3.Winding part- 2 It contains a number of imperfections in the form of thick places, thin places and slubs.pdf

It contains a number of imperfections in the form of thick places, thin
places and slubs. These will pose problems in the subsequent process and ultimate
hinder the cloth quality. Also, the ring cop is small in size and needs to be converted
into a bigger package

1. Winding part 2

2. Winding
YarnGuide
Yarnguidesaretheoneofthehelpinginstrumentstocontroltheyarnpath.
Yarnguidesarerequiredtoperformthewindingorunwindingprocessproperly.In
everyoperationwhereyarnsaretransferredfromonepackagetoanother,yarn
guidesarerequiredthere.Yarnguidesareusedduringwinding,warping,beaming
andweavingprocess.
Inwindingandunwindingitisnecessarytocontroltheyarnpath.Forside
withdrawalitispossiblefortheyarntopassalongasmoothvaryingyarnpath.But
foroverendwithdrawaltheyarnmustbecontrolledbyplacingguidesalongthe
yarnpath.
Yarnguidesarenormallymadeofhardsmoothsteelorceramic.Differentyarn
guidesaremadebytheyarnguidemanufacturer.Yarnguidesshouldbeperfectin
sizeotherwisewindingprocesswillbehampered.Theyarnpathshouldkeepclean
duringwithdrawaloftheyarn.Yarncleaneralsoplacedalongtheyarnpath.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 2

3. Winding
Necessity of yarn guides:
▪To control the yarn path.
▪To produce required shape package.
▪Minimize yarn vibration.
▪Reduce the chance of balloon formation.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 3

4. Winding
Types of yarn guides:
Selection of guide shape may depend on the yarn motion to be controlled.
Guides are two types-
1.A yarn end is required for threading: Ittakesextratimeinthreading.So,
speedofoperationisdecreased.Theyarnexperiencedmorefriction.No
possibility to run out the yarn. More costly. Shapeoftheyarnguidesaremaybe
asfollow:Ceramicinserttype,Trumpettype,Bushorrollertype.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 4

5. Winding
2.Ayarnendisnotrequiredforthreading:Threadingisveryeasy.So,the
speedofoperationincreased.Theyarnexperiencedlessfriction.Possibility to
run out the yarn. Low cost. Shapeoftheyarnguidesmaybeasfollow:Pigtail,
Slottedtype,Posttype.
So,yarnguideplaysanimportantroleinwindingoperation.Weshouldbecareful
duringtheselectionofyarnguide.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 5

6. Winding
Yarn Tensioner
Yarn tensioners are devices by the help of which tension is given to the yarn.
This is an important device because it enables us to provide necessary tension to the
yarn as it moves through the different parts of the machine.
Types of tensioning device: Tensioning device can be classified into two groups.
1.According to the working principle:
▪Capstan tensioner.
▪Additive tensioner.
▪Combined tensioner.
▪Automatic tensioner.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 6
2.Depending on the type of the working
member acting on the yarn:
▪Ball type.
▪Washer type.
▪Disc type.
▪Roller type.
▪Comb type.
▪Two zone type.

7. Winding
Capstan Method
This is the simplest form of yarn tensioning device where the yarn is passed
around posts where the tension on the yarn is provided from the friction between the
posts and yarns.
It works by the following formula:
OutputTension=InputTension×e
μθ

orT
2=T
1e
μθ

Here,
T
2=Outputtension.
T
1=Inputtension.
e=Constant
μ = Co-efficient of friction.
θ = θ
1+θ
2+θ
3 = Angle of lap.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 7

8. Winding
Additive method
In this method the yarn is passed through the middle of two surfaces in
contact. The force is applied from above to give suitable tension to the yarn.
T
2 = T
1 + 2μF
Here,
T
1=Inputtension.
T
2=Outputtension.
µ = Co-efficient of friction.
F = Applied force.

Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 8

9. Winding
Combined method
The combined system is a combination of capstan and additive method. This
device is a complicated system which on allows the addition of tension. We cannot
decrease the tension with this device. It is seldom used.
T
2 = T
1 + 2μF + T
1 e
μθ

Here,
T
1 = Input tension.
T
2 = Output tension.
µ = Co-efficient of friction.
F = Applied force.
θ = θ
1+θ
2+θ
3= Angle of lap.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 9

10. Winding
Automatic Method:
It is a simple tensioner in which yarn tension is controlled automatically. It
has a lever with spring loaded disc in one side and applied load in another side. The
device is designed in such a way that if applied tension is too high, then pressure on
disc is reduced to bring the tension back to its proper level.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 10

11. Winding
Important effects of tensioning device
1.If the tension is too high, then
▪The yarn can be damaged
▪The rate of yarn breakage will be high
▪The elongation property of yarn will change
▪Hard package.
▪Shade variation.
▪Weak the thin place.
2.If the tension is too low, then
▪Loose package
▪ Unstable package
▪ Slough off
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 11

12. Winding
If the tension varies/improper, then
1.Forman-madefilamentyarn,impropertensionwillcause
▪Changeinmolecularstructure
▪Variationincolourshades
2.Forstapleorspunyarn,hightensionwillcause
▪Yarnbreakageatthinplaces
▪Problem during unwinding
▪ Package unstable
▪ Irregularity among yarn
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 12

13. Winding
Factors influencing the selection of Tensioners
▪Thedevicemustbereliabletocontroluniformtension
▪Thedevicemustbeeasilythreadable
▪Itmustnotintroduceormagnifytensionvariation
▪Itmustnotintroducevariationintwist
▪Itmustnotbeaffectedbywear
▪Itmustbeeasilyadjustable
▪Itmustnotbeaffectedbyoilanddirt
▪Itmustnotencouragedirtcollection
▪Itmustbeeasilycleanable
▪Theoperatingsurfacemustbesmooth
▪Itmustbecheap
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 13

14. Winding
Parameters of Winding
Winding rate:
Winding rate is defined as the amount of yarn to be wound on the package per
unit of time i.e., the length of yarn in meter wound on package per minute. Its unit is
m/min.
Winding on diameter:
The diameter of the package on which the yarn is wound is called winding on
diameter. It changes continuously after each traverse. Its unit is cm.
Winding on surface:
The place where winding is done according to the time is called winding on
surface. Its unit is cm.
Traverse velocity:
The amount of distance travelled per unit time by the traverse guide is called
traverse velocity. Its unit is meter per minute. It is denoted by V
t.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 14

15. Winding
Angle of wind:
The angle contained between wrapped of yarn on the surface of package and
the diametrical plane of the package is known as angle of wind. It is denoted by θ.
Surface velocity:
The rate at which winding is carried out on winding on diameter is called
surface velocity. Its unit is m/min and denoted by V
s=ᴨDN.
Vs Package






Directionofwind
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 15

16. Winding
Net winding rate:
Net winding velocity is obtained by dividing the traverse velocity by sine
value of winding angle. It is also called real winding rate and denoted by V
r.
Sinθ =
??????
??????
????????????
Coil angle:
The angle contained between a wrap of yarn in the surface of the package
and the longitudinal plane of the package is called known as coil angle. It is denoted
by ß and is measure by degree.
θ= Angle of wind
ß= Coil angle
θ+ß= 90°
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 16

17. Winding
Wind:
Number of yarn coils wound on package during one single traverse (from
one end of package to another end).
Wind Ratio:
The wind ratio is the number of revolutions made by the package while the
yarn guide makes a single traverse from one end of the package to the other. (i.e.,
the number of coils laid on the package).
Traverse Ratio:
The traverse ratio is the number of coils laid on the package during a double
traverse of the yarn guide (from one end of the package to the other and back). It is
twice the wind ratio. It is also referred to as wind per double traverse.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 17

18. Winding
Traverse Motion
By the help of motion when a dynamic part of a machine moves in to & fro
motion, then this movement is called traverse motion. In the package winding by
the help of this motion yarn is wound evenly in a package.
Traverse method are mainly two types:
▪Reciprocating motion
▪Rotating motion.
Reciprocating motion:
▪By this motion, moving parts of a machine is passed a fixed distance & within a
several time, it re-back starting positions.
▪This motion is given by the help of cam. Traversing rod is connected with cam.
▪By the rotation of the cam moving parts of the machine gets to and fro motion.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 18

19. Winding
This motion is performed in two mechanism-
▪ A single guided rod and cam serving many winding spindles.
▪A guide rod and cam for both spindles.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 19

20. Winding
Rotating Traverse motion
Rotating traverse motion completes its motion by the rotation of a grooved
drum. On the surface of drums there contains grooved shape & yarn package is
wound & rotates with the surface contact of grooved drum.
Figure: Rotating Traverse mechanism.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 20

21. Winding
Tension Variation During Unwinding from Cop Build Package
Duringtheunwindingofyarnsfromcop
buildpackages(ringframe,bobbin,pirnetc.),
short-termandlong-termtensionvariationisnoticed.
Shorttermtensionvariationarisesduetothe
movementoftheyarnfromthetiptothebaseand
viceversa.
Ontheotherhand,longtermtensionvariationoccurs
duetothechangeinheightoftheballoonformed
betweentheunwindingpointandtheyarnguide.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 21

22. Winding
Theempiricalequationforunwindingtensionisgivenbelow.
Unwindingtension=????????????
2
[??????
1+C
2
??????
??????
2
]
Where,Hisballoonheight,rispackageradius(variesbetweentipandbase),mis
massperunitlengthofyarnandvisunwindingspeed.
Incaseofshort-termtensionvariation,onelayerofcoilisunwound,andtheyarn
withdrawalpointmovesfromtiptobase,boththeHandrincrease.However,the
proportionatechangeinrishigherascomparedtothatofH.Therefore,inevery
cycle,whenthewithdrawalpointmovesfromtiptobase,theunwindingtension
reduces.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 22

23. Winding
However,overalongperiodoftime,successiveconicallayersofyarnsare
removedfromthepackageandthustheconicalsectionofyarnsmovetowardsthe
baseofthepirn.Therefore,theballoonheightincreasesresultinginprogressive
increaseinmeanunwindingtension.
For short term tension For long term tension
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 23

24. Winding
Method of driving/ Driving of winding packages
i.Surface contact driving,
ii.Directly package driving at constant speed.
iii.Directly package driving at variable speed
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 24

25. Winding
Surface contact driving
In this system, the yarn package is placed with a surface contact of a drum or
roller. The drum is driven or rotated by the motor and machine gears and when it
rotates, the package also rotates in reverse direction at a constant speed.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 25

26. Winding
Directly package driving at constant speed
In this system, the yarn package is placed on a spindle and the spindle gets
motion by motor and gearing system. So, the package gets a constant angular speed
and here yarn take up rate is directly proportional to the package diameter. Here
yarn is passed through a yarn guide, yarn gets tension. Yarn is not twisted in this
method.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 26

27. Winding
Directly package driving at variable speed
In this system the yarn package is placed in a spindle and the spindle is
rotated with the motor. Therefore, the package gets motion directly from motor.
Here the rotational speed of package is varied inversely to package diameter to keep
winding speed constant.
.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 27