The cotton plant grows best in light loamy soil in areas with plentiful rainfall or irrigation and a long growing season. The seeds are usually shown by machine, in a continuous stream in row three to four feet apart. When the plants are a few inch high, the rows must be thinned by cutting out the undesired plants.
Upland cotton grows to a height of about four feet and blooms two to three months after planting.
Ginning
From the feild seed cotton moves to nearby gins for separation of lint and seed. The cotton first goes through dryers to reduce moisture content and then through cleaning equipment to remove foreign matter. This operation facilitate processing and improve fibre quality. The cotton is then air conveyed to gin stands where revolving circular saws pull the lint through closely spaced ribs that prevent the seed from passing through.
A typical gin will process about 12 bales per hour, while some of today's more modern gins may process as many as 60 bales an hour.
Object of ginning:
i) To separate fibers fully from its seeds.
ii) To collect seeds and waste together.
iii) To collect fiber without any faults.
iv) To separate whole fiber.
Types of ginning:
1) Saw ginning.
2) Roller ginning
3) McCarthy ginning
Importance of fiber properties in cotton spinning
1) Fiber fineness: Fineness is one of the most important parameter determining the yarn quality characteristics. Fiber fineness influences the number of fibers in the cross section of yarn.
2) Maturity : The maturity of cotton is defined in terms of the development of cell wall. A fully mature fiber has a well developed thick cell wall.
3) Fiber length: The average length of spinnable fiber is called staple length. Staple length is also one of the most important fiber characteristics.
4) Length uniformity: Length uniformity influences on-
Yarn irregulrrity
Ends down
High wastage in combing
5) Strength: Toughness of fiber has a direct effect on yarn and fabric strength.
6) Color: Color is particularly important as a measure of how well a yarn or fabric will dye or bleach.
7) Fiber elongation: Elongation is specified as a percentage of the starting length. The elastic elongation is of decisive importance since textile products without elasticity would hardly be usable.
Yarn production
Cotton is grown anywhere with long, hot dry summers with plenty of sunshine and low humidity.
Upland cotton grows to a height of about four feet and blooms two to three month after planting. When they fall off, the boll begins to develop. These seeds or bolls contain the seeds to which the fibers are attached. When the cotton must be picked soon after the bolls open to prevent the fibers from beaming discolores and dirty from exposure to the sun and weather.
Modernization efforts have brought major changes to the textile industry. Equipment has been streamlined and many operations have been fully operated with computers. Machine speeds have greatly increased.
Mixing:
Mixing is done for the same kind of fibers e.g, cotton and cotton fibers of different grades or origin.
Blending:
Blending is the mixing of two or more different fibers e.g, polyester and cotton fiber mixing.
Yarn preparation from fiber
The blow room contributes only about 5-10% to production cost in the ring spinning mill. From a cost accounting point of view, the installation itself is not a relevant cost factor; however the loss of raw materials that arises here is a factor. Blow room machines must eliminate foreign matter, but they can do this only with the simultaneous elimination of some of the good fibers.
The proverbs of the expert- 'The card is the heart of the spinning mill' and ' well carded is half spun'- demonstrate the immense significance of carding for the final result of the spinning operation.. The importance of carding is still greater where new spinning systems are concerned. The considerable influence of the card on yarn quality arises from the vary complex series of events in the process itself.
Within the overall spinning process, the combing operation serves to improve the raw material. Its use in production of medium, medium-fine and fine yarns enable a positive influences to be exerted primarily on the following yarn characteristics:
- Yarn evenness
- Strength
- Cleanness
- Smoothness
- Visual appearance From a purely commercial viewpoint the draw frame is of little significance- it usually contributes less than 5% to production costs of the yarn. However, its influence on quality, especially evenness, is all the greater for this. Further, if the draw frame is not properly adjusted, there will also be effects on yarn strength and elongation. The draw frame produces a sliver that already exhibits all the characteristics required for the creation of the yarn, namely an ordered, clean strands of fibers lying parallel to another. It is a fair question to ask why this sliver is not used as in feed material for the ring spinning machine., instead of being processed in an expensive manner to create a roving as feed for spinning. The ring spinning machine was invented in the year 1828 by the American Thorp. In 1830, another American, Jenk contributed the traveler rotating on the ring. In the more than 150 years that have passed since that time, the machine has experienced considerable modification in detail, but the basic concept has remained unchanged.
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