Notes on Weaving Technology – I

 Weaving Technology – I

Weaving:

Weaving is a method of textile production in which two distinct sets of yarns warp & weft are interlaced at right angles to form a fabric or cloth.

Winding:

The creation of large yarn packages that can be easily unwound, is called winding. This makes using the yarn on subsequent machines both easier and more economical. Winding is more than just transferring yarn from one package to another.

 

Object of Winding:

·       For weaving processes, this can be used to transfer yarn from one package to another.

·       To remove yarns faults like hairiness, neps, slubs, of foreign matter.

·       To clean yarn.

·       To increase the quality of yarn.

·       To get a suitable package.

·       To sore the yarn.

 Types of Winding

• Precision Winding.
• Non-Precision Winding.

Precision Winding

By precision winding successive coils of yarn are laid close together in a parallel or near parallel manner. By this process it is possible to produce very dense package with maximum amount of yarn stored in a given volume.

Features

• Packages are wound with a reciprocating traverse. 
• Patterning and rubbing causes damage of packages. 
• Package contains more yarn.
• Package is less stable. 
• The package is hard and compact. 
• The package is dense. 
• The rate of unwinding of package is low and the process of unwinding is hard. 
• The unwound coil is arranged in a parallel or near-parallel manner.

Non-Precision Winding 

By this type of winding the package is formed by a single thread which is laid on the package at appreciable helix angle so that the layers cross one another and give stability to the package. The packages formed by this type of winding are less dense but is more stable.

Features

• Only one coil is used to make this package. 
• Cross winding technique is used. 
• The package density is low. 
• Minimum number of yarn is wound. 
• The package formed is soft and less compact. 
• The stability is high. 
• Flanges are not required. 
• The rate of unwinding is high and the process is easy. 
• The packages formed have low density.]

Auxiliary functions of a winding machine:

1.     Creeling: Creeling is the removing of empty package and placement of the full package, in the feed region of the machine, ready to be unwound as part of the transfer process.

2.     Piecing: Piecing is the process of finding the ends of the packages and connecting them

3.     Doffing: Doffing is the process of removing the full package and placement of the empty package, in the delivery region of the machine, ready to receive yarn as part of the transfer process.

Methods of Driving in a Winding Machine:

1.     Surface contact driving

2.     Direct package driving at constant speed

3.     Direct package driving at variable speed

1. Surface contact driving
In this process the groove drum is rotated by the motor. The drum is in contact with the package so as the drum rotates the package also rotates. The grooves in the drum provide the traversing motion for the yarn. Here the winding rate stays constant as package diameter increases.

 2. Direct package driving at constant speed

In this system the yarn package is placed in a spindle and the spindle is rotated with the motor. Therefore, the package gets motion directly from motor. The package gets angular motion and the yarn take up rate is directly proportional to package diameter.

3. Direct package driving at variable speed

In this system the yarn package is placed in a spindle and the spindle is rotated with the motor. Therefore, the package gets motion directly from motor. Here the rotational speed of package is varied inversely to package diameter to keep winding speed constant.

Types of winding packages:

There are three types of winding package. They are:

1.     Parallel winding packages.

2.     Nearly parallel wound packages.

3.     Cross wound  

1. Parallel winding:

The threads of the warp beam are laid parallel to one another. A flanged package or beam is necessary for parallel packaging. Otherwise, the package would not be stable and would collapse. It is not necessary to traverse.

Example: warp beam, weavers beam

Advantage:

·       Many yarns can be wound at a time on the package.

·       No need of traversing mechanism.

·       Side withdrawal is not possible.

·       Yarn density is more.

·       No change of numbers of turns per inch.

 

Disadvantage:

·       Two side of the packet need flanged.

·       For yarn unwinding need separate mechanism.

·       Can not be over with drawl.

 

2. Near parallel wound:

This type of package usually has one yarn end wound on it. Near parallel wound packages are not self-supporting. Therefore, flanges, shoulders, or tapering are necessary for stability at the package’s ends.

Example: cop, flanged bobbin, pirn

Advantage:

1.     No need   flanged.

2.     Can be side withdrawal.

3.     No change of number of yarns turns per inch during winding.

Disadvantage:

1.     Need of traversing mechanism.

2.      Side with drawl is not possible.

 

3. Cross-wound package:

Single yarn ends are wound on the package at considerable helix angles, generally less than 800. Since this type of winding provides package stability, the edges do not need to be tapered or flanged. In this case, a cone or tube could be used to wind.

Example: Cone, Cheese

Advantage:

1.     No need of flanged.

2.     Can be over withdrawal.

3.     Yarn packages are stable.

Disadvantage:

1.     Number of yarns turns per inch is changed in this method.

2.     Quality of yarn is less.

3.     Need of traversing mechanism.

 

Types of winding machine:

a. According to package:

1.     Flanged bobbin winding machine.

2.     Cone winding machine.

3.     Cheese winding machine.

4.     Pirn winding machine.

5.     Cop winding machine.

b. According to winding:

1.     Precision winding machine.

2.     Non-precision winding machine.

c. According to drive:

 

1.     Direct drive winding machine.

2.     Indirect drive winding machine.

d. According to types of yarn use

For Warp Yarn:

 

1.     Upright spindle winding machine.

2.     Drum/cylinder winding machine.

3.     Warp winding machine.

4.     Cheese winding machine.

5.     Spool winding machine.

6.     Cone winding machine.

For Weft Yarn:

1.     Ordinary pirn winding machine.

2.     Automatic pirn winding machine.

3.     Cop winding machine.

Winding Efficiency:

Winding efficiency is the ratio of actual production and calculated production which is expressed as percentage.

Winding efficiency = Actual production / Calculated production × 100

It should be noted here that, calculated production is always higher than actual production.

Key Factors of Winding Efficiency:
There are some key factors of winding efficiency which have pointed out in the below:

1.     Yarn count,

2.     Work load per worker,

3.     Yarn quality,

4.     Maintenance and over hauling,

5.     Capacity utilization,

6.     Power failure,

7.     Worker efficiency,

8.     Humidity,

9.     Creeling time,

10.  Doffing time,

11.  Spindle of drum speed.

All the above key factors of winding efficiency have explained in the following:

1. Yarn count:
If yarn count is higher then winding efficiency will be higher. In the other word, yarn count is proportional to winding efficiency.

2. Work load per worker:
Here, winding efficiency will be decreased if work load per worker increases. Here, work load per worker is inversely proportional to work load per worker.

3. Yarn quality:
Winding efficiency will be increased if yarn quality increases. Here, yarn quality is proportional to winding efficiency.

4. Maintenance and over hauling:
Here, winding efficiency will be decreased if maintenance and over hauling of winding machine is not perfect.

5. Capacity utilization:
Capacity utilization is inversely proportional to winding efficiency.

6. Power failure:
Winding efficiency will decrease if power failure increases. Power failure is inversely proportional to winding efficiency.

7. Worker efficiency:
Worker efficiency is proportional to winding efficiency. That means, if worker efficiency increases, ultimately increase the winding efficiency.

8. Humidity:
In case of cotton yarn, humidity is proportional to winding efficiency. Without cotton yarn, humidity is inversely proportional to winding efficiency.

9. Creeling time:
Winding efficiency will be less if creeling time is more.

10. Doffing time:
Doffing time is inversely proportional to winding efficiency. That means, winding efficiency is less when doffing time more.

11. Spindle of drum speed:
If drum speed is more then winding efficiency will be increased.