Fabric defects in woven and knitted fabric - hitesh choudhary

Broken Ends woven in a bunchBroken ends woven in a bunch : This defect is caused by a bunch of broken ends woven into the fabric.. MENDING: The broken ends woven in a bunch can be remove

FABRIC DEFECTS

Hitesh Choudhary www.facebook.com/hitesh.choudhary1

Defination of defect :

i An imperfection that impairs worth or utility.

ii Want or absence of something necessary for

completeness or perfection.

iii 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

MENDING: Coloured portion is removed from the yarn with

a plucker The resultant bare patch can be corrected by

combing with metallic comb

Knots : Knot is a fastening made by tying together the ends

of yarn

CAUSES : Thread breaks during process of winding,

warping, sizing or weaving

MENDING: Non Mendable

 Broken tooth in the chain of gear system.

MENDING: The slub should be cut with the clipper from

both the ends The resultant bare patch can be corrected by combing with a metallic comb or by insertion of a separate thread with the help of fine needle

Broken pattern

Broken pattern : A broken pattern is the non continuity

of a weave/ design/ pattern

Broken Ends woven in a bunch

Broken ends woven in a bunch : This defect is

caused by a bunch of broken ends woven into the fabric

CAUSE : Failure of the weaver in attending the warp breaks properly

MENDING: The broken ends woven in a bunch can be

removed by using a plucker and the resulting loose ends should be cut with clipper As a result, a bare patch occurs and combing in both directions with a metallic comb can fill this up

Double end

Double end : When two or more ends gets woven as one This defect is characterized by a thick bar running

parallel to the warp

CAUSES : Wrong drawing, taking more ends in heald eye

MENDING: This fault can be corrected by pulling out the extra end with the help of needle A bare patch is formed and can be filled by combing in both directions with the help

of metallic comb

Float : Float is the improper interlacement of warp and weft threads over a certain area

CAUSES :

 Improper sizing (ends sticking)

 Broken end entangling with the other ends

MENDING: Only minor floats can be rectified The floating threads are cut with a clipper Combing in both direction rectifies the resultant patch

MENDING: The extra foreign matter can be pulled out with

a plucker Combing in both direction rectifies the resultant patch

Hole, Cut, Tear

Hole, Cut or Tear : This is self explanatory

CAUSES :

 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 particles woven in the cloth

MENDING: Non mendable

Missing Ends

Missing Ends : The fabric is characterised by a gap,

parallel to the warp The number of ends missing may be one or more

CAUSES :

 Loom not equipped with warp stop motion

 Dirty drop wires or accumulation of lint may prevent their dropping

 In electric warp stop motion, the electric bars are dirty or corroded

MENDING: When there are only two adjacent ends

missing, the fault can be rectified by combing in both

directions using a metallic comb This may fill the bare

patch formed due to missing ends

Missing Picks

Missing Picks : A narrow streak running parallel with weft threads 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 for

mending

MENDING: When there are only two adjacent picks

missing, the fault can be rectified by combing in both

directions using a metallic comb This may fill the bare

patch formed due to missing ends

Stitches : A Single thread float

CAUSES :

 Two adjacent ends sticking together during shedding for

a brief period of time

 In case of synthetic yarns, ends sticking together due to static charge during weaving

MENDING: Stitches are cut with a clipper from both the ends Combing in both the directions with the help of a

metallic comb may rectify the resultant bare patch formed

UNTRIMMED LOOSE THREADS

Untrimmed loose threads : Any hanging threads on the face of the fabrics are termed as loose threads

CAUSE : Tail ends not trimmed after piecing up

MENDING: These defects can be easily rectified with the help of clipper

WEFT BAR

Weft bar : An unwanted bar, running across the full width

of a piece which differs in appearance from the adjacent normal fabric

CAUSES :

 Difference in count, twist, colour, lustre

 Faulty let-off and take-up motion

MENDING: Non mendable

 Insufficient picking force.

 Slack ends in certain portion The sagging ends obstructs shuttle flight

MENDING: Non mendable

Lashing in

Lashing in : An extra piece of yarn woven into the fabric in the 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 set

properly

MENDING: This defect can be corrected by pulling out the extra pick from the selvedge end, which can be clipped with the help of clipper A bare patch is formed and can be filled

by combing in both directions with the help of mettalic

comb

Oil Or Stain

Oil Or Other Stain: These are spot defects of oil, rust, grease or other stains found in the fabric

CAUSES :

 Improper oiling/greasing of looms

 Oil stained Take up roller

MENDING:

1) 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.

1) 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 Weft

Oily 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 the

winding machine.

MENDING:

1) 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 Distortion

Local distortion : A Distortion occurs when there is

displacement of warp and/or weft threads from their normal position

CAUSES :

 The emery roll is worn out

 In filament fabric having low reed picks

MENDING: This defect can be corrected by combing in

both directions using a mettalic comb

SLOUGH OFF

Slough off : A slough-off is a bunch of weft woven into the fabric

CAUSES :

 Improper winding of the yarn onto the weft pirn.

 Improper shape and size of the pirn.

Reed Marks

Reed Marks : A warp way crack caused by a damaged or defective 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 PILES

Broken pattern due to defective piles : A broken

pattern is the result of non-continuity of the design/pattern in the pile fabric

CAUSES :

 Improper working of terry motion on loom.

 Improper functioning of jacquard.

 Missing pick.

MENDING: Non mendable

PILE LESS SPOT

Pile less spot : It is a spot without the pile

CAUSES :

 Improper working of terry motion on loom.

 Improper functioning of jacquard.

MENDING: Non mendable

UNEVEN OR LOOSE PILES

Uneven or loose piles : In this type of defect there is variation in 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

 Using different count thread.

MENDING: Non Mendable

Bunching up

Bunching up : This is largely influnced by take-up mechanism and whether it functions properly or not

CAUSES :

 Fabric take-up too weak

 Thick place in yarn

MENDING: Non Mendable

 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 a simple needle.

CAN BE AVOIDED BY :

 Precise yarn-guide setting.

 Needle change.

 Dial position readjustment.

 Use of fabric fault detector.

Holes or crack

Holes or crack : Local holes obtained when yarn breaks

during 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

Horizontal stripes

Horizontal stripes : Are caused by uneveness in the

courses They traverse horizontally and repeat themselves regularly or irregularly

CAUSES :

 Yarn feeder set badly.

 Differences in the yarn running-in tension.

 Jerky impulse from fabric take up

Mending : Non mendable

Verticle stripes

Verticle stripes : They can be observed as longitudnal gaps

in 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

Inspection : Inspection is the process of identifying and

mending the defects It is visual examination of fabric

REASONS 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 systems

4 Point system

of Shirt Pajama Sportswear Manufacturers.

Manufacturers Association (AAMA) point grading

system for determining fabric quality.

according to the Size and significance of defect.

4 Point system

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

10 Point system

oldest method.

depending on its length and whether it is in the warp (ends) or weft (fill) direction.

because points-per-length vary for warp and weft defects.

10”- 36” 10 Over ½ the width of fabric 10

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

Grading

1) 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.

• 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.

• 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 27 , 2009 , pp

1585-1586.

• 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- 570

THANK YOU ANY QUESTIONS ??