As nowadays good winding is the mirror of spinning mills, it is necessary
that this process is understood very well by all the personnel handling the
department. Yarn winding can thus be viewed as simply being a packaging
process, forming a link between the last few elements of yarn manufacturing
and the first element of fabric manufacturing process. Improper utilisation
of the features of the winding machine can not only cost heavily to the
spinning mills, but it can also lead to loss of good customers permanently.
Quality of the output material largely depends on the quality of the feed
material in any process. This article briefly encompasses the quality
requirements of ring cop in terms of yarn as well as package, which is to be
fed to cone winding.
Basic objectives of winding
1. To remove objectionable faults from yarn, and
2. To build packages of dimensions compatible with requirements of the
subsequent processes, which are equally important both for high speed
warping and shuttleless weaving.
Demands from cone winding process
In today’s competitive market, the customers are becoming more and more
sensitive with regard to quality. So, every parameter regarding yarn and
package quality is of prime importance and must be met out in a close
tolerance. To meet both qualitative and quantitative demands, one has to
exploit all the available features of winding machine in a judicious manner.
The quality criteria of a spun yarn to be efficiently converted into a woven
or knitted cloth, and its customer acceptability in terms of the cloth into
which it is woven or knitted. The control of the quality characteristics of
a yarn during winding can be done by off-line or on-line testing.
Flow Chart: 1
Quality of the yarn
New generation of high speed looms and knitting machines places
increasingly more stringent demands on the quality and processability of the
yarn. Companies, which are best able to respond to the challenge of
economically improving the quality of the yarn to effectively meet the
requirements of high-speed fabric producing machines are going to be
successful in a competitive market.
Types of yarn defects
The type of defects that result in yarn breakage during cone winding and
contribution of each category of fault as a percentage of total faults are
summarised as shown in Table 1.
The spun-in fly is originated from the spinning frame and the various
causes for this could be listed as below:
· Improper maintenance of spinning frame
· Higher short fibre content in the mixing
· Low humidity level in the department
· Spinning of coarse count in the adjacent frame
Acceptable deterioration in quality from ring bobbin to cone:
Irregularity can adversely affect many of the properties of textile
materials. There is deterioration in terms of U% & IPI values and
hairiness from ring frame bobbin to cone due to abrasion of yarn with
various contact points in yarn path. The average deterioration can be as
shown in Table 2:
Unevenness U %
3 to 5%
Thin places (-50%)
Thick places (+50%)
15 – 20%
Thus, a yarn with higher unevenness directly affects the costs of
production, the likelihood of rejection of a product and the profit. Keeping
the deterioration in mind, one has to decide winding parameters, eg, winding
speed, auto speed, tension, etc in such a manner that the final yarn would
attain the satisfactory quality.
A bobbin change occurs when yarn on the bobbin is fully exhausted during
winding. But if a bobbin is changed with yarn still left on it, we call it
‘Rejected Bobbin’. The quantity of yarn on the bobbin may vary from full
bobbin to only few layers of yarn.
The various reasons of bobbin rejection are as follows:
1. Bobbin Quality
· Long Tail End
· Deshaped Bobbin
· Overfilled Bobbin
· Bottom Spoiled Bobbin
· Ring Cut Bobbin
· Soft Bobbin
· Sick Bobbin
2. Bobbin Feeding in Magazine
· Presence of under-winding and back-winding while feeding the bobbins
in the magazine leads to rejection.
3. Top Bunch Transfer Failure
· Top bunch position is lower wrt bobbin tip.
· Blowing device does not come down to concentrate blow at the bobbin
· Very few numbers of coils at the bobbin tip.
· Removal of top bunch due to fault in cutter at the bobbin preparatory
or any other reason.
· Very few numbers of coils at the top bunch.
4. Fault in Winding Unit, Splicing failure.
5. Yarn Quality
· High degree of objectionable fault
· Count variation
·High Hairiness Bobbin
Ring frame-wise bobbin quality checking:
Whenever there is a count change in ring frame, the cop quality should be
checked. Proper quality of cop ensures higher winding efficiency. The cop
quality is checked as per the following parameters:
1. Bobbin Parameters:
||(Ring Dia – 3) mm
||Cop Dia x 1.2
||Less Chase :
· Slough Off
· Bobbin Rejection
· Bunch in cone
||60 to 70° shore for cotton
· More slough Off
||Winding & Binding Length
||2:1 to 3:1
||Bobbin Empty (Top)
||Lower setting at top:
· Slough Off
· Low yarn content
||Bobbin Empty (Bottom)
||Lower setting at bottom:
· Bottom spoiled
||1.5 to 2
||· Hard waste
· Startup Breakage
||Tension Break at bottom
2. Cop content:
Depending on the spindle lift and ring diameter, the cop content (in gms)
should be as follows:
||48 – 52
||48 – 52
||68 – 70
3. Diameter of the Cop:
The ‘Actual cop diameter’ must be checked against ‘Standard cop
diameter’. The standard cop diameter depends on the ring diameter.
Standard Cop Diameter = Ring Diameter – 3mm.
4. Back Winding:
The number of back winding coils should be around 1.5 to 2.5 and the maximum
length of back winding should not be more than 80cms.
5. Under Winding:
The number of under winding coils should be around 2 to 3 and the maximum
length of back winding should not be more than 20cm. As the under winding
and back winding increases, more time is wasted to open them up before
feeding in the magazine and also hard waste is increased.
6. Top Clearance:
The clearance from bobbin tip to yarn body of a full cop should be approx 10
mm. If the top clearance is too less, it may cause slough off at the start
of the bobbin unwinding
7. Bottom Clearance:
The clearance from bobbin bottom to yarn body of should be approx. 10mm. If
the bottom clearance is too less, it may cause bottom spoiled bobbin.
8. Yarn length per chase:
The length of yarn per chase should be around 3.5 to 5.5 m. If the length is
too long, it may lead to slough of during high speed unwinding.
9. Bobbin hardness:
The bobbin hardness should be around 50° to 55°. Soft bobbins results
Besides the above mentioned points, the cops should be also checked for long
tail end, deshaped bobbin, kirchi & lapetta, ring cut, overfilled and
bottom spoiled bobbin to ensure high production efficiency in winding.
Due to the ever-increasing emphasis on better quality of yarn for the
competitive market and process performance, the normal parameters of yarn
tenacity, unevenness and imperfections are not adequate to completely define
today’s quality. Besides the above mentioned traditional parameters, so
many factors influence the performance of the yarn in the subsequent process
such as process parameters in ring spinning & cone winding, work
procedures in ring spinning & cone winding and ambient conditions. So to
attain the expected quality for any applications such as weaving or
knitting, one should focus mainly on the fault free feed material
preparation because it contributes more than any other factor. Best winding
capabilities can be achieved through best bobbin quality.
1. Schlafhorst Autoconer 338 Manual.
2. Yarn Winding –Edited by P K Banerjee & R Alagirusamy, NCUTE
3. Allan Ormerod & Walter S.Sondhelm: Weaving --Technology and
4.W.Klein: The Technology of Short Staple Spinning.
Note: For detailed version of this article please refer the print version of
The Indian Textile Journal May 2008 issue.
R Senthil Kumar
Department of Textile Technology,
Indian Institute of Technology,
New Delhi 110 016.