PRECISION WINDING OR SPINDLE WINDING:
This is a yarn package defect. This defect gets occurred during yarn winding process. 'The patterning or ribbon formation (Ribboning ) can be defined as a yarn package defect to be occurring during yarn winding process, in which the yarn coils get laid on the top of the previous yarn coil'.
In other words, we can say that the yarn coils follow similar path repeatedly during winding. This repeatedly continuous yarn coils path causes patterning or Ribboning ( ribbon formation) in the yarn package getting wound.
At the starting of winding, the diameter of empty package is less than traverse drum. As the winding gets begins, the package diameter increases rapidly. When the package diameter gets equal to traverse drum, the patterning zone gets started. The ratio between rotational speed of traverse drum and package gets equal to whole number (1). As soon as diameter of package gets increased the patterning zone gets ended. This kind of situation created every time when the ratio between rotational speed between traverse drum and package gets equal to an integer ( whole number. The patterning can be classified as below:
When the package diameter gets relatively large, the rate of increase of package diameter gets slow. We can say that diameter change takes long time. In this stage, the patterning results for long time.
This kind of patterning results at the starting of winding. Since the rate of change of package diameter gets very fast at the time of starting, so that the patterning persist for very short period.
ANTI PATTERNING DEVICE:
If a yarn package has patterning or Ribboning defect in it, the yarn unwinding gets difficult during uses of this kind of package. A lot of end breakages get occurred during yarn unwinding. There are different types of anti patterning ( Ribboning ) devices used to prevent the patterning or Ribboning defect in the yarn package. The some of anti patterning systems being used in different winding machines are given below:
Improper winding speed:
The winding speed greatly influences end breakage rate during winding process. The speed of winding machine is selected according to the yarn tensile strength, count, and thick and thin places present in the yarn to be wound. The winding tension gets increased when the winding speed is increased. This increase in tension causes end breakage. The yarn having poor tensile strength gets wound on lower winding speed. The thin and thick places present in the yarn always increase the chances of end breakages, so that the yarn having poor tensile strength and high imperfection should get wound at low winding speed.
Setting of slub catcher:
The improper slub catcher setting also causes excessive end breakage during winding process. The clearance between top and bottom blades of slub catcher is selected according to the yarn count. The low clearance causes end breakage. If clearance is more than required, the extra thick places can be passed into the yarn being wound on the package.
Some times, the yarn coils get laid outside the edges of the package. These outside laid coils are known as stitches in the package. These stitches causes very big trouble during unwinding of yarn. The end breakage rate gets increased due to stitches in the package. The bottom stitches are very serious problem in yarn unwinding. The nose stitches also create snarling and bunches formation during unwinding.
possible causes of snarling are given below:
Sometimes, ruptured yarn comes out from the package during unwinding. This ruptured yarn cause big trouble during weaving. The main causes of yarn rupture in the package are given below:
• Soft package:
It is very serious package defect. This defect causes yarn coils slippage during unwinding. The whole package gets rejected many times. This problem create due to low winding tension.
• Soft nose package:
If the nose of the package gets much soft, there may be serious problem during yarn unwinding. Almost half of the package may be rejected. This defect causes when the operator increases the yarn tension in the middle of the package. When the winding re starts with increased yarn tension, the winding density gets increased. The top layer of package put pressure on bottom layer. Thus the nose of the package comes out of the package. Winder should not increase tension after starting the winding machine. We should adjust the yarn tension at starting time only.