. Hydraulic brake
system
16. Brake shoe
17. Cooking and
reserve tank
18. Squeezing roller
28
29. 5. Auto leasing machine:
Machine specification:
1. Brand: Todo 2. Origin: Japan
Machine parts:
1. Needle
2. Scissors
3. Clip
4. Needle guide
5. Sensors
6. Gear railing
7. Steele brush
8. Nylon yarn
9. Yarn guide
10. Counting sensor
11. Lock clip
6. Auto knotting machine:
Machine specification:
Brand: Todo
Model: Himac L
7. Air jet weaving machine: Toyota JAT710
Machine specification:
Brand: Toyota
Series: JAT710
Model: JA2S
190Tp EF T710
Origin: Japan
Drive:
Super-fast start-
up motor
Start, stop, and
forward/reverse
slow motion
activated by
pushbutton
operation
Solenoid-brake
stoppage
Automatic
compensation
for fixed-
position stops
Beating:
Two-sided crank
drive with oil
bath
Multiple short
sleysword
Nominal Reed
Space (R/S):
140cm to 390cm
Let-Off:
Electronic let-
off motion
Positive easing
type, double
back rollers
(Adjustable
forward/back
position)
Variation:
Negative easing
29
30. type, double
back roller
(Adjustable
up/down
position)
Take-Up:
Mechanical
take-up motion
Weft Insertion:
High-propulsion
main nozzle,
conical tandem
nozzles
Tapered sub
nozzles, Stretch
nozzle
New super-
responsive
solenoid valves
Sub tanks with
direct
connection to
valves
Auto pick finder
Automatic weft
insertion device
(ATC)
Temple:
Upper temple
Stop-Mark
Prevention:
Selectable main
motor start-up
Selectable
machine
stop/start angle
Adjustable let-
off amount,
One-shot weft
insertion
Fell forward
Yarn Beam
Flange
Diameter:
800mm, 930
mm, 1,000 mm
Shedding:
Negative cam
shedding
(maximum of 8
heald frames)
Positive cam
shedding
(maximum of 10
heald frames)
Crank shedding
(maximum of 6
heald frames)
Dobby shedding
(maximum of 16
heald frames)
Electronic
shedding
(maximum of 16
heald frames)
Jacquard
shedding
Selvedge:
Left/right rotary
full-leno
selvedge device
Waste Selvedge:
Waste selvedge
on the right with
catch yarn
Stop Motion:
Electronic warp
stop motion
Leno-selvedge
& waste-
selvedge break
stop motion
Reflecting type
weft detector
(double feeler)
Four-color LED
signal lamp
Lubrication:Oil
bath lubrication
system for main
parts
30
31. Grease
lubrication
Main Control:
New interactive
touch-screen
color function
panel
32-bit CPU &
function panel
Fiber-optic &
Ethernet LAN
communication
network
Function Panel
Features:
24-hour &
weekly
efficiency
graphs
Warp out/cloth
doff forecast,
Timing checker
Automatic initial
condition setting
(ICS)
Intelligent filling
controller (IFC)
Troubleshooting
, Stoppage cause
display
Weaver’s
monitor
Others:
Centralized
regulator
Power outage
stop function
Emergency alarm function
Machine parts:
1. Weavers
beam
2. Tension
rollers
3. Lease and
ease rods
4. Droppers,
droppers bar
5. Reed, reed
holder
6. Temple
7. Heald frame
8. Main, sub,
tandem,
stretch
nozzles,
nozzle valves
9. Take up,
cloth, main
rollers
10. Cam, gear
11. New
Automatic
Weft Brake
System
(ABS)
12. New
Automatic
Pick
Controller
(AFC or
APC)
13. Weft
Insertion
Device for
Yarns of
different
Types and
Counts
14. Air Gripper
System
(AGS)
15. Balloon
Cover
31
32. 16. Electric
Drum
Pooling with
Weft
Separation
17. Twin Beam
18. Double
Beam
19. Electronic
Take-Up
(single pick
density or
multiple pick
density type)
20. Constant
Tension
Take-Up
21. Electronic
Selvedge
Motion
(ESM)
22. 4-Thread
Half-Leno
Selvedge
Device
23. Tuck-In
Selvedge
Device
(left/right
and center)
24. Center
Selvedge
Device
25. Warp
Breakage
Area
Indicator
(with 6 or 12
divisions)
26. Toyota
Automatic
Pick
Operator
(TAPO)
27. Speed
Control
Inverter (SC
Inverter)
28. Fully
Automatic
Centralized
Lubricator
29. Toyota Total
Computer
System
(Internet-
TTCS)
30. Toyota
Monitoring
System
(TMS)
Toyota JAT 810
Main specifications:
Drive: Super-fast start-up motor. Start, stop, and forward/reverse slow motion
activated by push-button operation. Solenoid-brake stoppage. Automatic
compensation for fixed position stops.
Beating: Two-sided crank drive with oil bath. Multiple short sleysword.
Let-Off: Electronic let-off motion. Positive easing type, double back rollers
(adjustable forward/back position)
Take-Up: Electronic take-up motion.
32
33. Weft Insertion: High-propulsion main nozzle. Conical tandem nozzle. High-
efficiency tapered sub nozzles, stretch nozzle. New super-responsive solenoid
valves. Sub tanks with direct connection to valves. Auto pick finder. Automatic
Timing Controller (ATC).
Temple: Upper cover temple (lower mounted).
Stop-Mark Prevention: Selectable main motor start-up. Selectable machine
stop/start angle. Adjustable let-off amount. One-shot weft insertion. Fell forward
Selvedge: Left/right rotary full-leno selvage device.
Waste Selvedge: Waste selvage on the right with catch cord.
Stop Motion: Electric warp stop motion. Leno-selvage & waste-selvage break
stop motion. Reflecting type weft detector (double weft detector). Four-color LED
signal lamp.
Lubrication: Oil bath lubrication system for main parts. Grease lubrication.
Main Control: Large 12-inch interactive touchscreen color function panel, 32-bit
CPU & function panel. Fiber-optic & Ethernet LAN communication network.
Function Panel: Features 24-hour & weekly efficiency graphs. Doffing/warp out
forecast, Timing checker. Automatic Initial Condition Setting (ICS). Intelligent
Filling Controller (IFC). Troubleshooting, Stoppage cause display. Weaver’s
monitor, Weave Assist System (WAS).
Others: Centralized regulator, Power outage stop function. Emergency alarm
function, Toyota Monitoring System (TMS).
Pretreatment:
Singeing and desizing machine:
Machine specification:
1. Brand: Kusters
and Osthoff
2. Origin: Germany
3. Model no.: Vp99 4. Tank (chemical)
capacity: 1000
liters
33
37. Raw Materials:
HFL never compromises on the quality of raw materials it uses for the manufacturing
process. It procures raw materials from leading raw material suppliers both locally and
globally. Main raw materials of Hamid Fabrics
Limited include (a) yarn and sizing chemical for its weaving unit (b) various types of
gray fabrics, dyes, chemicals for pretreatment, finishing and specialized chemicals for
special fabrics finishing.
Types of Raw materials:
The raw materials on which the production depends are following.
1. Yarn:
Yarn is the main raw materials for production of fabric. Better quality of fabric can be
ensured by the use of better quality of yarn. So yarn is important among all the raw
materials.
Yarn Composition Count Type
100% Cotton 7 Ne to 40 Ne Combed, Carded, OE and
Ring
Blended Cotton 7 Ne to 40 Ne Combed, Carded, OE and
Ring
Lycra ~ 70 D
2. Chemicals:
Chemicals are the major part of dyeing and finishing operation. The main types of
chemicals used in HFL are: 1. Sizing Chemicals, 2. Effluent treatments, 3.Dyes and
Auxiliaries.
Source of raw materials:
After many years of sourcing, HFL is quite stable in vendor selection. The Company has
built up a strong relationship with raw material suppliers based on mutual benefit. Names
of the key suppliers of the raw materials are following.
37
39. Consideration on quality of raw materials:
Raw materials used in HFL are of better quality. For checking the raw materials
managers of each section of weaving mill do some tests. They use some of raw materials
in its intended purpose & observe the performance of the raw materials.
If the raw materials fulfill the requirements, then it will be accepted. Otherwise it will be
rejected. Raw materials which are used in production should be ensured of better quality
before they are used in production. So that production of fabric can be carried out
smoothly and good quality of finished goods can be ensured.
Annual requirement and Cost:
The following data are collected from the Annual Financial Report (2013, 2014).
1. Hamid Fabrics Ltd. Unit 1
Material consumed:
Opening stock of raw materials = 52,288,746
Add: purchase during the year = 581,799,283
Less: closing stock of raw materials = 26,939,581
Material Consumed = 607,148,448
Factory Overhead:
Sizing Chemicals Stock on 1 July 2013 = 302,200
Add: Purchase during the year = 20,532,025
Less: Stock at 30 June 2014 = 231,225
Sizing Chemicals Consumed = 20,603,000
Fuel, oil, lubricants = 8,233,369
Spare parts = 3,497,142
2. Hamid Fabrics Ltd. Unit 2
Material consumed:
Opening Stock of Raw Materials = 23,874,729
Add: Purchase during the year = 284,476,106
Less: Closing Stock of Raw Materials = 12,733,261
Material Consumed = 295,617,574
39
40. Factory overhead:
Dyes & Chemicals Stock on 1 July 2013 = 64,149,796
Add: Purchase during the year = 351,498,437
Less: Stock at 30 June 2014 = 90,487,665
Dyes & Chemicals Consumed = 325,160,568
Fuel, oil, lubricants = 3,015,329
Spare Parts (Electrical & Mechanical) = 20,973,857
3. Yarn Consumption during 2013,2014 financial year:
Items
name
Oening as on 1 July,
2013
Purchase/production Consumption/ Sales Closing as on 30 June,
2014
Quantity Amount Quantity Amount Quantity Amount Quantity Amount
Yarn
(kgs)
254,454 63,824,050 2,059,164 581,799,283 2,206,491 616,559,167 107,127 29,064,166
4. Contingent Liabilities
This has been considered as per IAS 37" provisions, Contingent liabilities, and
contingent assets". As on 30 June 2014 following dues revealed as contingent liability
of the company.
Particulars:
Letter of credit (Raw Materials) = 476,740,000 BDT
Payment in foreign currency
During the period under review following transaction took place in the form of
foreign currency:
Particulars:
Raw materials = 423,858,840
Spare parts = 14,762,216
Capital Machinery = 11,775,673
40
41. Remarks:
The company has high concentration on Square Textiles Ltd for local yarn purchase
(BDT 337.1 million in 2012), although long relationship with the particular supplier
supports the company to mitigate supplier concentration risk. Management of the
company expects that the very high dependency of square textiles ltd will be declined in
the upcoming year. The company mainly imported raw materials from Singapore,
Thailand, and India. Long relationship with the supplier, proper production planning, raw
material procurement strategies and structured monitoring system support the
management to keep raw material management risk at low.
41
43. Process flow:
The production of woven fabric is followed by sequential stages. The flow is here.
Raw materials: Yarn
Twisting: when required
Warping
Sizing
Drawing and Denting
Weaving
Grey Fabric Inspection
Singeing and Desizing
Scouring and Bleaching
Mercerizing
Dyeing
Washing
Stentering
Sanforizing
Finished Fabric inspection
43
44. These processes are described following.
Warping:
Objective of warping: The objectives of warping is to arrange a convenient number of
warp yarns of related length so that they can be collected on a single warpers beam, as a
continuous sheet of yarns which can be used for sizing.
Operation:
1. The warping machine is situated just at the right side of the shed. The godown of
yarn is behind the warping machine, so the taking out of the yarn packages are
easily brought to the creel.
Fig 5.1.1: Warping creel fig 5.1.2: Headstock
2. The yarn packages are kept in polybags to retain the moistures that was provided
by the yarn manufacturers.
3. The average humidity provided by the yarn manufacturers is around +8 %.
4. The creel operates at 50 % capacity and other 50% is done on the next cycle (the
half is being fed while the other half is being run.
5. Not a single cone is used to the hundred percent capacity. Every cone is used up
to 80 to 85 % capacity and then those are discarded and sold outside of the
factory. This is because when the cone is used up to 85% capacity it loses its rate
of flow of unwinding from the cone and if the warping continues with this cone
the yarn breakage rate skyrockets and the productivity lowers at an alarming rate.
It has been calculated that the sale of these cones is more profitable than using
these in warping and in subsequent processes and finally selling the cloth.
6. Before the warping starts and after the cones are installed, the yarns from every
cone in a single rod of the creel are joined together to bring to the machine head
with ease.
44
45. 7. The yarns are brought to reed first and then these are taken over a supporting
beam which is covered by ply wood material.
8. Every yarn is clamped on the attached thistle of a long bar before the warping
starts. The bristle (brush like) is made of nylon fiber.
9. The warp beam is clamped in the head and rotated with gears.
10. The yarn package holders in the creel have bleeping lights. If there is no yarn
through the tensioner near a cone, the light keeps lit red and if there is yarn the red
light bleeps (keeps being on and off again).
11. When a yarn breaks the yarn package holding every rod turns side so that the re
knotting can be done easily, fast and flawlessly.
12. The protective cover which closes and covers the machine head is made of strong
and thick plastic.
13. The protective cover consists of a pressing rod that presses the top most layer of
yarn that has been brought to the creel in the position just before the supporting
beam.
14. The machine is high speed warping machine and it is covered with protective
cover while being run for safety of the operators.
15. The machine is operated through interactive digital interface.
16. The digital monitor shows primarily the current situation of the operation. Like;
the length of yarn already wound onto the beam, the number of beams have
finished which is preset to a number planned to be done by the operator in his
shift, the speed of beam (rpm), the number of cones currently being used to make
the beam, the amount in percentage of the beam being wound.
17. There are options of control on this screen like: to stop and start the beam
revolving, to slower the beam speed which is shown as a picture of a tortoise, to
fasten the beam speed (to bring it to set speed) which is pictured as a running
rabbit, to widen the reed spacing, to narrowing the reed spacing and some other
minor setting.
18. Whenever a problem occurs; the screen shows the number of that particular
problem in a red box with a short description of that problem and if necessary,
stops the beam revolution automatically. For example: when a yarn breakage
45
46. occurs the machine stops and screen shows the description that yarn has broken
with the particular position of the creel with particular cone holder no.
19. Whenever the protective cover is opened for any reason, the screen shows
20. Many a time the machine faces downtime mainly because of yarn breakage.
21. The speed of warping at is such that when the production is highest and the yarn
breakage rate is lowest.
22. The yarn in warp beam are continuously being cleaned (in downtime) by an air
compressor driven thin veined pipe throughout the process.
23. The yarn packages/cone holders in creel and the creel itself is also cleaned by air
compressor driven high speed air flow through a pipe after every operation ends
with the removal of every maximum useable amount used cone.
24. The machine itself contain a metal rod like metal device that helps the yarn to get
warped without getting entangled and also helps to clean the yarn from fly fibers
by air flow.
25. Some operators are running the machine while the others are for fixing the yarn
breakage as soon as it happens.
26. The floor also contains fly fiber which is continuously being cleaned by the
cleaning persons so that it can’t get back on the yarn.
27. The floor is really spacious and well ventilated and optimally lighted for keeping
the production as smooth as possible.
28. Everyone on the floor wears mask for safety.
29. It’s always checked if the productivity of the workers is to the maximum level and
the wastage of time is little or none.
30. The finished beam is placed serially just at the starting point of the sizing machine
so that the material handling is kept to minimum with little time wastage with
maximum productivity.
46
47. Fig 5.1.3: Completed warp beam Fig 5.1.4: interactive user interface
31. Every finished warp beam is kept with a label showing the yarn count, buyer etc.
32. For maximum time utilization motor driven forklifts are used for movement of
finished beam doffing.
33. There is an optimal point of relaxation and wastage of time and product. If the
worker is relaxed in his job the quality of product maximizes but time wastage
could be high, moreover if he is too relaxed and does his job fast, time waste will
be lower but the product quality could also hamper. So there must be an optimal
point where the worker is enough relaxed with maximum product quality and
lowest time wastage.
34. The beam in the machine is a revolving thing so it creates magnetic field that
could be harmful to the pacemakers and digital memory (phone memory etc.).
35. The machine contains another beam covered with wood like board material that
press the warp beam while warping is done to press the beam in order to produce
a compact beam with uniform density and tension.
36. There is a machine problem that is at the beginning of each cycle there is a very
big percentage of yarn breakage that slower the production rate and increases
machine down time, during that time the machine can’t run at high speed that
intensifies the time wastage.
37. As the warping progresses the rate of yarn breakage decreases and the machine
starts running at higher and higher speed.
38. The rate of the speed increase is about 300 < 400 < 500 < 700 m/min.
39. When a yarn breaks that particular yarn is torn further from the breaking point on
the beam, then the whole length up to the point in cone is torn and a new end of
47
48. yarn is brought to the beam and gets knotted. This is done so that the tension
variation that happened on the yarn does not exist and create faulty products in the
subsequent processes.
Fig 5.1.5: Reed fig 5.1.6: Yarn drawing on beam
40. When the broken yarn is torn from the beam the operator becomes very careful so
that the removal of the torn yarn does not hampers the tension of the adjacent
yarns.
41. During winding in the mid-level, the yarn breakage rate is inversely proportional
to the machine speed.
42. The machine’s stop motion is a combination of electrical sensors and digital
actuators. The yarn guides in the creel contains the sensors which send signal to
the machine when a yarn breaks down and the machine stops the beam
immediately which is actuated digitally in the machine.
43. There must be no hanging hair or hanging cloth near the machine.
44. The no. of ends in every beam is decided by the no. of ends in the sized beam
which would be made combining 12 warp beams.
Fig 5.1.7: Creeling fig 5.1.8: Warping end by unusable cones
48
49. Points to be checked to improve high speed warping machine:
1. Better uniformity in the tension of individual yarns is the provision of adjusting the
tension of separate groups of warp yarns over the height of the warping creel.
2. Enlarging the mass of bobbins & warping beam winding.
3. Increased number of bobbins when warping yarn of low linear density & a greater
number of yarns in the warp.
4. Improved shape of winding on the warping beams & uniformity of the specific density
of winding.
5. Higher accuracy in warp measuring & reduction of wastes caused by irregular winding
of warps from the beams at sizing.
6. Compensation of warp tension at starting & stopping of the machine & slow running at
starting a new warping beam.
7. Increase of labor productivity in warping by partial or full automation of bobbin
change.
Yarn breakages during warping:
During high speed warping yarn breakage is the most common problem. There are some
specific places where yarn breaks. For this breakage many reasons are responsible.
During the study some places are identified & the causes are found. They are described
below-
1. Yarn packages: Many times yarn breaks in packages. Winding faults are mainly
responsible for this. Yarn can’t be unwound from packages & consequences the yarn
breakage takes place. Yarn package holder sometimes causes breakage due its defect.
2. In the middle of yarn packages & tensioning device: Yarn also breaks in the middle of
tensioning device & yarn package. Tension variation is the main cause of yarn breakage.
Also the yarn quality has an effect on yarn breakage. Lower yarn quality results in
frequent yarn breakage.
3. Shutter: Shutter is the place where the yarn guide & sensors are placed. Yarn passes
through the yarn guide & sensors in the shutter. In shutter yarn also breaks. Dust, slubs,
neps are the main causes for warp breakage in shutter.
49
50. 4. In the middle of shutter & reed: Yarn also breaks in the place of between the shutter &
the reed. Yarn tension, dust are the main reasons for yarn breakage. It is the long distance
which yarn travels the warping machine. No yarn guides are placed in this distance so
yarn tension must be controlled here. Otherwise frequent yarn breakage will take place.
SIZING
Objectives of sizing:
1. Improve the weavability.
2. Maintaining good fabric quality by reducing hairiness, weakness, and by
increasing smoothness, strength of yarn.
3. Increasing the tenacity of cellulose yarn.
4. Increasing the elasticity.
5. Removing projecting fibers.
6. Reducing electrostatic formation.
Units of sizing machine:
1. Back beam unit.
2. Re winding unit
3. Pre wetting unit
4. Sizing unit.
5. Drying unit.
6. Dividing unit
7. Beaming unit.
Operation:
1. The warp beams are installed on the beam creel. Usually 12 or 10 beams are installed
to produce sized beams though there can be installed highest 16 beams at the same
time. Bu, then again, the number of warp beams depend on the epi of size beams.
2. The total no. of warp beams must be an even number.
3. The warp beams revolve using brake shoe process driven from the motor.
4. First half of the beams produce one layer of yarn that is positioned on top just before
the size boxes and the next half of the beams produce another layer of yarn that is
positioned under the first layer.
50
51. 5. The first layer of the yarn goes through the first size box and the second layer goes
through the second size box.
6. The baths have overhead driers above with cylinders.
7. At the end of the size box with drier there is a cooling section.
8. The first layer of yarn goes through its own first overhead drier and the second layer
of yarn goes through the second overhead drier after being sized in bath.
9. After crossing through the drying cylinders and cooling section cylinders the both
layers of yarn gets combined and comes by a roller.
10. The combined layer comes after getting pressed by pressing rollers from the cooling
section.
11. After coming down from the cooling section, the combined yarn layer goes through a
pressing roller and a delivery roller.
12. This section has separate manual control, to control the run of the rollers and the nip
differences of the rollers.
13. Then this combined layer gets divided into multiple layers before getting wound onto
the beam.
14. First the combined layer gets divided into two layers by a lease rod.
15. Then each of the layers get divided again by two other lease rods and produce four
layers.
16. Again these layers get divided into eight layers by more lease rods.
17. Then all these divided layers enter the headstock in combined form.
18. At first all the layers get through the reed.
19. When the size beam runs, a protective woven net, made of metal, covers the front
opening, so that there is no entry to the beam during its run.
20. After entering through the reed the yarns go over a roller, and then through under a
pressing roller and then again over a delivery roller and finally to the size beam.
21. After one size beam is produced and the yarns are taped along the width at the top
just after the yarn cross the reed. This is for the uniform and organized position of the
yarn on the beam for the subsequent process.
22. The tape used is surgical in nature for its better stickiness.
51
52. 23. The completion of a sized beam ends with removing it from the head and carrying it
with a forklift.
24. After completing the required length of a beam, the yarns over it are taped and cut
with a knife
25. The main ingredient for the sizing is a combination of several products bought in
paper sack form from the manufacturer.
26. The recipe, take up percentage, temperature, pH etc. changes depending on the
required quality of the product and sometimes buyer requirement of the final product,
the quality of the yarn, count of the yarn.
27. There are two section in the size boxes; the first part gets the yarn wet with soft water
and the next part does sizing.
28. There are several number of rollers in the size box for the perfect application of the
size material to the yarn and also for the easy passage of the yarn layer.
29. The final beam in the size box acts as a pressing roller. This roller and its setting is
particularly important because it is the roller which acts as to let the yarn get sized
according to the requirement, no more no less.
30. After getting pressed by this pressing roller the yarn layer goes through to the drying
section. So this roller is cleaned using a brush after every several minutes so that if
there were any chunk of size material, no matter how small, gets dumped. Because
these chunks could get attached to any number of yarn and after drying get hard and
might cause breakage of yarn when the yarn goes through the reed.
31. The stand which carry the warp beams are regularly cleaned with high speed air flow
driven by high pressure air compressor so that the fly fibers are removed and does
not get back on the yarn, sized or unsized.
32. Two large chimneys attached on each of the overhead driers to let out the steam and
other gaseous material emitted from the dried sized yarns.
33. The size boxes have manual controls on each sides to on and off the water flow, size
material flow, and the revolving of the rollers in the size boxes.
34. This control panel also help configure the speed of the revolving, the distances of
rollers from each other. Etc.
52
53. 35. In the size box, on the size bath where the yarn gets impregnated with size material
there is a protective metal (iron) made net so that it gets protected from something
falling in it by mistake or getting touched by any worker which would result in both
contamination of size material and severe physical harm to the person.
36. After finishing one size beam, a new empty beam is brought to the headstock and
clamped in the precise position.
37. The headstock has both manual input (for some particular operations) and interactive
digital interface to control and observe (for controlling both the headstock and the
drying chamber).
38. The reed is made to move left and right all the time so that the yarn density gets
uniform and entanglement occurs.
39. The headstock have manual control for some things; like, to control the movement of
the reed, to close and open the protective cover. It also have manual control to clamp
the beam by the buttons of moving the beam clamp right and left and the beam holder
under the beam moving up and down for clamping and positioning it perfectly.
40. The size box, headstock etc. have large red colored emergency stop button. These
have to be pressed hard to stop the machine in case of any accident.
41. The worker distribution:
In the headstock:
Control the speed of the beam speed, check any entanglement, stops the beam when a
beam is finished, install new empty beam after finishing a new beam (doffing).
In the size box:
Clean the size box roller, make the size chemical mix in the mixing tank, set the
temperature of the mixing tank, clean the mixing tank surrounding, check the yarn
movement through the size bath, clean the size bath and check the condition of the yarn
that comes out of the cooling section.
In the creel section:
Install new warp beams and remove empty beams, cleans the beam creels at end of the
operation, check for any yarn breakage.
53
54. 42. Using all of the warp beams is almost never done because of being safe from risk
of entanglement and for higher productivity. And also bearing in calculation that
using all the beams could make the productivity highest, there is used the number
of beams of an optimum point between maximum production and least risk of
entanglement.
43. For setting the warp beams on the back beam unit, a crane system is used.
44. When the warp yarn comes to end the machine is stopped. The yarn are cut from
the entry point of the sizing bath rollers. The rest of the yarns and layer till the
sizing head remains.
45. At the end of the full use of all the warp beams to make sized beams and before
loading new material, the two size bath rollers, bath trays including the remain
yarn layer are washed thoroughly to start applying sizing material freshly. Also
the drums in dryers are washed and dried using a cloth.
46. The new warp beam yarns are knotted with existing ends of the bath entry. This is
not knotted in traditional sense, that is, the each single yarn is not knotted with
each single yarn of the bath entry. Instead the yarns of the first half of the warp
beams are taken from the warp beams and tied like rope and taken to the first size
bath and there the yarns are also made into a rope. Then these rope are tied
together. Same goes for the second half of the warp beams. In making of these
ropes, when the yarn takes the full width of the roller by revolving the rollers, the
yarn layer on beam are taped full widthwise so that they can retain the space and
don’t gent entangled and also it helps the starting a new batch of sizing.
47. At the beginning of the revolving of the beam to make sized beams, until all of
those left yarn in the size bath of previous batch, the tied rope and taped portion
of the yarn are discarded, the size bath does not start working. The sizing (bath
penetration) starts after the discarding.
48. The dividing of layers is done by manual tying of layers from two separate layers
of yarn based on the grouping of the back beams into two groups. Before entering
the reed of machine head, the yarn layers are divided by inserting Steele rods and
the marking is recognized by those rope tied along the width.
54
55. 49. The layers are tied with thin rope along the width and then it is run through the
bath, rollers, drying section and finally to the machine heads.
50. The sizing begins with firstly the underlying trolley is filled with hot water which
produces steam which increases the temperature of the yarn passing. Secondly
wetting the passing layer of yarn with water.
51. After that the yarn goes over several rollers and get dipped in size material and
the last roller in the sizing bath is the pressing roller which presses the layer to
squeeze the extra size material from the yarn. The pressure difference between
this roller and the sizing roller meaning the sized yarn can determine the amount
of size a yarn is supposed to get. This is fixed valued calculated from the yarn
count, the product quality expected and requirement of end products.
52. All these layer dividing is done for precision winding of sized yarn and
entanglement free winding and uniform density.
53. There are manual control panel and manual measuring to fix the distances of
rollers form each other.
54. Before the yarns, coming from different layers, enter the reed, they are checked
with fingers so that no entanglement is occurred and if there is any it can be
separated.
55. When a beam is completed with sized yarn, the beam is separated and new beam
is inserted, while doing this the machine is not stopped totally, only the speed is
made slower.
56. If a yarn breakage occurs in warp beam, the yarn is not re knotted, rather it is
taped on the beam. Because reknotting could create tension variation and
subsequently affect the quality of fabric to be produced.
57. The machine speed is directly proportional to the size material insertion to the
bath from the mixing tank.
58. When the machine runs faster, the insertion becomes more and it is lower when
machine runs slower. This is due to ensuring uniform insertion rate.
59. If the warp beams are finished and the sized beam is not filled to its total capacity
the sized beam is taken to loom as it is. New warp beams are then installed to start
new size beam making from fresh.
55
56. 60. There is a yellow line (border) on the floor around the machine which indicates
that inside this area, movement is limited to the operators and one must move
with strict caution.
Fig 5.2.1: Back beam section fig 5.2.2: Headstock
Fig 5.2.3: Size bath fig 5.2.4: Reed
Fig 5.2.5: beam moving by crane
56
57. MIXING:
1. There are two tanks just by the side of size baths.
2. One is mixing tank and the other is storage tank.
3. The mixing tank has an opening covered with metal netting. This opening is used for
pouring size ingredients.
4. There is a platform by the side of the tank to stand on because the tank opening is
higher for average workers height.
5. The mixing tank make the mixture for the size and the storage tank stores and supplies
the size materials to the size baths.
6. There is an electronic control panel box only for the tanks which has a screen that
shows the temperature, time.
7. The mixing tank consists of revolving blades inside of it which is driven by motors
positioned upon it.
8. The mixing and storage tanks, size baths include a number of pipe lines. One pipe
brings the water from the water reservoir. Another pipeline goes from the mixing tank to
the storage tank which carry the size materials to it. The pipeline which provides water to
the mixing tank, also provides water to the size baths. The storage tank also consists of
mixing, driven by motors so that the size material is produced with further precision. The
storage tank also consists of two pipeline to send the mixture to the size baths. The pipes
are covered with thick aluminum foils so that the temperature is retained.
9. There are steam carrying pipes which are larger in diameter comes from the boiler
room and provides steam to the both dyeing section and the tanks.
10. Both the tanks consist of let off tap to dump the waste size chemicals.
11. After a whole batch sizing, about 80% of the remaining size materials of size baths
are sent back to the storage tank.
12. There are sealing (on/off) handle bars to stop or let go of the size material to the tank
and bath.
13. There are several pumps attached to the tanks, baths to deliver the size materials.
14. When a mixture is being prepared, the tank opening is tightly sealed off.
15. There are dripping under the let off taps, to prevent it 100% is not possible. A jar is
placed under the tap to keep the floor clean.
57
58. 16. There are large drains under the tanks and size baths to easily dispose of the waste,
liquid and solid.
17. The mixing recipe is made such a way that it modifies yarn characteristics but does
not change the aesthetic, physical characteristics of it.
18. There are anti-mildew and antiseptic agents in the size recipe.
19. The adhesive, usually in granular form, is mixed with water and heated to form a
paste which ultimately becomes a viscous fluid. Starch is a complex carbohydrates which
combines with water, this causes the material to swell and change character. The
viscosity of the boiled starch is controlled to a great extent by the amount to which the
surface of the granule is dissolved. This in turn is affected by the recipe, the degree of
mechanical mixing, the temperature, and time of boiling. It will be seen that under certain
conditions prolonged boiling will cause a decline in the viscosity. Similar effects can be
obtained by over vigorous mechanical working. In both cases, this is caused by breakage
of the fairly weak hydrogen bonds formed during the gelatinizing phase. The viscosity is
one of the important factors influencing the amount of size picked up the yarn.
20. In size bath, the pressing rollers, the upper one is covered with rubber and lower one
is stainless steel.
21. The rate of substance entering the size bath is as same as it’s leaving the bath, so there
is no gradual accumulation or depletion in the system.
Fig 5.2.6: Tanks Fig 5.2.7: Interactive user interface
58
59. Drying:
The warp sheet passes through hot cylinder after the sizing unit. It helps yarn to dry. A
certain temperature is set on the cylinder which acquired by the steam. There are two
types of cylinder used in drying section. One is Teflon coated cylinder and other one is
dry cylinder. The function of Teflon cylinder is to make the warp yarn enable to pass
through the dry cylinder. Teflon does not permit size solution to attach with cylinder.
Otherwise size will make cylinder inactive and heating can’t be done. Teflon cylinder is
driven by yarn tension. Dry cylinder makes yarn dry by removing water from it.
Fig 5.2.8: drying cylinders
Chemicals used in sizing machine:
There are units of production in this factory. They have different procedure in using
sizing chemicals. They are following.
Specification Unit 1 Unit 2
Name and ingredients Starch, tetra size, unisoft,
dalda, sago, wax.
Bentex CM 500 ( Modified
starch, pVA, CMC, wax)
Brand Local Bentex Company ltd.
Origin Local Thailand.
The causes or factors behind the consideration of size materials are following.
1. Chemicals are non-degrading to yarn.
2. Compatible with the machine equipment; can be easily removed.
59
60. 3. Lack of odor.
4. Natural pH.
5. Insensitive to high temperature.
6. Rapid drying.
7. Easily prepared and no skimming tendency.
Size Cooking:
Before using size materials in machine it must be cooked. The procedure of size cooking
is simple. At first the required amount of size chemical is weighed. Then it is mixed with
water of 6 liters ¡n cooking tank. The cooking procedure is controlled by machine where
temperature time are all set before starting cooking. Normally they run the cooking tank
with 95°C temperature for 30 minutes. After the cooking he size materials is transferred
to reserve tank supply the se solution to sizing unit through a pump. After making the
size solution two points are considered. One is refractive value & another is viscosity.
Refractometer is used to determine the refractive value of size solution. There is a scale
on this meter which shows the value. The viscosity is measured with a viscosity cup.
There are specific value of refractive & viscosity for specific fabric production. If these
values coincides with the predetermine value, the size solution will be used in sizing. As
a result, a perfect weaving beam can be produced.
Some examples of sizing for production of specific fabric are given below-
Fabric
construction
Fabric
design
Total
ends
Yarn
type
Amount
of
chemical
(kg)
Size
chemical
Water
amount
Temperature
and time
20x12/128x64 2/2 twill 7000 Ring 98 Bentex
CM 500
600
liters
95º C and
30 minutes
16x12/117x67 3/1 twill 6456 Ring 85+2
20x10/116x56 3/1 twill 6550 Ring 88+5
30x30/154x86 2/1 twill 8520 Card 95+2
20x16/128x60 3/1 twill 7140 OE 86
16x12/108x56 3/1 twill 6150 OE 72+5
60
61. 30x10/152x65 3/1 twill 8640 Card 95+5
40x40/133x99 Poplin 7600 Comb 86
Properties of yarn after sizing or sized yarn properties: Due to sizing there is a change in
different properties of yarn as-
1. Smoothness: Higher
2. Weight of the yarn: Higher
3. Yarn diameter: higher
4. Hairiness: Lower
5. Flexibility: Lower
6. Absorbency: Lower
7. Weakness: Lower
8. Static electricity: Lower
9. Elasticity: Higher
10. Strength: Higher
11. Frictional resistance: Increased
12. Abrassional resistance: Increased
Factors affecting size take up:
Factors Higher size take up Lower size take up
Fiber character Mature fiber Immature fiber
Yarn character Hairy yarn Lower hairiness
Yarn count Coarser yarn Finer yarn
EPI Higher epi Lowe epi
Uniformity Low uniformity High uniformity
Tension on warp Low tension Higher tension
Roller weight Higher weight Lower weight
Roller dia High dia Lower dia
Wet ability High wet ability Lower wet ability
Size concentration High size concentration Lower size concentration
Temperature 60° c Relative
Warp Breakage in sizing
1. Faulty warp: faulty warp may be different types and different causes. Example:
uneven, immature, nepped, slubby, Hairiness.
2. Weak warp yarn: for less yarn twist, broken fibers in yarn.
3. Faulty preparation of yarn
4. Repeating warp streaks: less squeezing.
5. Size spots: faulty mixing of size ingredients.
6. Shimmer of fiber
7. Sandy size: Large size adhesive particle.
61
62. 8. Hard sizing: excessive concentration, uneven sizing, improper drying, size
dropping, size sticking.
9. Crossing of warp ends: during sizing the yarn overlap with each other in any case.
10. Uneven and improper tension: if tension of beam is not constant.
11. Defective machine parts: the surface of cylinder faulty, yarn supply of back beam
is not properly tensioned.
12. Faulty adjustment: not proper adjustment of comb, separating rod and other parts.
13. Excessive machine speed: if weak yarn, it will break due to high speed.
14. Insufficient care of machine: if machine parts are inert.
15. Unsuitable humidity: with humidity, the quality of yarn changes.
16. Workers faults.
Faults in sizing
1. Size spots: size materials should be added gradually to the mixing tank for good
mixing. If it is added at once, spots are appeared on the yarn.
2. Repenting warp streaks: this defect is due to uneven tension in the pre beam.
3. Shinnery: this defect is due to the friction between the yarn and drying cylinder.
4. Sandy warp: due to not crushed or grind the size material properly.
5. Ridge beam: this fault occurs due to uneven distribution of yarn in wraith.
6. Hard sizing: if the size materials are applied too much, the size becomes hard
which causes hard sizing.
7. Improper drying: if under drying is done, bacteria is formed and yarn breakage
occurs. And if over drying is done, hard sizing is occurred.
8. Size dropping: this defect due to no optimum viscosity of the size solution.
9. Size stitching: due to improper drying after sizing.
10. Uneven sizing: due to over or under sizing. Due to over or under concentration of
size liquor.
Tension controls in sizing
1. Let off tension: tension during unwinding from beam. When unwound from
beams, all let off tension are uniform.
62
63. 2. Inlet tension: when yarn passes in to the size box and immersed into size box,
tension can be controlled.
3. Wet zone tension: for this tension variation, take up percentage varies, so this
tension is controlled.
4. Dry zone tension: when yarn passes through the surface contact of cylinder, this
tension is controlled otherwise uneven drying occurs.
5. Winding on tension: tension of final beam is controlled. If winding is not done
properly in final beam with proper tension, creates problem in weaving.
6. Spreading tension: when yarn is passed as sheet form, this tension is controlled.
Automation in sizing
1. Steam pressure control.
2. Size level control.
3. Steam pressure control.
4. Moisture control in sized warp.
5. Stretch control.
6. Measuring unit control.
Viscosity of size solution:
Viscosity of size solution is very important for good sizing. A high viscosity will not
penetrate the fibers in the core of the yarn and moreover warp will be harder than
necessary and will be harsher and will make yarns entangled. Also, lower the viscosity,
weaker the yarn will be because of squeezed out size.
Figure 5.2.9: Viscosity cup
Measurement of viscosity:
The viscosity cup is immersed in the size tanks and the cup is filled with size solution.
The time for dripping of size solution through the cup is measured by a stop watch.
63
64. Viscosity values:
Fabric construction Fabric design Total ends Viscosity
20 x 10/116 x 56 3/1 Twill 6550 35-40 seconds
30 x 10 /152 x 65 3/1 Twill 8640 40-45 seconds
20 x 12 /128 x 64 2/2 Twill 7000 40-45 seconds
20 x 30 /126 x 80 2/1 Twill 7140 40-45 seconds
20 x 10 /116 x 56 3/1 Twill 6550 35-40 seconds
20 x 12 /128 x 64 2/2 Twill 7000 40-45 seconds
16 x 12 /117 x 67 3/1 Twill 6456 35-45 seconds
Refractivity:
Refractivity of a size solution is measured by refractometer. With the refractometer the
solid particle percentage with respect to water present in the solution is determined.
Refractometer is an analog instrument for measuring a liquid's refractive index. It works
on the critical angle principle by which lenses and prisms project a shadow line onto a
small glass reticle inside the instrument, which is then viewed by the user through a
magnifying eyepiece.
In use, a sample is placed between a measuring prism and a small cover plate. Light
traveling through the sample is either passed through to the reticle or totally internally
reflected. The net effect is that a shadow line forms between the illuminated area and the
dark area. It is where this shadow line crosses the scale that a reading is taken. Because
refractive index is very temperature dependent, it is important to use a refractometer with
automatic temperature compensation. Compensation is accomplished through the use of a
small bi-metallic strip that moves a lens or prism in response to temperature changes.
Figure 5.2.10: Refractometer
64
65. Refractivity values:
Yarn Count Yarn type Ends per inch Refractive
percentage
20 Ring 128 11%
16 Ring 117 9.5% (+)
20 Ring 116 10%
30 Card 154 11%
20 OE 128 10%
16 OE 108 8%
30 Card 152 11%
40 Comb 133 10%
Loom preparation
Before weaving a fabric, it is need to set up a warp sheet in loom. There are some
processes which must be done before weaving. The sequence is following.
1. Drawing
2. Denting
3. Leasing
4. Gaiting
5. Knotting
These processes are done sequentially for starting a woven fabric production. These steps
are too much important. If there is any fault, fabric production will hamper.
Drawing:
According to fabric design, the process of passing the warp thread through the heald eye
and dropper is called drawing. Drawing can be done manually or by using auto drawing
machine. In auto drawing machine, time is needed more than manually drawing. So
drawing process is done manually.
Drawing process
In manual drawing process a drawing frame is used where heald frames are hanged with
heald wire and dropper. The warp yarn is then drawn through the dropper and the heald
eye of the heald wire by a drawing hook. The drawing is done in a way that is followed
by drafting plan of a specific fabric design.
65
66. For example, a specific design of a fabric is 3/1 twill. To produce this fabric 4 heald
frames are needed. The sequences of heald frames will be 1 2 3 4. This means that the
first warp yarn of the fabric will be drawn through the first heald frame's first heald wire.
The 2nd, 3rd, 4th warp yarn will be drawn through the first heald wire of the 2nd, 3rd, 4th
heald frame respectively. But the 5th warp yarn will be drawn through the 2nd heald wire
of the 1st heald frame. The rest warp yarn will be drawn with same sequence. So in
manual drawing, the worker must be highly skilled and efficient. Otherwise the desired
fabric production will hamper.
In auto drawing machine warp yarn is only fed. A person is needed to catch the warp yarn
and pass them through the drop wire and heald eye according to drawing plan. In this
process skilled labor and less time is required than the automatic process. So manual
process is widely used.
Fig 5.3.1: warp through drop wires
Drawing components:
1. Drawing frame: it is a frame where heald frames with heald wires and dropper bar with
droppers are hanged. It helps with drawing process to be done easily.
2. Heald frame: The available heald frames at HFL are following.
Heald frame Old New Damage Purchase Total Frame height
Crank 50 80 30 52 152 47.4mm
Cam 175 312 487 55mm
dobby 85 85 170 34mm
3. Heald wire: Heald wire is the important component of drawing. The shade formation
of warp yarn during weaving is greatly assisted by heald wire. Normally the heald wire
has a height of 28.5 mm. Heald eye of the wire is the place where warp yarn is drawn.
66
67. 4. Dropper: Dropper is another component of drawing process. It is mainly used for
stopping the loom when warp yarn breaks. There is a dropper bar where droppers are
placed. Droppers are made of steel and dropper bars are made of two components steel
and copper. The size of dropper is 166mm x 11mm x 0.3mm.
Denting
The process of passing the warp yarn which are already drawn through the dropper and
heald wire through the dent of the reed is called denting. Denting is done quicker than the
drawing process. There are two types of denting. It can be manually or it can be done in
auto denting machine. But manual process is mainly followed. It is convenient to carry
out the denting process.
Denting Process
Denting is mainly done manually. In manual denting process the drawn warp yarns are
drawn through the reed of the dent by using an instrument called denting plate. This plate
is inserted through the dent of the reed. Then warp yarns are drawn through the reed by
pulling the yarn with the denting plate. The number of warps yarns per dent space
depends on denting plan, reed count, and fabric width.
In auto denting machine one person is needed to feed the warp yarn to machine. There
are a sensor and a hook in auto denting machine. When the sensor of the machine touches
the warp yarn, the hook comes upward and catches the yarn. After that, it takes the warp
yarns downward. The hook along with the sensors travels one part to another part of the
machine frame automatically.
Reed count selection
Before denting, selection of reed count is important. It is mainly depends on fabric width,
ends per inch and ends per dent. A selection of reed for a specific fabric production is
following.
Fabric width= 60.42 inch
Total ends of fabric= 8000
Ends per dent= 4
Again, we know that reed count means that it has half of its count per dent per inch.
67
68. Now, ends per inch= 8000/60.42= 132.40~~132
Reed count= (132/4) x 2= 66
It means that this fabric production needs reed which is of 66 count. Reed count 66
means that it has 33 dents per inch approximately.
Reed specification
Brand: Takayama, Osakama, Jungril
Origin: Japan
Dimession: 81 inch x 4.75 inch x 0.25 inch
Thickness of dent: 0.15 mm
Drawing and denting plan of fabrics
The drawing and denting plan depends on the fabric construction and fabric design. Some
examples in HFL are following.
Fabric construction Total
ends
Fabric
design
Reqd.
no. of
heald
frame
Drawing plan Ends
per
dent
Reed
count
20x(30+10/120x80 7400 Dobby 6 1 2 3 4 5 6 5 48
30x16/136x74 7600 Herringbone 4 1 2 3
4/1234/2143
4 60
40x40/133x100 7600 Poplin 4 1 2 3 4 2 120
40+40x30/2/124x100 7130 Oxford 4 1 2 3 4 2 112
30x20/154x88 8520 Bedford 6 1 2 3 4 5 6 3 92
30x30x30D/133x85 6800 Canvas 4 1 2 3 4 4 50
20x16/100x52 5800 Rib stop 4 2 3 4 1(5
repeat/234/11
2 92
30x20/130x77 7600 4/1 satin
twill
5 1 2 3 4 5 3 78
20x20/140x84 8000 2/2 s twill 4 1 2 3 4 4 66
68
70. Leasing
The process of separating the warp sheet into two parts for facilitating the weaving is
called leasing. Leasing can be done only by using auto leasing machine. The main
function of auto leasing machine is to separate the warp yarn according to fabric design
& another function is to count the warp yarn.
Figure 5.3.2: Auto leasing machine
Leasing process:
In auto leasing machine a leasing frame is attached with it. At first a weaver’s beam is
placed in front of the machine. Then beam warp sheet is tied with two small locking clips
in the leasing frame. L key is used to tie the warp sheet with the small locking clip. Then
the warp sheet is brushed with a steel brush to separate the warp yarn individually. The
extended warp sheet is cut by scissors. Then leasing is done by auto leasing machine. A
nylon yarn with the machine is used to separate the warp sheet. The machine has a
counter sensor which displays the no of warp yarn.
Gaiting:
The process of placing the heald frames according to lifting plan & dropper bars on the
loom to start the weaving process is called gaiting. It is mainly a manual process. The
placement of heald frames is an important task because the desired fabric design is only
possible when drawing & lifting plan is done accurately. If there is any mistake to place
the heald frame on the loom the desired fabric design will not be produced.
70
71. Gaiting process:
Mainly the gaiting is done manually. There is a frame carrier in the weaving floor which
is used in transferring of heald frame & dropper bar. At first the frame & bar are taken to
frame carrier from drawing frame. Then the carrier is taken to the loom & place the frame
and the bar on the loom from carrier. The placement should be done very carefully so that
the warp yarn can be knotted very easily. There are some livers on which the heald
frames are placed. The livers are set on a plan so that it lifts the heald frame according to
a plan. So if the frames are not placed properly, the lifting will not be properly done. In
drawing section the heald frames are set according to lifting plan & drawing is also done
in accordance with lifting plan. So, there need not very skill to place the heald frame.
Knotting:
The process of tying the pattern warp yarn with the weaver’s beam warp yarn
successively is called knotting. Knotting is a fully automatic process. It is done to
facilitation the production & reduces the time of production. Knotting can be carried out
within 30 minutes. It also reduces the labor cost.
Knotting process:
Knotting is done by auto knotting machine with knotting frame. Combing must be done
before knotting. At first the warp beam is loaded in the weaving machine. Then knotting
frame is placed in front of the machine. In this frame knotting m/c is placed & knotting is
carried out. After the frame placement pattern warp sheet is leased by using a leasing
card. Brushing is also done by dally. Beam warp sheet is then pulled to knotting frame &
is tied up in parallel form using two small locking clips with sufficient tension in the
lower position of the knotting frame. L key is used to tie the warp sheet. The beam warp
sheet is brushed with steel brush to separate the warp yarn individually. On the other
hand, pattern warp sheet is brushed by wooden brush & it is then placed to roller brush
with sufficient tension. The pattern warp sheet then tied up in parallel form with two big
locking clips in the upper position of knotting frame. Big comb is used in pattern warp
sheeting. The extended warp sheets outside the clips are cut by scissors. Then the
knotting machine is placed on the knotting frame. The machine is started & knotting is
carried out by knotting the pattern warp yarn with beam warp yarn.
71
72. In knotting machine there are three important parts. They are needle, cutter and knotter.
The function of cutter is cut the warp yarns. Needle is used to let the warp yarn to
knotting zone and the function of knotting parts is to knot the warp yarns.
Fig 5.3.3: knotting machine Fig 5.3.4: knots
For knotting, needle is very important element. Needle used in knotting is of different
number. The no. of needle depends on the count of warp yarn. Because different counts
of warp yarn need different no. of needle. With same needle different counts of yarns
can’t be knotted.
The workable needle and yarn count combination is following.
Yarn count Ne Needle no. Quantity
16 or 12 65 2 pieces
20 or 40 55 2 pieces
30 45 3 pieces
40 35 3 pieces
72
73. Weaving
Weaving is the process of interlacing of warp & weft yarn according to a design of fabric
for preparing fabric is called weaving. The longitudinal threads are called warp and the
lateral threads are called weft. One warp thread is called an end and one weft thread is
called a pick. Cloth is usually woven on a loom, a device that holds the warp threads in
place while filling threads are woven through them. The way the warp and filling threads
interlace with each other is called the weave. The majority of woven products are
produced with one of three basic weaves: plain weave, satin weave, or twill. Woven cloth
can be plain, or can be woven in decorative or artistic designs. Weaving consists of some
mechanisms. They can be classified as three motions.
Fig 5.4.1: Toyota air jet looms
1. Primary motion: This motion includes shedding mechanisms, picking mechanisms &
beat up mechanisms.
2. Secondary motion: This motion includes take up & let off mechanisms.
3. Tertiary motion: This motion includes warp & weft stop motions.
These three motions are involved in weaving process & this is called weaving cycle.
Modem weaving machine has all of these motions to carry out the weaving process. In
Hamid Fabrics Limited there is only one type of loom in which its fabric production is
carried out which is Air jet weaving machine. In case of Air Jet weaving machine, a jet of
air is used to insert the weft yarn. High speed operation is possible here. At present this is
the most popular type of loom and its functions are excellent overall.
73
74. Shedding mechanisms:
The process of separating the warp sheet into two layers one layer is raised & other is
lowered during weaving is called shedding mechanisms. The air jet loom & the rapier
loom have their own shedding mechanism. Air jet has positive cam shedding, crank
shedding and dobby shedding. They art described here.
Air jet loom: in air jet weaving machines shedding is done by outside cam shedding
mechanism. In this mechanism bottom close shed is formed. Shedding cam is used to
form the shed. There are many shedding cams for various fabric designs.
Cam Shedding:
The mainly used ones are: 2/1 twill cam, ½ twill cam, 1/3 twill cam etc.
Figure 5.4.2: Positive cam shedding motion; the first drawing was taken from ref. [1]; AₒABBₒ, BₒCDDₒ - four bar
mechanisms; DₒEF - slider crank mechanism, 2, 2’ - double shedding cam; 3, 3’ - rollers; 4 - oscillating follower; 5, 6,
7, 8, 9 - links; 10 - heald frame.
1. In cam shedding mechanism, cam is attached with cam shaft. Cam shaft is driven
by motor through gearing. A bevel gear & a bevel pinion are used to transfer the
motion of motor to cam shaft.
2. When cam rotates, it pushes the jack lever. Jack lever then goes downward and a
connection lever connects the jack lever with frame lever.
3. When jack lever comes downward it pushes the frame lever through connecting
lever. Frame lever then moves to left side.
4. DRPs are connected with frame lever. When frame lever moves to left side, they
both move upward. Heald frames are supported by the DRP. So when the two
DRP move to upward, heald frame goes to upward also. Hence bottom dose shed
is formed.
74
75. 5. The dwell time of heald frame depends on the shedding cam. When cam releases
the jack lever it returns back to its initial position. Frame lever also moves to right
side through connecting lever. Consequences DRPs move downward as well as
heald frame also come to its initial position.
Crank Shedding:
Crank shedding mechanisms are simple and relatively cheap to use. However it can only
be used for plain weave fabric constructions. In this system the harnesses are controlled
by the crank shaft of the weaving machine. For each crank shaft revolution a wheel is
rotated half a turn, which changes the harness position. This system is only used in air-jet
and water- jet machines where high speed is achieved.
Figure 5.4.3: Crank shedding
Figure 5.4.4: Crank type of shedding motion; AₒABBₒ - crank rocker mechanism, BₒCD - slider crank
mechanism, 2 - crank, 3, 4, 5 - links, 6 - heald frame.
Figure shows a schematic view of the crank shedding motion. It consists of a crank
rocker mechanism (AₒABBₒ) and a slider crank mechanism (BₒCD). The crank (link 2)
rotates at half of the loom’s speed. The crank’s continuous rotation is transmitted to link
75
76. 4 by link 3. During one revolution of the crank, link 4 swings between its foremost and
rearmost positions. The slider crank mechanism converts the angular displacement of link
4 to the linear displacement of the heald frame. The foremost position of link 4
corresponds to the bottom position, and the rearmost position of link 4 corresponds to the
upper position of the heald frame. Heald frames change position in each loom revolution,
and therefore the crank’s shedding motion generates a heald frame motion only for plain
weave.
Dobby Shedding:
Each harness frame is controlled by a cam unit. The cam unit converts the irregular rotary
motion of the main drive shaft directly into the linear motion required for the harness
frame drive. The essential element is a crank mechanism enclosing a cam with ball
bearings. A ratchet placed on the outside of the cam connects it with the driver, and by a
180° rotation of the cam causes a lifting motion. The ratchet is controlled according to the
pattern of the control unit.
Figure 5.4.5: Rotary dobby cross-section [2]; b - link fixed to dobby shaft; c - eccentric link; d - metal piece (ratchet);
e, f, g, h - links; j - electromagnet.
Figure shows a rotary dobby cross section. Link b is fixed to the dobby shaft. A metal
piece (d) is pivoted on the eccentric (link c) and can rotate around its pivot axis. A spring
(not shown in the figure) forces the metal piece to rotate in the clockwise direction, and
hence the metal piece presses on link b. There is a ball bearing between links b and c (not
seen in the figure). There is also a ball bearing between link c and link e. Links g and h,
the electromagnet (j) and the metal piece (d) constitute the pattern selection mechanism.
Link g can rotate around its pivot by the action of the electromagnet (j) via link h. If link
g is rotated in an anticlockwise direction, then the metal piece rotates in the clockwise
direction, and its bottom tip becomes engaged in the groove on link b. If link g is rotated
76
77. in a clockwise direction, it presses the upper tip of the metal piece and disengages it from
link b by rotating the metal piece (d) in an anticlockwise direction. When the engagement
happens, link f rotates in an anticlockwise direction during the 180° rotation of the dobby
shaft (i.e., link 1). Link f dwells at its foremost position during the 180° rotation of the
dobby shaft, if the engagement does not occur. The dobby shaft stops after every 180°
degree rotation, and the pattern selection mechanism engages or disengages the metal
piece with link b. If the engagement happens, then link f moves to the other position.
Otherwise, it remains in the same position. The motion transmission mechanism of the
cam shedding mechanism can also be used as a motion transmission mechanism for a ro-
tary dobby. In this case, link f of the rotary dobby corresponds to link 4 of the motion
transmission mechanism. The foremost position of link f of the rotary dobby corresponds
to the higher position of a heald frame, and the rearmost position of link f corresponds to
the lower position. As a result, the counterclockwise rotation of link g of the pattern
selection mechanism corresponds to the higher position of the heald frames, and the
clockwise rotation to the lower position.
Fig 5.4.6: positive dobby shedding
In contrast to the continuous rotation at a constant speed of the drive shaft of the crank-
and cam-shedding motions, the rotary dobby shaft has to rotate intermittently with 180°
increments to allow the engagement or disengagement of the metal piece with link b. A
mechanism called the ‘modulator’ is used to convert the continuous rotation of a loom
main shaft to the intermittent movement of the rotary dobby shaft.
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78. Picking mechanisms:
The process of inserting the weft yarn that has been inserted across the warp yarns
through the shed during weaving is called picking mechanism. In air jet weaving machine
picking is done by the flow of the. The process of picking is described here.
Figure 5.4.7: Air jet filling insertion with open profile reed
Air jet loom: The picking process of air jet loom is mainly done by the flow of air. It is a
shuttle less mechanism.
1. In air jet weaving machine the weft yarn is pulled from the supply cone package
which is mounted on creel at constant speed which is controlled by EDP just in front
of the yarn package.
2. EDP contains approx. 15 turns of weft yarn & removes a 1enh of weft yarn
appropriate to the width of the fabric being woven. There is an EDP pin in EDP
which lets the weft yarn.
3. Weft yarn passes through tandem nozzle. WBS holds the yarn until the shed is
opened for picking. After tandem nozzle weft yarn passes through the main nozzle.
4. The main nozzle begins blowing air so that the weft yarn is set in motion as soon as
the WBS lets the weft yarn. The weft yarn is then blown into guiding channel of the
reed with shed open.
5. The weft yarn is carried through the shed by the air currents emitted by the sub nozzle
along the channel. The initial propulsive force is provided by the main nozzle.
Electronically controlled relay nozzles provide additional boosters jets to carry the
yarn across the shed.
6. At the end of each insertion cycle the ABS holds the weft yarn. Then weft yarn is
beaten in after weft yarn is cut. At last the shed is closed.
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