Winding is the process of transferring yarn or thread from one type of package to another to facilitate subsequent processing. It is a process in which yarn from bobbins, which is the end product of ring spinning, are converted into suitable form of package. This transfer of yarn from one type of package to another package, more suitable for the subsequent process is also called winding. Main objectives of winding process are to increase the package size, clear yarn faults and produce a package suitable for subsequent process (size and shape).
The yarn packages are either parallel or tapered, with respect to shape, as shown in Figure 1. The parallel packages may also have flanges, while tapered packages are without flange.
Types of Winding:
According to density:
- Precision winding
- Non precision winding
According to type of package:
- Cone winding package
- Pirn winding package
- Flange winding package
- Cheese winding package
- Cop winding package
According to the build of the package:
- Parallel winding package
- Near parallel winding package
- Cross parallel winding package
According to methods of drive:
- Positive or direct drive
- Negative or indirect drive
According to the future of automation:
- Conventional winding
- Modern winding
Precision wound packages are characterized by their constant number of coiling per rotation of the package. The winding angle decreases as the package diameter increases. In true precision winding, the package is driven through the spindle and the yarn is displaced by a separate system, such as propeller blades or thread guides (Figure 2).
A precision winding machine builds precision wound packages. Conventionally, in a precision winding machine, package is directly driven by mounting it on a spindle. Therefore, these winders are also called spindle driven winders.
There is no slippage in the drive or uncontrolled displacement of yarn, hence the term “precision winding”.
Main issues of precision winding are,
- Constant winding ratio.(permanent number of coiling per rotation as diameter increases)
- Variable winding angle (decreases as package diameter increases)
- Moderate cost of machine.
- Acceptable package stability.
- Good liquor flow properties
- Excellent unwinding properties.
Precision winding machines use separate elements to drive the yarn package and to displace the yarn. Digital tension control systems, helps to produce packages of absolutely uniform density from inside to outside and from top to bottom, whereas random winders produce a predictable and inherent variation in density from inside to outside.
Non Precision Winding:
In non precision winding process, winding package consists of a single yarn. Here, wounded single yarn laid in the winding package at substantial helix angle so that the wound yarn cross one another and provide stability. In case of non-precision winding process, less dense package is formed. The package formed in non precision is soft and less compact.
Auxiliary Function of Winding:
Creeling: Creeling is the placement of full packages in position ready to be unwound as part of the transfer operations. An alternative meaning is the removal of the exhausted packages and their replacement with full ones.
Piecing: Piecing is the finding and connecting of the ends on the packages. The connection between the ends can be made by knotting adhesion or welding but the former is by far the most common. Such connections are required whenever an end breaks or when a creeling operation has been completed.
Doffing: Doffing is the removal of newly wound packages and the replacement of these by empty packages which will receive yarn during the transfer process. It will be noted that creel packages are emptied as the packages to be doffed are filled.
Difference between Precision and Non Precision Winding:
|Precision winding||Non precision winding|
|1. No. of coils remain constant from the first layer up to the full diameter of package.||1. No. of coils per traverse of yarn guide decrease with increase in package diameter.|
|2. No air gaps.||2. Air gaps is found here.|
|3. Winding angle is 90°or near 90°||3. Winding angle is less than 80°|
|4. Bobbin can be wound by 1 or more yarn.||4. Bobbin can be wound by only one yarn.|
|5. Less stable package.||5. More stable package.|
|6. The yarn package is hard and more compact.||6. The yarn package is soft and less compact.|
|7. Flanged bobbin is needed.||7. Flanged bobbin is not needed.|
|8. Yarn tension is relatively more at the time of winding.||8. Yarn tension is relatively less at the time of winding.|
|9. Process is less hairy.||9. Process is more hairy.|
|10. Yarn package density is more.||10. Yarn density is less in the package.|
|11. Difficult to dye, only surface yarn is dyed properly||11. Easy to dye.|
|12. Yarn coil is arranged in the parallel or near parallel.||12. Yarn coil is arranged in traversal.|
|13. One or more yarn can be wound in package here.||13. Single yarn is wound here.|
|14. Yarn withdrawal from the package takes more time and it is relatively difficult.||14. Yarn withdrawal from the package takes less time and it is comparatively easier.|
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Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.