2. Total Textile Process at a Glance

3. PROJECT
ON
Root Causes Analysis of knitted
Fabric Faults & Their Remedies
33

4. Content
 Introduction
 Causes of Fabric faults due to yarn
 Causes of Fabric faults due to knitting
 Causes of Fabric faults due to Dyeing &
Finishing
 Conclusion
44

5. Introduction
Due to increasing the demand for quality knitted fabrics,
high quality requirements are today greater since customer
has become more aware of “Non-quality" problems, in
order to avoid fabric rejection, knitting mills have to
produce fabrics of high quality, constantly. Detection of
faults during production of knitted fabric with circular
knitting machine is crucial for improved quality and
productivity. Any variation to the knitting process need to
be investigated and corrected. The high quality standard
can be guaran-teed incorporating appropriate quality
assurance. Industrial analysis indicate that quality can be
improved, and defect cost minimized, by monitoring of the
circular knitting process.
55

6. Our aim of this project is to study on root causes
analysis of knitted fabric faults. To do so we have
collected various type of faults from many
industries and classify them in a systematic
manner
66

7. Causes of Fabric faults due to Yarn
Almost all the defects appearing in the horizontal
direction, in the knitted fabric are, yarn related.
 These defects are mainly:
I) Barriness
II) Spirality
III) Shrinkage
IV) Thick & thin place
77

8. I). BARRINESS
Definition:
Barriness defect appears
in the Knitted fabric, in
the form of horizontal
stripes of uniform or
variable width.
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Fig: Barriness

9. Causes Of Barriness:
factors which may cause or contribute to barre are
listed as follows:
 Raw material/fiber
 Yarn formation /supply
 Knitting machine
9

10. Raw Material/Fiber:
Failure to control fiber diameter (micronaire
or denier) from lay down to lay down.
Too high a C.V. of micronaire in the lay
down for a given mill's opening line blending
efficiency.
Failure to control the fiber color in the mix
(grayness Rd, yellowness +b).
10

11. Yarn Formation/Supply:
 Poor blending of fiber in opening through finisher
drawing.
 Mixing yarns of different counts.
 Mixing yarns from different spinning systems.
 Mixing yarns with different twist level/twist direction.
 Mixing yarns with different degrees of hairiness.
 Mixing yarns with different amounts of wax.
 Excessive back winding or abrasion during this
process.
11

12. Knitting Machine:
 Improper stitch length at a feed.
 Improper tension at a feed.
 Variation in fabric take-up from loose to tight.
 Excessive lint build-up.
 Variation in oil content.
 Worn needles, which generally produce length
direction streaks.
 Uneven cylinder height needles (wavy barre).
 Double feed end.
12

13. Remedies:
 Ensure uniform Yarn Tension on all the feeders.
 The average Count variation in the lot, should
not be more than + 0.3
 Ensure that the yarn being used for Knitting is
of the same Lot / Merge no.
 Ensure that the hardness of, all the yarn
packages, is uniform, using a hardness tester.
13

14. II).SPIRALITY
Definition:
Spirality appears in the
form of a twisted
garment, after washing.
The seams on both the
sides of the garment
displace, from their
position & appear on the
front & back of the
garment.
14
Fig: Spiraility

15. Influencing Factors:
A) Influence of yarn properties
 Count
 Twist
 Blend
B) Influence of fabric properties:
 Fabric Stitch length:
 Fabric Structure
 Fabric Tightness
15

16. (III). SHRINKAGE
 A dimensional change resulting in a decrease in the
length or width of a specimen subjected to specified
conditions is known shrinkage. Shrinkage is mainly
due to yarn swelling and the resulting crimp increase
during washing in case of cotton fabrics
16

17. Causes of Shrinkage:
 Twist factor: twist factor increases so that
shrinkage will be increases,
 Stitch length: stitch length increases so that
shrinkage will be increases,
 GSM: GSM increases so that shrinkage will be
increases
17

18. Remedies of Shrinkage
 Keep the Grey Fabric in loose plated form,
immediately after the roll is cut.
 Store the finished fabric also in the plated form & not
in the roll form.
 Allow the fabric to relax properly, before it is cut.
 Give maximum overfeed to the fabric, during the
processing, on the Stenter, Compactor & the
Calendaring machines.
18

19. (IV) Thick & Thin Places
It causes due to yarn
problem. If thick &
thin places remain in
yam & fabric is knitted
with that yarn, then,
this problem found in
fabric.
Fig: Thick Thin Place
19

20. Causes of Fabric faults due to Knitting
 Almost all the defects appearing in the vertical
direction, in the knitted fabrics, are as a cause of bad
Knitting Elements. And some defects appear randomly
in the knitted fabrics, due to the wrong knitting
machine settings & that of the machine parts
 About Different type of faults are discuses bellow
21

21. Cracks Or Holes
Local holes obtained when yarn breaks during
loop formation.
Causes
 Presence of knot in yarn.
 Weak places in yarn.
 Yarn tension too high.
 Yarn too dry.
 Yarn - guide not properly
set,
 Poorly lubricated yarn. Fig: Hole
22

22. Remedies:
 Use of flat knots.
 Yarn regularity control.
 Yarn consumption & coulier re-adjustment.
 Precise yarn - guide resetting.
 Air humidification.
 guide blowing.
 Use of protective filter creel.
23

23. Pin Hole
Causes:
 Improper tension.
 Same drive for both knit & tuck
stitch.
 Curved needle latch.
Remedies:
 Different drive have to maintained
Needle has to change.
 Needle has no change.
Fig: Pin Hole
24

24. Fly Contaminations
Causes:
 Presence of dead fibers & other foreign materials, such
as; dyed fibers, husk & synthetic fibers etc.
 Dead fibers do not pick up color during Dyeing.
25
Fig: Fly contamination

25. Remedies
 Use rich fiber mixing for the yarns, to be used for
Knitting, in order to have less dead fibers, appearing in
the fabric.
 Rigid control measures in the Blow Room, to prevent
the mixing of foreign matters in the Cotton mixing
26

26. Needle Broken
Causes:
 High Yarn Tension
 Bad Setting of the Yarn Feeders
 Old & Worn out Needle set
Remedies:
 Ensure uniform & the right Yarn
tension on all the feeders.
 Keep the recommended gap,
between the Yarn Feeders & the
Needles.
 Periodically change the complete
set of needles.
Fig: Needle Broken
27

27. Sinker Mark
Causes:
 Sinker not cleans.
 Defected /broken sinker.
 When darts deposited in
sinker, it is raised & causes
this fault.
Remedies:
 Sinker has to be clean.
 It should be checked that the
sinker having correct
thickness and depth.
 Replacement of defected
sinkers.
28
Fig: sinker mark

28. Stains or Oil Lines
Causes:
 Grease & Oil stains from the
unguarded moving machine
parts
 Fabric touching the floors &
other soiled places, during
transportation, in the trolleys.
29
Stains appear as spots or patches of grease, oil or dyes of
different color, in a neat & clean finished fabric surface
Fig: Stain or oil line

29. Remedies:
 Wash & clean the dyeing machine thoroughly, after
dyeing every dye lot.
 Follow the dyeing cycle of Light- Medium- Dark
shades & then the reverse the cycle, while dyeing the
fabric.
 All the lubricated moving machine parts, should be
protected, with safety guards
30

30. Fabric Press Off
 Fabric press off appears, as a big or small hole in the
fabric, caused due to the interruption of the, loop
forming process, as a result of the yarn breakage, or
closed needle hooks.
31
Causes:
 End breakage on feeders, with
all needles knitting.
 Yarn feeder remaining in lifted
up position, due to which, the
yarn doesn’t get fed in the
hooks of the needles.
Fig: Press off

31. Remedies:
 Needle detectors, should be set precisely, to detect the
closed needles & prevent the fabric tube from
completely pressing off.
 Proper yarn tension should be maintained, on all the
feeders.
32

32. Lycra out
Causes:
 Fail to catch the Lycra yarn by needle.
 Low tension of Lycra yarn.
 Lycra yarn breakage.
 Faulty auto stop motion
Remedies:
 Ensure the feed of lycra yarn to every
needle.
 The tension of lycra yarn should be
uniform.
 Auto stop motion should work
properly
33
Fig: Lycra out

33. Lycra Drop
Causes:
 Low tension of Lycra yarn
 Fail to catch the Lycra yarn by needle
Remedies:
 Ensure the feed of lycra yarn to
every needle.
 The tension of lycra yarn should be
uniform.
34

34. Slub
Causes:
 Usually caused by a thick or
heavy place in yarn or by ling
getting onto yarn feeds.
Remedy:
 By using Good quality yarn
Fig: Slub
35

35. Causes of Fabric faults Due To
Dyeing & Finishing
37

36. The Dyeing and finishing related defects are, as follows
Shade variation/Uneven
shade
Pin-hole damage
Crease mark
Dye spots
Dead cotton on dyed
cotton
38
Wrong slitting
Lycra burn
Band line
Dust

37. Shade Variation/Uneven Shade
 Sometimes, there appears to be a
difference in the depth of shade
between the roll to roll & from place
to place, in the same roll. The defect
will show up clearly in the garments
manufactured from such fabric.
Causes:
 Shade variation can be as a result of
mixing of the fabrics of two different
lots.
 Shade variation is also caused by the
variation in the process parameters
i.e. Time, Temperature & Speed etc.
from one fabric roll, to the other.
39
Fig: Shade Variation/Uneven Shade

38. Shade variation can appear to be in fabrics with GSM variation,
caused due to the uneven stretching, unequal fabric overfeed %
etc.
Remedies:
 Ensure that the grey fabric used for one shade is knitted from
the same lot of the yarn.
 Ensure that the same process parameters (Width, Overfeed,
Temperature & Machine Speed etc.) are used, for each roll of a
dye lot.
40

39. Pin Hole Damage:
Causes:
Oxidation of the knitting oil/lubricant on
the fabric stored for a long duration.
Presence of sharp metallic part in some
parts of machine
Presence of heavy metal ions in peroxide
bath.
Remedies:
Check presence of any sharp object in
machine
Provide magnetic filters in water/ steam
line
41
Fig: Pin Hole Damage

40. Crease Mark:
 In knit dyeing crease mark is a common dyeing
fault.
Causes:
 More cycle time.
 Faulty plaiting device.
 Slack on tight selvedge causes creases at an angle to
each selvedge.
 Incorrectly set bowed-expander.
 Variation of heating and cooling rate.
 Improper fabric movement.
Remedy:
 Anti- creasing agents are used to avoid crease mark
problem.
42
Fig: Crease Mark

41. Dye Spots
Causes:
These are most often caused by
operators not correctly mixing and
thoroughly dissolving the dyestuff, in
the right amount of water.
Dye bath hardness.
Not agitation of dyestuff.
Remedies:
 Use adequate amount sequestrate to
lower bath hardness.
 Proper agitation.
43
Fig: Dye Spots

42. Dead Cotton On Dyed Cotton:
Causes:
Poor quality cotton
More abrasion during process
Remedies:
Try to minimize the abrasion
during process
Use acid Cellulosic softener
44
Fig: Dead Cotton On Dyed Cotton

43. Wrong Slitting:
Causes:
It causes due to operator
carelessness. Sometimes workers do
not slit fabric through slitting mark.
Remedies:
 Operators have to slit fabric
through slitting mark or fed fabric
in slitting m/c in proper way so that
m/c can slit fabric through slitting
mark
45
Fig: Wrong Slitting

44. Lycra Burn:
Cause:
Overflow heat on the fabric during
heat setting.
Incorrect speed of stenter m/c
during heat setting.
Remedies:
 Provide correct temperature in
stenter m/c.
 To keep correct speed of stenter
m/c.
46
Fig: Lycra Burn

45. Band Line:
Causes:
If the fabric is wet condition in long time.
During drying the fabric if any part of the fabric is wet then
it can occur.
Un proper fixing during dyeing
Remedies:
 To use short time for wet conditioning of the fabric.
 Equal drying of the fabric.
 Proper fixing during dyeing.
47

46. Dust:
Causes:
Due to dirty finishing floor.
Unclean the trolley of finishing floor.
Due to unclean the m/c surface.
Unclean the compactor m/c after using the
varies color of fabrics.
Drop the footstep in white fabric.
Remedies:
 To keep clean the finishing floor.
 Clean the trolley of finishing floor.
 To clean the m/c surface.
 Clean the compactor m/c after using varies
color of fabrics.
48
Fig: Dust

47. CONCLUSION:
Detection of faults during production of knitted fabric is crucial
for improved quality and productivity.
This presentation will present and discuss the detection of faults
and malfunctions during the production remedies of knitted
fabric.
We believe that our work will help the knitters to identify the
source of de-tected faults & proposes specific solutions for
theses faults causes. So Knitters can take necessary remedial
steps to overcome the faults.
49

50. 1. Yarn Manufacturing Technology
Link : http://www.facebook.com/pages/Yarn-Manufacturing-
Technology/485014954866808
2. Fabric Manufacturing Technology
Link : http://www.facebook.com/pages/Fabric-Manufacturing-
Technology/459520217425605
3. Garments Manufacturing Technology
Link : http://www.facebook.com/pages/Garments-Manufacturing-
Technology/472364799463126
3. Wet processing Technology
Link : http://www.facebook.com/pages/Wet-Processing-Technology-Dyeing-
/468645219825404
4. Fashion-Design-and-Technology
Link : http://www.facebook.com/pages/Fashion-Design-and-
Technology/587655294583875?ref=ts&fref=ts
My Facebook Textile related Pages
http://www.textilelab.blogspot.com (Visit My Blog for more Info )