fabric manufacturing technology-1


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fabric manufacturing technology-1

  1. 1. TEXTILE A Textile was originally a woven fabric but now the term textile and its plural textiles are also applied to fibers, filaments, yarn and most products for which these are a principle raw material. The product includes threads, cords, ropes, braids woven, knitted, non-woven fabrics, nets, household textile, geo-textile, medical textiles etc. WEAVING Weaving is the action of producing fabric by the interlacing of warp and weft thread. The warp threads are placed along the length of the fabric and the weft threads are placed along the width of the fabric. Example of Different Textile- Geo-Textile: Embankment Medical Textile: Non-alginate fabric, Bandage tape etc. Non-woven Fabric: Tea bag, Tissue paper. House Hold Textile: Curtain, Cover of soffa set. Southeast University – Department of Textile Engineering 1
  2. 2. FLOW CHART OF WEAVING Yarn (In the form of spinner’s package) Warp Preparation Weft Preparation Winding (cone, cheese) Winding (Cop, Pirn, Cone, Cheese) Warping (Pre beam/ Warper’s beam/ back beam) Weaving (Fabric) Sizing (weaver’s beam) Drafting, Drawing, Pinning Denting, Looming Weaving (Fabric) Three types of yarn package are mention bellow Cone Flange bobbin Cheese Southeast University – Department of Textile Engineering 2
  3. 3. TYPES OF FABRICS 1. Woven fabric (Shirt) 2. Knitted fabric (T-shirt) 3. Non-woven fabric (Tea pack) 4. Special fabric (Fire proof fabric, water proof fabric) OBJECTS OF YARN PREPARATION Yarn preparation is important to facilitate the next processes of weaving. The objects of yarn preparation are mentioned bellow:  To remove yarn faults ( there are 23 types of yarn faults)  To transfer the yarn from spinner’s package to a convenient form of package which will facilitate weaving.  To have desired length of yarn on a package.  To clean the yarn for better appearance and performance.  To make good quality fabric.  To reduce labour cost. FAULTS TO BE REMOVED DURING YARN-PREPARATION 1. Thick place 2. Thin place 3. Slubs Place 4. Loose fibers 5. Count variation Southeast University – Department of Textile Engineering 3 Intentional Unintentional
  4. 4. 6. Foreign particles (seed, leaf, dust, bollworm, honeydew) 7. Neps QUALITY OF GOOD WARP The essential features of good warp is mentioned bellow-  The yarn must be uniform, clean and free from knots as much as possible.  The yarn must be sufficiently strong with withstand the stress and friction without end breakage.  Knots should be a standard size and type. So that they can pass the heald eye, dropper, read easily.  The warp must be uniformly sized and size coating should be thick enough to protect the yarn various function.  The ends of warp must be parallel and each must be wound onto a weaver’s beam at an even and equal tension.  All warp yarn should of same size in length. Southeast University – Department of Textile Engineering 4
  5. 5. TYPES OF PACKAGE  Cone (for warp yarn)  Cheese (for warp yarn)  Spool (for silk, jute warp yarn)  Flanged bobbin (for warp yarn)  Cop (for jute weft)  Pirn (for cotton weft)  Spinner package TYPES OF PACKAGE WINDING There are three types of package winding available. 1. Parallel wound package 2. Near parallel wound package 3. Cross wound package 1. Parallel Wound Package Features a) Many yarn can be wound at a time. b) No need of traversing motion. c) Side withdrawal is possible. d) The density of yarn is more. e) No change of twist/inch. Southeast University – Department of Textile Engineering 5 PACKAGE
  6. 6. f) For yarn unwinding separate mechanism is needed. g) Two side of the package needed flanged. 2. Near Parallel Wound Package Features a) No need flange here. b) Both side and overend withdrawal is possible. c) Twist/inch can be changed. d) Traversing motion is needed. 3. Cross-Wound Package Features a) Here no flange is required. b) Traversing mechanism is must. c) Twist/inch changes. d) Only overend withdrawal is possible. e) Yarn ballooning occurs during unwinding. f) This package is very stable. Southeast University – Department of Textile Engineering 6
  7. 7. TYPES OF PACKAGE DRIVING There are three types of package driving system. A. surface contact driving (indirect system) B. direct driving at constant angular speed C. Direct Driving At Variable Angular Speed A. SURFACE CONTACT DRIVING (INDIRECT SYSTEM) In this system, the yarn package is placed with a surface contact of a drum. The drum is driven by a motor and some gear. When it rotates the package also rotate is reverse direction. Southeast University – Department of Textile Engineering 7 PACKAGE DRIVING
  8. 8. B. DIRECT DRIVING AT CONSTANT ANGULAR SPEED In this system, the package is placed on a spindle. The spindle is driven by a motor and some gears. So the package gets a constant angular speed. Here yarn take up rate is directly proportional to the package dia. C. DIRECT DRIVING AT VARIABLE ANGULAR SPEED In this system, yarn package is directly driven at a variable angular speed to give a constant yarn speed. Here the package speed is inversely proportional to the package radius, I.e. Package speed Southeast University – Department of Textile Engineering 8 1 Package radius
  9. 9. The appearance of the curved path of running yarn during unwinding or overend withdrawl from package under appropriate winding condition through a guide, placed above and in line with the axis of the package at an adequate distance from it, the yarn assumes the appearance of a balloon shape. This circumstance of assuming balloon shape of yarn is called ballooning. Southeast University – Department of Textile Engineering 9 BALLOONING
  10. 10. FACTORS EFFECTING THE SHAPE AND SIZE OF BALLOON  Package size Ballooning  Yarn guide distance Ballooning  Lift the package Ballooning  Count of yarn Ballooning  Air resistance Ballooning  Unwinding rate. Ballooning The unwinding process of yarn from package is called yarn withdrawal. There are two types of yarn withdrawal system: 1. Side Withdrawal 2. Overend Withdrawal 1) Side Withdrawal The features of side withdrawl of yarn are given bellow; a) Package will rotate in side withdrawal. b) Yarn twist will be unchanged. c) No formation of balloon occurs. d) It is applied to flanged bobbin. e) The rate and speed of unwinding is slow. Southeast University – Department of Textile Engineering 10 YARN WITHDRAWAL OR UNWINDING
  11. 11. 2) Overend Withdrawal The features of overend withdrawl are given bellow; a) Package remains stationary during unwinding. b) Formation of balloon occurs. c) Twist/inch of yarn changed. d) Generally cop, pirn, cone, chess are packages used for overend withdrawl. e) The rate of unwinding is high. In winding and unwinding some small component control yarn path which is very necessary, yarn guide is used to perform this job. TYPES OF YARN GUIDE There are two types of yarn guide a) Yarn Guide For The Yarn Whose Ends Are Required For Threading; Southeast University – Department of Textile Engineering 11 YARN GUIDE
  12. 12. For this type of yarn guide extra time is needed for threading. So speed of operation is decreased. The yarn which passes through this guide faces more friction. Like Ceramic, Tumpet, Bust b) Yarn Guide For The Yarn Whose Ends Are Not Required For Threading; Here threading is very easy. So the speed of the operation is high. Yarn passes through this guide faces less friction. During winding, we have to impart proper tension to yarn, so that we can get a stable and undamaged package. So we pass the yarn through a device called tension device. Types of Tension Device There are four types of tension device as follow; a) Capstan Tensioner. Southeast University – Department of Textile Engineering 12 Figure: Yarn Guide TENSION DEVICE
  13. 13. b) Additive Tensioner. c) Combined Tensioner. d) Automatic Tensioner. A. CAPSTAN TENSIONER It is the simplest type of yarn tensioner. It works only by deflecting the yarn around fixed posts. This includes a capstan effect on yarn. It works by the following formula: Output Tension = Input Tension × eμθ or, T2 = T1 eμθ Where, T2 = Output tension. T1 = Input tension. e = Constant tension = 2.78 μ = Co-efficient of friction. θ = θ1+θ2+θ3 = Angle of lap. B. ADDITIVE TENSIONER This is also a simple technique of applying tension on yarn. In this device a dead weight or spring is used in the middle of the two surfaces in Southeast University – Department of Textile Engineering 13
  14. 14. contact and the force is applied to give suitable tension to the yarn. Hence the output tension is expressed by, T2 = T1 + 2μF Where, T1 = Input tension. T2 = Output tension. μ = Co-efficient of friction. F = Applied force. C. COMBINED TENSIONER It is the combined form of additive and capstan tensioner. The device permits the tension level to be raised to any desired level, but doesn’t permit a reduction of tension. Here output tension is expressed as follow: T2 = T1 + 2μF + T1 eμθ Where, T1 = Input tension. T2 = Output tension. μ = Co-efficient of friction. F = Applied force. θ = Angle of lap. D. AUTOMATIC TENSIONER It is a simple tensioner in which yarn tension is controlled automatically. It has a lever with spring loaded disc in one side and applied load in Southeast University – Department of Textile Engineering 14
  15. 15. another side. The device is designed in such a way that if applied tension is too high. The pressure on disc is reduced to bring the tension back to its proper level. There are some effects of tension to the yarn or package: They are a) If tension is too high. Southeast University – Department of Textile Engineering 15 EFFECT OF TENSIONING
  16. 16. b) If tension is too low. c) If tension varies. a) If Tension is Too High  Hard package.  Breakage rate increases.  Elongation of yarn  Shade variation.  Weak the thin place. c) If Tension Varies  Problem during unwinding.  Package unstable.  Irregularity among yarn. Auxiliary Function in Winding  Creeling.  Piecing.  Doffing. CHOICE OF TENSIONING DEVICE  It must be reliable.  It must be easily threaded.  It must neither introduce nor magnify tension variation.  It must not change the twist of yarn.  It must not be affected by wear.  It must be easily adjustable.  It must not be affected by the presence of oil and dirt.  It must not encourage the collection of dirt and lint.  It must be easy cleaning.  The operating surface must be smooth. Southeast University – Department of Textile Engineering 16 b) If Tension is Too Low  Loose package.  Unstable package.  Slough off.
  17. 17.  It must be cheap.  It must not cause any type of damage to yarn i.e. shade variation, elongation yarn breakage. PRECISION WINDING FEATURES  Packages are wound with reciprocating traverse.  Package contains more yarn.  Low stability of package.  Hard and more compact package.  Low unwinding rate.  The wound coils are arranged parallely or near parallely. FEATURES OF NON-PRECESSION WINDING  Coils are cross wound.  Package is of low density.  Less amount of yarn is stored in package.  High stability of package can be obtained.  Flange is not necessary.  Unwinding rate is very high. Difference between Precession and Non-Precession Winding Precession winding Non-Precession winding 1. The wound coil arranged parallel or near parallel. 1. The coil is cross wise wound. 2. The yarn density of the package is high. 2. The yarn density of a package is low. 3. Flanged bobbin may be used. 3. Not use of flanged. 4. The yarn package is hard and more compact. 4. The yarn package is soft and less compact. 5. Low stability of the package. 5. High stability of the package. 6. Winding angle is 90° or near 90° 6. Winding angle is less than 80° 7. The bobbin is wound with one or more threads 7. The bobbin is wound with single thread. Southeast University – Department of Textile Engineering 17 WINDING
  18. 18. 8. Yarn tension is comparatively high. 8. Yarn tension is comparatively low 9. Unwinding rate is low. 9. Unwinding rate is high. MATH-1 Calculate the time required to wind 500 lbs of 24 Ne cotton yarn on 15 drums, where the actual production per drum per minute is 560 yds. Given Production= 560yd/min/drum, 24 Ne, yarn= 500lb, time=? Solution 24 Ne means, 1 lb. of yarn contains = 24X840 yds. yarn 500 lbs. of yarn contains = (24X840X500) yds. yarn 560 yds. of yarn to wind in 1 drum needs =1 min 1 yd. “ “ “ 15 drum “ =1/ (560X15) min. (24X840X500) yd “ “ 15 drum = (24X840X500) / (560X15) min. =1200 min. =20 hr.(ans.) Math-2 Calculate the drum required to wind 900 lbs of 25 Ne cotton during the time 28 hrs, where the actual production per drum per minute is 600 yds Given, Production=600yd/min/drum 25 Ne, Yarn=900 lbs, time=28 hr., Find number of drum. Solution 25 Ne of yarns means, 1 lb of yarn contains = 25X840 yd yarns. 500 lb of yarn contains =(25X840X900) yd yarns. 600 yds. of yarn to wind in 1 min in = 1 drum 1 yd ’’ ’’ ’’ (60X28) min in = 1 / (600X60X28) drum. Southeast University – Department of Textile Engineering 18
  19. 19. (25X840X900) yds. ’’ (60X28) min = (25X840X900) / (600X28X600) drum = 18.75 drum = 19 drum (ans.) Winding is a part of total number of ends of a warp in full width on to a back beam from cone or cheese is known as warping. OBJECTS OF WARPING  To prepare a beam to make a fabric.  To increase the wave ability of fabric.  To make a convenient yarn sheet for sizing.  To wound up required length of yarn onto a warp beam.  To facilate the weaving of complex color pattern.  To make reusable small packages REQUIREMENT OF WARPING During warping the following requirements should be fulfilled. 1. The tension of all wound end must be uniform and possibly constant throughout the withdrwal process. 2. Warping should not impair the physical and mechanical properties of yarn. 3. The surface of warping package must be cylindrical. 4. A pre-determined length of yarn should be wound on beam from every package. 5. The production rate of warping should be as high as possible. 6. If possible, yarn faults should be removed. TYPES OF WARPING Mainly there are two types of warping, a) Direct/ high speed warping b) Sectional warping. Southeast University – Department of Textile Engineering 19 WARPIN
  20. 20. Some Other Special Types of Warping Are Available a) Ball warping b) Chain warping c) Cross warping A. SECTIONAL WARPING Sectional warping is a process of preparing warp beam over two stages. In first stage yarns are wound in narrow tapes on a large drum. Then in the second stage the rewinding of the warp onto a beam is performed. This process is slow but suitable for complex color pattern. B. DIRECT/HIGH SPEED WARPING High speed warping is a process of preparing warp beam directly from yarn package. Here all the yarns are wound on a simple flange beam at a time. This process is suitable for single color pattern. FEATURES OF SECTIONAL WARPING  Sectional warping is suitable for producing color fabrics with different pattern.  Production is less in sectional warping. So it is a costly process.  In sectional warping, tension cannot be kept uniform.  Here tapered drum is used as drum.  Hand weaving is necessary to produce sample fabric for bulk production. FEATURES OF HIGH SPEED WARPING  High speed warping is suitable for producing fabric with same count and same color yarn.  Higher amount of yarn is required here.  The speed and production of a high speed warping is very high.  Here simple flanged bobbin is used as beam. Southeast University – Department of Textile Engineering 20
  21. 21. Difference between Sectional Warping and High Speed Warping High Speed Warping Sectional Warping 1. Used to produce common fabric. 1. Used to produce fancy fabrics. 2. Production is high. 2. Production is low. 3. Large amount of yarn is required. 3. Small amount of yarn is required. 4. Weavers beam is produced after 4. Weavers beam is directly sizing. produced. 5. Cone and Cheese is used. 5. Flanged bobbin or drum is used. 6. The process is cheap. 6. The process is expensive. 7. High creel capacity. 7. Low creel capacity. 8. Most commonly use. 8. Rarely used. Control System in Warping  Tension control  Balloon control  Stop motion  Yarn cleaner Southeast University – Department of Textile Engineering 21 Faults in Warping  Off center warp  Reged or uneven warp  Cross end  Snarl formation  Hard/soft beam  End missing
  22. 22.  Length control  Surface speed control  Proper yarn density  Static electricity  Traverse control  Fly control Description of Different Control Systems in Warping 1. Tension Control: Tension should not be low or high during warping. Because due to lower tension package will be unstable, entangled and snarling will occur. Whereas high tension will cause yarn breakage. The tension should be just and uniform throughout the process. 2. Balloon Control: Balloon controlling is necessary so that the yarns does not entangled with one another. For this, yarn guides should be placed at right positions. 3. Stop Motion: The m/c should stop itself if any yarn breakage occurs at any point. So stop motion system is necessary to control. 4. Yarn Cleaner: Proper setting should be maintained to remove yarn faults. 5. Length Control: the Length of warp sheet should be controlled. It is done with a measuring roller in combination with a suitable counting device by stopping the device machine after winding pre-determined length of warp yarn onto the beam. 6. Surface Speed: The surface speed of beam should be controlled specially when a large change in warp diameter is involved. Southeast University – Department of Textile Engineering 22
  23. 23. 7. Proper Yarn Density: In warp sheet the yarn ends/inch, means yarn density, is to be controlled. Because without proper yarn density the fabric will be uneven. 8. Static Electricity: It is specially required in case of man-made fibres. It is controlled to avoid yarn entanglement. It is done by: i. Chemical fiber finishes ii. Ionization of air. iii. Humidification of air. 9. Traverse Control: In sectional warping traverse rate of beam should be controlled. 10. Fly Control: In staple fibres lints, small trashes may cause problem by flying around the working area. So this fly should be controlled to have a pleasant working atmosphere. Description of Different Faults in Warping and Their Remedies: 1. Off Centre Warp: If beam or wraith is not set properly i.e. it is not centric due to carelessness this type of fault occurs. Remedy: Beam or wraith should be placed proper 2. Rigid or Uneven Warp Surface: This may occur if i. Yarn density [ends/inch] is very low. ii. Different counts of yarns is wound on beam/ iii. Yarn density is uneven. Remedy: yarn density and count should be maintained properly. 3. Cross Ends: If occurs due to faulty knotting after end breakage. (Joining broken end with wrong end) Remedy: Knotting and tension should be done carefully. 4. Snarl Formation: Snarl form due to over tension, highly twisted yarn and careless operation. Remedy: Tension should be kept proper and yarn twist should be as required. 5. Hard/Soft Beam: If during winding yarn on being yarn tension is low or high soft and hard beam forms. It may also occur due to uneven pressure on drum or beam. Southeast University – Department of Textile Engineering 23
  24. 24. Remedy: Tension and pressure should be maintained even. 6. End Missing: If yarn breakage occurs m/c should be stopped immediately. If such cannot be done the broken end of yarn cannot be found out. This is end missing problem. Remedy: Stop motion system should be very active and m/c should be stopped immediately after end breakage. 7. Haphazard Knotting: if various length of yarn is wound in creel packages then during beaming different end will finished in different time. So knotting would be in various places of the warp. This will haphazard knotting. Remedy: In creel packages same length of yarns should be present so that all yarn finish at a certain place of warp. 8. Length Variation: It may occur due to fault stop motion. It means if the stop motion system stops the m/c before winding required length of yarn on beam length variation occurs. Remedy: Stop motion should be checked carefully. Let, s = traverse length. L = Axis at length of warp on drum. d = empty beam dia. D = full beam dia. dm = = mean dia. X = tape distance α = taper angle v = volume of yarn stored on beam. Let, Southeast University – Department of Textile Engineering 24 Relation between Taper Angle and Amount of Yarn on a Beam
  25. 25. s >x, so as to maintain stability. V = - = ( - ) = (D+d) (D-d) = πL ( ) ( ) From figure, we can see that, dm = , mean dia and = x tan α So , V = π L dm (x tan α) or, V > π L dm (S tan α) if, x > s or, V < π L dm (S tan α) if, x < s So, V S tan α if α = 90° then V = s tan 90°= α So unlimited amount of yarns can be wound if flange stays perpendicular to beam barrel. Practically this is impossible. But this type of package permit’s to wind high amount of yarn. The method of applying a gelatinous film forming substance of starch on warp yarn before weaving is known as sizing. Object of Sizing  To protect the yarn from abrasion with heald eye, back rest, reed etc. during weaving.  To improve breaking strength of cellulosic yarn.  To increase yarn smoothness.  To reduce yarn hairness.  To increase yarn elasticity and stiffness.  To decrease yarn extensibility.  To hinder generation of static electricity for synthetic and blended yarn.  To increase yarn weight. Sizing Ingredients and Their Functions Some important size ingradients and their functions are mentioned below- Southeast University – Department of Textile Engineering 25 Π2 4 D + d 2 D - d 2 SIZING
  26. 26. 1. Adhesive 2. Lubricants or softeners 3. Antiseptic or antimildew agent 4. Deliquescent or Hygroscopic agent 5. Weighting agent 6. Anti-foaming agent 7. Tinting agent 8. Wetting agent 1. ADHESIVE Adhesives are mixed with water in granular form and heated to form a paste which ultimately becomes a viscous fluid. The followings do as adhesives in a size:  Maize, corn, wheat, rice, potato starch.  CMC (carboxyl methyl cellulose).  PVA (poly vinyl alcohol).  PVC (poly vinyl chloride). The functions of adhesives are as follows;  To increase yarn strength.  To reduce yarn hairiness.  To increase elasticity and stiffness.  To increase smoothness. 2. LUBRICANTS OR SOFTENERS Mineral waxex, vegetable waxes, animal fats; mineral oils, vegetable oils, tallow, Japan wax etc. are used as lubricants or softeners. Function Southeast University – Department of Textile Engineering 26
  27. 27. If softeners are not present in sizes the yarns will not be sufficiently extensible. Then the size would crack and particles would drop away from the yarn .And this, in turn, would create local stress concentration. 3. ANTISEPTIC OR ANTIMILDEW AGENT ZnCl₂, phenol, carboxylic acid, salicylic acid are used as antiseptic or antimildew agent. Function i. It helps to store the sized yarn protect it from bacteria and fungi. ii. It prevents the growth of mildew on yarn during storage. 4. DELIQUESCENT OR HYGROSCOPIC AGENT Hygroscopic agents present in size absorb moisture from air glycerin, CaCl₂ are some deliquescent agent. Function a) To prevent the brittleness of size. b) To absorb moisture from air. c) To prevent excessive dyeing of yarn. 5. WEIGHTING AGENT China clay, CaCO₃, Na₃, PO₄, France chal etc. are used as weighting agent. These are to be used specially for those fabrics that are to be solid in grey state. Function a) To increase the weight of yarn hen fabric. b) To impart fullness and feel to fabric. Southeast University – Department of Textile Engineering 27
  28. 28. 6. ANTI-FOAMING AGENT Pyridine, benzene etc.as used as anti-foaming agent. Function: To prevent the formation foam 7. TINTING AGENT Blue is used as tinting agent. Function: a) To increase luster or brightness. b) To produce a pale color in dyeing. 8. WETTING AGENT Sulphanol A, soap, avirol, MgCl2 etc. are used as wetting agent in a size. Their drawbacks are their high and very stable foaming ability. Function: a) To ensure the uniform distribution of the sizing solution on yarn surface. b) Reduce surface tension of the liquor. c) Increase size absorbency. TECHNOLOGICAL CHANGES OCCURE DUE TO SIZING The following technological changes of a yarn/fabric occurs due to sizing – 1. INCREASE IN BREAKING STRENGTH 2. INCREASE ABRASION RESISTANCE 3. INCREASE IN STIFFNESS 4. INCREASE IN ELASTICITY 5. INCREASE IN FRICTIONAL RISISTANCE 6. INCREASE IN YARN DIAMETER 7. DECREASE IN YARN HAIRINESS 8. DECREASE IN STATIC ELECTRICITY FORMATION DESCRIPTION 1. INCREASE IN BREAKING STRENGTH Southeast University – Department of Textile Engineering 28
  29. 29. During sizing adhesive materials create bonds between fibers to fiber which, as a result, increase the breaking strength of the yarn. It increases 20-40% breaking strength of the fiber. 2. INCREASE ABRASION RESISTANCE After sizing the gap between fibers are filled with size due to the coating of size on the outer surface of the yarn. So their resistance against abrasion is increased. 3. INCREASE IN STIFFNESS After sizing flexibility or pliability of a yarn is decreased and stiffness is increased. 4. INCREASE IN ELASTICITY As extensibility of the sized yarn decreases, more force is to be applied to extend the yarn. This is means, elasticity of the yarn increases. 5. INCREASE IN FRICTIONAL RISISTANCE Sizing produces smooth yarn surface and so less friction occurs. Again size coating increases the frictional resistance of yarn 6. INCREASE IN YARN DIAMETER Due to coating of size ingredients the yarn diameter increase but yarn’s apparent diameter is decreased. 7. DECREASE IN YARN HAIRINESS By sizing protruding hairs of yarn fix with yarn and so yarn hairiness decreases mentionably. 8. DECREASE IN STATIC ELECTRICITY FORMATION Size materials contain hygroscopic agent and water which hinder the formation of static change on yarn surface. Again due to mass frictional resistance the formation of static electricity becomes less. SIZE TAKE-UP PERCENTAGE Southeast University – Department of Textile Engineering 29 Wt. of size material on yarn × 100%
  30. 30. Size take up % = Size Take up Percentage Depends on the Following Factors  Twist S.T  Yarn count S.T  Viscosity of size material S.T  speed of yarn passing through m/c S.T  Pressure of squeezing roller. S.T  Amorphousness of fiber in yarn. S.T  Flexibility of yarn S.T  Nature of adhesive. S.T  Time and Temperature. S.T SIZE CALCULATION MATH-1: A beam of wt. 260 lbs. contains 4000 sized warp of 1200 yds length. It the unsized yarn count is 30 Ne and empty beam wt. 50 lbs., then calculate - i. Wt. of size on yarn. ii. Count of sized yarn. iii. Size take-up percentage. Soln: 4000×1200 Weight of unsized yarn = yds 840×30 = 190.47 lb. Southeast University – Department of Textile Engineering 30 Wt. of unsized yarn
  31. 31. Wt. of sized Yarn = (260 – 50) lbs. = 210 lbs. Wt. of size material = (210 - 190.47) lbs = 19.53 lb. (Ans) 4000×1200 Wt. of sized yarn = yds. 840×C 4800000 or, 210 = 840×C 4800000 or, C = = 27.21 = 27 Ne (Ans) 840 × 210 Size take up percentage (%) = (wt. of size material on yarn / wt. of unsized Yarn) x 100 % = 19.53/190.47 x 100 % = 10.25 % (Ans) The loom is the contact point of the whole process of cloth production, ginning, opening, carding, spinning, winding, warping, sizing and beaming are done before weaving. A loom cannot be said a machine but it is a Southeast University – Department of Textile Engineering 31 LOOM
  32. 32. device which is used to produce woven fabric. Looms are generally driven either by line shaft or by individual motors fitted with it. Weaving Mechanism / Basic Principle of Weaving Weaving is the process of interlacement between the warp and weft in fabric according to a design of fabric. Basic principle or weaving mechanism is:  The yarn from the weavers beam passes round the back rest and comes forward through the drop wire of the warp stop motion to the heald eye of heald shaft which is responsible for the purpose of shade formation.  It then passes through the dent of reed which holds the thread at uniform spacing and it is also performed the beating up the weft thread that has been left in the triangle warp sheet form by the two warp sheet and reed.  In this way, weft yarn is meshes with last pick of fabric or cloth. Temple holds the cloth firm at the feed position and assist in the formation of a uniform fabric width. Then fabric passes over the front rest, take up roller, pressure roller and finally wind on to the cloth roller. DRIVING MOTION Southeast University – Department of Textile Engineering 32
  33. 33.  It is seen that the figure that, two tappet mounted with the one bottom shaft and it passed the treadle lever by treadle bowl to down direction.  There is a fulcrum at the end of treadle lever and another end of lever is joined with heald shaft by yarn.  Top roller acts as intermediate of two rope of heald shaft from which rope passes over the top roller.  When shedding cam or tappet pressed on the treadle lever by treadle bowl, then one heald shaft is down while another is up and shedding is formed. Such way, 2nd shedding tappet reverses full motion i.e. upper heald shaft is down and down heald shaft is up.  The mechanism of a power loom receives their motion from shaft that traverses from side to side in the loom and is driver from another. Their relative speeds are of importance since they give the mechanism that they drive.  The crank shaft being driven by the motor moves one revolution per picks. The motion of the teeth of the gear wheels connecting this shaft to the bottom shaft is always 2:1, so that the bottom shaft will move one revolution in ever two picks. Southeast University – Department of Textile Engineering 33
  34. 34. CLASSIFICATION Southeast University – Department of Textile Engineering 34 Loom Hand Loom Power Loom Ordinary Power Loom Automatic Power Loom Modern or Shuttle less Loom Hand Loom 1. Primitive or Vertical loom. 2. Pit loom (a) Throw shuttle loom. (b) Fly shuttle loom. 3. Frame loom (a) Throw shuttle loom. (b) Fly shuttle loom. 4. Chitttaranjan loom. 5. Hattersley loom Ordinary Motor 1. Common Motor. 2. Individual motor. Modern or Shuttle less Loom 1. Projectile Loom. 2. Rapier Loom. 3. Air jet Loom. 4. Multiphase.
  35. 35. LOOM MOTION Southeast University – Department of Textile Engineering 35 Loom Primary Motion Secondary Motion Tertiary Motion Primary motion 1. Shedding: (a) Tappet (b) Dobby. (c) Jacquard. 2. Picking: (a) Over pick (b) Under pick. (c) Modern pick. 3. Beating: (a) Single (b) Multiple (c)Variable. Secondary Motion 1. Take up (a) Positive (b) Negative. 2. Let off (a) Positive (b) Negative. (5 wheel, 7 wheel) Tertiary Motion 1. Warp stop motion 2. Weft stop motion (Centre, side) 3. Reed stop motion (Loose, fast) 4. Temple motion (Roller, reed) 5. Weft replenish
  36. 36. 1. Primary Motion In order to interlace warp and weft thread to produce fabric on any type of weaving machine 3 primary motion is necessary: I) Shedding: It is the process of separating the warp thread into two layers to form a tunnel called shed (through which shuttle carrying weft passes) is known as shedding. During shedding some yarns are raised up and some are depressed down create a tunnel. II) Picking: The method of passing the weft threads which traverse across the fabric through shed is called picking. The inserted weft is called a pick. III) Beating: It is the process of pushing the pick into the already woven fabric at a point known as fell of the cloth .By pressure of wraith to jointed feed side of the cloth is called beating. 2. Secondary Motion I) Take up motion: The motion which with draw (wound up) fabric from the weaving area at a constant rate and thus give required pick spacings and winds the fabric on to a roller is called cloth control or Take up motion. Positive Take up motions is mechanically driven. Negative Take up motions is spring drive. II) Let off motion: The motion which deliver warp to the weaving at the required rate and at a suitable constant tension by unwinding it from a flanged known as weavers beam is called let off motion. Southeast University – Department of Textile Engineering 36
  37. 37. 3. Tertiary Motion Tertiary motion is not must for fabric production but it is used for higher production. 1. Warp Stop Motion: Machine will be stopped electrically or mechanically. 2. Weft stop motion: It may be two types- (a) Side weft motion & (b) Centre weft motion. 3. Reed stop motion: Two types- (a) Fast reed motion. (b) Loose reed motion. SHEDDING Dividation of warp threads into two parts for insertion of weft threads is called shed and the mechanism of shed is called shedding, it is the first primary motion of weaving Types of Shed 1. Bottom close shed 2. Centre close shed 3. semi-open shed 4. Open shed Southeast University – Department of Textile Engineering 37
  38. 38. Primitive Loom /Vertical Loom Warp yarn is taken in a roller instead of beam and hanged in a wall and shed is produced by a piece of wood. In this loom the vertical frame is used to hold the warp in stretched condition. Weft is passed through the shed by hand. Beating is done by the pressure of hand. Take off action was done in a separate roller by hand. Let off was also by hand. Picking Beating One weaving cycle Shedding Primary motion Throw Shuttle Pit Loom In this loom, the frame was laid on a pit. Shedding was obtained by giving the pressure to the treadle levers suited inside of the pit by feet. The weaver throws the shuttle across the width of the cloth by one hand and catches it by another hand. Chittarajan Loom It is constructed by iron and wood. The principle characteristics of this loom is –  The two wheels upon a shaft connect the sley two ends with the help of two levers. Regulating the sweep of sley and force of beat up allowing less strain to weaver and uniform force to beat up.  The positive take up motion by the five wheels to regulate the picks per inch. The alternation of picks per inch is positive by changing the wheel to take up motion.  Negative let off motion with chain, lever and dead weights has been adopted in this loom to ensure uniform let off warp cloth is taken up by positive means. Southeast University – Department of Textile Engineering 38
  39. 39.  Shedding and picking motion work in the same manner as in the fly shuttle loom but the loom speed is greater than hand loom.  Shedding motions are generated manually but secondary motions like let off and take up are done automatically. So this loom may be called semi-automatic loom. Southeast University – Department of Textile Engineering 39
  40. 40. JUTE LOOM Hessian Loom  Used for comparatively fine fabrics  Larger loom width  2 heald shaft, one yarn/ heald eye  Finer reed  Two tappet and tappet are on bottom shaft  Small pinion on pin roller  Suitable for plain weave(1 up1 down)  Yarn count—7.5 lb/spindle  Backrest attach with frame Sacking Loom  Comparatively coarse fabric  Loom width is less  3 heald shaft,3 yarn/heald eye  Coarse reed  Larger pin on pin roller  Suitable for twill weave(2 up,1 down)  Yarn count (8-10), around 8.5 lb/spindle  Separate back rest  Tappets are on counter shaft. Advantages of Fly Shuttle Loom/ Reason for Choice of Fly Shuttle Loom  Higher m/c speed or weaving speed(60-80rpm) Maximum speed of Pit loom-60 rpm Hand through Pit loom-20 rpm Vertical loom-1 ppm  No. of heald shaft is higher  In fly shuttle loom, higher width fabric is possible  In Pit loom, only narrow width fabric can be woven  Solid and compact structure with minimum vibration Fly shuttle loom- more compact and solid structure -minimum vibration Southeast University – Department of Textile Engineering 40
  41. 41. -less space Pit loom-higher vibration -more space  Flanged weavers beam provided better selvedge Fly shuttle loom-wooden flanged weavers beam ensure better selvedge Pit loom- without flanged weavers loom  Adjustable back rest to suit quality fabric  Pit loom- fixed back rest 22  Let-off with lever arrangement -Uniform let-off of yarn is possible.  Adjustable sweep of sley –suit quality fabric. Pit loom-over hanging sley assembly -sweep of sley is not adjustable. Fly shuttle loom-sley assembly is supported by sley sword  More freely operated treadles.  More cloth on cloth roller is possible.  Positive take-up can be fitted.  Free picker  Dobby and jacquard can be fitted.  Suitable for both fine and coarse fabric. Difference between Hand Loom and Power Loom Southeast University – Department of Textile Engineering 41 Hand Loom Power Loom 1. Operating system is manual. 1. Operating by electric power. 2. Shedding is done by paddle and Picking, Beating is done by hand. 2. Shedding and Picking is done automatically. 3. Less production. 3. High production. 4. Slow running speed. 4. High running speed. 5. Check and striped fabrics are produced. 5. One color fabrics is produced.
  42. 42. 10 01 Construction 10 Plain 20 Twill 30 Satin 0101 00 Lifting pattern of the first warp yarn No. of adjacent warp yarns with identical lifting pattern Move number Difference between Hesian and Sacking Loom Hesian Loom Sacking Loom 1. One up one down plain weave. 1. Two up one down twill weave. 2. It has two heald shafts. 2. It has 3 eald shafts. 3. No of tappet 2. 3. No of tappet 3 4. No auxiliary shaft. 4. Need of auxiliary shaft due to more 2 tappet is called counter shaft. 5. A single yarn is passed through a heald eye. 5. Two yarns are passed through a heald eye. 6. Less spacing between warp yarns. 6. More spacing between warp yarns. 7. Finer thread is used. 7. Coarser thread is used. New condensed notation (DIN 61 101) Southeast University – Department of Textile Engineering 42
  43. 43. DEFINITION Knitting is the method of creating fabric by transforming continuous strands of yarn into a series of interlocking loops, each row of such loop hanging by the one immediately preceding it. The basic element of knit fabric structure is the loop intermeshed with the loops adjacent to it on both side and above and below it. TERMS  Kink of Yarn: Per loop from a single yarn.  Knitted Loop: two loops intermeshed.  Knitted Stitch: Three loops intermeshed.  Top Arc: Loop Head  Bottom Half Arc  Leg/ Side Limber  Needle Loop  Sinker Loop  Close Loop  Open Loop Southeast University – Department of Textile Engineering 43 Fig: knitting structure
  44. 44.  Wale: Vertical column of needle loop.  Course: Horizontal row of needle loop.  Stitch Density: Wales per Inch × Course per Inch.  Stitch length: Needle loop + Sinker loop  Extended sinker loop  Face loop  Back loop  Needle: Southeast University – Department of Textile Engineering 44 United Needle Independent Needle
  45. 45.  Knitting M/C: there are three types of knitting M/C – 1. Warp knitting: Gives vertical movement of yarn. 2. Weft knitting: Gives horizontal movement of yarn. 3. Other loop forming and combined M/C: Tri-axial.  Needle Carrier: Which carries needle.  Number of Feed System: The number of feeder by course.  Working Diameter: In circular knitting m/c, the distance from one needle exact to the other needle is known as working dia.  Working Width: In flat knitting m/c, the distance from first needle to the last needle is known as working width.  Gauge: Number of needle per inch.  Pitch: The distance the center from one needle to the center of another needle is known as pitch.  There Are Three Types Of Knitted Fabric  Selvage fabric Southeast University – Department of Textile Engineering 45
  46. 46.  Cut edge fabric  Tubular fabric  Open lap  Close lap DIAL Dial is the upper steel needle bed used in double knit machines. Into the grooves of the dial, the needles are mounted horizontally and are allowed to move radially in and out by their dial cams. The number of grooves per unit space conforms to the cylinder gauge in most of the cases. CYLINDER Southeast University – Department of Textile Engineering 46 O = over lap U = under lap  Over lap  Under lap Fig: Dial
  47. 47. The cylinder is a steel circular bed having grooves/tricks/cuts on its outer periphery into which the needles are mounted. With reference to the tricks, the needles move vertically up and down by their butt being in contact with the cam track. The number of tricks per inch i.e., number of needles per inch decides the gauge of the machine. Machines are built as low as 4 NPI to as high as 32 NPI. Based on the machine gauge, the fineness of the yarn to be knitted can be varied. The diameter of the cylinder also varied based on the type and width of the fabric and a maximum of 75 cm diameter machines are available. FEEDERS/STRIPPERS Feeders are the yarn guides placed close to the needles to the full circumference of the knitting zone. The feeders feed the yarn into the needle hooks and control the needle latches in their open position while the needle attain their clearing position. They consist of a yarn guiding hole and a bevel edge to guard the latches of the approaching needles. They are slightly curved to the corresponding curvature of the needle bed. Feeders may have two holes also for the purpose of plating. Yarn feeders can be divided into “positive” or “negative” types depending on the possibility of controlling the yarn feeding speed and uniformity. Southeast University – Department of Textile Engineering 47 Fig: Cylinder
  48. 48. The feeder brackets can be adjusted to set their distance from the needle and to ensure yarn feed into needle hooks. Stripers are the feeders designed to deliver two or more yarns individually to the same feed. They can be considered as moving guide replacing the holes of fixed guides. In a two color stripe, two different colored yarns are supplied by two stripper fingers and their engagement is controlled by an endless control chain which governs the guide change at the appropriate feeds. At each revolution, a counter may select the movement of all the striper chains. The stripes are used on both single and double bed machines. MACHINE DESCRIPTION Southeast University – Department of Textile Engineering 48 Fig: Feeders/Stripers Circular Knitting
  49. 49. Frame The circular knitting machine consists three major sections viz., yarn supply, knitting elements and fabric take-down. The Fig. 2.3 shows the machine frame, indicating its various parts. The knitting elements such as needles, sinkers, cylinder, cams and feeders are supported at the center called as knitting zone. Yarn packages are mounted at the overhead creels and yarns are fed to knitting zone through yarn guides, stop motions and feeders. The knitted fabric goes down inside the cylinder towards the centre of the machine, drawn into the take down device and finally collected on a roll winding mechanism. A fabric spreader gradually converts the tubular fabric into a double layer folded fabric by preventing the formation of pleats or creases. At the knitting zone, single knit plain machines are fitted with a cylinder and sinker ring, whereas the double knit machines have cylinder and dial. Drive The drive to the knitting machine is simple and direct. The motor imparts rotary motion to the rotating needle beds, such as cylinder and dial and also to the take-down and cloth winding mechanisms. Basic Elements of Knitting Southeast University – Department of Textile Engineering 49 1. Legs 2. Cylinder 3. Dial 4. Needle 5. Cam Parts 6. Feeder guide 7. Cam 8. Supply Package 9. Creel 10. Top Stop Motion 11. Anti Snarl Device 12. Tensioner MECHANICAL PRINCIPAL OF KNITTING TECHNOLOGY
  50. 50. 1. Needle 2. Sinker 3. Cam 1.NEEDLE: There are various types of needle are available in market which can be divided in the following group. a. Spring Bearded Needle b. Latch Needle c. Compound Needle SPRING BEARDED NEEDLE Stem: The stem around which the needle loop is formed. Beard: To create new loop. Eye/groove: To receive the beard. Shank or butt: To support and give strength to the needle. And control the movement of needle. Tip: To receive the latch spoon. Head: To open and close the latch. Stem: It around which the needle loop is formed. Southeast University – Department of Textile Engineering 50
  51. 51. LATCH NEEDLE Hook: It draws and retains the new loop. Latch blade: To give support and strength the latch. Latch spoon: To open and close the needle. Stem: This carries the loops in the clearing or rest position. Rivet: It works like a screw. Butt: Which serving to displace the needle along the needle bed slot. COMPOUND NEEDLE Tip: To receive the latch spoon. Hook: To form a new loop’ Sliding latch: To open and close the needle and help to form new loop. Dead weight: To give downward motion of the sliding latch. Lead: It works like a butt. Southeast University – Department of Textile Engineering 51
  52. 52. The sinker is the second primary knitting element. It is a thin metal plate with an individual or a collective action operating approximately at right angles from the hook side of the needle bed, between adjacent needles. Sinkers capable of producing loop fabric are well known in the knitting industry. In such machines the sinkers generally include a blade having an upper edge which defines a lower knitting level and a nib having an upper edge which is at an upper knitting level. Long loops are formed at the upper knitting level of the sinkers with a loop yarn and a base yarn is knitted over the blade. The sinkers may be formed and their movement controlled to cause either the loop yarn to appear on one side of a fabric and the base yarn on the other or the loop yarn to appear on both sides. FUNCTION Butt: To fix the sinker with the sinker bed. Shank: To give strength and support the sinker Buldge: To gives strength and support. Lower shank: To give strength and support to the sinker. Throat: To form new sinker loop. Clearence: To hold the sinker loop. Southeast University – Department of Textile Engineering 52 2. SINKER
  53. 53. FUNCTION OF SINKER There are three function of sinker. 1. Loop formation 2. Holding down 3. Knocking over 1. Loop Formation: On bearded needle weft knitting macShine’s of straight bar frame and sinker wheel type, the loop forming action is performed. The purpose of a sinker is to kink the newly laid yarn into loop as its forward edge of advance between two adjoining needle. 2. Holding down Sinker: The second function is hold down the old loop a lower level on the needle stem, then the new loop which are being formed and prevent to old loops from being lifted as the needles rise to clear from their hooks. 3. Knocking Over Sinker: The third function of the sinker is to knock over the old loops on the neck of the new loops. Sinker’s Operation 1. The held loop is positioned in the throat of the sinker when the sinker moves forward and the needle moves upward for clearing. The held loop is held by the throat and hence its movement along the needle is restricted. Southeast University – Department of Textile Engineering 53
  54. 54. 2. The sinker remains at its forward position when the needle attains its clearing position. 3. The sinker retracts when the needle comes down after feeding. At this stage, due to sinkers retraction, fabric or held loop is eased out. Also the sinker belly supported the fabric or held loop and hence its movements along the needle is prevented. 4. Sinker remains in backward position and the needle descends to its lowest position drawing the new loop through the old one. 5. Before the needle ascends, the sinker moves forward to push the knitted fabric a little and to hold the old loop away from the head of the needle and to be in a position to control the fabric. Southeast University – Department of Textile Engineering 54
  55. 55. The knitting cams are hardened steels and they are the assembly of different cam plates so that a track for butt can be arranged. Each needle movement is obtained by means of cams acting on the needle butts. The knitting cams are divided in to three groups. Such as 1) Knit cam 2) Tuck cam 3) Miss cam The upward movement of the needle is obtained by the rising cams or clearing cams. The rising cam places the needle at a certain level as it approaches the yarn area. Cams controlling the downward movement of the needles are called stitch cams. The lowest point to which the needle is drawn by the stitch cam is called the “cast-off” position. Guard cams keep the needle butts in their race-way. Running cams or [up throw Southeast University – Department of Textile Engineering 55 3. CAM
  56. 56. cams] the needle butts at a low level until they meet the next rising cam. Knitting Action of Latch Needle of Knit Loop 6. Knock over Position a. The old is falling on the neck Figure Description Southeast University – Department of Textile Engineering 56 of new loop. b. Thus the knit loop is formed. c. The latch is closed. 1. Rest Position a. The previously formed loops is in the hook. b. The needle which now starts to ascend. c. The latch is closed. 2. Tuck Position a. In this position the loop is on the latch. b. The latch is opened. 3. Clearing Position a. In this clearing position latch is opened. b. The loop is under the latch. 4. Feed Position a. New loop is on the hook. b. The old loop is under the latch. 5. Custom Position a. The latch is starting to close. b. The old loop is on the latch. c. The new loop is in the hook.
  57. 57. Knitting Action for Tuck Loop in Latch Needle Southeast University – Department of Textile Engineering 57 7. a. The latch is closed. b. The loop is in the hook. 8. a. The latch is close. b. The loop is in the hook. 9. a. The latch is open. b. The loops are on the latch. 10. a. The latch is open. b. The new loop is in the hook. 11. a. The new loop is in the hook. b. The latch is open. c. The old loops are in the hook. 12. a. The latch is open. b. The loops are in the hook. 14. a. The loops are under the hook. b. The latch is open. 13. a. The loop is on the latch. b. The latch is open. Figure description (Fig: 002)
  58. 58. Southeast University – Department of Textile Engineering 58 15. a. The loops are on the latch. b. The latch is close. 16. a. The old loop joins to the new loop. Knitting Action of Spring Bearded Needle (Knit Loop)
  59. 59. FIGURE DESCRIPTION 1. YARN FEEDING a. Beard is open. b. New yarn feed in the beard. c. Old loop is in the stem. Southeast University – Department of Textile Engineering 59 2. YARN KINKING a. Beard is open. b. Old loop is in the stem. c. Sinker kink the newly feed yarn. 4. PRESSING a. The beard is closed by pressure. b. The old loop is on the stem. c. The new loop is in the hook. 3. UNDER LAPPING a. The beard is open. b. The old loop is on the stem. c. The sinker takes the new loop to the front. 5. LANDING a. The beard is closed by pressure. b. The old loop start to going on the beard. c. The new loop start to going 6. JOINING AND CASTING OFF a. The beard is closed. b. The old loop is falling on the neck of the new loop. 7. CLEARING a. The beard is open. b. The loop is in the stem. (Fig: 002)
  60. 60. Jersey fabric is a type of knit textile made from cotton or a cotton and synthetic blend. Some common uses for jersey fabric include t-shirts and winter bedding. The fabric is warm, flexible, stretchy, and very insulating, making it a popular choice for the layer worn closest to the body. Jersey also tends to be soft, making it very comfortable. The textile is named for the island of Jersey. Jersey is the largest of a group of islands known as the Channel Islands, located between England and France. The island has a long history of human occupation, and is also well known for Jersey cows, typically raised for their rich, creamy milk. A knitting machine is used to make jersey, since it can create the small, even, close grained stitches associated with jersey fabric. Like many other knit fabrics, jersey fabric has a right side and a wrong side. The right side of the material is marked by a series of very small lines which run vertically, and the wrong side has a horizontal grain. In most cases, a garment made from jersey fabric is sewn with the right side facing out, unless the seamstress is making a deliberate stylistic choice. One of the reasons many people like to wear jersey fabric is the stretch factor. The fabric can stretch up to 25% percent along its grain. Garments made from the material have plenty of give as their wearers move, and also tend to cling to the body, since the fabric contracts as well as expanding. Knit dresses are usually made from jersey fabric, exploiting the clingy characteristic of the fabric. Jersey fabric is also available in a large assortment of colors and patterns to suit all tastes. Care directions for jersey fabric vary, depending on whether the fabric is entirely natural or partially synthetic. As a general rule, jersey fabric can be washed in warm water with like colors, and tumble dried on a medium setting. Bright colors will stay brighter longer if they are washed on a cold setting and dried on low. Try to avoid mixing bright colors and whites in the wash, as the colors may bleed. When sewing jersey fabric, it is recommended that the fabric be washed first, especially if it is cotton. All knits tend to shrink when they are washed, and washing beforehand eliminates shrinkage issues. It is also Southeast University – Department of Textile Engineering 60 What is Jersey fabric?
  61. 61. important to use a pattern specifically designed for knit fabrics, as the pattern will account for the stretch factor of the material. Most seamstresses also use a double layer of stitching or an overlock stitch on jersey fabric, to prevent unraveling. Knitting Fabric Structure 1. Plain structure 2. Rib structure 3. Interlock structure 4. Purl structure 1. PLAIN STRUCTURE Plain is produce by the needles knitting as a single set, drawing the loops from technical back and towards the technical face side of the fabric. Example: jersey blister, jersey lily, stocknitte etc. Features of Plain Single Jersey Fabric 1. Used only one set of needle to produce fabric. 2. Simplest and most economical production. 3. 40% potential recovery stretching. 4. Probability of curling of yarn. 5. Technical face is smooth and v-shape can be seen through the Wales. 6. Technical back is rough and wave shape appeared at the back thought the course. 7. It one yarn breaks, the needle loops successively unmosh through course, this effect is called laddering. Southeast University – Department of Textile Engineering 61 PRIMARY BASIC STRUCTURES
  62. 62. 8. Unroving of yarn can be prevented by binding off. Features of Plain Circular Knitting M/C 1. Single jersey is produce by plain circular knitting m/c. 2. One set of latch needle is used here. 3. Latch needle, sinker, cylinder, sinker ring revolve around the stationary knitting cam system. 4. Yarn supplied from cone placed either on end integral overhead bobbin stand or on a free standing side creel through tensioner, stop motion guide eyes down to the yarn guide. 5. Stationary yarn feeder are situated at a regular interval around the circumference of the cylinder. 6. The fabric in tubular form is drawn downward from inside the needle cylinder by tension roller and is wound onto the fabric batching roller of winding frame. 7. The winding down mechanism revolves along with the fabric tube. 8. As the sinker cam plate is placed outside on the needle circle, the center of the cylinder is open and the m/c is referred as open top or sinker top m/c. 2. RIB STRUCTURE The structure which requires 2 sets of needle operating in between each other so that wales of face side and wales of back side are knitting on each side of fabric is called rib structure. Features of Structure 1. It is normally knitting with 2 sets of latch needle. 2. Rib has vertical card appearance. 3. 1×1 rib has the appearance of technical face of plane fabric. Southeast University – Department of Textile Engineering 62
  63. 63. 4. Relaxed 1×1 rib is theoretically twice as thick and 1/2 the width of an equivalent plain fabric. 5. It is more expensive fabric to produce than plain. 6. It can be unravel from the end knitted last by the free loop’s head through to the back of each stitch. 7. It is a heavier structure. 8. It has no curling tendency. 9. Rib structures are elastic, form fitting and retain wormth better than plain structure. Uses: Rib is suitable particularly for the top of the socks, cuff, collar rib border of garments, gloves etc. FEATURES OF CIRCULAR RIB M/C 1. In this m/c, one set of needle is arranged vertically in the cylinder and another set of needle is arranged in the dial of the m/c. 2. Here both dial and cylinder rotates where cam with yarn feeder remain stationary. 3. The needle of dial and cylinder are arranged in different position alternatively. 4. No sinker is required for this m/c. 5. Not more than 2 cam tracks are possible for dial of this m/c. FEATURES OF INTERLOCKING STRUCTURE 1. Interlocking has the technical face of plain fabric on both sides. 2. Interlock course requires 2-feeder per course. 3. Reverse loop cannot be seen. Southeast University – Department of Textile Engineering 63
  64. 64. 4. Interlocking relaxes by about 30-40% or more compared with its knitting width. 5. This is balance, smooth, stable, structure. 6. Fabric is thicker, heavier and narrower than rib of equivalent gauge. 7. Finer, better, more expensive yarn is required. 8. Bath horizontal and vertical stripe can be produced. 9. Production is lass. FEATURE OF PURL STRUCTURE 1. It has the similar appearance to pearl droplets. 2. Purl structure have one or more wales which contain both and back loop. 3. Both sides’ needle and sinker loops are prominent. 4. The tricks of the two needle bed in purl m/c are exactly opposite to each other and in same plane. 5. Double ended batch needles are used in purl m/c. 6. Two types of m/c are available for purl structure. a. Flat m/c b. Circular m/c 7. The simple purl structure is 1×1 purl. 8. Purl fabric is twice as thick as plain fabric. Southeast University – Department of Textile Engineering 64 KNITTING ACTION OF RIB CIRCULAR M/C
  65. 65. 1. REST POSITION In this position, both the dial and cylinder needles are in stationary position. And the latch is closed. 2. TUCKING POSITION FOR DIAL In this position, the needle of dial comes forward and the loop falls on the opened latch of the needle. And the cylinder’s needle remains stationary. 3. TUCKING POSITION FOR CYLINDER Southeast University – Department of Textile Engineering 65 FIGURE DESCRIPTION
  66. 66. In this position, the needle of cylinder comes forward while the needle of dial is on the forward position. The loop falls on the opened latch of the dial needle. 4. CLEARING POSITION FOR DIAL In this position, the dial’s needle goes more forward and the loop goes under the opened latch of the needle. 5. CLEARING POSITION FOR CYLINDER In this position, the cylinder’s needle goes more forward and the loop goes under the opened latch of the needle. 6. YARN PRESENTING POSITION In this position, the newly presented yarn is laid in the open needle hooks of both the needle. 7. CAST ON POSITION In this position, the both needles catch the new yarn on their head and start to come in backward position. Then the old loops close the latch of the both needle. 8. KNOCK OVER POSITION In this last position, the both dial and cylinder needles come to their backward position. The old loops knock over the newly made loops. Formulas No. of feeder=No. of cam= No. of course. = Southeast University – Department of Textile Engineering 66 Knitting Calculation Production × 1000 × 1000 × 1000 RPM of cylinder × π × Cylinder dia × gauge × loop length (mm) × Tex × 8 × 60 × efficiency %
  67. 67. No. of sinker= No. of needle= No. of loop = π D’’ G mm Number of needle = m = m = gm. Production = = kg/shift Here, D’’ = cylinder dia G = gauge L = stitch length F = No. of feeder T = tex number For single jersey: Production in weight, = kg/shift Southeast University – Department of Textile Engineering 67 Π D’’ G × l 1000 Π D’’ G l ×N ×F 1000 Π D’’ G l ×N ×F ×T 1000×1000 Π D’’ G l ×N ×F ×T × 60 × 8 1000×1000 × 1000 RPM of Cylinder × No. of feeder × π × Cylinder dia × gauge × loop length (mm) × Tex × 60 × 8 × efficiency % 1000 × 1000 × 1000
  68. 68. Production in length, = yards/shift For Double Jersey Production in length = yds/shift Production in weight = Single jersey production in weight × 2 kg/shift Southeast University – Department of Textile Engineering 68 CPM CPI RPM of cylinder × No of feeder × 60 × 8 × efficiency % CPI × 36 Single jersey production in length 2
  69. 69. Given, Southeast University – Department of Textile Engineering 69 Math-1
  70. 70. CPI = 66 Cylinder dia = 25’’ Cylinder RPM = 20 Loop length = 2.2 mm Yarn count = 70 tex Gauge = 22 No. of feeder = 90 Efficiency =90 % Find the production of the m/c in weight and production in length. (Both single and double jersey) and find no. of needle. SOLUTION For single jersey; 20 × 90 × 3.14 × 25 × 22 × 2.2 × 70 × 60 × 8 × 90% Production in weight = = 229.79 × 0.9 = 206.8 kg/shift (Ans) No. of needle = π D’’ G = 3.14 × 25 x 22 = 1727 (Ans) Southeast University – Department of Textile Engineering 70 1000 × 1000 × 1000
  71. 71. Production in length = yds/shift = 327.27 yds/shift (Ans) For double jersey; Production in length = = 163.6 yds/shift (Ans) Production in weight = 206.8 × 2 = 413.6 kg/shift (Ans) Here, PROOF GSM = lb/inc2 = lb/inch2 = × gm/m2 Southeast University – Department of Textile Engineering 71 20 × 90 × 60 × 8 × 90% 66 × 36 327.27 2 W × C × l 25.4 × 36 × 840 × Ne W × C × l 768096 × Ne W × C × l 768096 × Ne 453 1 2 39.37 1m= 39.37 inch. 1 inch= 1/39.37 1 lb= 453 gm
  72. 72. = × 453 × (39.37)2 gm/m2 = × 702148.5957 gm/m2 = gm/m2 GSM = gm/m2 (Proved) Southeast University – Department of Textile Engineering 72 W × C × l 768096 × Ne W × C × l 768096 × Ne W × C × l ×0.915 Ne W × C × l ×0.915 Ne