GUL AHMED TEXTILES no.8 internship report (sfdac)

ACKNOWLEDGEME NT

We proudly present our report which is based on PRETREATMENT. For this report we are extremely thankful to the talented people that worked and helped us in sorting out

our

circulated

questionnaires

and

confusion

throughout the internship especially we would like to thanks Mr. SALIM-U-DIN the manager of PRE-TREATMENT department,

MR.RIZWAN

and

many

other

skillful

personalities and worker whose co-operating was very beneficial & studious for us

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.

College of textile n polymer engineering (SFDAC)

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12 BATCH (2006-10) GROUP STUDENTS ∞ SHAHBAZ KHAN

([email protected])

∞

([email protected])

SAHAB IMTIAZ

∞ M.SHARIQ ∞

([email protected])

WAQAS MAQSOOD ([email protected]) Dated: 21 august 2009

TABLE OF CONTENTS

OBJECTS

PAGE

NOs.

COMPANY INTRODUCTION PROCESS FLOW BATCHER MACHINE SINGEING & DESIZING SCOURING & BLEACHING MERCERIZATION

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TESTING LAB

INTRODUCTION The group began trading in textiles in the early 1900’s. With all it’s knowhow and experience .Gul Ahmed Textile Mills Ltd. was incorporated as a private limited company, in the year 1953. In 1972 it was subsequently listed on the Karachi Stock Exchange. Since then the company has been making rapid progress and is one of the best composite textile houses in the world. The mill is presently composite on 8 units in Karachi with an installed capacity of approximately 130,296 spindles, 223 wide width air jet looms, and a state of the art wet processing and finishing unit. Gul Ahmed’s fine textile products represent a unique fusion of the century old traditions of the east and the latest textile technology of the west. The purest of cotton fibers, produced from the fertile lands of the Indus Valley, are spun, woven and processed into the finest quality cotton and blended products through a combination of latest technology, skills and craftsmanship of this traditional industry.

. In recongnition of Gul Ahmed commitment towards the safety of their processes and products,Gul Ahmed textiles have been awarded Oeko-tex Certification. The management system of Gul Ahmed Textile Mills Ltd. has been assigned and certified as meeting the requirements of SA (social accountability) 8000:2001”.

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In this report we have emphasize on a couple of factors, the highlights are process flow, plant design and lay out, process parameters etc,

PROCESS FLOW PLANNING PRODUCTION PROGRAM

GREY ISSUEANCE

Batching (inspection)

TO DYEING office & where ever req.

PRE TREATMENT

FOR DYEING

FOR PRINTING

-- SINGEING

-- SINGEING

-- DESIZING

-- DESIZING

-- SCOURING

-- SCOURING

-- BLEACHING

-- BLEACHING

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-- EQUALIZING

-- EQUALIZING

-- MERCIRIZING

-- MERCERIZE

IF REQUIRED -- EQUALIZE

After 100% inspecting the material, the fabric is graded as per according to number of defects, then goes for mending or rejected while the selected material is transformed into a batch type of package with the help of batcher machine.

BATCHER MACHINE Batcher machine is used to made batch of the fabric. The fabric is rolled on a iron roll which is fixed on a `A` frame arrangement. It is made for easiness in carriage while processing and for accumulating a large length of fabric at one package without spoiling fabric.

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WORKING OF BATCHER MACHINE: IT is a very simple process. The pile of fabric is placed before the machine .The pile is threaded on the tension rods and through the guide roll it enters into the scray where it is lifted upward with the help of compensate roll where it further goes into the tension rods and from the tension rods it passes through the expander roll . Here the fabric is expanded along width wise . Then after expander roll pendulum arm is introduce, it is an important part of the machine the running of the fabric is maintain smooth as well as the width of the fabric is maintain by the automatically moving its arm let suppose if the fabric falls on the right side of the pendulum arm it will move towards left side so that the width remains the same. After this component again the two expander rollers with pendulum arm is further introduce to the fabric, and after that the fabric is wound on the A shape frame to form our required batch with the help of winding arm. Now the batch is ready to face the next and important process, which is singeing process.

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The first most important process in the pre-treatment operation is the singeing .Normally the singeing and the desizing is carried out at same instant.

SINGEING & DESIZING Singeing is the removal of protruding fiber-end at the surface of the cloth in order to improve their surface appearance and sharp surface for printing. If not done, this will disturb the appearance of dyed and printed fabric. Normally the singeing process is carried out by two methods which are, using hot plate or using flame. The important parameters in singeing are: • • • • •

Singeing position Flame intensity Fabric speed Distance between fabric and burner Moisture in the fabric coming for singeing

If any of the above parameters are not optimal, the result may be faulty singeing.

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In GUL-AHMED TEXTILEMILL there are four singeing machine which are; 1. MENZEL 1(old singeing) 2. MENZEL 2 3. GOLLER SINGEING MACHINE 4. OSTHOF-SENGE In all these machines flame is used to remove protruding fibers without scorching the fabric. In the old singeing machine which is MENZEL 1.contains a simple burner, while MENZEL2 which is latest machine contain an adjustable burner which can be set according to the desire width After singeing the fabric immediately fed into chemical box for achieving desizing objectives (its dipped immediately after singeing to avoid fire risk).

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MAIN COMPONENTS OF MACHINES 1. Tension rods 2. Guide or Measuring rollers 3. Brush rollers 4. Singeing box 5. Chemical tank or Desize box

FUNCTION OF THE COMPONENTS 1. Tension rod : The function of tension rods is to give tension to the fabric and to avoid crease formation.

2. Guide Roll : Fabric is then passed over the guide rollers for feeding the fabric in to the brush rollers. In this roller the meter counter is also working for counting the length which is continuously feeding from the batch.

3. Brush Rollers: Before singeing the fabric is brushed tolosen and raise the fiber ends and moved rapidly normally about 100m/min.

4. Singeing box : After brush roller the fabric is moved over arrow of gas burner to burn protruding fibres.The flame is preferred over hot plate because flame penetrate in to pores of the fabric. The flame can be set in to the following conditions; 1. Burner can be set as it touches the tip of the protruding fibers. 2. Flame touches the cloths directly without deteorating the fabric. For avoiding the burning of fabric or protecting fabric from the yellowish shade the flame is composed of 70% of air and 30% of gas. For achieving 10

the accurate results it is suggested that the flame color should be of light blue.

5. Chemical tank for desizing : After the completion of singeing the fabric immediately fed in to the chemical tank for removing the coating of fabric done from sized paste to prevent the breaking of warp yarn during the process of weaving. In GUL AHMED the desizing is carried out using 2 processes which are oxalic and enzymatic .the oxalic is done when the blend is used and for cotton enzymatic desizing is done, also depending on the type of size paste used. Oxalic padd is basically not actual desizing it is DEMINERALIZING, to remove iron particles with in the the fabric, which will oxidize during bleaching and create pin holes in fabric, the PVA or CMC size material removes through boiling water simply. OXALIC PADD RECIPE : FOR COTTON, Oxalic acid Felosan RGN Bexion NE

10 g/l 5 g/l 4 g/l

FOR PC, . 2 g/l , 4 g/l , ----

(wetting agent )

Pad @ 90% pick up, Temp 60°C, PH 2-3, Batcher rotation time 4-6 hrs. Enzymatic desizing basically consist of 3 main phases, 1- Application of enzymes 2- Digestion of the starch 3- Removal of the digestion product The enzymes are only active with in a specific range of PH and temperature. PH must be maintained by suitable PH stabilizer. Chelating agents are used to sequester metal ions which may be injurious to the enzymes. Certain salts may be used to enhance the temperature stability of enzymes.

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After desizing the fabric is batched on roller. The rolling cloth is wrapped in a plastic sheet to avoid drying of fabric and rotate slowly for few hours (8 hour rotation time for ENZYMATIC DESIZING and 4-6 hour for OXALIC DESIZING). The batch is then placed on the next process which is the continuous process of scouring & bleaching.

SCOURING & BLEACHING SCOURING; The ultimate purpose of scouring is to make material highly and uniformly absorbent. (i-e the removal of natural impurities like wax, fats, oils). When oils and fats are heated with a solution of sodium or potassium hydroxide, they hydrolyzed into glycerol and the alkali salts of fatty acid, these salts of fatty acid are soaps therefore his particular hydrolysis is reffered to as soponification, temp OILS & FATS + NAOH

SOAPS

EMULSIFY WAXES Waxes are considerably more resistant to soponification than fats, they forms emulsion when shaken with water containing soap.

BLEACHING; Scouring removes almost all the impurities except natural coloring matters which are ultimately broke down with bleaching agents. Bleaching is necessary for producing white goods either as finished products or for dyeing pastel shades. An oxidizing bleach works by breaking the chemical bonds of a chromophore (part of a molecule that has color). This changes the molecule so that it either has no color or else reflects color outside the visible spectrum.

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SCOURING & BLEACHING on Goller MACHINE

Continue below

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The fabric is passed through the tension rods then the guide roller guide the coming fabric towards the washing tank for removing all previous auxiliaries and size paste from it. Then the fabric is dip in to the mechanism known as DIPSET-1 containing caustic soda, sequesting agent TGA, wetting agent RGN. In this the main objective of scouring is achieved and then the fabric is padded and passed through the adopter plate. The showering of chemical is done, then the doctor plate scrap the fabric. The fabric is then goes in to the Roller bed steamer, in which fabric is steamed for about 5-15minutes using temperature 99°c. The steaming machine is consist of 42 bed roll, that rotate very slowly and push the fabric forward until it comes to off point. The star roll is used to pull the fabric. It may be noted that the concentration of chemical and time of treatment for scouring depend upon the unit-weight and the degree of impurity of the fabric. The fabric is then goes to the washing range where it the scoure chemicals is washed off. There is two washing tanks where fabric is washed, then the fabric is dip in to the DIPSET-2 containing H2O2, sequesting agent & caustic soda. Then the fabric is pre heated and goes into the steamer for 5-20 min at 105°c.

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After steaming the bleach fabric is than goes to the washing range of goller scouring & bleaching machine. The washing range is consists of five washing tanks. The temperature of first four washing tanks is about 90°c and the last tank is also used for the neutralization of the fabric. The PH is maintained to about 6-8 After washing the fabric is squeezed by squeezing rollers. The fabric is then passed through the bow rollers for expanding the fabric along width wise. After bow roller the fabric is dried by drying cylinders. After that the fabric comes down in the scray compensator roller, after that the fabric is passed through a series of tension rods and bleached batch is produced by winding on A-FRAME by the wind-arm. Now the batch is ready for conducting next operation which is mercerizing.

J-BOX SCOURING & BLEACHING In J-box scouring and bleaching is done in rope form. J-BOX contains components such as saturating box, j-box, which are not found in goller

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machine. It is old and time taken operation and the material process in this machine is of local type.

PROCESS OCCURING ON J-BOX

The fabric from batch is passed through the washing machine and after washing it goes in to the saturator where the scouring chemical is applied on fabric. After saturator the fabric is stored in j-box. The time residual of the fabric is not constant but the approximate time for storing is 1-2 hour and is different for different material. After j-box the fabric is then washed in two washing tanks, than after scouring the fabric is then goes in to the saturator2 for bleaching purpose then the fabric is stored in J-BOX 2(1 hour for PC, 2hour for cotton). After that the fabric is washed in washing range and transferred in to the white pits chamber for storing in GUL AHMED.

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After that passed through DETWISTER to open twist and transforming the fabric from rope form to open width form, then passed through drying cylinders and batched on A-frame.

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MERCERIZATION It is an important operation of the cotton wet processing industry by virtue of its resultant effects. The effects of Mercerization are as follow. • • • • •

Increase in moisture absorption. Increase in luster. Increase in strength. Increase in dye uptake Increase in chemical reactivity of fibers

For Printing mercerization depends upon the type of print requirements if reactive print is required then mercerized process have to be done where as for pigment print mercerization is not required. In GUL AHMED There are three machines of mercerization the fabric passage is same in these machines but when Goller mercerize is compare with the Faisalabad mercerize it is found that result is more accurate in FAISALABAD mercerize as compare to Goller but material can be mercerize more as machine is longer as compare the FAISALABAD mercerize. The last mercerize machine, which is commonly used for local market, which is also the machine of Goller.

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FABRIC ROUTE IN MERCERIZING MACHINE

After bleaching the Ends/Picks of the fabric are disturbed and also fabric is shrinked upto 5-10%, therefore to regain fabric original width and Ends/Picks fabric is conditioned to be passed through the STENTER MACHINE, it`s also depends upon the material requirement. After prestenter the fabric batch is placed on a mercerizing machine.

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The fabric is passed through a number of guide and Bow rolls. After that the material is dipped in to the main section, which is a STRONG LYE containing chamber. The number of chambers in mercerizing machine is different and depends upon the manufacturer of the machine. In this chamber the material is continuously treated with caustic soda of about 2630°Be @ 60°c. The lye is showered in zigzag manner the fabric is rolled over a number of padder. Load cell are used to maintain tension to the coming fabric. If the material is subject able for reactive print mercerization is necessary, where as on the other hand for pigment print no mercerize material is required. After strong lye the fabric is passed through weak lye chamber. The temperature is increased upto 85°c and caustic concentration is decreased upto 7-8°Be, this gradually reduction in caustic concentration stabilize the mercerized material, then in the stabilizing section caustic concentration is decreased upto 4-3°Be through counter flow of water. The mercerized material is rinsed and washed and PH is maintained in a washing range.

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WASHING RANGE OF MERCERIZING MACHINE

The next stage after weak lye section is washing. In goller machine there are four chambers as compare to FAISLABAD MERCERIZE in GUL AHMED, as it contains only two washing chamber. The temperature of starting chamber is about 90-95°c and last washing chamber contain room temperature. In continuous washing range of GOLLER MACHINES, neutralization is also alone by using formic or acetic acid. After neutralization the wet fabric is wound on a batch with the help of tension and winding arm.

IMPORTANT FACTORS During operation there are numerous factor, which can effect mercerizing process. Some of them are listed below; 1.Crease on the fabric can be formed this can be recovered by changing position of guider.

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2.Black spots or caustic spots can be produce on the fabric due to air lock occur in the padder. 3.If proper neutralization objective is not achieved there is a chance of acid remains in the fabric, which will result in degradation of fabric.

TESTING LAB Lab is an important part of any industry because lab gives direction for the production processes. The lab in GUL AHMED textile is also playing a vital role in maintaining the production efficient and as per customer requirement. It works on these criteria by collecting all the important information through a series of tests performed at set stages. The flow chart ot lab is shown below, TESTING LAB

APPLIED

FABRIC TESTING SECTION

RAW MATERIAL TESTING

SERVICE

GREY

IN PROCESS

FINISH

The during production testing is come under the In process section, a series of tests are performed after bleaching, which are shown in a flow chart wise manner.

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Process

TESTS

1- GREY STAGE

Warp count, Weft count Ends/picks , size % ,Fabric width , Gsm Blend Ratio.

2- PRETREATMENT

PH , Absorbency test , Tegawa Whiteness , Pilling Test , Fabric width

3- EQUALIZE

Bowing , Skew %

4- DYEING & PRINTING

Fabric width , weight/square meter warp / weft shrinkage % , Pilling Tear strength , Tensile strength Flammability test , Appearance Crocking (wet / dry) , Light fastness Perspiration to Acid , Alkaline.

5- FOLDING.

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CONCLUSION & RECOMENDATION Throughout our four weeks training in GUL AHMED textile, we learnt so many practical things about the pretreatment process. We study function and importance of pretreatment department and its procedure to do the production. We perceived about this organization that, it has a strong departmental structure and this is playing a vital role in the organization success. The pretreatment department can add up its efforts in the betterment of organization by reducing errors on consistent basis, as improvement is not a one day process it’s a slow day by day process. As now a days there is energy crisis in Pakistan also, the energy is costly, therefore department should strive for less wastage of energy by any means, as like gas mixture of Menzel 1 and 2 singeing machine in not appropriate. Steam and water leakages should be avoided in supply lines. The heavy mercury and Discharge lamps should be off when unnecessary maximum advantage of day light should be taken. Drying cylinders of goller bleaching can be isolated from the surroundings, as now more energy is used because of transferring of heat into the surroundings. The department should also go for preventive maintenance as when machinery started abnormal noise or jerk before it broke down. The attitude of the worker of department is well and proactive towards work especially MR.Manager, He frequently rounds the department and sure that every things and every one is appropriate, but it was observed that some workes are not interested in the company training program. The organization should also start developing new process and technological break through for the betterment of the country textile industry and should provide a plate form for this purpose to the experts and the students as because the future of the country textile industry is very tough and competitive to survive. 24

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