DEFINITION:
For the purpose of weaving yarn needs to be wound on suitable packages , is called winding.We can not get much yarn from ring, bobbin or hank. But for a continuous weaving process ,a suitable amount of yarn is needed . For this reason winding is necessary.
REQUIREMENTS:
A. Suitable size and shape is needed.
B. The yarn must not be damaged anyway.
C. Yarn have to wound so that it can be easily unwound .
D. During winding minimum fault should be observed.
E. The package should be cheap.
OBJECTS OF WINDING:
1. To transfer the yarn from spinner’s package onto a convenient form of package which will facilitate weaving or the net process of yarn preparation .
2. To have desired length of yarn on the package.
3. To remove yarn fault and improve quality.
4. To make good quality fabric.
5. To store the yarn properly.
TYPES OF WINDING PACKAGES & USES:
1. Parallel winding /parallel wound package:
The yarn is wounded parallel to each other on the package containing flanges on the both side of the package. There are so many yarns can be wound at a time. The density of yarn is more & no change of twist during winding. Number of turns per inch will not be changed. Side withdrawal is possible.
2. Near parallel winding:
In this winding package, one or more yarn which are laid near parallel to the layers . Flange is not necessary here. Number of yarn turns per inch is not changed. The package is comparatively stable. Traversing mechanism is needed here.
3. Cross winding/ cross wound package:
In this package a single yarn which is laid on the package and wound in a angle . Yarn quality is less here. Yarn twist is changed during unwinding. Traversing mechanism is needed here.
Classification of winding machines:
Winding machines can be classified in different ways and few of them are
discussed below:
1.On the basis of winding:
On the basis of winding, winding machines can be classified into two groups:
1. Precision winding
2. Non-precision winding
2. On the basis of package type:
On the basis of package type, winding machines can be classified into at least
Five groups as given below:
1. Cope winding machines (used for jute)
2. Cone winding machines (used for cotton)
3. Cheese winding machines (used for cotton)
4. Flanged bobbin winding machines (used for cotton)
5. Pirn winding machines (used for cotton)
3. On the basis of package drive:
1. Direct drive winding machines
2. Indirect drive winding machines
4. On the basis of yarn type:
(a) Warp yarn winding machines
(i) Upright spindle winding machine
(ii) Drum winding machine
(b) Weft yarn winding machines
(i) Pirn winding machines
(a) Ordinary pirn winding machines
(b) Automatic pirn winding machines
(ii) Cope winding machines
Wind angle :
It is the angle at which the yarns cross each other on a wound package. The angle between the yarn and the vertical axis is called wind angle.
Coil angle:
The angle between the horizontal axis and the fibre is called coil angle.
Winding ratio or wind:
It is the number of coils of yarn per traverse of yarn from one extreme end to
another extreme end of the package. More the number of coils per revolution
more is the density.
Precision winding:
Precision winding means that continuous coils of yarns on winding package are laid parallel or near parallel to each other.
• Very dense package is formed here .
• Produced maximum amount of yarn in a given volume .
Eg: flanged bobbin
Non Precision winding :
Non precision winding means that a single yarn laid in the winding package at substantial helix angle .So that the wound yarn cross one another .
• Less dense package is formed .
• Not used flanged bobbin.
Eg: cope ,cheese .
YARN WITHDRAWL OR UNWINDING:
Unwinding process of yarn from a package is called withdrawl . There are two types of unwinding.
• Side withdrawl:
1. Rotated positive or negative.
2. Costly for positive.
3. Yarn twist unchanged.
4. Low winding speed.
5. Not stable.
6. Used flanged bobbin.
• Over withdrawl :
1. Package is stationary.
2. Yarn twist changed.
3. High winding speed.
4. Cross wound package.
5. No need flanged bobbin.
TENSIONING DEVICE:
During winding yarn is passed through tensioning device to control tension , is called tensioning device.
Effects of tensioning device on yarn and yarn package:
Too high tension:
1. Damage the yarn.
2. Increase the breaking rate.
3. Change molecular structure.
4. Hard yarn package.
Too low tension:
1. Can lead to unstable package.
2. Loosely wound package have tendency to stough off.
TYPES OF TENSIONING DEVICE:
• According to working principle:
1. Capstan tensioner.
2. Additive tensioner.
3. Automatic tensioner
.
4. Combined tensioner.
• According to shape:
1. Washer type
2. Disc type
3. Roller type
4. Ball type
5. Two zone type.
AUXILARY FUNCTIONS OF WINDING:
• Creeling:
Creeling is the placement of full packages in position ready to be unwound as part of the transfer operation.
• Piceing:
Piceing is the connecting of the ends of the packages.
• Doffing:
Remove the wond package by empty package.
YARN GUIDE:
It is necessary to control yarn path.
• A yarn end is required for threading:
1. Takes extra time in threading.
2. Low production.
3. More friction.
• A yarn end is not required for threading:
1. Easy threading.
2. High production.
STOP MOTION:
Stop motion is used for:
1. Thread breakage.
2. Empty supply package.
3. Full delivery package.
BALLOONING:
While unwinding yarn produces balloon due to centrifugal force away from the axis .
Balloon is formed in flangeless bobbin like cope ,cone.
PIRN WINDING MACHINE:
Pirn winding is necessary to prepare weft yarn .Generally , the pirns used for powerlooms are larger and the yarn content will also be more . Thus the pirn winding machine is used generally for powerloom weaving. Pirn winding machine may be automatic or conventionl. The automatic pirn winding machine have certain devices such as tension control , bunching mechanism , coil distributor and stop motion.
Thus , the package of pirn will be perfect and content of yarn is more , so that weft replenishment will be at lower frequency , thereby increasing the weaving frequency.
Points to be considered during pirn Winding:
•Length of pirnas well as shuttle length.
•Diameter of pirn.
•Speed of winding.
•Less weight of pirn.
Main parts of the machine:
•Yarn guide.
•Tension controller.
•Stop motion.
•Traversing motion.
•Package drive.
Cone winding machine :
Cone winding machine is one of the types of winding machine . This is used for warp yarn preparation . The process of transferring yarns from bobbin, hank, ring etc into a cone package is known as cone winding machine.
Machine parts:
1. Traverse bar
2. Cam
3. Tensioning device
4. Slub cutter
5. Motor
Working principle:
•Gets motion from motor in one side of machine and cam shaft and drum shaft rotates by motor pulley.
•Yarn supply get from a bobbin and yarn go to the cone by yarn stop motion guide and yarn traversing guide.
•Since cones are on holder and are contact with drum, cones rotates due to the friction of drum and holder and become winding on yarn cone.
•This winding is controlled with yarn guide.
•Winding is stop with stop motion mechanism when yarn breakage.
•When cone gets predetermined width, discrete from drum contact automatically and placed new cone by taken out of the cones.
Production :
R.P.M. of drum = r.p.m of motor × (driver / driven)
Production rate = π d N ( surface velocity ) × no of drum.
Modern concept of winding:
•Individual motor
•Automation (sensors)
•Less time consuming due to auto piecing, knotting etc.
•High production rate/ Higher productivity.
•Uniformly wound package.
•Efficient and judicious fault removal/ Fault free package (sensors active when yarn break).
•Minimum damage to the yarn.
•Target setting of production automatic.
•Speed variation can be possible.
Winding parameters:
1.Winding rate:
Winding rate is defined as the amount of yarn to be wound on the package per unit time i.e. the length of yarn in meter wound on package per minute. Its unit is m/min.
2. Winding on diameter:
The diameter of the package on which the winding is done is called winding on diameter. It may vary according to the package. Its unit is cm.
3. Winding on surface:
The place where winding is done according to the time is called winding on surface.
4. Traverse velocity:
Traverse velocity is defined as the amount of traverse happened during winding per unit time. i.e. The length of traverse in m/min is called traverse velocity, it is denoted by Vt and its unit is m/min.
5. Surface velocity:
The rate of winding which is done on winding on diameter is called surface velocity. It is denoted by Vs and its unit is m/min.
6. Net winding velocity:
By dividing the traverse velocity with the sine value of winding angle is called net winding velocity. It is called real winding rate. It is denoted by V rand its unit is m/min.
7. Angle of wind:
The angle contained between a warp of yarn on the surface of a package and the diametrical plane of the package. Angle of wind may vary with the traverse speed. No of coils in a layer will be decreased with increasing the angle of wind. As a result amount yarns will less on the package. It is denoted by θ.
THE END
