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1
COTTON YARN MANUFACTURING PROCESS
DIPLOMA IN TEXTILE & APPEREL TECHNOLOGY
SRI LANKA INSTITUTE OF TEXTILE & APPAREL
2014/...
2
ACKNOWLEDGEMENT
I would like to express my special thanks of gratitude to my teacher Mr.Panagoda as well
as our lecturer...
3
CONTENTS PAGES
1. Cotton 4
1.1 Cotton Production & Harvesting 5
1.2 Seed Cotton Storage 6
1.3 Ginning 6-7
2 Cotton Yarn ...
4
1. Cotton
No one knows exactly how old cotton is. Scientists searching caves in Mexico found
bits of cotton bolls and pi...
5
1.1 Cotton Production & Harvesting
After cotton has been harvested, producers who use conventional tillage practices
cut...
6
Conventional cotton stripping machines use rollers equipped with alternating bats and
brushes to knock the open bolls fr...
7
storage until it is shipped to a textile mill for use.
A typical gin will process about 12 bales per hour, while some of...
8
2. Cotton Yarn Manufacturing Process
Yarn manufacturing is a sequence of processes that convert raw cotton fibres into y...
9
2.2 Carded yarn manufacturing flow chart
Combed yarn is most precious, finer and thinner than
the carded yarn. Because t...
10
Input Material Processing Machines Output Materials
Step 1
Raw Fibre Blow Room Lap
Step 2
Lap Carding Carded Sliver
Ste...
11
2.4Blow room
The section where the supplied compressed cotton bale turns into a uniform lap of
particular length by ope...
12
2.4.2 Objects of blow room:
● Opening- Opening of compressed cotton bales and cotton bales are made into small
tufts.
●...
13
Since the functions of the card are to place the fibres parallel and
remove other impurities so that perfect fibres can...
14
2.5.1 Objects of carding
 Opening and cleaning: To open and clean the fibres at single stage.
 To make the fibre stra...
15
2.6.1 Actions Involved in Draw Frame
Drafting
It is the process of increasing length per unit weight of sliver. It is m...
16
i. Equalizing
One of the main tasks of draw frame is improving evenness over short, medium and
especially long terms. C...
17
2.7 Combing
2.7.1Definition of Combing
Removing short fibres, neps and impurities by using combs is called combing.It i...
18
 When all the combed fibres have been withdrawn by the detaching roller, the top
comb is withdrawn and the cylinder co...
19
twisted roving is significantly better suited to this purpose.
2.The second reason is that draw frame cans represent th...
20
To build the roving in bobbin such a form which will facilitate handling, withdrawing &
transfer to the next process.
D...
21
It is the process of further drawing out roving to the final yarn count
needed, inserting twist to the fibres by means ...
22
2.9.2. Objectives of Ring Spinning
 To draft the roving fed to the ring spinning frame i,e to convert roving into very...
23
2.10.2 Following are the tasks of winding process
 Extraction of all disturbing yarn faults such as the short, long th...
24
forced into a traverse motion at speed that make it invisible, and finally rolled up into a
firm construction called pa...
25
Increases the tenacity of the yarn by improving the binding-in of the fibers on the
outer layers of the component singl...
26
3.4.2 Combed yarn
 The yarn is less hairy.
 The yarn is more regular.
 The yarn is more costly.
 The yarn is shinie...
27
3.5.3 Direct count
The count of yarn expresses the no. of weight units in one length unit. Thus higher the
count, coars...
28
 Accumulation of fly and fluff on the machine parts.
 Poor carding.
 Defective ring frame drafting and bad piecing
...
29
 Poor carding.
 Defective ring frame drafting and bad piecing
 Improperly clothed top roller clearers.
RECTIFICATION...
30
CAUSES
Eccentric top and bottom rollers
 Insufficient pressure on top rollers
 Worn and old aprons and improper apron...
31
EFFECT:
More end breaks in subsequent processes
 Shade variation in dyed fabrics
CAUSES:
 Slack tapes dirty jockey pu...
32
CAUSES
Careless oil in the moving parts,over head pulleys etc
 Piecings made with oily or dirty fingers
 Careless mat...
33
 Separators to be provided
 Excessive end breaks in spinning to be avoided
4.7 Hairiness
Protrusion of fibre ends fro...
34
 Optimum relative humidity to be maintained in the spinning room
 Wide variation in the properties of cottons used in...
35
4.9 Spun In Fly
Fly or fluff either spun along with the yarn or loosely embedded on the yarn
EFFECT
More breaks in wind...
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Cotton Yarn Manufacturing Process (1)

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Cotton Yarn Manufacturing Process (1)

  1. 1. 1 COTTON YARN MANUFACTURING PROCESS DIPLOMA IN TEXTILE & APPEREL TECHNOLOGY SRI LANKA INSTITUTE OF TEXTILE & APPAREL 2014/2015 Name : E.C.Maduranga Ediriweera Reg , No : DTAT-P/21/2014 Name Of Department : Courtaulds Clothing (PVT) ltd Name Of Lecturer : Mr.N. P. P .S. K. Pathirana Date : 21/02/2015
  2. 2. 2 ACKNOWLEDGEMENT I would like to express my special thanks of gratitude to my teacher Mr.Panagoda as well as our lecturer who gave me the golden opportunity to do this wonderful project on the topic Cotton yarn manufacturing, which also helped me in doing a lot of Research and i came to know about so many new things I am really thankful to them. Secondly i would also like to thank my parents and friends who helped me a lot in finishing this project within the limited time. I am making this project not only for marks but to also increase my knowledge. THANKS AGAIN TO ALL WHO HELPED ME.
  3. 3. 3 CONTENTS PAGES 1. Cotton 4 1.1 Cotton Production & Harvesting 5 1.2 Seed Cotton Storage 6 1.3 Ginning 6-7 2 Cotton Yarn Manufacturing Process 8 2.1 Textile Yarn Manufacturing 8 2.2 Carded yarn manufacturing flow chart 9 2.3 Combed yarn manufacturing flow chart 9-10 2.4 Blow room 11 2.4.1 Basic operations involved in the blow room 11 2.4.2 Objects of blow room 12 2.4.3 Actions of blow room 12 2.5 Carding 12-13 2.5.1 Objects of carding 14 2.5.2 Tasks of carding 14 2.6 Draw Frame 14 2.6.1 Actions Involved in Draw Frame 15 2.6.2 Tasks of Draw frame 15-16 2.7 Combing 17 2.7.1Definition of Combing 17 2.7.2 Working principle of cotton combing 17 2.7.3Objectives of Combing 18 2.8 Speed Frame 18 2.8.1 Necessity of Speed Frame 18 2.8.2 Objects/ Functions of Speed Frame 19 2.8.3 Operations Involved in Simplex Machine 19 2.9 Ring Spinning 20 2.9.1What is Ring Spinning 20-21 2.9.2.Objectives of Ring Spinning 22 2.10 Winding 22 2.10.1A basic diagram of winding m/c 22 2.10.2 Following are the tasks of winding process 23 3. Yarns 24 3.1 Definition of Yarn 24 3.2 Yarn Classification 24 3.3 Types of cotton yarn 25 3.4 Differences between card yarn and combed yarn 25 3.4.1 Carded yarn 25 3.4.2 Combed yarn 26 3.5 Yarn Count 26 3.5.1 Types of yarn count 26 3.5.2 Indirect count 26 3.5.3 Direct count 27 4. Yarn Fault 27 4.1. Slubs 27 4.2 Neps 28 4.3 Thick and Thin plces 29 4.4 Soft Yarn 30 4.5 Oil Stained Yarn 31 4.6 Bad Piecing 32 4.7 Hairiness 33 4.8 Foreign Matters 34 4.9 Spun In Fly 35
  4. 4. 4 1. Cotton No one knows exactly how old cotton is. Scientists searching caves in Mexico found bits of cotton bolls and pieces of cotton cloth that proved to be at least 7,000 years old. They also found that the cotton itself was much like that grown in America today. In the Indus River Valley in Pakistan, cotton was being grown, spun and woven into cloth 3,000 years BC. At about the same time, natives of Egypt’s Nile valley were making and wearing cotton clothing. Arab merchants brought cotton cloth to Europe about 800 A.D. When Columbus discovered America in 1492, he found cotton growing in the Bahamas Islands. By 1500, cotton was known generally throughout the world. Cotton seed are believed to have been planted in Florida in 1556 and in Virginia in 1607. By 1616, colonists were growing cotton along the James River in Virginia. Cotton was first spun by machinery in England in 1730. The industrial revolution in England and the invention of the cotton gin in the U.S. paved the way for the important place cotton holds in the world today. Eli Whitney, a native of Massachusetts, secured a patent on the cotton gin in 1793, though patent office records indicate that the first cotton gin may have been built by a machinist named Noah Homes two years before Whitney’s patent was filed. The gin, short for engine, could do the work 10 times faster than by hand. The gin made it possible to supply large quantities of cotton fibres to the fast-growing textile industry. Within 10 years, the value of the U.S. cotton crop rose from $150,000 to more than $8 million.
  5. 5. 5 1.1 Cotton Production & Harvesting After cotton has been harvested, producers who use conventional tillage practices cut down and chop the cotton stalks. The next step is to turn the remaining residue underneath the soil surface. Producers who practice a style of farming called conservation tillage often choose to leave their stalks standing and leave the plant residue on the surface of the soil. In the spring, farmers prepare for planting in several ways. Producers who plant using no-till or conservation tillage methods, use special equipment designed to plant the seed through the litter that covers the soil surface. Producers, who employ conventional tillage practices, plow or “list” the land into rows forming firm seed-beds for planting. Producers in south Texas plant cotton as early as February. In Missouri and other northern parts of the Cotton Belt, they plant as late as June. Seeding is done with mechanical planters which cover as many as 10 to 24 rows at a time. The planter opens a small trench or furrow in each row, drops in the right amount of seed, covers them and packs the earth on top of them. The seed is planted at uniform intervals in either small clumps or singularly. Machines called cultivators are used to uproot weeds and grass, which compete with the cotton plant for soil nutrients, sunlight and water. About two months after planting, flower buds called squares appear on the cotton plants. In another three weeks, the blossoms open. Their petals change from creamy white to yellow, then pink and finally, dark red. After three days, they wither and fall, leaving green pods which are called cotton bolls. Inside the boll, which is shaped like a tiny football, moist fibres grow and push out from the newly formed seeds. As the boll ripens, it turns brown. The fibres continue to expand under the warm sun. Finally, they split the boll apart and the fluffy cotton bursts forth. It looks like white cotton candy. Since hand labour is no longer used in the harvest cotton, the crop is harvested by machines, either a picker or a stripper. Cotton picking machines have spindles that pick (twist) the seed cotton from the burrs that are attached to plants’ stems. Doffers then remove the seed cotton from the spindles and knock the seed cotton into the conveying system.
  6. 6. 6 Conventional cotton stripping machines use rollers equipped with alternating bats and brushes to knock the open bolls from the plants into a conveyor. A second kind of stripper harvester uses a broadcast attachment that looks similar to a grain header on a combine. All harvesting systems use air to convey and elevate the seed cotton into a storage bin referred to as a basket. Once the basket is full, the stored seed cotton is dumped into a boll buggy, trailer or module builder. 1.2SeedCotton Storage Once harvested, seed cotton must be removed from the harvester and stored before it is delivered to the gin. Seed cotton is removed from the harvester and placed in modules, relatively compact units of seed cotton. A cotton module, shaped like a giant bread loaf, can weigh up to 25,000 pounds. 1.3 Ginning From the field, seed cotton moves to nearby gins for separation of lint and seed. The cotton first goes through dryers to reduce moisture content and then through cleaning equipment to remove foreign matter. These operations facilitate processing and improve fibre quality. The cotton is then air conveyed to gin stands where revolving circular saws pull the lint through closely spaced ribs that prevent the seed from passing through. The lint is removed from the saw teeth by air blasts or rotating brushes, and then compressed into bales weighing approximately 500 pounds. Cotton is then moved to a warehouse for
  7. 7. 7 storage until it is shipped to a textile mill for use. A typical gin will process about 12 bales per hour, while some of today’s more modern gins may process as many as 60 bales an hour. 1. Module Feeder 11. Conveyor Distributor 2. Suction Telescopes 12. 9000 Feeder 3. Big-J Feed Control 13. 161 Gin Stand 4. Vertical Flow Drier 14. Centrifugal Cleaner 5. Incline Cleaner 15. 24-D Tandem Lint Cleaners 6. Stripper Cleaner 16. Battery Condenser 7. Stick Machine 17. Covered Lint Slide 8. Tower Drier 18. Belt Feeder 9. Incline Cleaner 19. 9300 Up-Packing Universal Density Bale Press 10. Impact Cleaner 20. Bale Tying 21. Bale Bagging And Conveying
  8. 8. 8 2. Cotton Yarn Manufacturing Process Yarn manufacturing is a sequence of processes that convert raw cotton fibres into yarn suitable for use in various end-products. A number of processes are required to obtain the clean, strong, uniform yarns required in modern textile markets. Beginning with a dense package of tangled fibres (cotton bale) containing varying amounts of non-lint materials and unusable fibre (foreign matter, plant trash, motes and so on), continuous operations of opening, blending, mixing, cleaning, carding, drawing, roving and spinning are performed to transform the cotton fibres into yarn. Even though the current manufacturing processes are highly developed, competitive pressure continues to spur industry groups and individuals to seek new,more efficient methods and machines for processing cotton which, one day, may supplant today’s systems. However,for the foreseeable future, the current conventional systems of blending, carding, drawing, roving and spinning will continue to be used. Only the cotton picking process seems clearly destined for elimination in the near future. Yarn manufacturing produces yarns for various woven or knitted end-products (e.g.,apparel or industrial fabrics) and for sewing thread and cordage. Yarns are produced with different diameters and different weights per unit length. While the basic yarn manufacturing process has remained unchanged for a number of years,processing speeds,control technology and package sizes have increased. Yarn properties and processing efficiency are related to the properties of the cotton fibers processed. End-use properties of the yarn are also a function of processing conditions. 2.1Textile Yarn Manufacturing If you want to make a yarn you will have two methods to follow. One is Carded yarn manufacturing method and another is Combed yarn manufacturing method. Carded yarn manufacturing method. Combed yarn manufacturing method
  9. 9. 9 2.2 Carded yarn manufacturing flow chart Combed yarn is most precious, finer and thinner than the carded yarn. Because the Carded Yarn is produced by following some less manufacturing steps than the Combed Yarn Input Material Processing Machines Output Materials Step 1 Raw Fibre Blow Room Lap Step 2 Lap Carding Carded Sliver Step 3 Carded Sliver Draw Frame Draw Frame Sliver Step 4 Draw Frame Sliver Fly /Speed Frame Roving Step 5 Roving Ring Spinning Yarn (Spinning Bobbin) Step 6 Spinning Bobbin Winding Cone 2.3 Combed yarn manufacturing flow chart Combed yarn is more precise than card yarn. Here is the process flowchart of Combed Yarn. The main purpose of Combed yarn manufacturing is to create a yarn which is highly finer and highly qualified.
  10. 10. 10 Input Material Processing Machines Output Materials Step 1 Raw Fibre Blow Room Lap Step 2 Lap Carding Carded Sliver Step 3 Carded Sliver Draw Frame 1 Draw Frame Sliver Step 4 Draw Frame Sliver Sliver Lap Lap Step 5 Lap Ribbon Lap Ribbon Lap Sliver Step 6 Ribbon Lap Sliver Comber Combed Sliver Step 7 Combed Sliver Drew Frame 2 Draw Frame Sliver Step 8 Draw Frame Sliver Fly /Speed Frame Roving Step 9 Roving Ring Spinning Yarn (Spinning Bobbin) Step 10 Spinning Bobbin Winding Cone
  11. 11. 11 2.4Blow room The section where the supplied compressed cotton bale turns into a uniform lap of particular length by opening, cleaning, blending or, mixing is called blow room section. It is the first step of spinning. The section consist a number of different machines used in succession to open and clean the fibres. 2.4.1. Basicoperations involved in the blow room: ● Opening- Opening is the first operation in the blow room carried out to the stage of flocks in the blow room and to the stage of individual fibres in the cards. ● Cleaning- To remove the impurities, foreign materials and the raw materials as clean as possible. ● Dust removal- To remove the dusts which are completely enclosed in the flocks. ● Blending- To achieve the required quality of yarn by blending different kinds of cotton into a particular ratio. ●Even feed of the material- To produce a lap of uniform weight per unit length or, to process the maximum quality which is suitable for carding.
  12. 12. 12 2.4.2 Objects of blow room: ● Opening- Opening of compressed cotton bales and cotton bales are made into small tufts. ● Cleaning- To eliminate dust, dirt, broken leaf, seed particles, grass and other foreign impurities from the fibre. ● Blending/mixing- To produce a comparatively good quality cotton fibre by mixing different types of cotton together. ● Lap forming- (a) To convert the opened and cleaned fibre into a sheet of particular width and uniform weight/unit length is called lap. (b) To give a cylindrical shape to the pre determined lap by winding it in the lap pin and to make it suitable for the next process carding. 2.4.3. Actions of blow room: (a) Action of opposite spike(Opening) (b) Action of air current(Transport Cleaning) (c) Action of beater and grid bar(Cleaning and opening) (d) Action of regulating motion(Uniform output) 2.5 Carding Carding is the second stage of cotton spinning. It is defined as the reduction of entangled mass of fibres to filmy web by working them between two closely spaced relatively moving surfaces closed with sharp points i.e. wires. The process of using a card (a thistle or teasel) for combing textile fibres. This consists of combing or brushing fibres until they are straightened and placed parallel. For this, the imperfect fibres and other impurities have to be removed. James Hargreaves and Louis Paul were two of the persons concerned with this invention and improvements to carding. Since then, innumerable attempts have been made to improve these machines, but in spite of this and also the latest improvements made, carding remains essentially the same as established nearly 200 years ago.
  13. 13. 13 Since the functions of the card are to place the fibres parallel and remove other impurities so that perfect fibres can be drawn in sliver, the rollers of carding machine have to be so arranged, as would perform these functions perfectly. Carding machine consists of 3 cylinders, covered with cards. (1) Taker-in is smallest, (2) Main cylinder is the largest and (3) The doffer. The outer contact cylinder lap feeds cotton to roller C, which rotates on a smooth iron table D. Here all the dirt is removed, and the fibres are straightened by combing. The cotton then passes along these cylinders as shown by arrows. The flats further flatten the fibres and also place them loose but parallel. When these are ultimately fed to doffer, its teeth draw these in light fleece and these are then further drawn into slivers, and deposited into coiler can G.
  14. 14. 14 2.5.1 Objects of carding  Opening and cleaning: To open and clean the fibres at single stage.  To make the fibre straight and parallel (Parallelization of fibres)  To remove the small trash particles which have not been taken out from the blow room line.  To remove the naps and motes.  Individualization of fibres ; i,e. separation of fibres from each others.  Elimination of the remaining impurities.  Attenuation; draft.  To produce thick rope form of fibres called slivers which is suitable for subsequent processing. 2.5.2 Tasks of carding  Opening of individual fibres.  Elimination impurities.  Elimination of dust.  Disentangling of naps.  Elimination of short fibres.  Fibre blending.  Fibre orientation.  Sliver formation. 2.6 Draw Frame. Draw frame is a machine for combining and drawing slivers of a textile fiber (as of hemp for rope manufacture or cotton for spinning). Drawing is the operation by which slivers are blended, doubled and leveled. In short staple spinning the term is only applied to the process at a draw frame. In drawing slivers are elongated when passing through a group of pair rollers, each pair is moving faster than previous one.
  15. 15. 15 2.6.1 Actions Involved in Draw Frame Drafting It is the process of increasing length per unit weight of sliver. It is mainly due to peripheral speed of the rollers. Doubling The process of combing two or more carded sliver into a single form is called doubling. In draw frame m/c generally six slivers are fed to convert into one i.e. six doubling. Drawing In the cotton industry the term is applied exclusively to processing on the draw frame, where the operation is one of doubling and drafting. Drawing= Drafting + Doubling. Diagram of draw frame 2.6.2 Tasks of Draw frame i. Equalizing ii. Parallelizing iii. Blending iv. Dust removal
  16. 16. 16 i. Equalizing One of the main tasks of draw frame is improving evenness over short, medium and especially long terms. Carded slivers are fed to the draw frame have degree on unevenness that cannot be tolerated in practice and slivers from the comber contain the “infamous” piecing. It is obscured by draw frame. Equalizing is always performed by a first process, namely doubling and can optionally also be performed by a second process, namely auto leveling. The draft and the doubling have the same value and lie in the range of 6 to 8. ii. Parallelizing To obtain an optional value for strength in the yarn characteristics, the fibers must be arranged parallel in the fibre strand. The draw frame has the tasks of creating this parallel arrangement. It fulfils the task by way of the draft, since every drafting step leads to straightening the fibres. iii. Blending In addition to the equalizing effect, doubling also provides a degree of compensation of raw material variation by blending. Their results are exploited in particular way in the production of blended yarns comprising cotton or synthetic blends. At the draw frame metering of the individual components can be carried out very simply be selection of the number of slivers entering the machines. iv. Dust Removal Dust is steadily becoming a greater problem both in processing and for the personnel involved. It is therefore important to remove dust to the greatest practical extent at every possible point within the overall process.
  17. 17. 17 2.7 Combing 2.7.1Definition of Combing Removing short fibres, neps and impurities by using combs is called combing.It is the process of separation of long desirable fibres of same length from the short fibres, neps and all remaining foreign materials of the fibre stuck. The fibres also become straight and parallel. 2.7.2 Working principle of cotton combing All the combers operate intermittently, both ends of the fibres are combed separately by needles and the continuity of the strand is maintained by an ingenious method of piecing up the separated combed tufts, shortly, the process is operated as follows –  The lap prepared for combing is fed into the machine between the feed roller and the bottom nipper. At the front of the nipper, the top nipper is positioned to gripe the lap as it passes to be combed at the front end of a fringe.  The protruding fibres beyond the nipping point are combed by the passage of raws of needles fastened of a cylinder and situated below the lap. The cylinder with the needles revolves and carries away the short fibres, neps, and impurities from the front part of the fringe. The wastage are removed from the cylinder needles by a brush and collected around an aspirator.  When the cylinder comb completes its action, the top comb then comes down to perform its action at the back part of the fibre fringe. Meanwhile, the partly combed fibres are withdrawn through the top comb by detaching rollers.
  18. 18. 18  When all the combed fibres have been withdrawn by the detaching roller, the top comb is withdrawn and the cylinder comb operates on new sets of fibres as before.  The top comb operates again but before the rollers draw away the newly combed fibres, then turn backwards a little so that, the new fibres can be over lapped with those withdrawn in the previous combing and in this way the continuity of the combed web of fibres is maintained.  The combed web delivered by the rollers is passed through a trumpet to consolidate the fibres and to make a sliver which is pulled along a table alongside other slivers from the other combers delivered by the same machine. 6 or 8 slivers are drawn into a single sliver by a drafting mechanism at the end of the sliver table and passes into a sliver can. 2.7.3 Objectives of Combing  To remove naps in the carded sliver.  To make the fibre more parallel and straight.  To produce a uniform sliver of required per unit length.  To remove the fibre shorter than a predetermined length.  To remove remaining impurities in the comber lap. 2.8 SpeedFrame Simplex is an intermediate process in which fibres are converted into low twist lea called roving. The sliver which is taken from draw frame is thicker so it is not suitable for manufacturing of yarn. Its purpose is to prepare input package for next process. This package is to prepare on a small compact package called bobbins. Roving machine is complicated, liable to fault, causes defect adds to the production costs and deliver the product. In this winding operation that makes us roving frame complex. There are two main basic reasons for using roving frame. 2.8.1 Necessity of Speed Frame: 1. The first reason is related to the required draft. Sliver is a thick, untwisted strand that tends to be hairy and to create fly. The draft needed to convert this to a yarn is in the region of 300-500. The drafting arrangements of ring spinning machines, in their current forms, are not capable of processing this strand in a single drafting operation to create a yarn of short-staple fibers that meets all the normal demands on such yarns. The fine ,
  19. 19. 19 twisted roving is significantly better suited to this purpose. 2.The second reason is that draw frame cans represent the worst conceivable mode of transport and presentation of feed material to the ring spinning frame. 2.8.2 Objects/ Functions of Speed Frame: 1.Attenuation of drawn sliver to form roving of required count by drafting. 2. Insert small amount of twist to give required strength of roving. 3. Wind the twisted roving on to the bobbin. 4. Build the roving in bobbin such a form which will facilitate handling, withdrawing & transfer to the next process. 2.8.3 Operations Involved in Simplex Machine: 1.Creeling 2.Drafting 3.Twisting 4.Winding 5.Building 6.Doffing Creeling To feed the sliver by the help of several rows of driver rollers to the machine.  Creel draft  Creel Stop motion  Block creeling Drafting To reduce the wt/unit length of sliver to make it suitable for ring spinning system. Twisting To insert small amount of twist to give required strength of roving. Winding To wind the twisted roving on to bobbin. Building
  20. 20. 20 To build the roving in bobbin such a form which will facilitate handling, withdrawing & transfer to the next process. Doffing To replace an empty bobbin at the place of full roving bobbin. 2.9 Ring Spinning The Ring Spinning is the most widely used form of spinning machine due to significant advantages in comparison with the new spinning processes. The ring spinning machine is used in the textile industry to simultaneously twist staple fibres into yarn and then wind it onto bobbins for storage. The yarn loop rotating rapidly about a fixed axis generates a surface referred to as "balloon". Ring frame settings are chosen to reduce yarn hairiness and the risk of glazing or melting the fibre 2.9.1 What is Ring Spinning? Ring Spinning is the oldest of the present day spinning processes. Fiber material is supplied to the ring-spinning machine in the form of roving. The fiber mass of the roving is reduced by a drafting unit. The twist inserted moves backwards and reaches the fibers leaving the drafting unit. The fibers lay around one another in concentric helical paths. The normal forces encountered by the fibers enhance the adhesive forces between the fibers and prevent fibers from flying or slipping past each other under the tensile strain.
  21. 21. 21 It is the process of further drawing out roving to the final yarn count needed, inserting twist to the fibres by means of a rotating spindle and winding the yarn on a bobbin. These three stages take place simultaneously and continuously. A mechanically driven spindle, on which the yarn package firmly sits, is responsible for twist. A stationary ring is around the spindle, which holds the traveler. Yarn from the drafting unit is drawn under the traveler, and then led to the yarn package. In order to wind the twisted yarn on a bobbin tube carried by the spindle, the traveler is required to cooperate with the spindle. The traveler moves on the ring without any physical drive, but is carried along by the yarn it is threaded with. The rotation rate of traveler is lower than the spindle, and this difference in the speeds of traveler and the spindle enables the winding of the yarn on the tube. A controlled up and down movement of the ring determines the shape of the yarn package, called Cop or Bobbin. Ring spinning technology provides the widest range in terms of the yarn counts it can produce. Ring spinning is a comparatively expensive process because of its slower production speeds and the additional processes (roving and winding) required for producing ring spun yarns. Ring spun yarns produce high quality and are mainly produced in the fine (60 Ne, 10 tex) to medium count (30 Ne, 20 tex) range, with a small amount produced in the coarse count (10 Ne, 60 tex) range. End uses include high quality underwear, shirting, towels.The fibers in the ring yarn are highly parallel and helical in nature, and the fiber arrangement is uniform along the thickness of the yarn. The yarn has a compact structure, with essentially no wrapper or hooked fibers. The self-locked structure is the result of intensive fiber migration, which in turn is influenced by the triangular geometry of the spinning zone and the high spinning tensions. The high axial strength of the yarn is the result of unique self-locked structure.
  22. 22. 22 2.9.2. Objectives of Ring Spinning  To draft the roving fed to the ring spinning frame i,e to convert roving into very fine strand called yarn.  To impart strength to the yarn by inserting the necessary amount of twist.  To collect twisted strand called yarn onto handy and transportable package by winding the twisted thread on a cylindrical bobbin or tube. 2.10 Winding In spinning process; winding are the last steps. After winding yarn package are used for making woven or knitted fabrics. Winding process can be defined as the transfer of spinning yarn from one package to another large package (cone, spool, cheese, pirn etc).one the other hand it can be defined as the transfer pf yarn from bobbin, hanks etc into a convenient from of package containing considerable long length of yarn. A process of accumulating yarn on a package to facilitate the next process is called as winding. 2.10.1 A basic diagram of winding m/c:
  23. 23. 23 2.10.2 Following are the tasks of winding process  Extraction of all disturbing yarn faults such as the short, long thick ,long thin, spinners doubles, etc  Manufacture of cones having good drawing - off properties and with as long a length of yarn as possible  paraffin waxing of the yarn during the winding process  introduction into the yarn of a minimum number of knots  achievement of a high machine efficiency i.e high produciton level The winding process therefore has the basic function of obtaining a larger package from several small ring bobbins. This conversion process provides one with the possibility of cutting out unwanted and problematic objectionable faults. The process of removing such objectionable faults is called as yarn ‘ clearing’ . Practical experience has proven that winding alters the yarn structure.This phenomenon does not affect yarn evenness, but affect the following yarn properties  thick places  thin places  neps  hairiness  standard deviation of hairiness If winding tension is selected properly, the following tensile properties are not affected  tenacity  elongation  work- to- break But excessive tension in winding will deteriorate the above said tensile properties. Changes in the yarn surface structure due to winding cannot be avoided. Since the yarn is accelerated from zero speed to 1200 or 1350 meters per min in a few milli seconds while being pulled off the bobbin, dragged across several deflection bars and eyelets,
  24. 24. 24 forced into a traverse motion at speed that make it invisible, and finally rolled up into a firm construction called package or cone. 3.Yarns 3.1 Definition of Yarn A yarn is a constructed assemblage of textile fibers which acts as a unit in fabric formation. 3.2 Yarn Classification 1. Staple Fiber Yarns or Spun Yarns(single yarn): Spun yarns are made by mechanical assembly and twisting together(spinning) of staple fibers. Ring spinning, Rotor spinning, Wrap spinning, Air-jet spinning etc. machines are used to produced this spun or single yarns. 2. Ply Yarn: Single yarns are used in the majority of fabrics for normal textile and clothing applications, but in order to obtain special yarn features, particularly high strength and modulus for technical and industrial applications, ply yarns are often needed. A folded or ply yarn is produced by twisting two or more single yarns together in one operation, and a cabled yarn is formed by twisting together two or more folded yarns or a combination of folded and single yarns. The twisting together of several single yarns.
  25. 25. 25 Increases the tenacity of the yarn by improving the binding-in of the fibers on the outer layers of the component single yarns. Ply yarns are also more regular, smoother and more hard wearing. The direction of twisting is designated as S or Z, just as in single yarns. Normally the folding twist is in the opposite direction to that of the single yarns. 3. Filament Yarns: A filament yarn is made from one or more continuous strands called filaments where each component filament runs the whole length of the yarn. Those yarns composed of one filament are called monofilament yarns, and those containing more filaments are known as multifilament yarns. For apparel applications ,a multifilament yarn may contain as few as two or three filaments or as many as 50 filaments. In carpeting, for example, a filament yarn could consist of hundreds of filaments, Most manufactured fibers have been produced in the form of a filament yarn. Silk is the only major natural filament yarn. 3.3 Types of cotton yarn There are two types of cotton yarn according to their manufacturing process, 1. Carded yarn. 2. Combed yarn. 3.4 Differences between card yarn and combed yarn. 3.4.1 Carded yarn The yarn is more hairy.  The yarn is more irregular.  The yarn is cheaper.  The yarn is less shiny.  Some trash may be present in the yarn.  Neaps can be present in the yarn.  Possibility of irregular twist distribution in the yarn.
  26. 26. 26 3.4.2 Combed yarn  The yarn is less hairy.  The yarn is more regular.  The yarn is more costly.  The yarn is shinier.  No trash can be present in the yarn.  Neaps are not available in the yarn. 3.5 Yarn Count The yarn count is a numerical expression which defines its fineness or coarseness. It also expresses weather the yarn is thick or thin. A definition is given by the textile institute – “Count is a number which indicates the mass per unit length or the length per unit mass of yarn 3.5.1 Types of yarn count: Indirect system - English, Metric, Worsted. Direct system - Tex, Denier, Lbs/Spindle. 3.5.2 Indirect count The count of yarn expresses the number of length units in one weight unit. Thus higher the count, finer the yarn. The system is generally used for cotton, worsted, linen (wet spun) etc. English system It is defined as the number of hanks 840 yds per pound is called yarn count Metric system It is defined as the number of hank (1000m) per kg. Worsted system It is defined as the number of hanks (540yds) per pound.
  27. 27. 27 3.5.3 Direct count The count of yarn expresses the no. of weight units in one length unit. Thus higher the count, coarser the yarn. The system is generally used for synthetic fibre, jute, silk etc. Tex systemor, Lea count It is defined as the weight in grams of 1000m is called tex count. Denier The number or, count in the denier system is the weight in grams of 9000m. Decitex weight in grams of 10000 meter 4. Yarn Fault 4.1 Slubs An abnormally thick place or lump in yarn showing less twist at that place. EFFECT More end breaks in the next process.  Damaged fabric appearance.  Shade variation in dyed fabrics. CAUSES
  28. 28. 28  Accumulation of fly and fluff on the machine parts.  Poor carding.  Defective ring frame drafting and bad piecing  Improperly clothed top roller clearers. RECTIFICATION  Machine surfaces to be maintained clean.  Proper functioning of pnemafil/roller clearers to be ensured.  Broken teeth gear wheel to be avoided and proper meshing to be ensured.  Better fiber individualisation at cards to be achieved.  Optimum top roller pressure &back zone  Setting at ring frame to be maintained. 4.2 Neps Yarn containing rolled fibre mass, which can be clearly seen on black board at close distance; measurable on Uster imperfection Indicator. EFFECT Damaged fabric appearance  Shade variation in the dyed fabrics  An abnormally thick place or lump in yarn showing less twist at that place is called slubs CAUSES  Accumalation of fly and fluff on the machine parts
  29. 29. 29  Poor carding.  Defective ring frame drafting and bad piecing  Improperly clothed top roller clearers. RECTIFICATION  Machine surfaces to be maintained clean.  Proper functioning of pnemafil/roller clearers to be ensured.  Broken teeth gear wheel to be avoided and proper meshing to be ensured.  Better fiber individualisation at cards to be achieved. 4.3 Thick and Thin Plces Measurable by Uster Imperfection Indicator and observable on appearance EFFECT Eccentric top and bottom rollers  Insufficient pressure on top rollers  Worn and old aprons and improper apron spacing  Improper meshing of gear wheels  Mixing of cottons varying widely in fiber lengths and use of immature cottons
  30. 30. 30 CAUSES Eccentric top and bottom rollers  Insufficient pressure on top rollers  Worn and old aprons and improper apron spacing  Improper meshing of gear wheels  Mixing of cottons varying widely in fibre lengths and use of immature cottons RECTIFICATION Eccentric top and bottom rollers to be avoided  Top arm pressure checking schedules to be Maintained strictly  Wide variation in the properties of cottons used in the mixing to be avoided  Better fiber individualisation at cards to be achieved.  Correct spacers to be utilised 4.4 Soft Yarn Yarn which is weak indicating lesser twist
  31. 31. 31 EFFECT: More end breaks in subsequent processes  Shade variation in dyed fabrics CAUSES:  Slack tapes dirty jockey pulleys  Improper bobbin feed on the spls  Less twist in the yarn  Bad clearing at the travellar RECTIFICATION: Vibration of bobbins on the spindles to be avoided  Proper yarn clearing to be ensured  Periodic replacement of worn rings and travellars to be effected 4.5 Oil Stained Yarn Yarn stained with oil EFFECT Damaged fabric appearance  Occurrence of black spot in fabric
  32. 32. 32 CAUSES Careless oil in the moving parts,over head pulleys etc  Piecings made with oily or dirty fingers  Careless material handlings RECTIFICATION Appropriate material handling procedures to be followed  Oilers to trained in proper method of lubrication  Clean containers to be utilised for material transportation 4.6 Bad Piecing Unduly thick piecing in yarn caused by over End piecing EFFECT More end breaks in subsequent process  Increase in hard waste CAUSES Wrong method of piecing and over end piecing  Twisting the ends instead of knotting RECTIFICATION Tenters to be trained in proper methods of piecing
  33. 33. 33  Separators to be provided  Excessive end breaks in spinning to be avoided 4.7 Hairiness Protrusion of fibre ends from the main yarn structure EFFECT More end breaks in winding  Uneven fabric surface  Beads formation in the fabric in the case of polyester/cotton blends CAUSES Use of cottons differing widely in the properties in the same mixing Use of worn rings and lighter travellars  Maintaining low relative humidity, closer roller settings and very high spindle speeds RECTIFICATION Use of travellars of correct size and shape and rings in good condition to be ensured  Periodic replacement of travellars and suitable  Roller settings to be maintained
  34. 34. 34  Optimum relative humidity to be maintained in the spinning room  Wide variation in the properties of cottons used in the mixing to be avoided 4.8 Foreign Matters Metallic parts, jute flannel and other similar foreign matters spun along with yarn EFFECT Breaks during winding  Formation of holes and stains in cloth  Damaged fabric appearance CAUSES Improper handling of travellers  Improper preparation of mixings RECTIFICATION Removal of foreign matters(such as jute fibres,colour cloth bits) to be ensured during preparation of mixing  Installation of permanent magnets at proper  Places in blow room lines to be ensured
  35. 35. 35 4.9 Spun In Fly Fly or fluff either spun along with the yarn or loosely embedded on the yarn EFFECT More breaks in winding CAUSES Accumulation of fluff over machine parts  Fanning by workers  Failure of over head cleaners  Malfunctioning of humidification plant RECTIFICATION Machinery surfaces to be kept clean by using roller pickers  Fanning by workers to be avoided  Performance of over head cleaners and humidification plants to be closely monitored

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