Warp Knitting a verstile and rigid structure

Intro

1. Lecture
Dr. Danish MahmoodBaitab
WarpKnitting

2. WeftKnitting WarpKnitting
1.Yarns runs in vertical or wale direction
during knitting and loopformationtakes
placewalewiseinverticaldirection
2.Needlesknitaltogetherinaknittingcycle.
3.Large number of yarns are needed for
knitting a fabric hence yarnissupplied
generallyintheformofwarpbeam
(numberofbeamsmaybe2ormore)
4.Filamentyarnsaremostlyused
5.Morepreparatoryprocessesarerequired
beforeknitting
1.Yarnrunsinhorizontalorcourse
directionduringknitting and loop
formation takes place course wise in
horizontal direction
2.Needlesknitsequentiallyinaknitting
cycle.
3.Only one or a few yarn(s) (152
maximum) is/are needed during
knitting a fabric and yarnissupplied
generallyintheform ofconeholdin
acreel.
4. Stapleyarnsarepreferablyused
5.Lesspreparatoryprocessesare
requiredbeforeknitting
2

3. 3
WarpKnitting
•Warp knitting differs from weft knitting, basically, in that each needle
loops has its ownthread.
•The needles produce parallel rows of loops simultaneously that are
interlocked in a zigzagpattern
•Thestitchesonthefaceofthefabricappearvertically,butataslight
angle;andthestitchesonthebackappearhorizontallyasfloatsata
slightangle.
•Thesefloatscalledlaps,orunder-laps,areadistinguishing
identificationofwarpknits.
•Warp knitting may be flat or tubular and can be produced in many
varieties ofpatterns.
•It can yield cloth with a dimensional stability almost equal to woven
fabrics.

4. Warp KnittingProduction
https://www.youtube.com/watch?v=KSlkY5Z6hhM&start=125
4

5. MachineElements
5

6. Warp knittedStructures
Typesof
Warp
Knitting
Tricot
Raschel
Crochet
MilaneseSimplex
Ketten
raschel
Warpand
weft-
insertion
6

7. Machine Elements: Tricot vsRaschel
7

8. 8
LoopFormation

9. Guide BarMovements
GuideBas
Motions
Swing
Forward
(Overlap)
Backward
(Underlap)
Shog
Vibration
(Over/Under
lap) 9

10. Tricot Loop formation: BeardedNeedle
10
The restposition

11. Warp Knitting Loop FormationBeard
Needle
11
Warp Knitting, Bearded Needle with Sinker andPresser,
Loopformation

12. Warp Knitting LoopFormation
12
https://www.youtube.com/watch?v=1OCbLOD8Fyk

13. Warp Knitting Loop FormationCompound
Needle
13
Warp Knitting, Loop formation, Compound
needle

14. 14
Warp Knitted StructureProperties
•Consumerslikewarpknitsbecauseoftheirsmoothness,possible
sheerness,wrinkleandshrinkresistance,strength,andabrasion
resistance.
•Warp-knitfabrics,ascomparedwithweftknits,alsohavecertain
otheradvantages.
•Warpknitsdonotravelorrunandarelesssusceptibletosnagging.
•Qualityisusuallybetter;stitchdefinition,texture,andfabriccoverare
generallybetterthaninweftknits.
•Warpknitshavesuperiordimensionalstability.
•Productsrangingfromhairnetstorugsmayheproducedbywarpknitting,
dependinguponthemachineandtechnique

15. 15
WeftKnitting WarpKnitting
Plain, Rib, Interlock andPurl Tricot, Milanese, Raschel, Simplex,Ketten,
Rascehl, Crochet, Weftinsertion
Less dimensionallystable More dimensionallystable
Lessspeed Morespeed
Less wrinkle and shrinkageresistance Mores wrinkle and shrinkageresistance
Less strength and abrasionresistance More strength and abrasionresistance
Sequentially feeding to eachneedle Each needle has its ownthread
May ravel from end and easilysnagged Do not ravel and less snagging(Tearing)
Sweaters, T Shits, Socks, Trousers,sports
wear, Cuffs, Collars,Waistbands
Curtains, Table Covers, SleepWears,
Lingerie, Geo Textiles, Carpets,Bandages
C
o
mparis
o
n
o
f
War
p
and
Wef
t

Kn
it
t
ing

16. Warp knitting lapping and chainnotation
16

17. Five basic overlap/underlapvariations
1-An overlap followed by an underlap in the opposite direction (closedlap)
17

18. Five basic overlap/underlapvariations
2-An overlap followed by an underlap in the same direction (openlap)
18

19. Five basic overlap/underlapvariations
3-Only overlaps and no underlaps (openlaps)
19

20. Five basic overlap/underlapvariations
4-Only underlaps and no overlaps(laying-in)
20

21. Five basic overlap/underlapvariations
5-Neither overlaps nor underlaps(miss-lapping)
21

22. Open and closed lap pillarstitches Atlaslapping
22
Warp knitted fabric anddesigns

23. Face and back of single guide bar warp knittedfabric
TechnicalFace
TechnicalBack
23

24. Face and back of two guide bar warp knittedfabric
24
TechnicalFace TechnicalBack

25. 25
Notations of twoguide
bar warp knitted
fabrics
Queenscord
Sharkskin

26. 26
Structures of two guide bar warp knittedfabrics

27. Muhammad Usman Javaid:FALL2017(PostMID) 27
Tricot Raschel
Compound and BeardedNeedle Compound and Latchneedle
Warps beams are arranged behind or above
themachine
Warps beams are arranged above the
machine
Operation can be made from front sideof
machine
Operation can be made from frontand
back side ofmachine
Finer gauge machines (7.08-15.74N/cm) Coarser gauge machine (2.36-12.6N/cm)
Tricot machine use Sinkerbar Raschel machine use trickplate
Angle between yarn and fabric take up is90
degree
Angle between yarn and fabric take upis
upto 180degree
Higher in speed 2800rpm Lower in speed 1600rpm
Continuous filament yarn isused Mostly staple yarn isused
Soft, wrinkle resistant, gooddrapabilityLess soft and wrinkleresistant
Machine width (201-533cm) Machine width (191-584cm)
One needle bar or two needle bar
Shirts, Sleep wear, Loungewear
One needle bar or two needle bar
Veils, Laces, Nets,Carpets
Warp
Knitting