internship at alok industries vapi

1. OBJECTIVES OF TEXTILE INTERNSHIP

The objective of the textile internship includes the coverage of the following given departments:-

Spun yarn production Grey fabric production (both woven and knits) Dyeing process Printing process Quality control and testing (testing procedures, quality parameters and various defects and their control)

Textile Internship at Alok Industries, Vapi, Gujarat

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Alok industries Company profile 2.1 INTRODUCTION Alok industries Ltd is one of India’s largest Vertically Integrated Textile Company. It is head quartered in Mumbai with its manufacturing units in Vapi,Silvassa & Navi Mumbai. The company is an end to end provider of Integrated textile solutions with five core divisions :- Cotton yarn, Apparel fabrics, Home textiles ,Garment and Polyestor yarns.

FIG:- ALOK INDUSTRIES PRODUCT WHEEL


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2.2 HISTORY & EVOLUTION Alok industries

was established in 1986 as a

private limited company, with it’s first polyester text rising plant being set up in 1989. It became a public limited company in 1993. Over the years, it has expanded into weaving, knitting, processing, home textiles and garments and to ensure quality and cost efficiencies they have integrated backward into cotton spinning and manufacturing partially oriented yarn through the continuous polymerization route. It also provides embroidered products through Grabal Alok Impex Ltd., their associate company which is the main reason for their evolution into a diversified manufacturer of world-class home textiles, garments, apparel fabrics and polyester yarns, selling directly to manufacturers, exporters, importers, retailers and to some of the world’s top brands. Alok has recently entered the domestic retail segment through a wholly owned subsidiary, Alok Retail India Limited , with a chain of stores named ‘H&A’ that offer garments

and home textiles at attractive price points.

2.3 VISION OF THE ORGANIZATION “To be the world's best- integrated textile solutions enterprise with leadership position across products and markets, exceeding customer & stakeholder expectation”.

2.4 MISSION OF THE ORGANIZATION


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The company aims at achieving the following objectives: ⊕

Offer innovative, customized and value added services to customers.

⊕

Actively explore potential markets & products.

⊕

Optimize use of all resources

⊕

Maximize people development initiatives

⊕

Become a process driven organization

⊕

Be a knowledge leader and an innovator in the businesses

⊕

Exceed compliances and global quality standards

⊕

Be an ethical, transparent and responsible global organization

2.5 REMARKABLE MILESTONES


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YEAR 1986

MILESTONE Incorporation of the Company

1993

Becomes a public limited company with a Rs. 4.5 crore IPO

2003

Export Trading House status granted

2006

Texprocil silver trophy awarded for second highest export in manufacturer exporter – made ups category

2007

ISO 9001:2000 certification obtained Gold Trophy for best export performance to ‘Focus LAC’ countries awarded by Synthetic & Rayon Textile Export Promotion Council Awarded Silver trophy for highest fabric exports and Bronze trophy for highest made ups export

2008

Awards from TEXPROCIL for 2007-2008

Gold Trophy for highest exports of bleached/yarn dyed/ printed fabrics.

Silver Trophy for highest export of made ups Bronze Trophy for highest global exports


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4. PROCESS FLOWS 4.1 PROCESS FLOW AT NARROW WIDTH PLANT(WOVEN, KNITS , YARN)

Buyer’s requirement: - Requirements and specifications required are sent

Prod. Development and Lab dip: - development of swatches of the shade sent by the buyer samples are developed as per spec. and sent for buyer’s approval.

Buyer comments- The buyer approval or comments for some changes. If some changes are asked for then the samples are re-developed and sent again

Pre-Production sampling: - The Product development department develops nearly 100 –200 pieces in the approved shade. Out of these adequate pieces are sent to the buyer.

Buyer’s approval: - The buyer’s approval of the piece which meets his standards and this sample serves as the standard towel for reference between the buyer and the manufacturer.

Purchase order: - The buyer sends the bulk order in the form of purchase order.

Sales order: - The sales order is prepared and given to the PPC department of the plant through the plant merchandiser

Production Planning: - As per the sales order the PPC makes the production plan along with the material requirement plan.


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Material procurement:- A purchase order is generated for the required dye ,chemicals and other required raw materials to the suppliers

Processing order:- Production order is given to the preparatory and dyeing departments.

Processing: - Processing and finishing takes place as per the processing plan.

Folding and inspection:- inspection takes place of the processed good which then packaged

Final Q.A: The final Q.A takes places before packaging and dispatch to assure quality of goods

Shipment :- The goods are dispatched.


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4.2 PROCESS FLOW AT TERRY TOWELS PROCESSING PLANT

Buyer’s requirement: - At first the buyer sends his requirement for towel according to feel, look and absorbency. He also specifies the towel design and dimensions.

Prod. Development and Lab dip: - development of swatches of the shade sent by the buyer samples are developed as per spec. and sent for buyer’s approval.

Buyer comments- The buyer approval or comments for some changes. If some changes are asked for then the samples are re-developed and sent again

Pre-Production sampling: - The Product development department develops nearly 100 –200 pieces in the approved shade. Out of these adequate pieces are sent to the buyer.

Buyer’s approval: - The buyer’s approval of the piece which meets his standards and this sample serves as the standard towel for reference between the buyer and the manufacturer.

Purchase order: - The buyer sends the bulk order in the form of purchase order.

Sales order: - The sales order is prepared and given to the PPC department of the plant through the plant merchandiser

Production Planning: - As per the sales order the PPC makes the production plan along with the material requirement plan.

Material procurement:- A purchase order is generated for the required dye ,chemicals and other required raw materials to the suppliers


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Processing order:- Production order is given to the preparatory and weaving departments.

Processing: - Weaving and finishing takes place as per the processing plan.

Cut & Sew and Packaging:- Stitching and packaging takes plan as per the cut & sew plan.

Folding and inspection:- inspection takes place of the processed good which then packaged

Final Q.A: The final Q.A takes places before packaging and dispatch to assure quality of goods

Shipment :- The goods are dispatched.


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PART II Weaving

(Terry

weaving)


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1. WEAVING (TERRY WEAVING) 1.1 Introduction The weaving department forms the core of fabric production in a textile industry. In this department our study concerns about the weaving of terry towels i.e. uncut pile weaving. The weaving department has following sub departments in it:

•

Textile design department

•

Weaving preparatory department

•

Weaving department

•

Grey folding department


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1.2 PROCESS FLOW FOR TERRY WEAVING

YARN

DYED YARN

GREY YARN

SECTIONAL WARPING

DIRECT WARPING

WAXING/SIZING

SIZING

WEAVING

GREY

PROCESSSING

MADE UPS


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1.3 TEXTILE / WEAVING DESIGN DEPARTMENT The objective of this department is to prepare a pattern for the weaving process to

‟ achieve the desired effect and look on the fabric as per the buyer s specification. The department receives the specifications from the marketing dept after which sampling is done and samples are sent for approval, approved designs then go further for production. The department performs the following works:1. Designing of the product 2. Analysis & feasibility of product 3. Preparation of bill of materials required for preparing the product The various Qualities or types of towels developed are:•

Piece dyed towels(grey towels)

•

Yarn dyed towels

•

Yarn dyed and grey velour towels(cut pile)

•

Yarn dyed and grey partial velour towels(partial cut pile)

Cad software’s used for weave design developments are:•

Textronics design dobby for development of dobby designs

•

Net graphics texcelle for developing jacquard designs


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1.4 LAYOUT OF THE TOWEL The basic structure of towel is divided into these main parts: 1. Plain: - A tightly woven strip mainly a twill /any compact weave. 2. Hem: - A Strip woven for the purpose of folding and stitching the hem 3. Terry bar: - A terry bar is a short width terry weave dividing the hem and the border. 4. Border: - A strip woven for the purpose of providing aesthetic appeal and may be woven as per buyer specification. 5. Body: - The body contains the main terry part that consists of pile loops all over. 6. Selvedge:- selvedge is the right and left borders of the towel which are generally woven in leno weaves

PLAIN HEM TERRY BAR BORDER

BODY

BORDER TERRY BAR HEM PLAIN


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1.5 WEAVING PREPARATORY DEPARTMENT In the weaving preparatory mainly warping and sizing is done for the purpose assistance in the the weaving process. The yarn requirements are determined as per the design and then warping is done first

1.5.1 PROCESS FLOW OF WEAVING DEPARTMENT

WARPING PLAN

SIZING

DESIGNING

WARPING

TRANSPORT WEAVERS BEAM TO WEAVING DEPT

1.5.2 WARPING There are

2 warping machines of which there is a direct warping machine from

benninger with a creel capacity of 640 creels and another sectional warping machine from Prashant gamatex with a creel capacity of 680 creels. Before warping plan is made following things have to be considered: •

Cone length

•

Beam capacity

•

Required length


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1.5.2.1 DIRECT WARPING The cones are placed on the creels and the ends are passed through two pre stationary rods out of which one is stationary and one is movable. These rods are responsible to give proper tension to the yarns. There is also an auto ply tension unit with light indicator to control tension during running and stops the machine The yarns are passed through a zig-zag yarn guide(dents) to the gear-controlled cylindrical beam which continuously rotates and prepares the warping beam. There is also a display at the front of the operator which indicates the breakage cone row and column number.

Fig :-Benninger direct warping m/c

Presser roller which is in contact with the warp beam ensures uniformity in formation of the warp beam and in cylindrical form. Singles yarns are preferred for direct warping, as they are to be sized in the successive process.


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Technical details of the machine Beam capacity

1250 kg (60000 m)

Warping speed

20 to 1200 m/min

Beam length

2400 cm

Creel capacity

640

Yarn tension

610 dN

Max count range

13s- 16s

These warpers beam from the direct warping machines are converted to weavers beam while sizing

1.5.2.2 SECTIONAL WARPING Sectional warping is done in some versatile intricate and majorly yarn dyed pieces where the consumption of different warp yarns is different depending on the design of the towel. The drum roller intermittently winds the yarns from creels and the beam automatically moves laterally to get a uniformly wound section beam as per the data fed according to the required design. This section warper’s beam is then waxed by a winding roller in a continuous manner which successively gets wound on to

the

weaver’s beam. Double yarns are preferable to be sectional warped. The leasing and section reeds are used to separate different coloured yarns and

determine number

of yarns in a dent respectively. Sectionally warped beams do not require sizing hence these are directly converted into weavers beam, then the warper’s beams are carried by the trolleys to the sizing department

Features

of

sectional

Fig:- Prashant Gamatex Sectional Warping warping machine(manufacture –Prashant Gamatex) •

Separate Warping & Beaming Structure.


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•

Optical device for precise Sectional width measurement & setting

•

Optical device for precise Sectional width measurement & setting

•

Constant beaming tension.

•

Constant warping and beaming speed.

1.5.3 SIZING The sizing process aims at providing extra strength to the warp yarns for withstanding tension and abrasion during weaving. There are 2 sizing machines of Benniger and west point. Sizes like Terry size are used which contain starch based or synthetic like polyvinyl alcohol or a water soluble acrylic polymer, depending on the fiber content of warp yarns.

1.5.3.1 Benninger sizing machine (Ben –sizetec)

Fig:- Benninger Sizing Machine The sizing section of the weaving department has 2 sizing machines with 12 creels for the warpers beam(zone1). The warped beams are put on the creels and all the warp ends are passed through various cylinders without any inter-yarn entanglement and messing up of yarns.They are passed into

a bath of a water base sizing

solution.The bath has a temperature of 90 oC which has two nip rollers and two dip rollers which guide the yarn for proper sizing through proper bathing.The yarns have a continuous movement through the solution as

they travel through the drying

cylinders which have a temperature of 140 oC, 130 oC, 125 oC, and 110 oC in the respective cylinders in the drying chambers (ZONE 2 AND 3). Leasing region is the dry region from where the yarns get separated by dividing rods to avoid yarn grouping


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which could create difficulties in weaving. Thus by the automatically monitored and controlled system, the yarns are wound on the weaver’s beam. These weavers’ beams are transferred to the looms. Technical details :Speed of sizing

90-100mts /min

Temperature in the bath

950c

Tension in input yarn

650 N

Tension in output yarn

1050N

No. of creels

12

No. of drying cylinders

12

Temperature

37 0 c

Relative humidity

68 %

Fig :- BEN-SIZETEC

1.5.3.2 WEST POINT SIZING MACHINE


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The west point sizing machine has the same operational process as that of Benninger sizing machine. The machine is used as an alternative to the Benninger sizing machine.

Fig: - WARPERS BEAM CREEL

Technical specification

Beam

⊕

Creel

Maximum No. of Beams

⊕

Section Beam

30 800 mm/1000 mm/1250 mm

Flange Diameter

Size

⊕

Box

No. of Boxes Sizing system

1 Single dip - Single nip or Double dip - Double nip

Dryer

⊕

No. of

up to 24 drying Cylinders. Predryer

Cylinders

in the multiples of 4 to 6, and final Dryer having 4/6 or 8 cylinders


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Beam Winder

⊕

Working width

1800 mm to 4000 mm

⊕

Beam flange

up to 1250 mm

diameter ⊕

Max. Yarn Speed

⊕

150 Meters per minute Both side motorised

Carriage Tension

Auto Control

Fig:- SIZING BATH


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1.6 WEAVING PLANT LAYOUT WEAVING DEPT.

EXIT

JACQUARD M/C JACQUARD M/C

JACQUARD M/C

DOBBY M/C E X I T

DOBBY M/C

DOBBY M/C

DOBBY M/C

E X I T

DOBBY M/C

DOBBY M/C

FUTURE EXPANSION

Textile Internship at Alok Industries, Gujarat PIPEVapi, BEAM TROLLEY-2

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1.6.1 INTRODUCTION After the sizing process of the pile and the ground beams, they are manually transported to the weaving looms. All the looms present in the weaving department are Toyota air jet looms. According to the production plan looms are allotted for specific towel weaving. The beams of the pile & ground are gaited on to the loom as specified in the loom plan and design plan. The design through floppy/ programmer is set on the looms. The loom process control parameters for the functioning of the beams are set, like the reed, the pick, the terry motion, let off, take up etc & weaving starts.

Pile beam Reed Tension rod Temple rod

Tension roller

Dobby shedding healds

Fabric roller

Ground beam

Fig : TERRY WEAVE MECHANISM WITH DOBBY


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1.6.2 WEAVING MACHINERY

1.6.2.1 TOYOTA AIR JET LOOMS SThere are 36 dobby looms out of which 18 machines are of 20 shafts and other 18 are of 16 shafts.. Technical specifications of Toyota air jet looms Working width available on the 340 cm loom Speed of the machine / Rpm of 450 machine Type of fabric produced Warp yarn counts usable on loom Weft yarns count usable on loom Weft insertion

100% cotton towels 2/20s 12s,14s,16s,20s,2/20s single electric drum,

Reed count in use Gsm of fabrics

exchange electric drum 60 “ ,56”,64” 400,500,450,600

possible

for

2, 4, 6-color

production Shedding:

negative cam, positive cam, crank,

Selvage type possible on loom

dobby, electric shedding, jacquard Left/right rotary full-leno selvage device.

There are 12 jacquard looms of which 6 are regular jacquard looms with jacquard attachments ( stabouli LX1602 ) and other 6 are jumbo jacquards with jacquard attachments (stabouli LX 3202) . The LX 1602 and LX 3202 electronic Jacquard machines are particularly suitable for weaving flat fabrics and terry cloth on all types of air jet looms, 2688 hooks are present in LX 1602 attachments

to while 8192

hooks are present in LX 3202.In regular jaquards the 3 hooks are controlled by a single knife while in a jumbo jacquard for every hook there’s a knife..These jacquards are

easily

adaptable and versatile in nature. These jacquards minimize threads

stress and Precise lifting mechanism with no vibration.


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Fig:- AIR-JET LOOM WITH JAQUARD

Fig:- LX 1602 Jacquard

Fig:- LX 3202 Jacquard

1.6.3 WEAVING MECHANISM Firstly the weavers beam is loaded into the loom. Then the yarns from the weavers beam are knotted to yarn ends left after the previous weaving process.


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Knotting process saves time required for drawing yarns one by one from heed frame and reed. It usually takes 20 to 25 minutes to load a weavers beam and get the loom started for repetition of old designs. Drawing in

Here 16/20 heald dobby attachments are used for terry towel designing. The pile threads are drawn on four healds, & the ground threads (if the loop formation is to be continuous) on eight healds. 2 healds are used for leno and 2 are used for selvedge. Drop pin Mechanism (stop motion)

There are drop pins for every single yarn. Yarn is passed through the whole provided in the drop pin. Each pin has a bar passing through it such that it does not touch the pin when yarn is in tension If yarn breakage occurs in any yarn, the pin drops and it touches the bar and a sensor is activated, which in turn stops the machine. The yarn is spliced manually. Shedding

Selected yarns are lifted according to different weave construction to create space for insertion of weft yarn by different mechanisms which form a basis of classification of loom.(jacquard/dobby).

Picking


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Air jet mechanism is used for picking mechanism.In the formation of the pile loops, the speed of the pile beam (let off) is more than the speed of the ground beam.During weaving of the borders of the towel, let off is same for both the beams. Beating up

The weft thread that has been inserted across the warp thread in a shed is pushed upon the fell of the cloth. This process is carried out by a reed which is a comb like structure through gaps of which warp yarns are passed. Two temples are provided at both the ends. They pull the fabric produced and keep a pre determined tension in warp yarns. They also assist in take up mechanism. Let Off

There is a sensor at the torsion roller which regulates the tension of the warp sheet and also send message to the sensor present in the let off roller so as to decide how much warp is required to be let off.It allows the warp yarns to move in forward direction by unwinding weavers beam maintaining a predetermined warp tension. Take Up

A motor is provided which winds the fabric produced in the loom. Once the cloth roller for winding of the towel is full the roll is doffed & sent to the Grey folding area.

1.6.4 ADDITIONAL ATTACHMENTS TO THE LOOM


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Some other important attachment are as follows : 1. Creel Stand - They are used to yarn cheeses for weft insertion. 2. Package Sensor -

This ensures no loose or miss

pick. 3. Pre Winder - It acts as temporary storage of yarn and

ensures uniform tension of yarn.

4. Weft Break Sensor - These are in contact with the

weft yarn and stop the machine in case of weft yarn breakage. Fig :- Weft creel 5. Auxiliary Nozzle - This nozzle has small openings for air jet inclined in forward

direction which give a forward motion to weft thread. Nozzle is not fixed and moves with the motion of thread. 6. Main Nozzle - It is fixed nozzle and the working is similar to that of auxiliary nozzle. 7. Relay Nozzle - These inclined nozzles are provided on the path of the weft yarn.

They provide an air jet which provides a uniform. motion to the weft yarn towards other end.

8. Feelers - There are 2 sensors provided on the right side of the loom. The function

of h1 feeler is to sense the miss pick or sort pick. Function of the filler is to sense the broken pick or wrong pick. If any of these two sensors are activated, machine stops. 9. Cutter - Two cutters are provided at either ends which cut the extra weft yarns.


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10. Tucker - It binds the remaining yarn into the selvedge. 11. Catch cord - It catches and holds the filling yarn.

1.6.5

TERRY WEAVE CONSTRUCTION

The Turkey towel structures form a class of warp pile-termed “terry” pile – in which certain warp threads form loops or curls on the face of the cloth.


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Only one kind of weft may be used, but 2 series of warp threads, placed on separate beams, are necessary for the production of the cloth- viz. ground threads & pile threads.

fig:- TERRY WEAVE CONSTRUCTION

The distinguishing feature of this class of pile is that the looped structure is produced by employing a special reed motion & warp easing arrangement which enables the loops to be formed on the upper or lower, or both upper& lower surface of the cloth,many different kinds of terry motions are used, but in every case the object is to cause two succeeding picks of wefts to be left a short distance from the fell of the cloth, & then to beat up these two picks along with the following pick.In weaving the cloth the ground warp beam is heavily tensioned, so that these threads are held tight all the time. The picks 1 & 2 are first woven into the proper sheds, but are not beaten fully up to the fell of the cloth by the slay at the time of insertion in their sheds; but when the pick no.3 is inserted, the parts are so operated that the three picks are driven together into the cloth at fell. During the beating up of the third pick the pile warp threads are either given in slack, or are placed under very slight tension. with the result that the slack pile warp threads are drawn forward thus forming two horizontal rows of loops of piles, one projecting from the upper & the other from the lower surface of the cloth.


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Fig:- Continuous Apparel width processing and yarn dyeing plants

PART III……

DYEING


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1. WOVEN APPAREL WIDTH DYEING (NARROW WIDTH PROCESSING)

FIG:- NARROW WIDTH PLANT

1.1 INTRODUCTION Dyeing /processing is the most delicate section of the textile industry. Several parameters are to kept in mind while performing operations. The processing unit in the beginning receives greige fabric from the either the silvassa plant or other external sources .this shipment of fabric is received by the greige department which performs the initial actions before fabric is ready for further processing. Fabrics processed here in all the machines are of an average width of 48 inches/160 cm.


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1.2 PROCESS FLOW FOR WOVEN PROCESSING

GREY FABRIC

PRE-TREATMENT RANGE

IF COTTON

MERCERIZATION

IF NOT COTTON

DYEING

FINISHING

PACKAGING AND INSPECTION


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1.3 GREY ROOM /GREIGE DEPT The main operations of the grey room include opening up of fabric rolls and combining them into A-frame batches for assisting continuous processing. These Aframe batches are used for the purpose of combining many fabric rolls of small meter age into one continuous roll of maximum capacity of 4500 kg. There are 5 greige opening machines of local brand (Topiwalla).these machines process the fabric from the rolls to A-frame at a speed of 150metres/minute.

1.3.1 PROCESS FLOW IN GREY ROOM

GREY ROLLS

GREY ROLL OPENING MACHINE

A- FRAME BATCH

CONTINOUS SINGEING AND DESIZING RANGE


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1.3.2 GRIEGE FABRIC OPENING The fabrics are sourced from the silvassa plant from where 95 % of the supply is received and the other 5% is from external sources. The product mix available and processed:-

Fabrics by weight:-Light, medium, heavy Fabrics by blend:- PolyCotton, Cotton Viscose, CottonLycra, Cotton Spandex Fabrics By weave:- Twill,Plain,sateen,satin, dobby, design(Jacquard) The fabrics are also avaible in grades of A, B, C, D which are already graded when received. 2000 Steel Racks have been provided for storage for upto 29 lakh fabric rolls. Fabric roll placement style for storage is of cross –layered type .Average length of fabric on a A-frame batch is 4500 mts Fbric Rolls are opened and converted into A-frame batches and sent for further processing of singeing and desizing.

1.3.3 SINGEING AND DESIZING Fig:- Gas Flame

Singeing is the process of surface hair.Singeing is done via gas flames which come in contact with fibers and burn them. The fabrics run in perpendicular

the direction

of

the

gas

flames for singeing. Fig: Gas burner Singeing and desizing are performed as a combined process in the grey department.

There

are

3

machines

operations

are

on

which

performed.

these All

machines are German (osthoff senge) manufactured(models:-VP99-H (2 m/c) &VP-

99(1

m/c).These

machines

have

Processing speeds in range of 60-120 mts/min.


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Light fabrics :- 120 mts/min Heavy fabrics- 60 mts/min

Chemicals used in desizing:Wetting agent :- assists increase in absorbency. Enzymes :- required for removal of sizes applied to fabrics.

Chelating agents :- restricts the reaction of any metal ion with any added chemicals. These machines can process up to 30,000 mts /day The machines have single gas flame chamber with 2 burners, 1 impregnating chamber for desizing chemical application, a steam box for assisting chemical activation for desizing ,3 extracta chambers for

washing off the chemicals and

delivery customers( steam rollers ) for machine meant for yarn dyed if the fabric is required in dry condition. The temperature for washing and steam box is 95 0. Two methods for desizing : •

Hydrolytic desizing: - in this after the chemical application through impregnation the batches are rotated at a uniform speed for 24 hrs for desizing agents activation and avoid leaching out of chemicals from the batch. To perform this type of desizing a single machine is available which only singes and impregnates the desizing chemicals

•

Enzymatic desizing: - In this the chemical activation is done by rotation in a steam chamber with a required dwelling time required for chemicals to activate. To perform this type of desizing 2 machines are available which have a steam box for this purpose.

Fig:-Singeing and Desizin

Hydrolytic) range


Page 37


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1.4.1 PRE-TREATMENT RANGE There are 3 continuous pre-treatment ranges available which perform the above said preparatory process in a continuously. Fabrics from greige department arrive here and are fed into the machine. It is a composite machine range where the fabric is desized, washed, bleached and dried before it is dyed.The entire process takes 25 – 30 minutes to complete. The process flow of the pre-treatment range is as follows: Feeding

. Fabric from the A-frame trolleys is fed into scray where through the feed roller whose speed can be controlled separately from the other rollers in the machine. The Scray acts like a storage device for the fabric roll as it enters the extracta chamber. This storage device temporarily holds the grey fabric such that rate of feeding the fabric can be controlled as well as it gives time for the operator to stitch the upcoming roll to the end of the present fabric without actually stopping the unit. Washing

The fabric is passed through the 3 washing chambers each with the Benninger Extracta technology. The main purpose of these washing chambers is to wash away the extra chemicals from the surface of the fabric. These chambers have the capacity of holding 180 litres of water respectively. The impure water is continuously flushed out and is replaced by fresh water such that the level of 180 litres is maintained in the chambers. The temperature maintained in the first chamber is 95 0 C and the following two is maintained at a temperature 800 C each. The fabric takes a total of 3 minutes to pass through these chambers spending 1 minute in each chamber. The fabric is then passed to the bleaching chamber. Bleaching

The fabric after passing through the washing chambers is passed on to the Injecta chamber.

Here,

the

bleaching

chemicals

like

H2O2,Wetting

agent,Stabilizer,Reserver(chelating agents),NaoH are impacted on the cloth woth


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high velocity. Sometimes even whitening agents are added to achieve extra whitness.Here, the bleaching is done through the peroxide method. The fabric is passed through this chamber and goes into the steam chamber which has the benbleach technology for assisting the bleaching process, at a temperature maintained at 95o C and 3 bars pressure. The pH of the solution maintained is 13 – 14. The fabric nearly stays nearly 15 minutes in this chamber before it is passed on the washing chambers, the chemicals are fed automatically into the chamber from the storage tank which is stationed beside the machines. Similarly, the water level is also maintained. These chemicals are supplied to the storage tanks from the colour kitchen Washing

From the bleaching chamber the fabric is then passes through 3 washing chambers which have Benninger Extracta technology.. The main purpose of the washing chambers is to remove the extra chemicals that accumulate on the surface of the fabric. The temperature maintained at the first washing is 95 oC and the remaining two maintained at 80o C each. The fabric spends approximately 2 minutes in each washing chambers. After this the fabric is passed to the neutralizing chamber. Neutralization

After passing through the washing chambers the fabric is passed on to the neutralizing chamber which is similar to that of the washing chamber with the only difference that this chamber is supplied with the neutralizing agent. The neutralizing agent is used to neutralize the excess peroxide and caustic soda present on the fabric surface which may hamper the dyeing process later. The fabric takes 2 minutes to pass through this chamber where the temperature maintained is 60 oc. After this the fabric is passed onto the delivery customer. Drying

The fabric is passed through a series of steam heated

delivery customer rollers.

These rollers rotate at a speed of 50 rpm. The rollers are present in two sections of 5 each in each vertical column. They are arranged in such a way that alternatively rollers rotates in clockwise direction and

anti-clockwise direction and the fabric

alternatively passes through these rollers and dried before it finally wound onto a A-


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frame roller. The fabric coming out of the pre-treatment range is termed as RFD ( Ready for Dyeing Fabric). The Average production rate is estimated to be 80-100 mt-min. There are different machines for light and medium weight fabrics, heavy weight fabrics and limp and stretchable fabrics, machine suitable for limp fabrics

has drums in its washers

instead of rollers for avoiding any type unnecessary expansion or width reduction.

Fig : PRE-TREATMENT RANGE


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1.4.2 MERCERIZATION

Fig:- MERCERIZER RANGE

Mercerization is a preparatory process mainly used for cellulosic fibres when lustre is important or light shades are to be dyed. Benninger mercerizer with equipped with the Ben-dimensa technology is used for the mercerization process. There are three mercerizers out of which 2 machines are based on the chain principle, while the third machine is of chainless principle exclusively used for heavy/bottom weight fabrics. The Average processing speed is 60-70 mts/min Chemicals used in the process for mercerization are: •

NaoH, Organic acid, Caustic soda.

Fig:-Impregnation Chamber


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Fig:-Impregnation and Dwelling zone

The fabric is fed into the machine via the feed rollers and the weft straighteners to the chains which lead to the impregnating chamber where the NaOH is sprinkled on the stretched fabric held by chains. The intensive impregnating zone is followed by the reaction zone. In the retention compartment of the DIMENSA the chainless principle with lifting top rolls is employed. At the start of the stabilizing zone that is immediately after the Mercerizing section there is a stenter section using the chain principle. Ultimate stabilization is done in a conventional, highly effective stabilizing compartment with chainless guidance. Stabilizer chemical is sprinkled for assisting in removal of NAOH. Fig:- Stabilizing zone

The final section comprises a high-efficiency washing and neutralizing zone consisting of EXTRACTA, or TRIKOFLEX compartments, where temp maintained is between 90-95 C and pH-5-6, organic acid is used

for neutralization.The

final

Mercerized fabric has a pH of 5 and can also be labelled as RFD.

Fig:- Washing and Neutralization


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Fig:- Washin g and Neutralization

1.5 DYEING After completion of the pre-treatment processes the batches are marked as RFD (Ready for Dyeing).The dying process is decided by the dye used, preferred fixation process and quality desired. The prominent dyes used for the dyeing are reactive, disperse and vat

1.5.1 PROCESS FLOW FOR DYEING


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PURE COTTON FABRIC :-

PRE-TREATED FABRIC (cotton )

Cold pad batch

Colour development

Pad dry padding

Continuous dyeing

Pad steaming for curing

Washin g

Dyed fabric

BLENDED POLYCOT DOUBLE BATH PROCESS

Pre-treated (Polycott fabric)

Disperse dyeing in CDR

Reactive dyeing in CDR

Reduction clearing on pad

Washing on washing /soaper Reduction clearing on pad Textile Internship at Alok Industries, Vapi, Gujarat

Page 45

BLENDED FABRICS POLYCOT SINGLE BATH PROCESS

Pre-treated (Polycott fabric)

Dyeing is single bath solution of reactive as well as disperse dyes on CDR

Dyed fabric

Washing

1.5.2 COLD PAD BATCH

Fig: - kuster’s dye pad


Page 46

The cold pad batch machines are used for applications of only reactive dyes. There are three cold pad batch machines from benninger known as kusters dye pad. The colour requirement of a fabric is directly dependent on the following:

The length of the fabric to be dyed The pick up of the fabric in percent The GLM of the fabric.(Gram per linear metre) Dyeing process

takes around 16 hrs for dyeing at

room temperature. It can produce a range of light, medium and dark colours. CPB has a vertical arrangement of rollers for dipping the fabric in dye solution. The count of rollers may vary from 1 to 4. The machine may operate in a range of 50-60 mts/min.

The

dye to chemical ratio may vary but

standard ratio used is of 4:1.

Fig:-single dip single nip

The various chemicals used in the dyeing trough are:-

Fixer chemicals - Sodium silicate and Rocoflo - anyone used for fixing. Reactive dyes . Soda and caustic After impregnation of the dyestuff the finishing rollers and squeezing unit squeeze out the unrequired dye solution. These batches then require fixation/curing dwell time for which the batches are kept under rotation(to avoid any leaching out of any dyestuff) in the RFD storage generally for 16 hrs.Each machine has 3 dye and 2 chemical tanks with each having a capacity of 800 lts. Approx production is 20,000-22,000 mts/shift.

Benefits of Cold pad batch :Uniform linear liquor application by two deflection-controlled rolls throughout the entire batch.

“n” number of reproducibility of all dyestuff and chemical applications.


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No side-to-center shading, due to smooth treatment of the selvedge’s

Fig : Dy e solution dosing

1.5.3 MONFORTS THERMOSOL Fig:- Monforts Thermosol


Page 48

The Monforts thermosol is a continuous dyeing range in which the pre-treated fabric is given as input and a completely dyed fabric is received at the output which is then sent for finishing. This is mainly used for the following types of dyes: Fig:- Monforts Thermosol Dyeing Range Disperse modified vat dye and reactive There are 2

monforts thermosol which have similar construction and only differ in the number of IR dryer Chamber which one machine has a single unit while the other has two, requirement of dryers depends upon the application required. The machines have a Thermex hot flue chamber which has 28 rollers in 3 chambers.

The temperature of the chambers are: Dye Vat Reactive disperse

Chamber1 110oc 110 oc 180 oc

Chamber2 110 oc 110 oc 203 oc

Chamber3 120 oc 120 oc 203 oc

The chemicals are put in the wetting chamber along with dyes which includes :

Binders Softner Glaubers Salt Acetic acid

Fig:- IR dryer


Page 49

The fabric is fed through the Feeding section which then passes into the section Wetting unit

where it is dipped in the akalis required for dye fixation

and

dye

solution are present as required. The fabric then passes on to air passage rollers that assist the penetration of dyes after which fabric pass into the IR dryer units where through heat of the IR burners partial or pre-drying is

performed where up to 40 %

of the moisture is removed. Temperature is maintained at 450 oC , the fabric then passes into the Thermex hot-flue where the measuring and control unit (chamber atmosphere) control the temperature and the Steam injection unit provides steam for heating the chamber. After the curing process the fabric is completely dyed and received at the Outlet section. The speed of the machine varies from 45-50 mts /min and generally runs at 25-30 mts /min at a average.

1.5.4 BENNINGER THERMOSOL

Fig:- Beginner thermosol

The Benninger thermosol is mainly used for vat , reactive and disperse

dyeing

process. The machine is mainly based on the working process principle of pad-dry pad steam method in which the dye impregnation and drying is done on the themosol


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while the pad steam/curing is performed on the Benninger pad-steam machine.The fabric is fed into the machine by various rollers /a scray. The fabric subsequently enters the dyestuff trough where it comes in contact with the dye solution, application method used is of single dip single nip. Then it passes through a intermediate air passage which assists in the dye penetration and then passing into the IR dryer unit for the purpose of pre drying which composes of 3 units and 3 burners heated at gradually increasing temperatures up to 450 oc. the pre drying process helps in removal of up to

40 % of the moisture. After pre-drying the fabric enters the therm

fix hotflue chamber in which the fabric is passed and dried at high temperature and high pressure, thus resulting in a completely dried fabric as the output. To constantly provide dyestuff solutions there are 5 storage tanks of which 4 are dye tanks and 1 is of chemical is of 4 with capacities ranging from 500-1500 lts. The dye: chemical ratio thus is maintained at 4:1 at an average.

1.5.5 BENNINGER PAD STEAM

Fig:- Benninger pad steam range

The pad steam machine lies in line with the thermosol machine for completion of the PDPS process(Pad dry Pad steam). The Benninger pad stream machine is basically used for the following purposes:-

Colour development Reduction clearing in case of blended fabric double bath dyeing.


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There are 3 Benninger pad steam machine’ s available for the above said objectives.Dyes which are processed in the pad steam machine are:-

Reactive dyes Vat dyes Chemicals used for reactive pad steam process are:-

Salt Soda ash Caustic Chemical for vat dye pad steam process is: - caustic hydro.

The fabric is fed through feed rollers

into the chemical trough where alkali for

fixation /chemicals for reduction clearing are applied on the fabric through single nip single dip method after which it passes into the booster chamber where the special squeeze nip of the booster guarantees a uniform pickup, independent from production speed and fabric weight. The fabric then moves into the recta chamber with rollers where steam treatment is given to the fabric at high temperature and high pressure.

Fig:- Reacta chamber

After which the fabric passes on to the extracta chambers. There are 9 extracta chambers that are used for the purpose of soaping, washing, neutralization and reduction clearing. In first two extracta chambers washing takes place at room temperature. In the following two chambers H2O2 for oxidation is added at 600C.In the next 3 chambers soaping and hotwash is done. In the concluding 2 washing chambers hot wash with neutralization is at 90-950c degrees. The delivery customer


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cylinders nip out any moisture in the fabric with steam heated cylinders and fabric is received in dried condition as output. The processing speed at an average is 50 mts/min. Fig:- Continuous Pad steam range

1.5.6 BENNINGER WASHER /SOAPER

The Benninger washer or soaper does the basic function of washing after the dyeing process in order to remove any unfixed dye on the fabric surface. There are two such machines which have in addition to them an Arioli flash ager which is a steamer used for two phase printing for a shortening

dwelling time for fixation of dyes in

printed fabrics. Printed fabric washing

Fabrics which are two phase printed using the vat dyestuff in a oxidized dyestuff without reducing chemicals and dried

are treated with a chemical bath

containing the reduction chemicals and alkali padded with face-side out using the kiss roll application technique and usually only the printed face is in contact with the fixation solution, after which, steaming and washing is done. Dekol+peroxide +acetic acid mixture is used for the soaping and washing of printed fabrics.

Textile Internship at Alok Industries, Fig:- flash Vapi, Ager Gujarat

Page 53

Recipe used in the flash ager:-

Glaubers salt Maize starch cooked. Invitier MR Soda ash Borex Caustic 48TW Hydro

Dyed fabric washing

The machine has in total 9 chambers in which 2 initial extracta chambers are for rinsing purposes and I chamber for application of the required chemicals during processing next 5 chambers are the washing setup which is used for washing after the dyeing . The soaping is done in two ways:

Cold Pad Batch Wash Cold Wash Cold Pad Batch wash – Dekol fbsn and acetic acid mixture is used for dyed fabrics from cold pad batch the fabric is first set for relaxation and passed through the heated chambers given as under The fabric is treated with water at 30 OC ,then treated with water at 40oC,then a soap solution of DECOL FBSN and acetic acid is applied at 60C,Normal washing with water at 90C takes place in the next 5 chambers ,Green acid of neutralizes the fabric at 80oc in the last neutralizing chamber


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COLD WASH – Cold wash is given to fabrics coming direct from the continuous dyeing range. The fabric is passed through the heated chambers given as under:

The fabric is treated with water at 30oC. It is then treated with water at 40 A soap solution of Arieanal +acetic acid is applied at 50C.Normal washing with water at 50C takes place following which green acid of 160 gpl neutralizes the fabric at 50 oc. The maximum speed of the machine goes up to 40 m/min.

The second washer has drums in its extracta chambers which are also known as Trikoflex; this makes it preferable for medium weight and light weight fabrics.

2. KNITS DYEING

2.1 INTRODUCTION Once the Marketing Department informs the PPC about the order given by the buyer, the PPC plans the amount of fabric to be made in the Silvassa’s Knitting unit before being sent to Vapi for processing.Buyers’ Specifications include the amount of the

fabric, the GSM etc. A specified percentage weight of fabric is processed in extra to meet consumption of fabric during the series of processes involved.

2.2 PROCESS FLOW FOR KNIT DYEING FABRIC KNITTING

GREIGE DEPT


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DYEING

FINISHING

INSPECTION

PACKAGING

2.3 GREIGE DEPARTMENT

There are 4 griege opening machine of Hsing cheng of which there are two machines each for open width and double folding . Double folding machines change the open width to tubular form for better dye pick up. Opened fabric are then received in plated form in a trolley.

Fig:- Hsing cheng open width fabric opener

The

mechanism

involving

tubular

conversion is a folding device for joining the two ends along the length of the fabric and the stitch the ends together with the help of a Kansai Sewing Machine . The machine is equipped with sensors to open the curved edges. The production capacities of these machines are 1500 kg/day whereas of open width grey opening machines it is


Page 56

2500 kg/day. After the grey opening, the fabric is sent to the dyeing department in trolleys.

Fig:- Hsing cheng Double folding machine

2.4

DYEING OF KNITS

Dyeing of knits is a delicate process for which rope dyeing in soft flow machines is preferred to avoid any unnecessary stretch that may occur during dyeing process. The dyeing is mainly of reactive and disperse type. There are 20 Sclavos Athena soft flow machines with capacities varying from 500-1500 kg the plant has a capacity of 850 tonnes per month.

2.4.1 DYEING PROCESS FLOW

GREY OPENING IF LYCRA HEAT SET

NO STRECH FIBER PRETREATMENT +

DYEING

FINISHING


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2.4.2 DYEING PROCESS Fabrics blended with stretchable fibres are heat set immediately after the opening of the fabrics rolls to set the yarns in the fabric and avoid any unnecessary stretch. Fig :- Sclavos Athena

Knit dyeing is basically carried out in batches. The dyeing in the soft flow machines begins with the RFD batch dozing into the machine through machine windows in rope form with one end tied along with a magnetic type piece so as to receive the tied knot after dyeing at the window after which water through the circulation pies is pumped and

a hot wash at 80 oC is given followed by a cold

wash. The pre treatment chemicals such as :- Wetting agent, NaOH provides assisting in impurity removal, H2O2- Hydrogen peroxide used as a bleaching agent are dozed from the addition tanks provided besides the machine

with the ph

maintained at 6.During all the dozing processes the fabric rope rotates on the tied reel in clockwise direction . After pre treatment the dyeing chemical dozing is done after chemicals from the storage tanks are mixed in the addition tanks at 60 oC for 15 mins, following colour, salt and soda dozing. After the required dwelling time an acid


Page 58

dozing is done following which soaping and rinsing along with a hot wash and cold wash. Softeners are also used during the soaping for finishing purpose if required. Temperature suitable for dyeing some fibres are as follows:-

Cotton :- 80oC – 850C Polyester: - 130 oC -135 oC. Dwell time required for various shades application: - Light :- 6-6.5 hrs, Medium –

7.0-7.5 hrs, Dark- 7.5-8.5 hrs, Extra dark:more than 8.5 hrs. Fig:- SOFT FLOW MACHINES

3. YARN DYEING

Yarn dyeing is a process of imparting color to a greige yarn. Thet yarn packages of greige yarn comes to Yarn Dyeing Department from the Spinning unit (Silvassa). These come in cheese forms having cardboard

package material at the core.the

range of yarns available range from 4s to 2/100s. There are two types of dyes used in the department. (a) Vat Dye (b) Reactive Dye

3.1 PROCESS FLOW FOR YARN DYEING

Winding

Pre-treatment

Dyeing


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finishing

Drying

Rewinding

3.2

WINDING

The first process in yarn dyeing is winding. Winding is required to transfer greige yarn from standard cardboard packages to soft packages. These

soft packages are

perforated in nature and are necessarily required for penetration of dye liquor into the package during the dyeing process.As the greige yarn cone package has nonuniform density thus to make the package of uniform density it is necessary to wind it. There are 5 SSM winding machines of which 3 of model TW 1-W with 50* 2 spindles and 3 of model PSW6 with 96 * 2 spindle. The diameter of the soft tube used is 74mm. The soft cones can be either be of plastic or of spring shaped steel tubes. A high speed winding is done from the greige packages to soft packages with Weight of the soft packaged yarn being constant at 1.15kgs.the finished width of the yarn packages range from 165mm-175mm. The dye package has the following requirements according to the different influences on the dyeing process: Density:

The regularity of the density within a package and from package to package has to be in a range of +/- 2.5 with regard to the capacity of the dyeing equipment the


Page 60

density should be as high as possible. This parameter is auto controlled on the machine. Shape:

Cylindrical packages are the preferrable for dyeing as cylindrical packages help optimum packing of the dyed vessel. Additionally the cylindrical packages have an even flow resistant which makes it much easier to achieve an even distributing of the dye stuff. Straight sides ensure an optimum sealing between the packages to avoid by-passing of the dyestuff.

Fig :- Requirements For soft cone winding

3.4

LOADING

Fig:- Rockwell Double girder crane


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After winding of soft packages, these are stacked/loaded on the package carriers which vary in capacity as per the machine in which they are used. These have perforated rods for circulating dyestuff and chemicals. The package carriers are then carried by a crane to its respective machine for dyeing purpose.

3.5

PRE-TREATMENT

Fig:- Fong’s yarn dyeing m/c

Yarn dyeing is done in batches. After placing the yarn carriers in the dyeing machines

of suitable capacity

the pre-treatment ,dyeing and finishing of the

yarns is performed together. In pre-treatment, scouring is done as the first step. Thereafter, yarn is put through a caustic soda bath followed by hydrogen peroxide and acetic acid treatment along with other chemicals. This process is carried out at 100°C. Machine capacity

Number of machine

25kgs

3

50kgs

2

54kgs

3

553kg

2

750kg

3

1070kg

3


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(sample dyeing) 6kg

3

3kg

3

1kg

3

3.6

DYEING PROCESS:

After the completion of the pre-treatment processes the chemicals are flushed out of the chamber and the packages are rinsed with water pumped in from the addition tank, simultaneously the chemicals and dyes required are prepared in the storage tank for dozing after rinsing. Then as per required sequence dozing of chemical and dyes are done with required dwell time. The dyeing can be of isothermal or migration type. Depending upon the intensity of the shade various temperatures and dwell time are as follows:-. Light shades - 60°C - 70°C for 40 - 60 mins. Medium shades - 80°C - 90°C for 60 – 80 mins. Dark shades like black - 80°C - 110°C for 80 – 90 mins. Chemicals used in dyeing are Glucose, Caustic soda, Sodium Hydrosulphite and Glauber’s salt. After the dyeing is finished then neutralization is done with an organic acid followed by soaping, hot wash and a cold wash.

3.6 FINISHING

Post dyeing the yarns are given finishing by the following chemicals :- Hydrogen peroxide, Pervalin RS, Acetic acid and Perfil 210.This process is carried out at 95°C.After finishing the packages are removed from the machines and dried in the hydro extractor and electro-magnetic dryers and then

rewinded on cardboard

packages from soft cone by SSM rewinding machines, after which the packages are ready for packaging dispatch. The total time taken for the whole process i.e. pretreatment, dyeing and finishing is 6 – 8 hrs, depending upon the intensity of the shades. •

4hrs - white shades,


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•

6 hrs - light shades

•

6 – 8 hrs for dark shades.

4. DYEING OF TOWELS. .

4.1 INTRODUCTION Dyeing of terry towels which has 100% cotton content reactive dyes are used because they are good colour fastness, eco-friendly, and also cheap.Rope dyeing is preferred mode of dyeing for towels as padding towels would tend to destroy their terry (pile).

4.2 PRE- TREATMENT Pretretment of towels is done in Benninger PTR range similar to that which was used

for woven pre-treatment. The towel PTR range differs in only an additional

reacta chamber meant for enzymatic desizing purpose. The following chemicals are used for pre-treatment purpose:•

Desizing agent

•

Wetting agent

•

Lubricating agent- reduce surface tension

•

Sequestering agent-reduce water hardness

•

H202


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4.3 DYEING Dyeing of towels is preferably done in a soft flow machine so as to avoid any destruction of piles/loops on the surface of the fabric. The rope dyeing technique is similar to that of knits. In rope

dyeing

the

towel

rope

is

run

in

predetermined number of cycles with a pre determined cycle time with max speeds upto 250 rpm. There are 7 theis soft flow dyeing machines with capacities ranging from 350 kg-1400 kg.The pre treated towels are dosed and then a rinsing is done after which dosing of dyeing chemicals is done. Liquor ratio(M:L) used IS 6:1

lt/kg. The

various Chemicals used for dyeing purpose are:•

Dyes:- Reactive dyes

•

Lubricants

•

Sequestrant

•

Levelling agent-

•

Salt

•

Soda ash-to maintain alkaline medium

•

Acetic acid

After the dyeing process soaping with dekol fbsn is done followed by neutralization by green acid and to give a soft feel softners of caustic and silicon base may be optionally added. The dwell time required for various colour shades are: •

Light :- 4 hrs

•

Medium :- 5 hrs

•

Dark:-6hrs


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•

Extra dark:- 8 hrs.

Machine capacity(kgs) 1400 1050 700 350 90

Number of machines 1 1 1 2 2


Page 66

5. Colour Kitchen Colour kitchen is an area where dye solution is prepared for bulk dyeing as per the recipe given from the laboratory. They have particular codes of various colour recipes. The proportion of chemical and dyes required for a particular is already fed into the computer. Whenever a batch card with the particular colour code comes to the colour kitchen that particular code number is fed into the computer and the respective proportions of dyes and chemicals is automatically taken. After this the prepared solution is passed to various tanks stationed beside the dyeing machines by means of pipes. There are different colour kitchens for the following departments: •

Woven processing

•

Knits and yarn processing

•

Printing

•

Towel dyeing


Page 67

PART IV..... PRINTING


Page 68

PRINTING OF WOVEN AND KNITS FABRIC Printing is the textile processing technique for localized application of dye/pigment is a

desired

pattern

/design.

The

styles

of

printing

are

carried

out are

reactive,discharge(white and colour),pigment. The printing section has its own design studio and colour kitchen for screen,dye/pigment solution development .

Printing Department

Design Studio

Colour Kitchen

Printing

1.1 DESIGN STUDIO The studio is responsible for the designing of the designs for screens which are required to be developed in accordance to the design specification provided by the buyer. There are 5 workstations which are equipped with Ramsete III version 8.33 for design development. Screen preparation department is the provided by the ready designs and its specification for the preparation of screen.


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ENGRAVING:

After receiving the design developed for screen, work in the screen preperation starts with the engraving. Nickel made Fine mesh ready screen of varying circumferences of 640mm,819mm and 914 mm are available .CST Inkjet printing unit is used for the purpose of engraving.Coating of the screens is done with the combination of three constituents namely, Photo emulsion (readymade liquor), Dichromate and Distilled water which is done as per the design The design development is done through the ink when the screen is exposed to uv-light ,coating hardens to retain itself and then washing in reggiani screen washing machine to wash off the undried ink, thus the inked part becomes the area of penetration for the colour pigment

in

the

rotary

screen.

Thereafter the coating on the screen is cured in the embee curing machine for 2 hrs at 100°C f. After which the screens are finally dried in the femate Climatizer

Fig:- ENGRAVED NICKEL SCREE

Fig:- CST SCREEN ENGRAVING MACHINE

DIGITAL PRINTING:


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The screen preparation department also houses Mimaki Textile Inkjet is the machine used for digital printing. Digital printing is done at a very small scale for only special purposes. Any type of fabric can be printed upon using this machine

Fig:- Mimaki Textile Inkjet printer

Appoximately 60 million colors can be printed using this machine. Ripmaster is the CAM used for controlling these machines operations.

1.2 AUTO KITCHEN Auto color kitchen is responsible for making the paste for printing by using various chemicals & dyes and regularly suppy the machines as required. The kitchen has 5 silo storages for urea(hygroscopic agent),sodium bicarbonate, Potassium carbonate used for reactive printing paste, Resist salt(oxidizing agent),soda ash. These silos supply to the automatic prepeartion unit(1000 lts) for paste preparation.

Key Ingredients for printing paste are :-

Binder: - 18% binder is used for dark shade. 6% binder is used for lighter shade. Luprimol (STG) - It act as softner which reduces hardness of the water and paste soft. Lutexgel(HIT) - It act as thickner to make viscous paste of the dye. Fixing agent(LF) -It act as fixer & rubbing fastness will increase.


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Rongolite (ST) -It act as reducing agent for white and color discharges. For 100 % cotton fabric sodium sulphoxylate is used , for blended fabrics Zinc Sulphoxylate is used. There is a roto mix machine for the colour preparation which is dosed by chemical by various dosing systems which prepare the colour paste in large open tubs which are transported to the machine for dosing the paste to the screens.

1.3 PRINTING:

The Textile printing practised at Alok is the rotary screen methods for which there are 3 Reggiani rotary printing machines, 1 Lakshmi rotary printing machine and a sample printing machine from Reggiani. In addition to this there are Two Aroli Loop Agers that are used for the purpose of curing.


Page 72

1.3.1 PROCESS FLOW FOR PRINTING

REACTIVE PRINTING

PRINTING

DRYING

STEAMING

SOAPER


FINISHING

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DISCHARGE PRINTING

PRINTING

DRYING

STEAMING

CURING

SOAPER FINISHING

PIGMENT PRINTING

PRINTING

DRYING

CURING

SOAPER

FINISHING

1.3.2 PREPARATION OF CLOTH FOR PRINTING

The wet preparatory processes are all carried out on the Benninger PTR where as for knits its done in the Sclavos soft flow machines. Apart from wet preparations the cloth is brushed & sheared on lafer shearing machine by being passed over rapidly revolving knives arranged spirally round an axle, which rapidly and effectually cuts off all filaments and knots, leaving the cloth perfectly smooth and clean and in a condition fit to receive impressions of the most delicate engraving. Some figured fabrics, especially those woven in checks, stripes and crossovers, require very careful stretching and straightening on a stenter frame, before they can be printed with certain formal styles of pattern which are intended in one way or another to correspond with the cloth pattern. Finally, the cloth is wound around a hollow wooden or iron centers into rolls of convenient size for mounting on the printing machines.

PRINTING MACHINERY

A rotary printing machine prints designs with enraved designs on a curved cylinder.. Substrate here is a continuous fabric roll which is to be printed and further modified if required (e.g. die cut, overprint varnished, embossed).


Page 74

The initial development of the samples is done using CAD in the studio using which the screens are developed after which the Reggiani sample printing machine is used for preparation of samples . The normal width of this machine is 70”. It can be extended up to 120’’

1.3.3.1 LAKSHMI ROTARY PRINTING MACHINE

For printing, rotary printing machines are used which is of an Indian brand – Lakshmi. Up to 12 colors design can be printed in this machine. The screens are mounted

on

the

screen

stations

provided ,for each color in the design a screen is used with the color paste being provided into the screen through a pipe and a squeeze arrangement within the screens apply pressure to enable printing paste penetration.

Fig:- Lakshmi screen printing range

The fabric is fed through rollers to the printing table and is stabalized in width by a guiding system .As the fabric passes under the screen rollers the colors are applied as per design. The capacity of this machine is 20 to 100 meters/seconds depending upon factors like design and the number of colors in that design and the types of the fabric (coarser takes less time as compared to finer fabric).The machine is preequipped with the under-bed washing and drying unit which cleans and dry up the belt after each cycle . After printing rollers, the drying unit dries printed fabric in a 5 chamber arrangement dedicated for drying. After drying, the fabric is sent to the polymerizer for fixation, i.e. the fixing of dyes /pigments.


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1.3.3.2 REGGIANI MACHINE

Fig:- Reggiani screen printing range

There are 3 Reggiani rotary printing machines out of which 2 machines can print up to 12 colors and the third machine can print upto 14 colors. The Reggiani screen printing range is has similar operation run as that of the Lakshmi rotary printing machine. The only difference in both the machines is the application of glue in the Reggiani machine by a glue roller that ensures that the fabric sticks to the running conveyor belt as it passes under the various screen rollers for coloration. Fig:- Reggiani Screen printing machine

After printing it enters the heating chamber where there are 5 chambers that dry the printed fabric with high temperature and pressure. Two machines out of three have the dryer in on-line position where as the third machine has an dryer in over head


Page 76

position. The dried fabric received is then received in a batch form or plaited (preferable) and then sent for curing. Technical details of Reggiani Rotary printing machine Number of colours

12 & 14(max 24 colors)

Printing speed

30 to 45 m/min max(90 m/min)

Printing width

72” to 80”

Multi repeat printing heads (screen 640 to 1200 mm size) Squeegee system

UNIFLUX continuous magnetic field

Process control for Reggiani dryer

Reactive printing

I Chamber

1500c +/- 15

II Chamber

1500c +/- 15

Speed

30 +/- 15 mts /min

Pigment printing

I Chamber

1650c +/- 15

II Chamber

1650c +/- 15

Speed

40 +/- 15 mts /min

Discharge printing

I Chamber

900c +/- 10

II Chamber

900c +/- 10


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Speed

20 +/- 10 mts/min

1.4 ARIOLI LOOP AGER

After the printing process is completed the fabrics have to undergo a curing process for the polymerization of the dye applied in printing.

Fig: Arioli loop ager machine

To perform the required curing process and polymerization of pigments with standard long loop treatment there

are two Arioli Loop Agers available which fix the dyes

through high temperature treating with a suitable dwelling time. This machine is suitable for both woven and knits .The fabric is then fed into the loop ager chamber


Page 78

where short loops are formed which allows increasing the dwelling time. With such a system, the most delicate discharge prints and colouring overlapping may be safely treated without risking rubbing or marking. Pigment prints polymerizing in hot air is done at temperatures up to 160°C. If reactive dyes are used, the temperature of the dye is kept 102°C Fig: Arioli loop ager curing range

Process control of loop ager printing machine

Pigment printing Chamber 1

160oc

Chamber2

160oC

Speed

39 mts/min

Reactive printing Chamber 1

107oc

Chamber2

102oC

Speed

24 mts/min

Discharge printing Chamber 1

107OC


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Chamber2

102oC

Speed

33 mts/min

Technical details of loop ager

Fabric capacity

87 yds/80 mts

Roller widths

87’’

Working speed

22 yds/min

Dwell time

4-40 secs


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internship at alok industries vapi

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