2012 Textile Internship Report - arvind denim devision

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NATIONAL INSTITUTE OF FASHION

TECHNOLOGY

2012 Textile Internship

Report

Arvind Naroda

By:

Vishakha Chopra

8/17/2012

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ACKNOWLEDGEMENTS

I would like to thank Arvind, Naroda unit for giving me the

opportunity to undergo a training in the textile department and for

extending their support towards us all throughout our internship

I would also like to thank NIFT, Mumbai for giving us this

opportunity and facilitating our internship

It was a great learning experience throughout to see one of the most

well planned and advanced textile units. We take the opportunity to

thank all the people who guided us through the entire process and

made our training a success by sharing their knowledge.

I would like to thank Ms. Milli Das, Sr. H.R. at Arvind, without whose

support and guidance the internship couldn’t have been completed

satisfactorily.

I am also grateful to our College mentor Mr. Ranjan Saha for guiding

us at every stage and making this project a success

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I. PROJECT ABSTRACT

Project type Textile internship

Industry Arvind Mills Limited – Lifestyle Fabrics

Address Denim Division

Arvind Limited Naroda Road Ahmedabad – 380025 Gujarat India Tel: +91-79-30138000 Fax: +91-79-30138671

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A

IM

:

The project is based on a ten day internship , in Arvind Mills denim Department. It covers all the information and learning experiences related to manufacturing of textiles, denim in this case and all the processes involved namely:

 Spinning  Dyeing  Weaving  Finishing  Testing  Packaging

The main objectives of the project/internship were:

1. Understanding basic principles of production of textiles.

2. In depth study and understanding of all process involved in textile production and the machinery and equipment used.

3. Knowledge about the company

4. Understanding the company’s process flow in production

5. Study the work environment and practices followed for textile production. 6. Asses the faults and critical factors of production and determine the practices

adopted by Arvind Mills.

C

OURSE

O

F ACTION

:

We devoted one day to visit each department related to the production of denim. In the departments, head of departments were assigned to us, for detailed explanation of the process involved. The head Of Department showed us the individual processes, explained the work flow and showed us associated machinery. We maintained a learning diary and took down noted on all information that we could acquire from the department.

We then spent half an hour to one hour, depending upon the process, in each department, exploring the various machine features, writing down specifications and talking to the machine operators about the various problems faced during production.

After the industrial visit, we would go home and take down additional information from the internet and any other available source, note in in our learning diary and compile this document side by side, so as to not miss out on any important details.

Parts of this document have not been copied from anywhere, except for definitions, company or industry related information, diagrams and pictures.

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INDUSTRIAL PROJECT INDUCTION TIME TABLE

DATE TIME DEPARTMENT HEAD OF DEPARTMENT

21-05-2012 10:00 hrs to 15:00 hrs. Spinning Devesh Shah

22-05-2012 10:00 hrs to 15:00 hrs Dyeing Hitesh Shah

23-05-2012 10:00 hrs to 15:00 hrs Weaving Deepak Pandya

24-05-2012 10:00 hrs to 15:00 hrs Finishing KB Shah

25-05-2012 10:00 hrs to 15:00 hrs Quality Assurance Pranab Karmakar

28-05-2012 10:00 hrs to 15:00 hrs Inspection

And Packaging RT Shah

29-05-2012 10:00 hrs to 15:00 hrs Production Planning

And Control Ajay Dwivedi

30-05-2012 10:00 hrs to 15:00 hrs Marketing Smita Deshpande

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I

NDIAN

T

EXTILE

I

NDUSTRY

:

• Indian textile industry and Market Size

 Textiles sector contributes to 14 per cent of industrial production

 4 per cent of National GDP

 10.63 per cent of country's export earnings

• Market Size

 India's share of global textile exports is expected to increase from the current 4% to around 7% over the next three-years

• Growth Rate

 3-4 percent during the last six decade

 9-10 percent during last five year

• Scope of rivalry  Raymond India  Welspun India Ltd  Alok Industries  Gokaldas Exports  Arvee Industries

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I

NTRODUCTION TO

T

HE

C

OMPANY

A

BOUT THE COMPANY

:

Arvind Limited started with a share capital of Rs 2,525,000 ($55,000) in the year 1931. With the aim of manufacturing the high-end superfine fabrics Arvind invested in very sophisticated technology. With 52,560 ring spindles, 2552 doubling spindles and 1122 looms it was one of the few companies in those days to start along with spinning and weaving facilities in addition to full-fledged facilities for dyeing, bleaching, finishing and mercerizing. The sales in the year 1934, three years after establishment were Rs 45.76 lakh and profits were Rs 2.82 lakh.

In the mid 1980’s the textile industry faced another major crisis. With the power loom churning out vast quantities of inexpensive fabric, many large composite mills lost their markets, and were on the verge of closure. Yet that period saw Arvind at its highest level of profitability. At this point of time Arvind’s management coined a new word for it new strategy – Renovision. It simply meant a new way of looking at issues, of seeing more than the obvious and that became the corporate philosophy.

The national focus paved way for international focus and Arvind’s markets shifted from domestic to global, a market that expected and accepted only quality goods. Cottons were the largest growing segments. But where conventional wisdom pointed to popular priced segments, Renovision pointed to high quality premium niches. Thus in 1987-88 Arvind entered the export market for two sections -Denim for leisure & fashion wear and high quality fabric for cotton shirting and trousers. By 1991 Arvind reached 1600 million meters of Denim per year and it was the third largest producer of Denim in the world.

In 1997 Arvind set up a state-of-the-art shirting, gabardine and knits facility, the largest of its kind in India, at Santej. With Arvind’s concern for environment a most modern effluent treatment facility with zero effluent discharge capability was also established.

Arvind has carved out an aggressive strategy to increase its current operations by setting up world-scale garmenting facilities and offering a one-stop shop service, by offering garment packages to its international and domestic customers.

Of Lee, Wrangler, Arrow and Tommy Hilfiger and its own domestic brands of Flying Machine, Newport, Excalibur and Ruf & Tuf, is setting its vision of becoming the largest apparel brands company in India.

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B

OARD OF

D

IRECTORS

:

CHAIRMAN

Mr. Arvind N. Lalbhai

He is a Science Graduate and has been associated with the Company for over 60 years. He has been the Director since March 1974 and Managing Director since January 1975 till November 2002. He is the former President of the Federation of Indian Chambers of Commerce and Industry.

WHOLETIME DIRECTORS

Mr. Sanjay S. Lalbhai, Managing Director

A Science Graduate with a Master’s degree in Business Management, has been associated with the Company for more than 25 years.

Mr. Jayesh K. Shah, Director Finance

A Chartered Accountant having distinguished academic and professional career, has been with the group since the last 17 years.

OTHER DIRECTORS

Mr. Deepak M. Satwalekar

A ‘B. Tech.’ from The Indian Institute of Technology (IIT), Mumbai and a post-graduate in Business Administration from The American University, Washington DC, he is the Managing Director of HDFC since 1993; He is also Managing Director and Chief Executive Officer of

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HDFC Standard Life Insurance Corporation Ltd.; He has been a Consultant to the World Bank, Asian Development Bank, and other bilateral and multilateral agencies and has worked in several countries. He is a member of Governing Council of various management and educational institutions and government expert groups.

Ms. Rama Bijapurkar

She is a Bsc (Hons) and MBA from IIM –A and has worked for McKinsey, Lintas and has been the Deputy Managing Director of MARG and a founder Director of MODE Services. She has also been consulting Hindustan Lever and other Indian and Multinational Corporates. She is visiting Professor at IIM- A. and is on the Board of Infosys Technologies Ltd., CRISIL, Titan Industries and Godrej Consumer Products Ltd.

Mr. Jaithirth Rao

With a Masters Degree from the University of Chicago and IIM-Ahmedabad, he is the Chairman and CEO of MphasiS BFL Ltd. and is on the Board of Cadbury India Ltd., Mahindra Holidays & Resorts India Ltd., IDFC Asset Management Company Limited and Gabriel India Limited

Mr. S. Sridhar (Nominee of EXIM Bank)

He is an Executive Director of Export-Import Bank of India

Mr. Balaji Swaminathan (Nominee of ICICI Bank)

A Sr. Gen. Manager and Chief Financial Officer of ICICI Bank Ltd, he is also Director on the Board of ICICI Infotech Ltd., ICICI One-Source Ltd., Kalyani Forge Ltd., Orient Paper & Industries Ltd. and Unison Hotels Ltd.

Mr. V.K.Pandit (Nominee of IDBI)

He is a retired IAS Officer. Former Secretary to the Government of India. He is on the Board of Shree Maheshwar Hydel Power Corporation Ltd. , Induj Enertech Ltd. and Neyveli Lignite Corporation Ltd.

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C

OMPANY

’

S VISION

(Information as collected from Company Website)

WE BELIEVE

In people and their unlimited potential; in content and in focus on problem solving; in teams for effective performance, in the power of the intellect.

WE ENDEAVOUR

To select, train and coach people to obtain higher responsibilities; to nurture talent, and to build leaders for the corporations of tomorrow; to reward, celebrate and activate all intellectual business contributions.

WE DREAM

Of excellence in all endeavors; of mutual benefit and prosperity; of making the world a better place to live in.

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A

RVIND DENIM DIVISION

:

Arvind is a pioneer the manufacture of denim in India. Today with an installed capacity of over 110 million meters per annum, The Naroda plant accounts for 89% of the

company's total denim fabric capacity of 108 million metres. CEO of Arvind denim devision is Mr. Aamir Akhtar

There are many delightful features of Arvind denim: the position of 3rd largest producer

of denim in the world; and an export network of 70 countries worldwide. Prominent

products in this category include ring denim, indigo voiles, organic denim, bi-stretch denim and fair trade certified denim. This is apart from regular light, medium and heavy weight denims. They come in various shades of indigo, sulphur, yarn-dyeds, in 100% cotton and various blends.

Arvind is a leading producer of denim worldwide. Design, Innovations and Sustainability have been their core competency and have played a key role in their success in producing the highest quality of denim and being the market leaders.

They have a huge DNTG department that is Development and New technogy that is the hub of innovation for denims. The use of sophisticated ultramodern technology under the guidance of world-renowned designers has enabled Arvind to deliver many firsts in the international markets. The facilities of Arvind Denim are accredited with ISO 9001, ISO 14001, OEKOTEX 100, GOTS, Organic exchange standard, FLO for fair trade and Lycra Assured. As one of the largest denim producers in the world, Arvind caters to quality

markets of Europe, US, West Asia, the Far East and the Asia Pacific. Labs are certified by

NABL (ISO 17025 certification) The labs are accredited by Dupont, Levi Strauss.

All the products are designed and modeled on the basis of expert design inputs coming from our designers based out of India, Japan, Italy and the United States. All Arvind Denim products come with the hallmark of distinctiveness and quality.

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M

AJOR INTERNATIONAL BUYERS

:

(Information as given by HR manager) Major Buyers:  Levi Strauss  Gap  H&M  Miss Sixty Also:  Mango

 Abercrombie And Fitch

 Jack and Jones

 Pantagonia

 Calvin Klien

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 Esprit

 Diesel

A

RVIND

’

S

B

RANDS FOR

D

ENIMS

:

Own Brands  Excalibur

 Flying

Machine

The Flying Machine brand is the oldest homegrown denim brand for Arvind. In 2007, it was revived and re-launched in a different avatar with a new logo,

placement and philosophy. Since then it has witnessed tremendous growth. Now the company wants to take it to the top three level.  New Port

 Ruff & Tuff

Licensed Brands  Gant, U.S.A.

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 SansaBelt  Izod  Pier Cardin Paris  Arrow  Cherokee

 U.S. Polo Arvind launched US Polo in 2008. It’s a premium knits-led brand having polo sports as its core theme. They have now decided to move US Polo jeanswear to a jeans floor in large format stores. This will enable them to be present on the same platform as other premium denim manufacturers  Energie Energie was launched in India

during A/W 2010. It’s a Rs 27 crores business for Arvind. The brand is for people who have been wearing jeans but need something more innovative, premiumThey offer our jeans at Rs 2,499 and go up to Rs 7,999.

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 Tommy Hilfiger

 Nautica

 Lee

 Wrangler

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II. PPC DEPARTMENT

The production Planning and Control department is the pne that materializes the production flow and monitors it. The head of PPC department is Mr Ajay Dwivedi.

The main objective of the production planning department is to execute mass production.

Sometimes the buyer selects the designs that he wants to get mass produced from the fabric database of over 8000 design collection developed by the research and Development department of Arvind Mills known as the DNTG department. The specifications and

procedures for such designs are already listed in the database and now the work of the ppc is to efficiently carry out those procedures

Other times the customer sends samples and requires the mass production for it. In such cases , the DNTG department develops the procedures involved for production of that sample by reverse engineering.

Refer to DNTG department section of the document for more details.

The PPC department then allots the machinery and time required for fulfillment of each procedure accordingly. The lead time is also decided by PPC on the based of order size, machine availability, profits involved and the urgency as per the consumer.

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In case of orders of lower quantities, the PPC has to strategise the execution of the order and plan whether or not to accept it, since dyeing machines of slasher and rope dye have limitations as to the minimum amount of dyeing, for best results and avoidance of wastage The PPC department also plans separately for orders of export and domestic market as the demand vary from region to region. Arvind also has its own retail brands, like ruf and tuf jeans etc, but they are treated as buyers and not subsidiaries.

The bottle neck opration that determines the lead time for the production is the weaving procedure. The loom capacity depends on the following factors:

 Construction of fabric  Loom Speed

 Efficiency

The production planning team need to coherently work on deciding whether the capacity of the plant is enough to fulfill the order in the given lead time.

Usually the lead time for any particular order is 50 to 55 days, including all quality checks inspection etc.

The thumb rule for calculation of lead time:  Pre- spinning procedures: 3 days

 Spinning: 15-20 days

 Warping and dyeing- 3 days

 For every weaving cycle- 3 to 4 days(weaving cycles depend on the order qty and above mentioned factors)

 Usually for one order about 8 to 10 weaving cycles required

 Finishing processes- 1 day for each process, if not covered in the integrated finish processing machine

 Inspection 2 to 3 days

 Washing 2 to 3 days

C

OSTING

:

 Spinning : Rs 1.10/kg/count (avg. weight 650gram/mtr)

 Weaving : Rs 0.21 / pick

 Dyeing : Rs 4/mtr

 Finishing : Rs 0.04/mtr

 Coating : Rs 4/mtr

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 Labor wage : Rs 6000 to 8,500/month

 Inspection: Rs 0.65/mtr RAW material :

 Cotton

 100 kilo cotton = 88 kilo of yarn(for combed yarn) (75% yarn realisation)

 Loss : 1 % sizing, 2.3 to 2.5 % weaving,1% warping (total 4 to 4.5%)

The production planning process for denims in Arvind is done on excel. Though an attempt was made previously to employ an ERP system, the project failed causing major loss of capital because an ERP system does not work for such a huge company with such diversification in the process.

Process control is not possible as each order has a different requirement and hence a different set of processes to be executed. Moreover, the lead time and cost calculations, that are supposed to be taken care of by the ERP system, cannot take into account of all the possible factors at a plant as huge as Arvind denims

The ppc head, Mr Dwivedi and his team are the ones, to plan each and every step of the production process, and it is their responsibility to deliver high quality products at the promised time.

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III. PRODUCTION PROCESS:

Spinning

Ball Warping

Beam warping

Drawing in Looming Rope dyeing Rebeaming Sizing Slasher dyeing Finishing Inspection Packaging

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1. S

PINNING

D

EPARTMENT

:

Spinning is the process of conversion of fiber to yarn

Process flow of spinning department:

LAYOUT OF SPINNING DEPARTMENT:

Blow room (opening, cleaning &

blending)

Carding

Drawing

Spinning

(open

end

rotar)

Winding

BLEND O M ET SLEEVE ROOM FILTER ROOM CARDING DEPARTMENT DRAWFRAMES COTTON GODOWN AUT O CO RO S TO RA G E OFFICE AUTOCORO DEPARTMENT

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 The cotton fiber grows in the seedpod or boll, of the cotton plant. Each fiber is a single elongated cell that is flat, twisted, and ribbon like with a wide inner hollow (lumen).It is composed of about 90 percent cellulose and about 6 percent moisture; the remainder consists of natural impurities. The outer surface of the fiber is

covered with a protective wax like coating which gives the fiber a somewhat adhesive quality.

 Bale of about 165-170 kg comes into spinning mill

Types of cotton Arvind Mills use:

1. Pakistan Cotton

2. J34 SG

i. (It is a selection from non descriptive hirustum mixtures.

Re-selection from Bikaneri Narma. It is sown in the months of April/May and the crop is ready for picking by October/December.. J34RG and SG are grown in the states of Punjab, Haryana and Rajasthan and total production per annum is around 2.6 million bales of each of 170 Kg.)

3. Shankar-6 Gujarat cotton

i. It is sown in the month of June-July and is ready for picking in November and may extend upto February. It is cultivated in an area of 4.4 million Acres in the state of Gujarat.

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a. (Organic cotton is being produced in-house by arvind mills, and also being procured from fully organic certified farms, as some environment

conscious customers prefer to use it.

b. Arvind’s organic cotton contract farming project is located in the cotton growing belt district of Maharashtra; Akola. )

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Blow room:

Process flow of blow room:

a) BLENDING

Machine used : Blendomat machine by Truetzschler

Model no. : BDT 019/2300

Bale layout: Both sides (2 rows)

Number of bales: 50-60

Weight of bales: 110-167 kg

Mode of bale laying: Manual

Material in process: Cotton with seeds and impurities

bale opener or

cotton plucker

GBR cotton

opener

axi flow

cleaner

MPM

multiple mixer

ASTA particle

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Steps:

Cotton is passed from bales and then to apron. Apron moves cotton to blending apron. Blending apron has sharp spikes the raise cotton until part of it is knocked off by the roll. Some of the cotton stays on apron.

The cotton knocked back by roll and continues to blend until picked up again by apron. Another roll strips off cotton that was not knocked back by previous roll.

Cotton falls on conveyor belt and is carried to next process that is blending through an overhead duct.

Why it’s been done?-

It is necessary so as to obtain uniformity of fiber quality

b) OPENING

Machine used : GBR cotton opener- opens about 400 kg/hr

Steps:

 Lint cotton falls on apron and passes between feeder rolls to beater cylinder. The rapidly whirling beater blades take off small tufts of cotton, knock out trash, and loosen up the mass.

 The two screen rolls are made of screen material and air is sucked out of them by fan.

 This draws the cotton from beater and condenses it on the surface of the screen rolls from which it is taken and passed on by the small rolls.

 Air suction through cotton takes out dirt and trash. Conveyor belt passes cotton to another type of beater. From beater the cotton passes to a conveyor and is carried to picker.

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It is necessary in order to loosen hard lumps of fiber and disentangle them; cleaning is required to remove trash such as dirt, leaves, burrs, and any remaining seeds.

GBR- Here the cottons are fed for homogenous mixtures and for removing dirts.MPM-8 – it has got 8 chambers. Generally used for homogenous mixture of fibers like while harvesting some cotton are from matured plants and some re not. So that it will affect the fabric. So, after homogenous mixing all will be the same.

c) Axi-flow cleaner-

This is fitted with beaters .Cotton moves from GBR to axiflow by suction and impurities fall below in a bin under the gravitational pull.Objective of AFC is separation of heavy parts (impurities) from cotton.The opened up mass of fiber rotates around two cleaning rollers (beaters) with cylinder steel pins which beat the fiber material, allowing the coarse particles to be separated.The time (in hours) of the passage of material can be regulated The speed range of the beaters varies from 400-600 rpm

Machine make: Trutzschler (Germany) Model: 052-2502

Pressure: 50-75 bar

Major parts: Two metallic perforated cylinders and waste collector

d) MPM multiple mixer-

Fitted with eight beaters. This sucks cotton from axiflowand pumps to asta meanwhile sorting the cotton fibers.Generally used for homogenous mixture of fibers

Make: Trutzschler

Model: 10236

Motor speed: 1750 rpm

Opening rolls speed: 800-850 m/min

Number of chambers: 10

Output: 30-36%

Pressure: 350 bar

Major parts: This machine consists of material feed, reserve tank, reserve tank flaps, optical sensor delivery, rollers, and

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material suction funnel.

e) ASTA:

Objective of ASTA is Heavy trash separation from cotton. The air and material enters the separation tank in a stream via upper channel and hit baffle plates. Heavy particles are removed away from the lighter fibers by negative acceleration and the force of gravity. The lower channel generates an opulent air stream in the area of baffle plates, which guides the fibers to the outlet.

Make: Trutzschler (Germany)

Model: ASTA 800

Principle: principle of aerodynamics

f) DUSTEX:

Dust removal is not an easy operation since the dust particles are completely enclosed in the flocks & hence are back during suction. The suction units remove dust 64% dust.

Model: CVT-4 1600

No. of machines: 2

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Carding:

Number of machines: 14

Model: DK 803

Humidity: 56.5%

Temperature: 33.3 degree Celsius

Production: 80 kg/hr.

Card cleaning efficiency: 62-67%

CV%: 1.2-1.7

Front Delivery speed: 210-240 meters per minute

Pressure: 325 pas

Carding is the process of removing impurities from fibers and producing a carded sliver of parallelized and straightened fibers

 Before the raw stock can be made into yarn, the remaining impurities must be removed, the fibers must be disentangles, and they must be straightened.

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 The work is done by carding machine.

 The lap is passed through a beater section and drawn on rapidly revolving cylinder covered with very fine hooks or wire brushes slowly moves concentrically above this cylinder

As the cylinder rotates, the cotton is pulled by the cylinder through the small gap under the brushes; the teasing action removes the remaining trashes, disentangles the fibers , and arranges them in a relatively parallel manner in form of a thin web.

 This web is drawn through a funnel shaped device that molds it into a round rope like mass called card sliver.

 Card sliver produces carded yarns or carded cottons that are serviceable to produce denim fabrics.

After carding, the carded slivers go to the draw frame

At Arvind mills:

 No of carding machines: 14 machines

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Drawing

Drawing is the process where the fibres are blended, straightened and the number of fibres in the sliver increased in order to achieve the desired linear density in the spinning

process. The drawing process also improves the uniformity or evenness of the sliver. The number of drawing passages utilised depends on the spinning system used and the end products

In arvind mills, the sliver is drawn through the draw frame twice. Draw frame used : Padamatex

Total of 12 draw frames at the plant

1ST_{PASSAGE: parallel alignment of fibers, 6 slivers converted into one}

2nd_{PASSAGE: output of the second passage of draw frame goes into open end/rotar}

spinning

Roving

In preparation for ring spinning, the sliver needs to be condensed into a finer strand known as a roving before it can be spun into a yarn The roving frame draws out the sliver to a thickness of a few millimetres and inserts a small amount of twist to keep the fibres together. The drafted twisted strand is wound onto a bobbin which is then transported to the ring frame and used as the feed package for spinning yarn.

Roving does not take place at Arvind Mills, as open end spinning is used, not ring spinning

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Spinning:

 The plant at Naroda works entirely on open end spinning technology/rotar spinning and produces 5400 to 5500 tonnes of yarn a month with 5472 rotars being around on campus.

 The speed of the rotar roll varies from 80,000 rpm to 130,000 rpm.

 Machine installed :autocoro comb+spin technology

 Corolab- automated yarn monitoring system(automatic detection of defects by drop wire technology)

 The maximum count of yarn is 20

Open end spinning:

 Rotor Spinning is a more recent method of yarn formation compared to Ring Spinning.  This is a form of open-end spinning where twist is introduced into the yarn without the need for package rotation. Allowing higher twisting speeds with a relatively low power cost.

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 In rotor spinning a continuous supply of fibers is delivered from delivery rollers off a drafting system or from an opening unit.

 The fibres are sucked down a delivery tube and deposited in the groove of the rotor as a continuous ring of fibre. The fibre layer is stripped off the rotor groove and the resultant yarn wound onto a package.

 The twist in the yarn being determined by the ratio of the rotational speed of the rotor and the linear speed of the yarn.

 Sliver is fed into the machine and combed and individualized by the opening roller.  The fibres are then deposited into the rotor where air current and centrifugal force

deposits them along the groove of the rotor where they are evenly distributed.  The fibers are twisted together by the spinning action of the rotor, and the yarn is

continuously drawn from the center of the rotor. The resultant yarn is cleared of any defects and wound onto packages.

 The production rates of rotor spinning is 6-8 times higher than that of ring spinning and as the machines are fed directly by sliver and yarn is wound onto packages ready for use in fabric formation the yarn is a lot cheaper to produce.

 Rotor spun yarns are more even, somewhat weaker and have a harsher feel than ring spun yarns.

 Rotor spun yarns are mainly produced in the medium count (30 Ne, 20 tex) to coarse count (10 Ne, 60 tex) range.

 The yarn is wound on a big package of about 4 kg.

 The use of this system has two basic advantages. It is fed by sliver, not as with the ring frame by roving, and so eliminates the speed frame from the process line. It can also be modified to remove any remaining trash, thereby improving the yarn quality.

Ring Spinning

Open-end Spinning

Bobbin rotates constantly for insertion of twist Spool does not need to be rotated to insert twist Cannot handle spools of bigger size Much larger spools can be wound

Can spin finer yarns 3-5 times faster than ring spinning

Uniform and strong yarn Uniform but flexible yarn with better dye ability

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Yarns for varied applications Yarns for heavier fabrics such as denims, towels and poplins

Stronger 20% more twisted but 15-20% weaker as the yarn

is coarser

Suitable for all staple fibres Not suitable for man-made staple fibre spinning except rayon as the fibre finish clogs the rotor

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2. W

ARPING

D

EPARTMENT

Warping is transferring many yarns from creel of single-end package forming

parallel sheet of yarn wound on to be a beam or section beam. Warping machines can

process all type of materials including coarse and fine filament and staple yarns, monofilament, textured and smooth yarns, silk and other synthetic yarn such as glass. A warp beam that is installed on weaving machine is known as weaver beam. A weaver beam contain thousand of ends, but in denim production a beam obtain from warping is known as section beam because denim is made from dyed yarn that’s why first section beam can be obtained and then these section beam are combined on the stage dyeing and sizing to get required number of ends for weaving process. In denim production initially the yarns are first dyed and then weaving process is carried out .

There are two method of yarn dyeing in denim production

 Rope dyeing.

 Slasher dyeing.

Warping method used for both method of dyeing are different. The process used for rope dyeing is known as “BALL WARPING” and for slasher dyeing “BEAM WARPING” method is used.

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BALL WARPING SYSTEM:-

 In this system of warping the yarns are wound on a large cylindrical roll in the form of twist less rope.

 The balls are used for dyeing of denim fabrics.

 This rope is wound onto a long cylinder called a log on a machine developed specifically for this purpose (the ball wrapper).

 Packager of warp yarn brought into the warping area one or two days prior to warping and allowed to condition to the ambient temperature and humidity of the area. They warp much easier if allowed to pre-condition in this manner.

 All of the packages are then loaded into a creel.

 The packages are placed onto adapters which are located on steel support pins throughout the creel.

 These adapters support the packages of yarn and insured that the package is remains aligned to the tensioning devices.

 The next step involves threading the tensioners.

 After dyeing process the roll ends are separated and wound another warp beam usually the leasing comb and a collecting reed is used to achieve tangle free lease section.

 The warp beam, so produced is then combined on sizing for applying the size past and making the weaver beam.

 In Arvind Mills, Ball warping involves creeling multiple ends of yarns (normally 350 to 500) and collecting them into a untwisted rope for dyeing.

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MACHINE SPECIFICATION OF BENNINGER’S WARPING MACHINE

Model AGCH 9240.

Max. Creel Capacity 640. (V-Creel used).

Min. Crel Capacity 334.

Speed 20m/min to 1200m/min.

Tensioner Type Electronic.

Pressure 200daN to 600daN.

I. Pressure set on the basis of fines and coarseness of the yarn count, i.e. more coarse

more pressure is required to make the compact warping beam.

II. In warping process humidity factor plays an important role because if humidity is

less than 80% then yarn breakage is more. For obtaining the required humidity humidification duct are installed.

III. To maintain the tension steel rods are used. Tension value is giving according to the

yarn count.

IV. Electronic sensors are used to sense the yarn breakages. WARPING MACHINE:-

Warping machine comprises on two parts,

1. Creel Section

2. Head Stock Section s

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In direct warping, yarn are withdrawn from the single end yarn packages on the creel and directly wound on a beam.

PASSAGE OF DIRECT WARPING M/C

Direct warping is used in two ways

a. ) Direct Warping can be used to directly produced the weavers beam in a single operation. This is especially suitable for strong yarn that do not require sizing. And when the number of warp end are relatively small.

b.) Direct Warping is used to make smaller intermediate beam called warpers

beam. The smaller beam are combined letter at the slashing stage (in the case of denim production they will combine at the stage of dyeing and sizing range) to produce weaver beam. This process is called beaming. For example if

weaver beam contain 9000 ends then there would we say 9 warper beams of 1000 ends. If this weaver beam were to be made at one stage, the creel

capacity must have 9000 yarn packages, which is hardly possible to manage and accommodate. In the production of denim option “b” is applied.

Warping Beam Drum Zig-Zag Guide Tensioner Stop motion Guide Creel

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Manufacturer

Sucker Muller Hakoba

Designation

NZB D1000 Sensowarp

Working width

1600

Suitable for processing the

following yarn

A11

Speed range

30 to 1000 mpm

Running speed

475 mpm

Braking mechanism

Electromagnetic brake

Tension range

8 to 50 cn

Measuring roller device

No

Pressing roller force

600 N/m

Pressure

6.0 bar

Comb

Zig zag (+ve)

Control

Electrical

Measuring instrument

Beam pressure

Indicator,tachometer,warp length

presetter

Beam drive

Spindle Driven

Beam doffing

Mechanical

Possible Beam Flange

Diameter

1000 mm

Size of Creel

700 Special feature of creel

Motorized creel cutting

Type of thread Tensioner

Pneumatic

Type of warp stop motion on creel

Electrical

Pitch

270mm

Other standard equipment of

warping

Length indicator



Warp tension checking



Movable wind screen

Maximum weight of yarn on beam

30-32 kgs

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3. D

YEING

D

EPARTMENT

:

There are 2 types of dyeing techniques used at Arvind Mills:  Slasher dyeing

 Rope dyeing

CAPACITY:

Total Capacity 110 million meters per annum Slasher Capacity 70 million meters per annum

Rope Capacity 40 million meters per annum

Dyes used:

 Indigo blue- china

 Sulphur dye- Black, Brown, Green

slasher

dyeing

beam warping combination of warp beams to form sheat dyeing and sizing

rope dyeing

ball warping dyeing rebeaming sizing

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Dyeing Technique:

1. Pure Indigo(light, Medium, Dark) 2. Pure Sulphur(black)

3. IBST- indigo bottom sulphur top 4. SBIT- Sulphur bottom Indigo top 5. Pigment dyes- rarely

The difference between slasher dyeing and rope dying is:

Rope dyeing Slasher dyeing

 Warp yarn are in the form of a

rope  Warp yarns are in the form of a beam

 Can only handle dying capacity of more than 11000 m.

 Short slots not possible

 Can handle dying capacity of more than 5000 m

 Short slots possible

 Good depth of shade and lower

washdown  Shade of depth not that good

 No center to Selvedge shade

variation  Center to selvedge shade variation may occur

 Rebeaming is required after process hence more time consuming

 Rebeaming is not required.

 More expensive machine as it is

huge  Less expensive machine

 It can only be done for coarse yarns, as the tension of the rope breaks the yarn

 Can be done for fine yarns too

 Oxidation time is much greater  The immersion and oxidation times are lower

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SLASHER DYEING (SUCKER MULLER)

Total no of slasher machines at Arvind Mills: & slashers

Ends combined: 575 ends, total of 25000 m Comines 12 warp beams into 1

In order to achieve fairly deep shades, the indigo is applied in a series of 6 dips(After each dip, darker shade is obtained, green oxidises to blue

 A slasher is a range is normally employed to apply size formulations onto warp yarns before weaving.

 This range when used for slasher dyeing of indigo, consists of section beams of warp yarn, which are forced into a sheet of yarn. 1 beam is 2500mts in length.

 12 beams layers are put together in a sheet.  Each beam has 575 ends.

Creel zone

Pretwet zone

Wasing zone(50 degrees. 22m/min)

Indigo Dyeing

Washing

Pre- drying

sizing

Post drying

Compensator

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 This yarn sheet is then fed into a scouring and washing section where natural impurities are removed.

 Temperature of C is maintained and the sheet of yarns is under water for 4-5

seconds. The next section is where indigo is applied. In order to achieve fairly deep shades, the indigo is applied in a series of 6 dips(After each dip, darker shade is obtained) and sky applications to allow for shade build up. There is continuous color feed in the dye bath. The dye application is followed by afterwashing normal water at 0 C and drying. With some machinery arrangement, warp size for weaving is immediately applied. or sizing the temperature of 90 C is maintained in starch solution.

 After starching post drying is carried out(5-7 % moisture) and thereafter there comes the leasing zone, where there is separation of layers which were pressed together. Here the number of beams in the leasing zone is equal to the number of layer pressed together, i.e. 12 beams. The next section is the headstock, here rolls on beams are prepared for weaving.

Slasher Dye Range

Slasher dyeing ranges have a number of advantages and unique characteristics. Slasher dyeing employs a sheet of yarn, which is wound directly onto a warp beam rather than ropes of yarn, which then requires additional handling. This type of dyeing works well with lightweight denims. In general, these machines require less floor space, enable smaller production runs, have a quicker turn over time, and are more flexible in their response to changes in the market. As an overall process these ranges have lower machinery cost; therefore, lower dye costs are realized for specific fabric types.

The chemicals used in the dyeing and sizing range are as under:

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Chemical Name Description Brand

Mercerol QWLF Mercerizing agent Clarient

Indigo Dye stuff china

Hyrdo Reducer for indigo BASF

Caustic soda 50% liquid For general purpose Local

Premasol NF Anti Foaming Agent BASF

Setamol BL Dispersing Agent BASF

Sodium Sulfide Reducer for Sulfur Black China

Sulfur Black BR-200% Dye stuff Arvind

Formic acid for pH control Local

Hydrogen peroxide for oxidation Local

(For sizing)

Chemical Name Description Brand

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Size-O-Bond Sizing Softener FFD

Wax Sizing wax Local

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ROPE DYEING

Morrison Rope dyeing range is installed at Arvind, Naroda.

In this method a warp beams first converts into rope beamers and then transfer to the 50 Rope Dyeing machine for the further process.

Rope-dye ranges enable to produce pure indigo, sulfur bottom, sulfur top, and colored denim yarn. The yarn goes through scour/sulfur dye, wash boxes, indigo dye vats, over a skying device (to allow oxidation to occur), through additional wash boxes, over drying cans and then is coiled into tubs which are transferred to the Long Chain Beaming process. There are 14 tanks in this machine starting form Mercerization till Lubrication. The speed range of this machine is 030m/min with the production capacity of 2 sets in same time, hence the production per day become 36000x2=72000m at the speed of 25m/min. Normally the count range in Ne use in rope dyeing is (16s6/s) OE and Slub both. The detailed description regarding each box will be presented on 25m/min to set a standard calculation.

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a) Creel Section:-

In this section 50 balls are setup at creels with generally 400 to 430 ends. Creels setup is as follows

a) The first section is known as setup section but after that it comes the machine layout portion i.e. there are 19 Boxes through which Rope passes for various parts as follows:-

Box

No:- Process Name Activity Temperature

1. Scoring Process ( Washing) If found Impurities of Yarns removed.

70._C

2,3,4. Pre-Dye washing Process Before Dyeing washing of Ropes. 50._C

5,6. Shading Process Shading taken care as per

requirement. N.A

7 to

14. Dyeing Process Indigo Tank do dyeing process for about 8 times i.e. Ropes enters and exit 8 times from this tank. N.A

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15 to

18. Post-Dyeing Process After Dyeing process this boxes gives a wash to Ropes to remove unnecessary dyes from surface of Ropes with the help of detergent.

Effluent Treatment Plants*

19. Softener Process At this stage dryness of Ropes taken care with the help of softeners. Opening of Ropes is done after Process.

N.A

* Effluent Treatment Plants is helpful in making a solid form of Indigo waste and make (pH) level neutralize

b)

Dry cans and Coilers: -

In this drying process is carried out through Cylinders and Coilers are used to make Quality arrangements and to make 400 to 430 ends separate from individual Ropes.

c)

Re-beaming department

Here they re-open the rope and winds it on beams so that they can be sized on next step. They have 6 Re-Beaming machines with the comb capacity of 410 ends. And there daily production is ~50,000m.

Re-beaming department

The Impact of this Process is that Dyeing Process is done with the possible nearest accuracy and efficiency but it involves more cost than Sucker Muller in respect of Machinery, Workers Skills and Working Environment. It gives 5 times more Production than Sucker Muller. Here Quality is more focused in terms of Purity issues of Indigo. It gives

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better penetration of Indigo on Ropes (Yarns) as Dyeing is done 8 times. It has a capacity of setting 40,000 meters at a time.

Indigo extracts from plants that are naturals and there are synthetic dyes. We must know that Indigo is Insoluble element and to make it applied on the Ropes (Yarns) Caustic is added to the Indigo to make it soluble. Still this is not enough this just a formation of Soluble but to apply on surface of Ropes it requires a pathway, which is given by Hydro, and it makes the (pH) in its acidic media so that Indigo is directly applied to the Ropes (Yarns).

The basic difference between Warp Dyeing and Rope Dyeing is that in Warp Dyeing- Dyeing and Sizing Process goes together whereas in Rope Dyeing the focus is mostly on Dyeing Process and then after the Ropes is filled into cans and then Ropes are opened as a Warp and thereafter Sizing part is done.

The lists of chemical use in dyeing are:

Chemical Name Description Company

Mercerol QWLF Mercerizing Agent Clarient

ALkapol ASD Wetting Agent Alka

TradersCausic soda

50% Liquid Caustic soda BASF

Premasol NF Anti Foaming Agent BASF

Setamol BL Dispersing Agent BASF

Indigo

China Dye Stuff

Sodium Hydro Sulfide Reducer for indigo BASF

Sulfur Black BR-200% Dye Stuff China

Sodium Sulfide Reducer for S.Black China

Formic Acid for pH control Tufail

Hydrogen peroxide for Oxidation Local

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Alkasoft 5200 Paste Softener

Traders Alka

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4. S

IZING

D

EPARTMENT

There are complete automatic computerized sizing machines (Benninger). Here they can load 2 sets at a time. In this machine, 2 sizing boxes having capacity of 400x2 lit in which warp sheet passes through in such a way that 6beams(half sheet) pass through 1st_{size box} and other half sheet pass through 2nd_{size box and then they combine together for weave} able beams. The avg. maximum workable speed is 4560m/min. the avg. production of this dept. per day is ~50,000m. Following chemicals we are currently using in Sizing are:

Chemical Name Description Company

Texo-Film Maiz Starch Starch Rafhan

Arca Base Acrylic Binder FFD Brothers Size-O-Bond Sizing Softener FFD Brothers

Checking and monitoring the sizing process

Programming the machine:-

The easy to follow visualization and recipe management, in which all the machine and textile parameters are stored, permit fast and simple programming.

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Sizing monitoring:-

The sizing process is automatically monitored. All setpoints are specified with upper and lower tolerance limits. Deviations from the programmed value are displayed at once and instructions for their rectification are explained in the language of the operator.

Controlled tensions:-

The special arrangement of rollers in the 3- roller set prevents threads from slipping through and keeps the thread tension constant in the dry split section when changing beams.

Reproducible size cooking:-

The SIZEMIX cooker, equipped with a high powered agitator ensures homogeneous liquor. The cooker is programmed via the size recipe at the machine PC. In this way, cooking temperature, water quantity and cooking time are preset and automatically maintained. Attendance takes place optionally from the PC or directly at the cooker.

Proposed numbers of ends/inch in size box:-

The table describes the numbers of ends/inch of ring spun an open end yarn in size box according to count.

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Maximum ends/inch in Size box

Yarn count Ring Spun Open End

10 35 31 20 50 45 25 56 50 30 62 56 35 66 60 40 71 64 50 80 72

Viscosity of size paste:-

Viscosity of size pate should not deviate from required value. Less viscose paste makes adhesion of size material well but coating on the surface of the yarn is not done properly. While paste with higher viscosity coats the yarn very well but adhesion of paste into the core of yarn in terms of increasing its strength is not done properly.

Size box temperature control:-

The degree of size penetration and coating depends not only on the nature of yarn & the size solution but also upon the viscosity which in turn largely depends on the temperature. It should be about 200F°-206F°. Fluctuation should be ±3 F°. The temperature gauge should be installed on the size box. Perforated copper pipe lining is laid in the bottom of size box to supply the steam for keeping the paste warm up to the above mentioned

temperature. Low temperature will make gelling of paste which will not penetrate through the yarn and higher temperature create thinning of the size paste which is also unsuitable to be used as sticky paste. So to maintain the temperature of above value is very important. If the size paste is prepared with rich PVA or CMC then temperature of 75C° to 80C° is sufficient.

Moisture content in the yarn:-

The moisture content in the sized yarn should not go below 6%. Otherwise the coating of size film will not allow absorbing moisture in the loom shed which is necessary for good working. For this moisture monitor is being supplied with the machine. The temperature of the drying cylinders should be kept 140-150 to maintain 6-7% moisture in the yarn.

5. WEAVING

Weaving is the interlacing of warp filling yarns perpendicular to each other at 90 degree. These are practically an endless number of ways of interlacing warp and filling yarn.

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WEAVING MACHINES (LOOM)

The waving machines are named after their filling insertion system. Schematics of the filling insertion systems that are used in the market are:

I. Shuttle II. Projectile III. Rigid rapier IV. Flexible rapier

V. Air jet VI. Water jet

Based on the filling insertion system, the weaving machine can be classified as shuttle and shuttle less weaving machines. Shuttle looms have been used for centuries to make woven fabrics.

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This system is most improved form of weft insertion. In this system, the mechanism and machine parts have been totally eliminated used to drive the weft insertion source. This facilitate to increase the insertion rate up to 2500 p.p.m this type of machine is firstly commercialized by Swedish engineer Max Paabo in 1951. weft thread is propelled using compressed air. It is simple operation with reduced mechanical parts and hence the maintanence cost is very low.

The working principles of air jet weaving machines are based on carrying the yarn by the friction of the air jet. During the yarn’s forward movement by the air in the sheds, the velocity of the weft yarn decreases because of the decreasing pressure and the disturbance on the air flow direction [. The air jet must provide a constant speed to the weft yarn along the weaving wideness. However, weft yarn of a certain mass is carried by a single jet at a limited distance. That is why the relay nozzles are installed at certain distances, in order to prevent a decrease in yarn velocity. The relay nozzle system and the general characteristics of the weft yarn speed in the shed. These are implemented on a movable hollow-needle or slay system. The basic function of the main jet is to load the weft yarn into the shed, and then to carry it to the first relay nozzle at a certain speed. The weft yarn suddenly reaches high velocity by means of the main jet. To preserve weaving defects and asynchronous beat-up movement, the weft yarn position and the instant velocity of the weft yarn must be fully controlled during the weaving process.

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Advantages of Air-Jet Weaving Machine

 High productivity

 High filling insertion system

 Reduced hazard because of few moving parts  Low noise and vibration

 Low spare parts requirements

 To increase the production of loom by increasing the speed and by increasing the width of loom

 Machines are versatile and roust to produces light to heavy value added fabric  Almost all loom motions are being controlled electronically

 These looms can be operated up to 40 looms per operated  Fully auto matic lubrication system

 Produce 100% export quality goods

LOOM MOTIONS

There are three types of loom motions which are given below;

IV. Primary Loom Motions a. Shedding

b. picking c. beating

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e. let-off motion V. Secondary Motion

 Warp stop motion  Weft stop motion  Warp protector motion  Weft replenishing motion

VI. Auxiliary Motion

 Terry motion  Selvedge motion  Weft petering motion  Temples

 Brake

Weaving Department

(Arvind Mill)

After passing through different processes such as Spinning, Warping, Dyeing and Sizing this is a stage where Raw Fabric is processed and then finally it goes to Finishing Department.

Now this stage is processed through Zax a loom set which is basically a model of Machines. These Machines works with a speed of 700 to 750 Rotations per Minute (RPM). There are 203 Machines out of which 159 are Zax Machines and 44 (209i) Machines. There are 13 meters per Roll as per customer’s requirements and after

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making a Raw Fabric, it generally goes for detecting the defects. Generally, yarn is produced from cotton, filaments, lycra, Polylycra.

Warp Beamers first installed to the Air jet loom set, which is Technology from Japan (Tsudakoma) and then after a weft is entered into nozzles through air pressure.

Warp is seen vertically on these machines and weft is horizontal to it. Weft enters through censors and passes the full lobby of warp and the dents of warp are set before starting the machine. Dents are defined as gap between two ends. The larger the dents the lesser will be the gap between two ends.

Generally, one machine produces 500 meters of Raw Fabric daily depends on picks. In addition, to produce in such a hassle environment you need to have 75 to 80 % of humidity required in every textile mills and due to this 10% contraction of fabric takes place in weaving department. There is inflow of cool atmospheric air from above

floor and outflow of air ventilation is given at underground level. There is air blower attached on the above of such machines to remove unwanted fibers on machines, which is continuously rotating for cleaning purpose.

After one beam is over there is a need for knotting to have a continuous production for Raw Fabric and for that, this department is having a Knotting machine to join the next beam. There are indicators on each machine for the Terminologies such as

T- Total Breakages W- Warp Damages F- Weft Breakages

L- Leno and other Breakages.

This indicators help operators in make out damages that occurs due to Dyeing and Sizing and sometimes due to weft also. Weft is procured from outside suppliers, so if there are more damages or breakages of weft then suppliers are to be aware and they will have to give more focus on these breakages.

Due to hassle, working environment workers are given Earplugs and Masks due to humidity level. There are 100 workers in a shift and total there are 3 shifts and

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approximately 300 workers work in this department. Recycles wastewater and converts denim waste to denim paper, in keeping with their eco friendly production process.

MAJOR DEFECTS :

 Band pick  Double end  Starting mark  Weft cut

The defect acceptance percentage at Arvind is 2.4 and efficiency is 85-87%, efficiency being measured in terms of number of picks to be inserted vis-à-vis actual number of picks inserted.

6. PROCESSING

/FINISHING

Finishing of grey denim fabric normally carried out after weaving. It takes an important role infabric properties, appearance, softness and residual fabric shrinkage.

The department churns out 300000 meters of finished denim cloth a day.

The main purposes of applying various finishes may be summarised as under.

1. HIGH SALES APPEAL: To impart properties of attractive appearance, supple handle,

softness and good drape.

2. HIGH WEAR QUALITY: This refers to adequate tensile and abrasion strengths,

dimensional stability, crease recovery and freedom from pilling.

3. BODY PROTECTION AND COMFORT: This relates to proper heat insulation,

moisture absorption and air permeability.

4. SPECIAL EFFECTS: These include water-repellency, reduced flammability, mildew

and moth-proofing, anti-static behaviour and soil release property

.

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Considering the existence of a large number and a great variety of the finishes for the cellulosic fibres, it is understandable that a completely satisfactory classification is not possible to make. The finishes are often sub-divided as physical and chemical, permanent and temporary, deposition and reactive etc. Sometimes the finishes are classified according to the effects obtained like appearance, wearing qualities, weighting etc. To complicate the matter further, the final folding and packing of the materials is sometimes included in the list. However the following description, though not perfect, is fairly rational and does justice to the topic.

Physical /Mechanical Finishes:-

(a) TEMPORARY / NON PERMANENT

(i) Calendering: Swizzing, Friction, Chasing, Schreiner, Embossing and Felt (ii) Beetling

(b) DURABLE

(i) Raising, Sueding, (Emerising or Peach Finish) (ii) Shrinkage Control Finishes

Chemical Finishes:-

(a) TEMPORARY / NON PERMANENT

(i) For Handle and Appearance: Softening, Stiffening, Weighting, Lustering (other than Mercerising)

(ii) Special Effects: Water-Repellency, Flame-Retardancy, Mildew Proofing

(b) PERMANENT

(i) Crease Recovery, Softening

(ii) Water-Repellency, Flame-Retardancy, Mildew-Proofing

Integrated Finishing Range for Denim

Arvind Mill, Naroda boasts of 2 integrated finishing ranges. In integrated denim finishing range, the singeing and shrinking is carried out in a single range. This reduces the process time, material handling, cost of production and labour cost.

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Process sequence

The processes of a typical Integrated denim finishing range includes the following stages:

Brushing: In the integrated finishing range, the grey denim fabric is first passed through a

brushing and suction unit, where loose lint, fluff are removed from the fabric surface. The protruding fibers adhere on the fabric surface are also raised to burned in the next process

Singeing: The denim fabric is then passes through a singing unit. Here the fabric is singed

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Menzel Denim Singeing Machine

Technical Data

 Machine speed : 10 to 100 Mts/ Min.

 Fabric width : 600 to 3200 mm.

 Drive : Ac invertor.

Chemical Padding: The denim fabric is then padded to apply finish to the fabric. Here the

fabric passes into a full immersion pad and finish is added at high wet pick up. The finish is necessary to properly lubricate fabric for the subsequent skewing operation.

Desizing (Dhall):

Continuous desizing ranges are suitable for eliminating the size material from denim fabric with the help of rapid enzymes in the impregnator tank. It is then developed in the steamer for suitable time. It is then subjected to intensive washing, and followed by cylinder drier. The inlet is into -scray . The staem temperature is 100 2 C, pressure of 1. 0. bar, while the wash oxes have normal water with temperature of 3 C.

Skewing: After chemical padding, the fabric is stretched by passing through two pulling

devices and then passes through a skewing unit, where it is skewed. Now, skewing being an important issue shall be dealt with more details. Skewness in twill Fabric :

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

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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.

Ideally warp and weft should be at right angle to each other in normal fabric. Skew in the fabric occurs when the warp are displaced from their vertical position or when the weft are displaced from their horizontal position.

Woven fabric skewness

The degree of skew movement depends upon yarn characteristics, weaving tensions, and the fabric structures.

Pre-drying: The fabric is then passes through drying cylinders for partial drying of the

fabric. Here 75-85% moisture are removed. The steam cylinders drive moisture in to the core of the yarns and reducing itto the 15-17% which is required for optimal sanforizing

Compressive Shrinking: Subsequently, the denim fabric passes through a compressive

shrinking unit where the denim fabric is pre-shrunk according to the grey potential shrinkage of the fabric, so that the residual shrinkage should be under tolerance limit. 100% cotton denim may require about 14% moisture for effective pre shrinkage. Moisture should be uniform thorough outthe length, width, and depth of fabric for effective

shrinking.

The compressive shrinkage unit consists of a heated and polished stainless steel cylinder, Tension Roller, Pressure Roller and guide rollers. Both the tension roller and the pressure can be adjusted as per requirement. A rubber belt cooling device is fitted with a water spraying arrangement on both faces of the rubber belt. Rubber belt unit is equipped with belt grinding roller and a suction device for dust removal from the belt grinding device.

Palmer Cylinder:

After the compressive shrinkage unit, the fabric is passes through a palmer unit, where the fabric is dried and iron. The functions of the palmer cylinder is:

• To dry the denim fabric to a level of about 4% relative humidity and set shrinkage, • Adjust the shrinkage,

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• It helps in precise adjustment of fabric shrinkage. It pulls the fabric and precisely control tension

on the fabric.

• It gives a pressing and calendaring effect on the preshrunk fabric

Cooling Unit

At the exit of the palmer there is a cooling can. The unit consists of one, two or three stainless steel jacketed cylinders equipped with chilled water circulation to cool the hot fabric as it comes out of the Palmer unit.

Delivery unit

The delivery unit consists of big batching arrangement and a plaiting device. A stainless steel scray can be equipped for continuous operation.

2012 Textile Internship Report - arvind denim devision

NATIONAL INSTITUTE OF FASHION

TECHNOLOGY