3. • What is Weaving ??
• Weaving is the interlacing of two sets of yarns,
namely warp and weft at right angle in order to
product fabric.
• In woven construction the yarns that are placed
lengthwise or parallel to the selvedge (edges
of the cloth) are called warp yarns. Each thread
or yarn in the warp is called an end.
• The yarns that run crosswise are called weft
(filling) yarns and each thread in the weft is
called a pick.
Introduction
4. warp yarn preparation
The stages involved in warp preparation are:
(a) Winding from spinner‘s package to
cones.
(b) Winding from cones to warp (i.e.
warping).
(c) Application of size and lubricant to warp
(1.e. slashing).
(d) Drawing-in or tying-in.
10. 2.1 Introduction
Winding is the process
of transformation of
spinning bobbin
yarn to the yarn
package,
Chapter Two
2.Winding
11. 2.1 Objectives of Winding and Yarn Passage
Winding Operation
winding operation consists
of unwinding one package
and rewinding onto
another.
Objectives of warp
winding process are:
Formation of suitable
package for warping
Checking and clearing
the yarn from
spinning
defects.
12. 2.2 Technical Requirements of Winding
Process
1. The physical and mechanical properties
of the yarn should not be impaired.
2. Package should be built to ensure easy
running off during warping at high speed.
3. The package should contain maximum
length of yarn.
13. Cont’d
4. The yarn ends should be tied with strong
knots of correct structure easily passing at
subsequent processing
5. The process should remove the
objectionable fault.
6. Yarn wastes must be as small as possible.
7. The yarn tension should be regular and
ensure constant winding condition
15. 1. Cope holder
A creel or stand is fixed
at the bottom of the
machine in front and
this accommodates ring
cops which are used as
supply packages.
The Function of Bobbin
Holder is to hold the
filled bobbins for
unwinding process.
16. 2. Balloon Breaker
The yarn after being
unwound from the
supply package is
immediately made
to pass through a
metallic thread
guide above it.
17. 3. Guides
Yarn guides are necessary to control the
yarn path during winding or unwinding.
They are generally made of ceramic or
steel material and are available in various
shapes depending on the unwinding
requirements.
18. 4. Tension device
One of the most important aspects of
winding is the control of yarn tension.
The tension device gives the required amount
of tension to the yarn during winding.
The tensioner serves for two purpose.
Firstly it enables the weak place in the yarn
to be removed and (HOW?)
secondly it helps to control the package
density of the wound package.
19. 5. Clearer or Slubs Catcher
These are also known
as snick plates or yarn
clearers.
They are used to
remove the yarn
imperfections such as
thick places, thin
places and slubs.
20. 6.Winding drum
This is the most crucial part of the winding
machine, on which the wound package is
built.
The winding drum performs the dual function
of winding the yarn on to the package (cone
or cheese) and traversing it longitudinally.
The grooves enable the yarn to be traversed.
21. 7. Cone or cheese holder
This is also known as the bobbin cradle and acts as a
support for the winding package which is in the form
of a cone or cheese.
The package is normally wound on metal or Bakelite
tubes or more commonly on paper cones.
The bobbin cradle is a device that supports the
wound package and enables it to be rotated at high
speeds during winding.
This device connected to an automatic thread stop
motion,
22. 8. Cradle
It’s function is to hold the cone
for winding.
It lies on upper part of machine
above the winding drum.
9.Sphere Former
It’s function is to form the spherical
shape of the cone
23. 10. Automatic broken thread stops motion(filer)
Since the wound packages rotate at high
speeds, it is necessary that stop devices be
provided to stop winding in the event of thread
breakage or exhaustion of supply package
during winding.
The stop motion should be able to immediately
lift the particular cheese or cone out of contact
with the winding drum in such an event.
If the cone or cheese is allowed to run what will
happen?
Further, the yarn on the cone will be damaged
due to being constantly rubbed .
24. 11. Full package stop motion
As soon as the wound package has reached the
preset or predetermined size, the full package
stop motion automatically lifts it out of contact
with the winding drum or shaft.
This is necessary to obtain equal length of yarn
on all the cones or cheeses of the particular set or
lot as otherwise it causes problems in warping
due to different cones in the warping creel
exhausting at different times.
25. The Basic mechanisms of warp winding zones
There are three basic
winding zones on winding
machines.
Unwinding zone
ƒTensioning , yarn
clearing and lubrication
zone
Package built(winding
zone)
28. 1. Unwinding mechanism
Therefore,
• Coarser yarn have higher tension
• High yarn velocity causes more tension on yarn which leads
to more breakage
• Tension is higher at nose as compared to shoulder
• Tension increases with the increase in balloon height
29. 2.Yarn tension mechanism
The needs for tensioning are:
It gives required winding density
It gives suitable tension to the yarn
It facilitates winding
It aids to remove weak yarns
Tension devises can be classified in to four
groups
30. (I) Multiplicative type (Post type or Capstan)
II) Additive type
Ti= Initial tension of yarn
To= Out put tension of yarn
μ= Coefficient of friction
between yarn and guide
θ= Angle of curvature
N= Weight of the Washer
31. (III) Disc type (Combination of additive & multiplicative
type)
Ti= Initial tension of
yarn
To= Out put tension of
yarn
μ= Coefficient of
friction between yarn
and guide
θ= Angle of curvature
N= Weight of the
Washer
