IntroductionDefination of defect :i. An imperfection that impairs worth or utilityii. Want or absence of something necessary for completeness or perfectioniii. A fault that spoils the material.Fabric defect : A Fabric Defect is any abnormality in the Fabric that hinders its acceptability by the consumer.
Importance of fabric defect• Due to the increasing demand for quality fabrics, high quality requirements are today greater since customer has become more aware of poor quality problems• To avoid Rejection of fabric, It is necessary to avoid defects.• Price of fabric is reduced by 45%-65% due to the presence of defects• Company image will go down.
List of fabric defects in woven fabrics• Coloured flecks • Missing ends• Knots • Missing Pick• Slub • Oil and other stain• Broken ends woven in a • Oily ends bunch • Oily picks• Broken pattern • Reed mark• Double end • Slough off• Float • Shuttle smash• Gout • Snarls• Hole, cut, or tear • Stitches• Lashing-In • Untrimmed loose threads• Local distortion • Weft bar
Coloured FlecksCOLOURED FLECKS Presence of coloured foreign matterin the yarn.CAUSES Cotton fibres getting contaminated during theginning stage with leaves, immature fibre, yellow fibre, etc.MENDING Coloured portion is removed from the yarn witha plucker. The resultant bare patch can be corrected bycombing with metallic comb.
KNOTSKnots Knot is a fastening made by tying together the endsof yarnCAUSES Thread breaks during process ofwinding, warping, sizing or weavingMENDING Non Mendable.
SLUBSlub Slub is a bunch of yarn having less twist or no twistand has a wider diameter compared to normal spun yarnCAUSES Improper carding/combing. Broken tooth in the chain of gear systemMENDING The slub should be cut with the clipper fromboth the ends. The resultant bare patch can be corrected bycombing with a metallic comb or by insertion of a separatethread with the help of fine needle.
Broken patternBroken pattern A broken pattern is the non continuity ofa weave/ design/ patternCAUSES Wrong drawing in of threads. Incorrect sheddingMENDING Non Mendable.
Broken Ends woven in a bunchBroken ends woven in a bunch This defect is causedby a bunch of broken ends woven into the fabricCAUSE Failure of the weaver in attending the warp breaksproperlyMENDING The broken ends woven in a bunch can beremoved by using a plucker and the resulting loose endsshould be cut with clipper. As a result, a bare patch occursand combing in both directions with a metallic comb can fillthis up.
Double endDouble end When two or more ends gets woven as one.This defect is characterized by a thick bar running parallelto the warp.CAUSES Wrong drawing, taking more ends in heald eye.MENDING This fault can be corrected by pulling out theextra end with the help of needle. A bare patch is formedand can be filled by combing in both directions with the helpof metallic comb.
FloatFloat Float is the improper interlacement of warp andweft threads over a certain area.CAUSES Improper sizing (ends sticking) Broken end entangling with the other endsMENDING Only minor floats can be rectified. The floatingthreads are cut with a clipper . Combing in both directionrectifies the resultant patch
GoutGout : Gout is a foreign matter accidently woven into thefabric.CAUSES Improper loom cleaning. Unclean environmentMENDING The extra foreign matter can be pulled out witha plucker. Combing in both direction rectifies the resultantpatch
Hole, Cut, TearHole, Cut or Tear This is self explanatoryCAUSES Sharp edges on cloth roll. Hard substance between layers of fabric in cloth roll Course temples used for fine fabric During removal of hard particles like, Iron particleswoven in the clothMENDING Non mendable
Missing EndsMissing Ends The fabric is characterised by a gap, parallelto the warp. The number of ends missing may be one ormore.CAUSES Loom not equipped with warp stop motion. Dirty drop wires or accumulation of lint may prevent theirdropping. In electric warp stop motion, the electric bars are dirty orcorroded.MENDING When there are only two adjacent endsmissing, the fault can be rectified by combing in bothdirections using a metallic comb. This may fill the barepatch formed due to missing ends.
Missing PicksMissing Picks A narrow streak running parallel with weftthreads caused due to absense of weft.CAUSES Faulty let-off and take-up motion. Faulty weft-stop motion. Fell of the cloth not adjusted after loom stoppage formending.MENDING When there are only two adjacent picksmissing, the fault can be rectified by combing in bothdirections using a metallic comb. This may fill the barepatch formed due to missing ends.
STITCHESStitches A Single thread float.CAUSES Two adjacent ends sticking together during shedding for abrief period of time. In case of synthetic yarns, ends sticking together due tostatic charge during weaving.MENDING Stitches are cut with a clipper from both theends. Combing in both the directions with the help of ametallic comb may rectify the resultant bare patch formed.
UNTRIMMED LOOSE THREADSUntrimmed loose threads Any hanging threads on the faceof the fabrics are termed as loose threads.CAUSE Tail ends not trimmed after piecing up.MENDING These defects can be easily rectified with thehelp of clipper.
WEFT BARWeft bar An unwanted bar, running across the full width ofa piece which differs in appearance from the adjacentnormal fabric.CAUSES Difference in count, twist, colour, lustre. Faulty let-off and take-up motion.MENDING Non mendable .
SHUTTLE SMASHShuttle smash Ruptued cloth structure characterised bymany broken warp ends and floating picks.CAUSES Improper timing. Insufficient picking force. Slack ends in certain portion. The sagging ends obstructsshuttle flight.MENDING Non mendable.
Lashing inLashing in An extra piece of yarn woven into the fabric inthe vicinity of the selvedge.CAUSES Defective setting of the shuttle box. Early or late picking. In case of auto loom, weft cutters worn out or not setproperlyMENDING This defect can be corrected by pulling out theextra pick from the selvedge end, which can be clipped withthe help of clipper. A bare patch is formed and can be filledby combing in both directions with the help of mettaliccomb.
Oil Or StainOil Or Other Stain These are spot defects ofoil, rust, grease or other stains found in the fabric.CAUSES Improper oiling/greasing of looms. Oil stained Take up roller.MENDING1) Keep the stained portion of the fabric over an absorbent pad. Apply the stain remover, wetting the stain and surrounding portion throughly.2) Rub gently to quicken the penetration of the stain remover.3) Rubbing should be done towards the centre of stain to avoid spreading.Note: Delicate fabric needs reduced pressure, otherwise, hole formation or displacement of the fabric will occur.
Oily EndsOily Ends These are oily warp ends.CAUSES Improper handling and storage of material in spinningdepartment. Oil-contaminated guides and oily hands during process ofwarping. Improper handling of warp beams.MENDING1) Keep the stained portion of the fabric over an absorbent pad. Apply the stain remover, wetting the stain and surrounding portion throughly.2) Rub gently to quicken the penetration of the stain remover.3) Rubbing should be done towards the centre of stain to avoid spreading.Note: Delicate fabric needs reduced pressure, otherwise, hole formation or displacement of the fabric will occur.
Oily WeftOily weft These are oily weft picks.CAUSES Improper handling and storing in spinning department. Weft package falling on oily ground. Handling the weft with oily hands. Weft carring baskets having oil. Dropping of oil on weft package during oiling of thewinding machine.MENDING1) Keep the stained portion of the fabric over an absorbent pad. Apply the stain remover, wetting the stain and surrounding portion throughly.2) Rub gently to quicken the penetration of the stain remover.3) Rubbing should be done towards the centre of stain to avoid spreading.Note: Delicate fabric needs reduced pressure, otherwise, hole formation or displacement of the fabric will occur.
Local DistortionLocal distortion A Distortion occurs when there isdisplacement of warp and/or weft threads from their normalposition.CAUSES The emery roll is worn out. In filament fabric having low reed picks.MENDING This defect can be corrected by combing in bothdirections using a mettalic comb.
SLOUGH OFFSlough off A slough-off is a bunch of weft woven into thefabric.CAUSES Improper winding of the yarn onto the weft pirn. Improper shape and size of the pirn. Harsh picking.MENDING The bulk yarn can be pulled out by means ofplucker. Combing in both direction with help of mettaliccomb can fill up the resultant bare patch.
Reed MarksReed Marks A warp way crack caused by a damaged ordefective reed.CAUSES Defective or damaged reed.MENDING Non Mendable.
List of fabric defects in terry and velvet fabrics• Broken pattern• Pile less spot• Uneven or loose piles
BROKEN PATTERN DUE TO DEFECTIVE PILESBroken pattern due to defective piles A broken pattern is theresult of non-continuity of the design/pattern in the pilefabric.CAUSES Improper working of terry motion on loom. Improper functioning of jacquard. Missing pick.MENDING Non mendable.
PILE LESS SPOTPile less spot It is a spot without the pileCAUSES Improper working of terry motion on loom. Improper functioning of jacquard.MENDING Non mendable
UNEVEN OR LOOSE PILESUneven or loose piles In this type of defect there is variationin the pile height over the surface of the fabric.CAUSES Improper working of terry motion on loom. Improper functioning of jacquard. Missing pick.MENDING Non Mendable.
List of fabric defects in Knitted fabrics• Bariness• Bunching up• Drop stitch• Holes or Crack• Crack fall out• Horizontal srtipes• Verticle stripes
BARINESSBariness A fabric defect characterized by textural bands orcolor bands in the course direction of a weft knitted fabric.CAUSES Use of irregular yarn having higher long term irregularities. Using different count thread.MENDING Non Mendable.
Bunching upBunching up : This is largely influnced by take-upmechanism and whether it functions properly or not.CAUSES Fabric take-up too weak. Thick place in yarn.MENDING Non Mendable.
Drop stitchDrop stitch: Local column of dropped stitches.CAUSES Yarn guide not set poroperly (i.e yarn is not fed properly during loopformation). Defective latch needle. yarn tension is not sufficient. Take-down is too high. Wrong yarn threading.MENDING This fault can be corrected by stitches reforming using asimple needle.CAN BE AVOIDED BY Precise yarn-guide setting. Needle change. Dial position readjustment. Use of fabric fault detector.
Holes or crackHoles or crack : Local holes obtained when yarn breaksduring loop formation.CAUSES Relation between cylinder and dial loop not correct. Weak places in yarn, Which breaks during loop formation Knots. Yarn running tension is too high.CAN BE AVOIDED BY Use of flat knots. Accurate yarn guide setting. Use of fabric fault detector. Use of yarn having lower hariness.
Cloth fall-outCloth fall-out : It is an area consisting of drop stitches lyingside by side. Here the yarn is not stitched by severalneedles laying near to each other.CAUSES Yarn brakage. It can also occur after a drop stitch especially when anempty needle with closed latch runs into yarn feeder andremoves the yarn out of the hooks of following needles.MENDING: Non mendable.
Horizontal stripesHorizontal stripes : Are caused by uneveness in thecourses. They traverse horizontally and repeat themselvesregularly or irregularly.CAUSES Yarn feeder set badly. Differences in the yarn running-in tension. Jerky impulse from fabric take up .Mending : Non mendable.
Verticle stripesVerticle stripes : They can be observed as longitudnal gapsin the fabric. The space between adjacent wales is irregular.CAUSES Bent needles. Heavily running needles. Damaged latch needle. Damaged needle hook. Damaged dial or cylinder.CAN BE AVOIDED BY : Needles and sinkers change after long time use. Use of fabric fault detector.
InspectionInspection : Inspection is the process of identifying and mending the defects. It is visual examination of fabricREASONS WHY INSPECTION IS CARRIED OUT: To remove defects. To minimize the future reoccurrences of the defect. To determine quality and hence the price of the fabric. To supply information to proper levels of management as to the qualities being produced
Different Grading systems1. point system2. point system3. point system4. Graniteville system5. Dallas system
Point system It is the most popular point system. It was published in 1959 by the National Association of Shirt Pajama Sportswear Manufacturers. The 4-point system, also called the American Apparel Manufacturers Association (AAMA) point grading system for determining fabric quality Faults are scored with penalty points of 1, 2, 3 and 4 according to the Size and significance of defect.
Point system DEFECT SIZE PENALTY3 inches or less PointOver 3 inches, but less than 6 PointOver 6 inches, but less than 9 PointOver 9 inches Point
Points to be considered in 4 Point system No more than 4 penalty points can be assigned for any single defect. No linear yard or meter can contain more than 4 points, regardless of the number of defects within that yard or meter. Each full width defect should assign 4 points. noticeable and severe defects are to be assigned 4 points for each yard or meter in which they occur, regardless of size.Advantages of 4 point system : Worker can easily understand it It has no width limitation
Point system This system was developed in 1950’s and is the oldest method. The system assigns penalty points to each defect depending on its length and whether it is in the warp (ends) or weft (fill) direction. The Ten-Point System is somewhat complicated because points-per-length vary for warp and weft defects. This method is still used by some manufacturers.
Point systemWarp defect Points Weft defect PointsUnder 1” Under 1”1” - 5” 1” - 5”5” - 10” 5” – ½ width of fabric10”- 36” Over ½ the width of fabric Advantage of 10 point system: Mostly used in woven finished fabric. High accuracy Disadvantage of 10 point system: It has width Limitation. Difficult in practical use.
Classification of Fabric after Grading1) Fresh or first quality fabric with no major or objectionable faults.2) Second : cloth having minor defects.3) Fents : The cut pieces of cloths measuring 90cm and more but less than 150 cm in length are graded as fents.4) Rags : The cut pieces of cloths larger than 25cm but less than 90 cm are regarded as rags.5) Chindies : These are the cloths having length of 25 cm or less.
Conclusions• Due to presence of fabric defect, it has to be sold at lower prices, or even in some cases as seconds, which creates a hugh value loss to the company.• To minimize value loss due to variety of defect occuring in the fabric, a manufacturer should try to minimize those defects by taking suitable remedies.
References• Textiles Committee, Ministry of Textiles, “A catalogue on woven fabric defects and visual inspection”• Circular Knitting (2nd edition) by Iyer , pp 236-239.• A project report on “ Comparision of yarn and fabric made from CULTON® cotton and Regular cotton” under guidance of PROF. Manish pujari.• K.L. Mak, P. Peng, K.F.C. Yiu Fabric defect detection using morphological filters Image and Vision Computing vol , pp -• Tamnun E Mursalin, Fajrana Zebin Eishita , Ahmed Ridwanul Islam Fabric defect inspection system using neural network and microcontroller Journal of Theoretical and Applied Information Technology, vol 4, july 2008 pp 560-