Quality Assurance of Knit Fabrics
Engr. Khandaker Sakib Farhad
8. Q.A.D:
The full abbreviation of Q.A.D. is Quality Assurance Department which is needed for the
purpose of checking the quality of the fabric.
Quality is mainly checked for ensuring that the fabric is suitable to meet all the requirements
according to the customer’s specified order. The quality can be classified by four types which
are discussed below:
1. Product based quality:
Product based definition of quality mainly depends on the quality. Product based
quality is more related to manufacture. More the number of units in specified time
more is product based quality. From the user point of view more number of units
in a specific cost is called product based quality.
2. User based quality:
The user based quality simply means the quality, whatever the customer says or
wants. In short, meeting or exceeding customer’s requirement and expectations.
3. Manufacturing based quality:
The definition of this quality means, meeting specifications or conformance to
requirements. It is nothing but manufacturing based quality. Any deviation from
meeting the requirements means poor quality.
4. Value based quality:
In this type of quality, there is more consideration of cost of a product or service.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.1. Organogram of Quality Assurance Department:
Quality Control Manager
Sample Incharge
Senior Quality Control Inspector
Quality Inspector
Quality Control Inspector
Sample Chaser
Quality Control
Trainee
Sample Helper
8.1.1. Inspection Process:
Inspection of the fabric is done by the quality inspectors intended for ensuring proper
quality of the fabric at various sections of the dyeing, Knitting and finishing section. The
System which is used by the ECHOTEX textile industry is 4Point inspection system. The
inspection process of ECHOTEX textile industry is discussed below:
8.1.2. 4-Points system:
The 4-points system are called American Apparel Manufacturers Association (AAMA)
Point grading system for determining fabric quality is widely used by the department of
defense in the united state and endorsed by the AAMA as well as the ASQC (American
Society of Quality Control)
In this system fabric faults are identified with defect point in the scale of i.e. maximum
defect point is 4.
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Quality Assurance of Knit Fabrics
Engr. Khandaker Sakib Farhad
8.1.3. Pointing System for Fabric faults:
The faults are pointed acceding to the size of the defect and the size of the hole in the
knitted fabric. For fault pointing system according to the size of defect is as follows:
Fabric defect size
Penalty point
Up to 3”
1 Points
More than 3” but less than 6”
2 Points
More than 6” but less than 9”
3 Points
More than 9”
4 Points
For fault pointing system according to holes and opening is as bellow:
Size of hole
Penalty points
less than 1”
2 Points
More than 1”
4 Points
Knot (4 types) less than 3”
1 Points
Slubs- less than 3”
1 Points
Total defect points per 100 square yds are calculated and normally those fabric roll
containing more than 40 points/100 yds are considered seconds however a garments
manufacture based on the price line and type of garments produced may use more or less
than 40 points / 100 yds as an acceptance criteria.
For example, a fabric rolls 120 yds long and 48 in width contains the defect:
Defects seen on the fabric sample
A. 2 defects up to sample
Defect points of every faults
2 1=2 points
B. 5 defect over 3 in but less than 6 in.
5 2=10 points
C. 1defect over 6in but less than 6 in
1 3=3 points
D. 1 defects over 9 in.
1 4=4 points
Total defects point
=19 points
Therefore,
Total Points Scord in The Roll ×3600
Inch×Total Yards Inspected
19×3600
= 48×120
Points/100 yd2 = Fabric Width In
= 11.9 defect points/ 100 yd2
So if the acceptance criteria are 40 points/100 yd2 then this roll is acceptable. The
maximum number of defect points to be counted against any one linear yard is points.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Overall fabric quality is assessed on the basis of the number of defect points per 100 yd2
of fabric.
8.2. General Rules for Inspection:
Some general rules are followed for inspecting a fabric which should be maintained during
inspecting a finished or grey fabric. During inspecting a fabric the rules which should be followed
is given below:
 Only one meter of fabric cannot be penalized more than 4 points.
 Any defect occurring repeatedly throughout the entire fabric should be marked.
 Combination of warp and weft defect running in one meter should not be
penalized more than 4 points in them.
 Fabric should always be inspected on face side only if it is not specified for back
side inspection.
8.2.1. Points for various Types of Fabric Faults:
The points are also different for different types of fault occurring in the fabric. During
inspecting a fabric in the Quality Control section of the ECHOTEX Dyehouse the various
common faults are pointed as below:
Faults
Points
Any size Hole
White Specks
Oil Stain
Chemical Spot
Water Drop
Fly Yarn
Slub
Rub Mark
Rust Stain
Yarn Contamination
4 points
1 points
1 points
1 points
1 points
1 points
1 points
1 points
1 points
1 points
As the above given faults are commonly found in the Finishing and Knitting Section of
the ECHOTEX Dyehouse, so these faults are regularly pointed but other than these type
of faults of the fabric, the fabric should be sent to the higher authority or be rejected.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.2.2. Inspection Machine:
Fabric inspection is usually done on fabric inspection machine. These machines measures
rolls of fabric by placing them over the inspection table under adequate light source and
rerolled as they leave the table. The amount of fabric rolls passed on the inspection
machine is measured by the metering roll on the machine. This inspection machine is
either power driven or the inspector pulls the fabric over inspection table. The defect are
tracked, marked and recorded on an inspection sheet. Such machine are also equipped
with equipments to control the length of the fabric is delivered from the back and also
monitor the back side of the fabric. The width of the fabric is most important for
manufacture of basis garments.
Inspecting
light
Metering
roller

Figure: QAD grey inspection machine.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.3. ECHOTEX Final Inspection report:
50
60
70
80
90
100
Wa4
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Penalty Point Legend
H= Hole
OS=Oil Stain
CH=Chemical Spot
WD=Water Drop
FY=Fly Yarn
WS=White specks
S=Slubs
R=Rub Mark
RS=Rust Stain
Yc=Yarn Contamination
IS: Insect Spot
Faulty Appearance
Four Points System:
US: Uneven shade,Np=
Napes
Cr= Crease mark, P=patches,
G/H=GSM Hole, HR=Hairy,
MS=Machine Stoppage,
N/L=Needle line,BR= Barre
Mark,CM=Crimple
mark,BW=Bowing,DC=Dead
Cotton,
SN=Snagging/M=Line
Mark,P/H=Pin hole
Size of Defect
Penalty
0-3"
1 Points
3-6”
2 Points
6-9”
3 Points
Over 9 inch 4 Points
Reject Qty:
40
M/C DIA XGG
30
Shift:
20
Yarn Lot:
10
Inspection By:
Buyer:………….Batch:………………Shade:………………Style:……………..Date :
Roll 1- 11- 21- 31- 41- 51- 61- 71- 81- 91- A/Dia A/GSM Pts/Mtr Class
Checked By:
Shade:
Inspect: Dryer/Comp/Stenter
Test Report:
Inspection Time:
Req.Width:
Req. GSM:
Grey Weight:
Final Inspection Report
Work Order:
Acceptance
Calculation
Factor=Roll Yardage (A)
=Total Point, Roll (B)
Formula=B/A× 100
=Points/100 Yards
< 40 PTSA
41-60 PTSB
61-80 PTSC
80 Above Reject
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.4. Grey Inspection report:
M/C
DiaX
GG
Finished
GSM
Finished
Dia
Grey
GSM/
St.Length
1-10
1120
2130
3140
4150
5160
6170
7180
8190
91100
Pts/
Mtr
Roll
Wt.
Cl
as
s
Inspection Time:
Grey
Dia
Faulty Appearance
GSM Hole=GH, Lycra out=LY, Barre
mark=BM ,Drop stitch=DS, Crease mark= CR,
Sinker mark=SM, Yarn Conta=CY, Fly
conta=FC, Slubs=S, Oil spots=OS, Press
off=PO, Wrong design=WD, Oil line=OL,
Uneven yarn=UY, Naps=N, Thick/Thin=T/T
Four Point System
Acceptable Calculation
Size of defect
Penalty
Up to 40 point = A
0-3”
>3-6”
>6-9”
>9”
Hole <1”
Hole <1”
1 Points
2 Points
3 Points
4 Points
2 Points
4 Points
41 to 60 point = B
Remark:
Inspection By:
Total Qty:
Formula
Point =
Total point ×100
Total length(in meter)
61 to 80 point = C
Above
Reject Qty:
Checked By:
Roll
Insp
= Rejected
155
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.5. Faults of fabric during Knitting:
The ECHOTEX has a renowned inspection section where not only internally knitted fabric faults
are detected but also the fabrics knitted in other industries are also inspected. In the inspection
section there are various faults found of the knitted fabrics. Some of the faults found during
knitting are discussed below:
 Hole.
 Lycra out.
 Lycra drop.
 Barre mark.
 Needle mark.
 Drop stitch.
 Crease mark.
 Sinker mark.
 Yarn contamination.
 Fly contamination.
 Slub.
 Oil spot.
 Press off.
 Wrong design.
 Oil line.
 Miss yarn.
 Uneven yarn.
 Naps.
 Thick and Thin.
 Needle broken.
 Loop.
 Stare.
 Yarn mixed.
 Patta.
 Color contamination.
 Wheel mark.
 Dirty yarn.
1. Hole:
During yarn breakage from yarn passage from the wheel to the feeder if the joining of the
yarn is done by normal binding process then hole could be produced in the fabric.
Hole
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Quality Assurance of Knit Fabrics
Engr. Khandaker Sakib Farhad
 Causes:








Using old lubricant or knitting oil which has been oxidized.
Longer needle latch holding time of the loop.
Unwanted sharp objects in the knitting machine.
If binding of broken yarn is not properly done.
Using yarns having knots slubs etc.
Using yarns having no moisture.
Yarn running in too high tension.
If the dial and cylinder does not work together
 Remedies:







Check the lubricants used for oiling the knitting machine.
Make sure all the loops are produced at a same speed.
Check for any unwanted sharp objects in the machine.
Using good quality yarn during knitting.
Check the tension of the yarn passage.
Check the speed of the running yarn.
Check if cylinder and dial of knitting machine is working together.
2. Lycra out:
If a yarn is torn during the passage of lycra yarn from the lycra stand to the feeder or if one of
the yarns are missing during passage than lycra out occurs. The lycra out is normally a gap mark
present throughout the fabric.
Lycra
Out
 Causes:
 If any lycra yarn is missed during knitting.
 If lycra yarn feeder arrangement is not proper.
 If lycra yarn tension is not proper.
 Remedies:
 Lycra yarn should be passed to the maintaining proper tension
 Broken ends of the lycra yarn should be immediately fixed.
 Proper cleaning of the lycra knitting machine should be done.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
3. Color contamination:
After the production of the fabric if there is presence of another colored yarn then this fault is
known as color contamination.
Color
Contamination
 Causes:
 It consists of single fibre, bunch of fibre or yarn pieces in varying colors.
 Presence of yarn during knitting having different color.
 Remedies:
 It is very difficult to remove. So need to be careful in process. Fly preventive
cover can be used.
 Before knitting of new fabric the machine should be cleaned by applying air
flow.
4. Miss yarn:
If a yarn is missed by the needles during fabric loop formation then miss yarn is occurred. This
miss tarn is normally caused if any yarn is not passed from the feeder while the yarn passage.
Miss
Yarn
 Causes:
 If any yarn is missed during knitting.
 If yarn feeder arrangement is not proper.
 If yarn tension is not proper.
 Remedies:
 Yarn should be passed to the maintaining proper tension
 Broken ends of the yarn should be immediately fixed.
 Proper cleaning of the knitting machine should be done.
5. Wrong Design:
If an unwanted design is occurred with the buyer specified design in the fabric then it is known
as wrong design. Normally this fault is caused while knitting dyed yarns as a result if there is a
cause of miss yarn or extra yarn supplied to the knitted fabric.
158
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Wrong
Design
 Causes:
 If the number of feeders for any individual yarn is not proper.
 If the produced stripe is not occurred according to measurement.
6. Thick and Thin:
When thick or thin place is found in the fabric design then this sort of fabric faults are normally
known as thick and thin. Generally thick and thin occurs if there is a passage of yarn having
uneven thickness.
Thick
Place
 Causes:
 Thick and thin places in the yarn.
 Fabric takes up too weak.
 Irregular present of slubs of yarn.
 Remedies:
 Controlling take-up speed in the knitting machine.
 Checking yarn before using for knitting.
 Checking thickness regularity of slubs yarn.
7. Fly contamination:
During knitting if any dirt, dust or any foreign particles pass into the yarn or the fabric and the
fabric is knitted with the fabric then that dirt or dust on the knitted fabric is called fly
contamination.
8. Yarn mixture:
If there is a presence of another yarn in the knitted fabric which is not identical to the yarns of
the knitted fabric then it is called yarn mixture. This fault is normally seen while dyed yarn
knitting or if a yarn dyed fabric is knitted previously on the knitting machine.
9. Slub:
If any uneven yarn is used during knitting of the fabrics which has both thick and thin place in
the yarn then the thick places found in the knitted fabric is called slub.
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Quality Assurance of Knit Fabrics
Engr. Khandaker Sakib Farhad
Slub
yarn
 Causes:

Usually caused by a thick or heavy place in yarn or by ling getting onto
yarn feeds.
 Remedies



By using good yarn quality.
Checking the supply yarn of the store.
Make sure that all the yarn packages are of same count and particular lot.
10. Loop:
If the needle is unable to catch the yarn in the needle latch then there occurs a gapping effect in
the fabric similar to the effect of needle broken but in this case instead of yarn breakage a
gapping effect in the fabric.
11. Wheel mark:
At the time of yarn passage from the wheel if the wheel is misplaced from its actual position
then a mark is produced throughout the fabric which is called wheel mark.
12. Needle broken:
Needle broken is normally caused when the needle is broken which causes tear in a particular
place of the fabric in the loops of that certain place.
Needle
Broken
 Causes:
 Due to dirt deposition in needle this problem occurred.
 This problem also can occur due to yarn tension variation.
13. Drop stitch:
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
If any problem occurs in the latch of the needle while catching the yarn then it could result in
drop stitch. If the miss stitch is seen in the fabric in a small area of the fabric then it is called
drop stitch.
Drop
Stitch
 Causes:











Yarn guide properly set.
Defective needle latch.
Yarn tension is not sufficient or too long stitches
Take down to high.
Wrong yarn treading.
Cylinder dials system too high.
Bad take up.
Very dry material.
Insufficient yarns tension.
Broken needle hooks.
Yarn feeder wrongly threaded-in.
 Remedies:
 Precise yarn guide resetting.
 Needle change.
 Yarn composition and collier re adjustment.
 Take down re adjustment.
 Dial position re adjustment.
 Yarn threading through the right bore.
 Use of fabric fault detector.
14. Oil spot:
When small circular oil marks are seen in the knitted fabric then it is called oil marks. Normally
oil spots occur during oiling the cylinder from the residual oils remaining in the needle.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Oil Spot
 Causes:
 During lubricating the machine if more needle oil poured on the machine.
 If excess oil is present on the cylinder and needles of the fabric.
 Remedies:
 Carefully using needle oil during oiling the machine.
15. Oil line:
Oil line is the vertical oil mark seen throughout the knitted fabric. Normally if more oiling is
done to a particular cam then oil marks occur.
16. Barre mark:
Barre mark is caused due to excess tension on the yarn while knitting the fabric. This excess
tension can whether cause elongation or shrinkage of the fabric.
17. Stare:
Stare is caused on the fabric when the needle latch is unable to grab the yarn and produces small
hole like star marks on the fabric.
Pin
Stare
Mark
 Causes:
 When needle latch is bent due to long time usage, then this problem occurred.
 Remedies:
 Needle must be changed.
18. Sinker mark:
Sinker mark is caused when the sinker is broken or it contains dirt on the sinker then the sinker
mark is seen on the fabric. This sinker mark is slightly larger than the needle mark.
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Quality Assurance of Knit Fabrics
Engr. Khandaker Sakib Farhad
Sinker
Mark
 Causes:




Sinker not clean.
Defected or broken sinker.
Incorrect depth of sinker which causes the stitch length to change while
the needle knocks over during its movement towards rest position.
When dirt’s deposited in sinker, it is raised and causes the faults.
 Remedies:



Sinker has to be clean.
It should be checked that the sinker having correct thickness and depth.
Replacement of defected sinkers.
19. Lycra drop:
Lycra drop is similar to Lycra out but in this case the gap mark in the fabric takes a small area or
space in the fabric, but not throughout the fabric.
Lycra Drop
 Causes:
 If any lycra yarn is missed during knitting.
 If lycra yarn feeder arrangement is not proper.
 If lycra yarn tension is not proper.
 Remedies:
 Lycra yarn should be passed to the maintaining proper tension
 Broken ends of the lycra yarn should be immediately fixed.
 Proper cleaning of the lycra knitting machine should be done.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
20. Yarn contamination:
Presence of any other foreign yarn in the knitted fabric is known as yarn contamination.
21. Patta:
Patta is caused when the yarn tension in the fabric is not proper, which causes the fabric to either
shrink or expand unexpectedly to a particular place of the fabric.
22. Wheel free:
If the tension of the yarn passage is less than the yarn passage tension of the wheel then it causes
wheel free problem on the knitted fabric.
23. Dirty yarn:
If the yarn used for knitting the fabric is dirty then the fault occurred in the fabric is that the
fabric has a dirty appearance which is called dirty yarn.
24. Press off:
When there is a larger hole in the fabric which causes the loops of the knitted fabric to tear up
inside the fabric is known as press off.
Pressoff
 Causes:



Yarn breaks before the yarn feeder.
Yarn package winding faults, poor package build-up.
Fibre fly block the yarn guides, feeders etc.
 Remedies:


Carefully feeding the yarn by the feeder.
Carefully yarn winding.
Choosing the yarn very carefully.

25. Uneven yarn:
Uneven yarn is responsible for various fabric faults. Such as, slub, needle broken, thick thin,
naps, etc.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Uneven
Yarn
26. Naps:
If there are thick places present in the yarn then that is known as naps.
8.6. Faults of fabric after dyeing:
In the Finishing section of ECHOTEX Dyehouse there is another inspection section where all the
finished fabrics are regularly inspected before reaching the garments section and the also various
corrective actions are taken for the proper buyer recommended appearance of the finished fabric.
The faults which are mainly occurred in the finishing section of the dyehouse are discussed
below:






















Hole
Oil Stain
Chemical Spot
Water Drop
Fly Yarn
White specks
Slubs
Rub Mark
Rust Stain
Yarn Contamination
Insect Spot
Uneven shade
Napes
Crease mark
Patches
GSM Hole
Hairy
Machine Stoppage
Needle line
Barre Mark
Crimple mark
Bowing
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics




Dead Cotton
Snagging
Line Mark
Pin hole
1. Rust Stain:
The stain mark which is caused by excess heat of the burners while passing through the
conveyer of the machines.
Rust Stain
 Causes:
 During passing the fabric through the Stenter or dryer machine if the
temperature of dyeing the fabric is too high.
 If the blower of the tenter frame is unable to spread the fire coming from the
nozzle throughout the fabric.
 Remedies:
 The speed and temperature of the tenter frame should be properly
maintained while passing the fabric through the tenter frame.
 Make sure the blower has the capability to pass the hot air uniformly
throughout the fabric.
2. Chemical Stain:
The stain mark which is caused by improper application of finishing chemicals and also due
to improper dissolving of the finishing chemicals.
Chemical
Stain
 Causes:
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics

The knitting industry unlike weaving uses oil to lubricate machinery
where the fabric is being produced. Such oil mixed with dust and
metallic powder can, cause stain on the fabric being knitted.
 Remedies:




Control of the oil itself, by applying it in minimum quantities and
delivering it continuously so that present in the fabric but does not
show up in any build up of solid material.
Using oils that are readily mixed with water so called securable or
clean oils.
The majority of knitted piece goods are wet finished before cutting and
therefore little oil staining will remain in finished fabric.
On stitch shaped garments tight control is needed as they are not wet
finished stain are dealt with during examination by solvent based
spotting guns.
3. Oil Stain:
The stain mark which is caused by applying needle oil in the knitting machine.
Oil Spot
 Causes:
 Storage condition.
 Core pH before drying.
 Packing used for while goods free from BHT [Butyl hydroxyl toluene].
 Remedies:
 Packing material used for while goods free atmospheric pollutants like oxides
and dimity etc.
 Packing material free from phenolic antioxidant.
 While good core pH should be 6.0-6.5.
4. Fly Yarn:
Fly yarn is also a knitting fault which is caused due to presence of dust particles on the
supplied yarn while knitting the fabric.
167
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Fly
Contamination
 Causes:
 It is caused if flying dust particles or colored yarn knitted with the fabric.
 By using dirty yarn.
 Remedies:
 By using good quality yarn.
 Proper cleaning of the machine before knitting.
5. Dead Cotton:
The presence of dead cotton fibers in the fabric causes very small white spots on the fabric
surface which occurs as there is no dye absorbency in the dead fiber contained areas of the
fabric.
Dead Cotton
 Causes:
 Poor cotton quality.
 More abrasion during process.
 Remedies:
 Try to maximize the abrasion during process.
 Use acid cellulose softener.
6. Uneven Shade:
If color difference or shade difference is seen on the fabric surface then the color or shade of
the fabric is called uneven shade.
168
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Uneven Shade
of Remazol
Reactive dyes
 Causes:
 Very rapid addition of dyes and chemicals.
 Uneven pretreatments (Scouring, Bleaching, Desizing).
 Lack control of dyeing machine like Machine speed.
 Temperature.
 Dosing time.
 Circulation pump.
 Plating device.
 Material: Liquor ratio.
 Remedies:
 Check addition of dyes and chemicals at a steadily increasing rate.
 Proper pretreatments.
 Proper control of dyeing machine.
Check the rope turn over time. Verify rope speed and chamber loading calculations.
7. White Specks:
White specks are the white mark seen on the fabric surface when it is passed through the
rollers as a result of presence of unwanted dust particles on the fabric surface.
8. Insect Spot:
During storing the fabric if dead insects are found on the fabric which causes mark on the
fabric surface then that is called insect spot.
9. Rub Mark:
Rub mark has a white mark appearance which is caused due to passage through the squeezer
machine or other rollers in the finishing machine as a result of excess friction.
10. Yellow Spot:
If there is yellowish color seen on a particular area of the dyed, bleached or softener treated
fabric then that specific spot on the fabric surface is termed as Yellow spot.
169
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Yellowish
spot in the
fabric

Causes:



Storage condition.
Core pH before drying.
Packing used for while goods free from BHT [Butyl hydroxyl toluene].
 Remedies:
 Packing material used for while goods free atmospheric pollutants like
oxides and dimity etc.
 Packing material free from phenolic antioxidant.
 While good core pH should be 6.0-6.5.
11. Dia Mark:
During the passage of the knitted fabric through the take down roller the fabric passes over
two pointed blades causing needle mark at one side and on the other side there is also a line
mark produced which is called the Dia mark.
Dia Mark
 Causes:


During passing the fabric through the spreader of the circular knitting
machine if the fabric passes at an irregular tension.
If the spreader has contains very sharp blades on both sides the needle
mark and dia mark both are caused.
 Remedies:


To avoid dia mark the fabric should be carefully passed through the
spreader.
The tension of take down mechanism of take down rollers should be
properly maintained.
12. Crease Mark:
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
The presences of unwanted line marks on the surface of the fabric due to presence of
mechanical pressure during fabric processing are called crease marks.
Crease
mark in the
fabric

Causes:





More cycle time.
Faulty plaiting device.
Incorrect set bowed expender.
Variation of heating and cooling rate.
Improper fabric movement.
 Remedies:

Anti-creasing agent are used to avoid crease mark problem.
13. Crample mark:
Crush mark or crample mark is mainly caused during reeling the fabric into the Dyebath
which a result of unbalanced speed of loading to the dye bath is reeling. Crample mark can
also be caused during passing the fabric through the finishing machines due to the uneven
pressure of the rollers.
Crample
mark in the
fabric
 Causes:
 Lower fabric speed.
 Lower liquid ratio.
 Higher rate of cooling.
 Remedies:
 Running with a higher fabric speed.
 Increasing the liquor ratio.
 A slower rate of cooling.
14. Pin Hole:
When small holes are seen in the fabric after dyeing which is occurred in the dye bath or in
the finishing section is called pin hole damage.
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Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Pin Hole
Damage
 Causes:



Oxidation of the knitting oil/lubricant on the fabric stored for a long
duration.
Presence of heavy metal ions in peroxide bath.
Presence of sharp metallic part in some parts in machine.
 Remedies:




Check presence of any sharp object in machine.
Provide magnetic filter in water or steam line.
Provide magnetic filter in water or steam.
Check if the used water for dyeing is properly softened.
15. GSM Hole:
The hole which is caused by cutting the fabric with GSM cutter while measuring the GSM
of the fabric.
GSM Hole
 Causes:

Continuous cutting of the fabric using GSM cutter for measuring GSM.
 Remedies:

For GSM measuring applying calculated value and indentifying the whole
weight and length to measure GSM.
16. Bowing:
If spirality occurs in the design or loop construction towards length and width direction of
the fabric then it is called bowing.
172
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
Bowing
 Causes:
 This structure consist of plain and lacost design where stitch where stitch
length for tuck stitch is kept same as all knit loops As a result waviness has
produced in lacost part.
 Remedies:
 Different SL for tuck stitch must be kept by adjusting VDQ pulley.
17. Snags:
Snags mainly occur while processing filament yarns. The tendency towards snagging can be
reduced by using yarns with a coarser single filament count, lesser crimp elasticity and
higher twist. During knitting all mechanical influences, caused by rough surfaces on yarn
guide elements, yarn feeders, needles, fabric take-up, etc. have to be avoided. Even after
knitting some snags can appear especially during fabric setting, if its storage and further
processing has not been undertaken carefully.
173
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.7. Corrective Actions taken for removing faults:
Fabric Fault
Corrective Action
Corrective Recipe
Chemical Stain
Anti Staining
Anti Staining: 1gm/l
Oxalic Acid: 3gm/l
Temperature Time : 800C 15min
Yellow Spot
Washing
Wetting Agent & Detergent: 0.5gm/l
Temperature Time : 900C 10min
Chemical Stain on
White Fabric
Bleaching
Half Bleach Caustic: 2gm/l
Hydrogen Peroxide: 2gm/l
Optical Brightening Agent: 0.1gm/l
Temperature Time : 950C 30min
Yellow Spot on
White Fabric
Bleaching
Half Bleach Caustic: 2gm/l
Hydrogen Peroxide: 2gm/l
Optical Brightening Agent: 0.1gm/l
Temperature Time : 950C 30min
Oil Stain
Anti Staining
Anti Staining: 1gm/l
Temperature Time : 900C 15min
Band Line
Anti Staining
Anti Staining: 1gm/l
Oxalic Acid: 3gm/l
Temperature Time : 800C 15min
Line Mark
Washing
Soaping Agent(Dekol SN): 0.5gm/l
Temperature Time : 650C 15min
Crease Mark
Softener Spot
Anti Creasing
Washing
Dirty Spot
Anti Staining
Anti Staining: 1gm/l
Temperature Time : 900C 15min
Rub Mark
Washing
Soaping Agent: 0.5gm/l
Temperature Time : 650C 15min
Hairiness
Enzymatic Treatment
Enzyme: 1% of Fabric weight
Temperature Time : 550C 40min
Uneven Shade
Bleach & Re-dye
Wetting Agent & Detergent: 0.5gm/l
Acid: 3gm/l
Temperature Time : 900C 10min
Bleaching Temperature Time : 950C 30min
Cotton Dyeing Temperature Time : (600C -800C) 30min
Polyester Dyeing Temperature Time : 1300C 30min
174
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.8. Flow Chart of Quality Control of Grey Fabrics:
Fabric inspection
On-line inspection
Off-line inspection
Outside
Inside
Outside
production
Fabric rolls checkfabric quality
Every machine checkfabric quality
Inside
production
Check with yarn count,
Stitch length, Dia &
Gauge
Fabric inspection 100%Fabric quality
First Bulk (first
roll)
Approved Sample (Solid
& Dyed Yarn)
Pass
Fail
Grey Store
100% inspection
for quality fabric
Approval card
(Knitting)
Pass
Fail
Grey Store
Reject -immediately
inform to executiveOutside factory
Approval card
(Finishing)
Pass
Fail
Grey Store
Reject -immediately
inform to executiveOutside factory
175
Engr. Khandaker Sakib Farhad
Quality Assurance of Knit Fabrics
8.9. Flow Chart of Quality Control of Dyed and Finished Fabrics:
Receiving fabric from Finishing Section
Matching Fabric Shade in Light box
Shade OK
Shade not OK
Separating from one roll to another
Passed to Dyeing &
Finishing Section
Determining the Fabric Faults
Visually and by Machine
Calculating the Fabric Faults
Fabric not OK
Fabric OK
Determining if the Fabric is
treatable
Passed to the Storage
Section
Pass to Dyeing &
Finishing Section for
Re-processing
Untreatable
Rejected
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