Denim washing

Denim washing

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  20 Ball Warping Ball warpingdepartment is the first step to making fabric. Here yarn from godown is supplied according to the required lot quality. The cones are supplied to the creel and passed through the tensioning devices and stop motion devices to the comb. The comb separates the yarn ends and supplies them uniformly removing any entanglements. Then the yarn is passed through a plastic cone which condenses this sheet of yarn into rope form. This plastic cone moves to and fro the width of the ball winding unit. The yarn is wound onto a metal roller. The length of yarn in one set is 22200 meters. When this length has been wound onto the roller, the roller is full and is replaced with a empty roller to continue the warping process. Machine: ● Mc Coy Ellison Model #680 HS winding Unit ● Mc Coy Creel Number of machines: ● 3 Creel capacity: ● 420 Cones/Creel (maximum creel capacity) ● Weighted tensioning device used ● For one set 12 balls are required
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  20 ● Speed ofwarping = 380 meters/min ● 22200 m in one Ball (length of yarn) ● 2 motors in warping unit to drive the ball ● 1 motor with fan in between two creels ● 2 reeds for leasing ● Stop motion devices for each individual yarn end ● Many of the stop motion devices were unplugged due to some fault. Rope Dyeing After the ball warping process, comes the rope dyeing process. In rope dyeing the yarn is dyed in rope form. The process starts with the balls of yarn prepared at the ball warping department onto the creels. The ends of rope of new ball are tied to the ends of the old finished ball so that time is saved. This is only done if there is no change in dyeing of the two lots. The rope of the complete set of 12 balls is creeled simultaneously. The ropes travel over guide rollers to the dyeing machine and into the first dye bath. This is the pre- wet/mercerize/bottoming dye bath. The rope passes through the dye bath and through the squeezing rollers which remove excess dye pickup. The dye pickup is allowed to oxidize in air by allowing the rope to move upwards to the rollers above. The rope passes through different dye bath which are discussed below. The dye used is vat dye which is applied in reduced form. Vat dye has to be first reduced with a strong reducing agent such as hydrogen peroxide so that it becomes in soluble form. After application the dye must be allowed to oxidize in air to enable it to return to its original form. After the application of indigo dye is done the topping is done. Topping is again sulphur dye application. Rope is washed in hot water to remove unfixed dye stuff. pH is neutralized with acetic acid dye bath and softener is applied in last dye bath. After this comes a series of drying cans which dry the wet ropes and then the ropes are collected in big storage tanks.
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  20 Machine: ● 12 TotalDye Baths ● 30 Creel Capacity ● Dye Baths capacity (2500 l) ● 36 Drying Cans ( 100-130 degree centigrade) Dyes used: ● Indigo (dyed at room temperature) ● Sulphur (dyed at 85 ^C) Shades: ● 0-99 Regular blue ● 200-299 Grey ● 300-399 Sandwich ● 400-499 Black ● 500-599 Bottoming ● 600-699 Topping Bottoming --- First Dye Bath Topping--- Last Dye Bath Sandwich --- Bottoming and Topping [Sulphur - Indigo- Sulphur] Dye Bath Recipe: ● 106 g chemicals added to 3000 l water ● This is prepared in the dye preparation tanks ● Chemicals contain : 1. Dye 2. Caustic 3. hydro 4. Wetting Agent 5. Dispersing Agent Dyeing Procedure: ● The ends from the yarn ball form a rope which enters the dyeing machine. ● First tank is ‘Bottoming Tank’ where sulphur dye is applied in reduced form. ● Air oxidation is allowed. ● Then a set of wash boxes, wash the unfixed dye. ● Then indigo is dyed in reduced form and allowed to oxidize in air. ● Washing is done. ● Topping tank where again sulphur is dyed. ● Softeners and formic acid tank where the pH is neutralized. Rollers: Pressure Temperature
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  20 Entry 50 PSI------- Bottoming 80 PSI 85^C Dye Bath 1-6 100 PSI RT Topping 40 PSI 80^C Wash Box 1 80 PSI 60^C Wash Box 2-3 90 PSI RT Wash Box 4-5 75 PSI RT/50^C Wash Box 6 90 PSI 70^C Softener 45 PSI RT ● Total number of Rollers/Padders =211 ● Bottoming Tank Capacity =1600 l Kitchen Tanks: ● Total tanks= 11 ● Used for preparation and storing of chemicals Tank# 1&2 Bottoming Tank# 3 Indigo Tank# 4&5 Caustic Tank# 6&7 Recovery Table Tank# 8&9 Topping Tank# 10&11 Softener Chemicals: ● Biosol softener ● Hydro Sulfite E (strong reducing agent) ● Natrium dithionite ● Sodium dithionite ● Reducer RDT Powder ● WDF Indigo Grain (dye) ● Primasol MF (Wetting Agent) ● Sewron 540 (Wetting Agent) ● Hydrogen peroxide ● Sentamol BL (Dispersing Agent) ● Florant LT (Sequestering Agent) ● Diresul Black RDT-RL ● Diresul Blue G-150 ● Diresul Indi Blue-R ● Direct Black RDF liquid ● Sulphur Yellow GR (2011) ● Sulphur Olive GR (2205) ● Sulphur Black
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  20 Shade: ● The numberof Dye Baths is adjusted according to the required shade. ● The prepared Dye Bath solution is always constant at 106g/3000 l. ● The shade is adjusted by adjusting the stroke of pump which transfers the dye bath from the preparation tank. ● After every 20 minutes concentration of hydro and pH of the dye bath is taken. The pH should be 11.2-12.2 ● Shade is also adjusted by changing the concentration of hydro. ● If a darker shade is required then the concentration of hydro will be increased. Comments: ● Worker safety is not ensured. ● Fans are being operated without grills, which is a safety hazard. LoopTex Looptex dyeing is also known as slasher dyeing process. In Looptex dyeing there is only one dye tank for sulphur dye bath and one for indigo dye bath. The yarn is dyeing in sheet form. Each sheet is dipped into the dye bath 4 times. Also after dyeing process the yarn sheet is sized. This process features dyeing and sizing operations in single machine. The sized yarn beam prepared is ready to be installed in weaving loom Machine: ● Looptex Kusters Corporation, Spartanburg ● Loopdye Switzerland ● 1 dye box (Indigo) ● 1 dye box (Sulphur/Pre-Wet) ● 5 Wash Boxes ● 1 Size Box In looptex dyeing there is only one indigo dye bath. The sheet of ends is passed through the dye bath four times by looping the yarn sheets around the machine. Procedure: ● In looptex, the yarn ends are creeled onto beams, usually 12 beams for one set containing 22000 m of yarn/end. ● These beams are installed on the creel. ● Yarns pass through the dye baths and onto the accumulator. ● Drying is done through dry cans.
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  20 ● Sizing isapplied on the size bath and dried using dry cans. ● Finally the ends are wound onto the beam. Dye Baths: ● Bottoming/Mercerizing 1. Bottoming: Sulphur Black (dye) +Caustic (18 Be) 2. Mercerizing: Caustic (18 Be) + Wetting agent (Floranit) Bottoming/Mercerizing is done at 85 ^C temperature and squeezing rollers pressure is 82 PSI. ● Hot Wash (70^C; 84 PSI) ● Pre wet (65^C; 85 PSI) ● Dye Box: ○ Indigo+ Hydro+ Caustic+ Dispersing agent ○ Room temperature, 75 PSI, pH = 11.8-11.85 ● Washing 1 (Room temperature; 90 PSI) ● Washing 2 ( 65^C ; 90 PSI) ● Washing 3 ( 70^C ; 90 PSI) Dry Cans: ● 12 dry cans for dyeing ● 14 dry cans for sizing ● Temperature range = 130-150^C Size Box: ● 1 size box ● Double dip ● Sizing capacity = 1000 l ● Temperature = 95-100^C Size Recipe: ● Wax ● Maize Starch ● Softener ● Size ● Water Preparation Tanks: ● Indigo preparation tank = 1000 l ● Indigo recovery tank = 2000 l ● Bottoming preparation =1800 l ● Bottoming recovery = 2000 l
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  20 ● Indigo feed= 289 ml/min ● 28% filled level ● 11 lease rods for sheet separation for sizing ● Normal machine speed = 20 m/min Accumulator: Accumulators are a set of rollers that accumulate the yarn sheets onto them. Whenever the machine is stopped due to beam changes or yarn breakages, the accumulator starts coming down, so that the yarn that is not being supplied is on the accumulator rollers. Dyeing is not stopped due to the accumulator. REBEAMING The rebeaming operation is done after the yarn in rope form has been dyed. In rebeaming department the yarn is rope form is taken and opened into individual yarn ends. These yarn ends are wound onto beams. This is the rebeaming process. In the rebeaming department there area two types of machines ● Griffin = 2 Machines. ● Mc Coy Ellison = 6 Machines Total there are 8 rebeaming machines. The yarn in rope form is in the collecting containers. The rope end from the container is taken and is passed through the guiding rollers installed above the containers. This allows the rope to be untangled and come in linear form. These guiding rollers then transfer the rope to different tensioning devices such as drums and rollers. Next these rope ends are fed to the winding head which contains the comb. The comb releases individual yarn ends from the rope and feeds it uniformly separated to the winding drum. The winding drum winds the yarn sheet to the beam. The length of the yarn in the beam is 22000m. Griffin: There are 2 Griffin machines in the rebeaming department. ● Maximum speed = 400mpm
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  20 ● Running speed= 238mpm ● Winding drum pressure = 75 PSI ● 3 motor drive system: ○ 1 motor in drum tensioner ○ 1 motor in rollers above cans ○ 1 motor in beam winding. ● Hydraulic dancer system. ● Cone winding drum installed. The main feature of griffin machines is the high speed of production and the dancer system. The hydraulic dancer is a device before the comb which maintains the pressure in the yarn rope. This is necessary for smooth operation and avoids the entanglement of ropes when machine is stopped. This machine also has unlimited reversible length Mc Coy Ellison: There are 6 Mc Coy Ellison machines in the rebeaming department. ● Running speed = 158 meters/min ● 2 motor drive system: ○ 1 motor in reversible tensioner ○ 1 motor in beam winding ● 45 m reversible length. The main feature of this machine is the reversible tensioner and the drum tensioner. The reversible tensioner maintains the necessary tension and guides the yarn rope. The drum tensioner contains brakes which are pneumatic. It changes the tension according to the requirement through increasing or decreasing the braking power in the drum. SIZING Sizing is a process of coating the warp yarn with protective size chemicals to increase strength. With sizing the strength of the yarn increases, the hairiness is decreased and friction is reduced. This results in fewer breakages due to friction between moving parts of the loom and inter yarn friction. The sizing process is performed after the rebeaming process. The beams of warp yarns that are prepared in the rebeaming department are sized. A set of beams is usually 12 beams. This contains the total number of ends for the required cloth quality. The set of 12 beams are installed onto the creel and the yarn sheets are creeled to the sizing box. The sizing box contains the size chemicals. The yarn is dipped in the size and squeezed by a set of squeezing rollers to remove excess size from the yarn. Next the yarn sheets are passed through heated dry cans with varying temperature. They dry the wet size applied on the yarn. These dry sheets are then passed through lease rods to separate the individual
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  20 yarn sheets andpassed through a comb. The comb separates the individual yarn ends and these ends are then winded onto a beam. This sized beam contains the total ends of the 12 beam set. Size recipe: ● Wax ● Softener ● Maize starch ● Water Machine name: ● Benninger Ben-Sizetec Machine specifications: ● Running speed = 60m/min ● Dry Can temperature =100-130 C ● Size box level = 250 mm max( 232 mm used) ● 2 size boxes ● Overall tension= 2.9% ● Beam diameter full= 1000mm ● Empty beam diameter= 150mm ● Creel capacity =16 ● Size box temperature =89 C ● Total dry cans=18 ● Squeezing pressure= 17.1 KN. ● Preparation tank = 1300 L ● Feeding tank = 1300 L There are two size boxes in this machine. Yarn sheets from 6 beams go into the 1st size box whereas the other 6 beams go into the second size box. The overall stretch in the yarn is about 2.9 %. Multiple counts can also be used in different beams. Size pick up is the amount of size that is applied onto the yarn. This can be changed by adjusting the squeezing pressure of the squeezing rollers. Temperature of Dry cans ● Dry can set # 1=135°C (4 cans) ● Dry can set # 2=115°C (2 cans) ● Dry can set # 3=140°C (4 cans) ● Dry can set # 4=115°C (2 cans) ● Dry can set # 5=120°C (4 cans) ● Dry can set # 6=110°C (2 cans)
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  20 After drying ofthe size in the dry cans there are lease rods. After the lease rods is the comb. This results in one continuous sheet of yarn ends. This sheet of yarn ends are wound onto the beam. One set of 12 beams results in approximately 13 beams of sized warp. The size chemicals in the size box are continuously heated and fresh size is introduced by means of pumps to keep the temperature and viscosity of size uniform. The pickup of the yarn is approximately 9.3 %. WEAVING The weaving process comes after the sizing process. The sized warp yarn beams are used as the warp yarn beam. Weaving is done by the intersection of warp and weft yarn. Warp is lifted with the help of headle wires to make an opening or shed for the weft yarn insertion to be made. Denim fabric is usually made with dyed warp yarn and white yarn is used for weft yarn. This gives the fabric the distinctive denim look. The five basic weaving motions are as follows: 1. Shed Formation 2. Pick Insertion. 3. Beating 4. Let Off 5. Fabric Take up There are two weaving departments. In total there are 184 looms installed in both weaving departments. Of these there are 72 projectile looms and 112 airjet looms. Projectile Loom: ● Machine : Sulzer Ruti Projectile Weaving Machine P7100 ● Grob Horgen Heald Frame ● Loom length = 360 cm ● D1 Projectile used ● RPM= 300-350 RPM The projectile looms weft insertion method is through a projectile, hence it is known as projectile loom. A projectile is a small metal bar like device with a gripper at one end. This gripper grabs the end of the weft yarn that is fed into it. The projectile is hit with a picking lever which is connected to the torsion rod mechanism. When the picking shoe hits the projectile, it forces the projectile to travel through the open shed and through the guides to the other side of the loom. This end is known as the receiving end. At the receiving end, the projectile is stopped by means of a brake system. The gripper is opened and the projectile is fed to the conveyer system which takes the projectile back to
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  20 the picking end.There are multiple projectiles operating in one loom. The path of the projectile in the shed is that of a projectile motion. The projectile motion has an advantage that two warp beams can be installed onto it thus increasing production. Also it produces the denim fabric of high quality. Air Jet Loom: ● Machine: Tsudakoma Airjet Loom ■ Tsudakoma Zax ■ Tsudakoma Zax E ■ Tsudakoma Professional ● Loom width = 160 cm ● RPM = 500-700 RPM The AirJet loom inserts the weft or filling yarn with the help of a jet of air. Airjet loom uses compressed air and releases it in the open shed using a profiled reed. The yarn is taken with the air pressure and reaches the other end of the loom. Profiled reed helps the yarn travel through the shed by reducing air dispersion. It also has sets of sub nozzles installed on the reed which release compressed air to make the traveling yarn glide through the shed. The main nozzle passes the weft yarn through the shed. The maximum RPM of airjet looms is 700 RPM. Both Projectile and Airjet Looms have automatic letoff and fabric take up systems. Both have the batchers to collect the fabric produced. Finishing There are two finishing departments # 1 and # 2. Finishing # 1 has 3 machines of mercerizing, stenter and sanforizing. Finishing # 2 has two machines for Mercerizing and Sanforizing. Finishing is the final wet processing step in the fabric manufacturing process. The fabric from the weaving department is sent to the finishing department in batches of cloth roll. These batches of cloth rolls are directly unloaded from the looms. In the finishing department different processing steps are performed on the fabric to meet the buyer’s requirements.
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  20 Finishing #1: In thisdepartment there are 3 machines: ● Mercerizing ● Stenter heat setting ● Sanforizing Mercerizing: In the mercerizing machine different steps are performed on the fabric. These steps in order are: ● Brushing ● Singing ● Mercerize ● Washing ● Softener ● Skew setting Brushing: In this process the fabric is passed through a chamber which is known as the brushing chamber. It contains brushes which brush off loose fibers, dirt and fluf from the surface of the fabric. The chamber also contains a suction fan which suctions off the brushed material. Singeing: Singeing is a process of removal of extruding fibers from the surface of the fabric through burning. In singeing the fabric is passed through a flame. Fabric is passed over the flame to burn off any fibers which are loose and may result in the formation of pills after or during treatment. Singeing is done on the face of the fabric two times. The face of the fabric is treated through flame two times. Mercerizing: Mercerizing is a process of caustic treatment of cotton fabric. Mercerizing gives the fabric luster, enhances strength and dimensional stability and improves absorbency of the fabric. Fabric is passed through a mercerizing tank which contains a solution of wetting agent and Caustic (Sodium Hydroxide) 25Be. The temperature of the bath is maintained at about 40- 45 C. Fabric passes through the bath with the help of rollers immersed inside the bath. The rollers also give tension to the fabric. Washing: After the mercerizing the fabric is washed 4 wash boxes. This is necessary to remove the caustic from the fabric before the next process is done. In the first 3 wash boxes we use water and in the 4th wash box we have a pH bath containing a solution of formic acid to neutralize the pH of the fabric. Softener:
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  20 After washing thefabric is treated with a softener. The fabric passes through a softener recipe solution and is treated with softener. The softener recipe includes Sansoft(Softener) and Acronat( Color fixing agent). Skew Setting: Next skew is imparted into the cloth. Normally 3.5-5% skew is inserted in the cloth. Skew is important in denim fabrics because if there was no skew in the fabric then the denim cloth would tear easily. During skew operation there is 6-7% shrinkage in width. After the skew setting rollers there are a set of dry cans whose temperature varies. Stenter HEAT SETTING Heat setting is the process of fixing the final width of the fabric through the application of tension and heat. Heat setting is done on a stenter frame. Different parts of the stenter frame are: ● Batcher ● Tough ● Padder ● Prewet ● Mahlo ● Coating ● Stenter ● Roller ● Winding Batcher: The fabric after the skew setting is rollers up in a batcher. This batch is installed on the stenter machine. It unwinds the yarn from the batcher and feed it in the machine. Tough: It is a tension sensor which senses the tension applied on the cloth. Pre-wet/ Padder: In pre wet moisture is applied to the fabric with the help of padder to remove excess moisture. Mahlo: Mahlo is a device which senses the moisture in the cloth. Coating: CF8 coating is applied here. If a quality requires the application of coating then coating is applied otherwise the coating section is bypassed. Stenter:
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  20 The stenter frameis SFF (Heat Set). In the stenter frame the fabric is heat treated in a closed chamber with the application of tension width wise. The stenter frame is made up of a clamping belt on both sides of the width of the cloth. The clamping belt chain clamps the edges of the cloth and stretches the cloth inside the heated chamber. The chamber is heated to 190 C and the speed of cloth is 22 mpm. Heat setting of the fabric increases the width of the fabric and reduces after wash shrinkages. Roller/ Winding: The cloth coming out of the stenter frame is rolled onto a batcher SANFORIZING Sanforizing is a process where by the fabric is run through a sanforizer; a machine that has drums filled with hot steam. This process is done to control the shrinkage of the fabric. It is a method of stretching, shrinking and fixing the woven cloth in both length and width, before cutting and producing to reduce the shrinkage which would otherwise occur after washing. Parts of the sanforizing machine are: ● J-Tray ● Steamer ● Eco ● Steamer roll ● Rubber belt ● Palmer ● Cooling roll ● Folding J-Tray: The fabric which has been rolled onto the batcher is unwinded onto the j tray. The j tray is a J shaped tray which is used as a fabric accumulator so that the machine stops are eliminated. Whenever there is a damaged spot on the fabric it is cut and removed and the fabric ends are stitched together. Also if the batch of fabric has finished then the new batch is installed and stitched at the back of the old batch. Due to excess fabric in the accumulator the machine operation does not stop. Steamer: Next the fabric goes into the steamer chamber. It is filled with steam to give the fabric moisture. Eco: After the steamer, the fabric goes through Eco. Eco also gives the fabric moisture. It uses rollers with filter water to moisten the fabric surface. Steamer Roll: After the Eco, there is a steamer roll which gives steam to the fabric surface.
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  20 Rubber Belt: The rubberbelt is a heated belt on which the fabric travels. It is the most important section of the machine. It is where the fabric contracts and expands to the rewuired witdh. The rubber belt is cooled with water to moisten it and cool it. The rubber belt is squeezed between the cylinder and the cloth is squeezed with it. This results in compression of the cloth. When the fabric leaves the rubber belt it expands with the rubber belt to the required width. Palmer: After compaction within the rubber belt unit, the fabric enters into the Palmer. Here the fibers are locked in their shrunken state by removing the moisture from the fabric. The temperature of the palmer is 110°C. The purpose of palmer cylinder is to dry a fabric to a level of about 4% relative humidity. Cooling Roll: After the palmer operation the fabric is cooled with the help of cooling roll. This contains cold water running inside the roll to cool the cylinder. The fabric at a higher temperature is passed onto the cool roller which cools the fabric and forces the fabric to come into its relaxed form. Folding: At the end of the sanforizing machine is the folding rollers. They fold the cloth onto collecting space. The running speed of the sanforizing machine is 35-40mpm. The maximum speed is 60mpm. FINISHING # 2 In finishing department # 2 there are two machines. ● Morrison Germany 2001: This machine has also a overdyeing unit installed with the regular finishing units. First the fabric is unrolled from the batcher and is fed into the brushing unit. After the brushing unit, the fabric is singed in the Osthoff Singeing unit. The Overdyeing step comes after singeing. The fabric is dyed with sulphur black. The dye solution contains sulphur dye(60g/L) with Caustic(25Be). The dyed fabric is passed through sqeezing rollers to remove excess dye. The dye is still unfixed so the fabric is passed through steaming chamber with steam temperature 102C. This fixes the dye in the fabric. This is follwed by washing tanks with hot water follwed by cold wash. After washing softener is applied and the sanforizing process is done and skew is imparted in the fabric. The fabric is sent to the J tray to be rolled in batcher. ● Monfort Germany 1995: This machine is very similar to the Morrison machine but it does not contain the overdyeing section. Also skew settings on the machine
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  20 can be automaticallyset, whereas in Morrison machine we have to manually adjust the skew settings by hand. During the finishing process certain damages can occur to the fabric. Some of these include over drying, over shrinking, introduction of creases, etc. These damages are unacceptable to the buyer and must be avoided. The normal rate of acceptance of damages is 3-5%. After the finishing process has been done to the fabric, the fabric is sent to the inspection tables. Here fabric is inspected for defects and imperfections. After inspection the fabric is cut into smaller lengths and wound onto paper rolls. These rolls are sealed with plastic packaging. LABORATORY All the tests related to the fabric testing are performed in the laboratory. The laboratory has all the necessary equipment for the testing of fabric according to the two international testing methods, ISO and AATCC. All the lots produced in production are tested to ensure the lot meets the customer requirements. The results of the tests are taken and compared to ensure they are in accordance with the specified allowed ranges. Also records of tests up to 6 months before are maintained for future references. The customer specifies the testing standards to be followed. Tests: Washing: in the washing test we test for color fastness to washing and dimensional stability to washing. This test is performed by ISO and AATCC methods. Color Fastness to washing: ● AATCC 61 2nd A ○ 2g/L WOB detergent (Without Optical Brightener) ○ 1 L Distilled water ○ Time=45 Min ○ Temperature= 49 C ● ISO 105 CO6 ○ 4g/L Detergent ○ 2g/L Sodium perbonate ○ Time= 30 min ○ Temperature= 40C Dimensional Stability to washing: ● AATCC 135 ○ Whirlpool Machine
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  20 ○ Time =45 min ○ Calibration is done after every 6 months ○ Temperature = 65+-1 C ● ISO 6330 ○ Program # 5A & 2A ○ Chemicals (IEC phosphate, reducing agent and peak activator) Abrasion tester: ● ASTMD-3855 Color Fastness to rubbing: ● Crock Meter ● 1.6cm diameter ● 10 cm drag ● 5x5 cm rubbing cloth ● American= 100% wet Pickup ● European= 70% wet Pickup Tensile Strength Test: ● Sample dimensions= 8x4 inches Stretch and Elongated ● ASTM D3107 method ● Fabric growth, stretch, elongation and fabric recovery ● Stretch for weft in 30 second ● Elongation for warp in 15 second Tear strength ● ASTM D1424 method ● ISO 13937-1 method pH Fabric: ● AATCC-81 method Colorfastness to ozone ● AATCC-129 method High humidity ● AATCC-109 method Low humidity ● Ozone test chamber ● Length capacity = 5ppm (particles per minute) Colorfastness to perspiration ● AATCC-81 method ● ISO-105-E04 method
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  20 ● 4.5-7.5 pHrequired for acidic and basic Skewness change in fabric ● AATCC-179 method ● ISO method also determine ● Inner dimension 35 cm ● Cut able width fabric = 64.6 inches ● Clockwise = Right-hand twill ● Anticlockwise = Left-hand twill Hunter LAB testing ● LAB reading ● L: Depth measuring (lighter to darker) ● A: Reddish or Greenish tone ● B: Yellowish or Blue tone ● Hue or Chroma (A&B are hue, while L is chroma) Observer specimen in 6 lights ● Checking the shade of the fabric ● 45˚ angle makes to see observer ● 70cm distance between observer and specimen Grey-Scale ● ISO requirement ● AATCC requirement If any fabric lot does not meet the allowable specified results, then it is sent for reprocessing in the finishing department. The lot is reprocessed to make the fabric pass the tests.
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  20 WASHING Washing is thefinal step in production. The washing department here produces only samples which are used for buyer references. Full scale washing process is not done as only the fabric after finishing is sold. Normally denim washing is done in apparel form. The processes performed in this department include: ● Scraping: Scraping is done on dry fabric. The fabric in stitched form is put on inflatable tubes and air is pumped into them. Then sand paper is then scraped onto the surfaces where the desired effect is needed. This results in the removal of dye from the scraped surface and gives a faded look. ● Grinding: Grinding is done with the help of pinning and tacking. Parts of the fabric are folded and tacked. This hides some of the surface. Grinding paper is run on this surface and then the tacks are removed to achieve faded or worn out effects. ● Pinning/ Tacking: pinning and tacking is done to protect certain areas of the fabric surface from exposure. The fabric is then washed and the exposed areas are washed but the tacked areas remain unwashed. Hence different effects are achieved. ● Wash: washing is done with detergents and stones washing. Stone washing is a process where abrasive stones are put in the washing cycle to help abrade the surface of the fabric with a natural overall faded look. ● PP spray (Potassium Permanganate): Potassium Permanganate is sprayed onto the surface of the fabric to give bleaching effect to the area. The areas treated with PP spray come out as whiter then the rest of the fabric. After PP spray, the fabric is neutralized with acetic acid. ● Resin Spray: Resin spray is the application of liquid resin. Resin is sprayed onto the desired spots of the fabric. Designs are made on the fabric and then the design is heat set in a oven to cure. The fabric is left to bake for 50 min in the oven. This results in 3d effects on the area of application of resin. ● Enzyme treatment: Enzymes are natural proteins that are found naturally. Different Enzymes are applied such as Acid and neutral Enzymes. Enzymes remove the color from the fabric surface. ● Bleaching: Bleaching is done with the help of hypo bleach (Sodium Hypo Chlorite). Bleaching is the removal of color from the fabric to achieve desired designs.
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  20 These samples aresolely made to show the buyer that what will be the outcome of particular washing technique on the end product.