Raw Materials
The main raw material required to produce carded yarn is raw cotton. As well known, cotton is imported from abroad. Besides, most regions in the country have the potential to grow cotton having different fines, staple length and color.
Along with cotton, different kinds of materials are used in the manufacturing of cotton yarn. Among the materials paper cones, plastic bobbins and cops, cans and plastic bags are very crucial for the spinning process. The total cost of these packing materials reaches up to 3% of the total cotton cost per annum.
Spinning Technology
In that last 2 decades various efforts were made in the development of new spinning technologies such as, Carded Spinning, Open-End Rotor Spinning, Open-End Friction Spinning, Air Jet Spinning, Core Spinning etc. But major progress has taken place in Ring and Rotor Spinning in which production rates were increased tremendously; the fields of application were extended the economy and product quality improved and the recycling possibilities remarkably developed.
In the back process of spinning line, production rates were increased in multiple ways. Apart from the productivity various automation and quality measures were introduced in the recent years. The purpose of the automation is to further ensure a consistently high quality at a higher efficiency and reduced personnel requirement. In the blow room machinery, automation in feeding, mixing, lap doffing or auto chute feeding direct to the carding section, as well as improved clearing and chute feed techniques are used to achieve a high degree of regularity in the sliver. Similarly high production cards are being used increasing with top production figures, optimal web and sliver quality. Thus high speed draw frames with modern drafting techniques, positive feed creel with optical stop motion, auto leveler, auto can change, main gears, sealed in oil bath, lead to higher productivity, fiber parallelization and sliver regularity.
Manufacturing Process:
The sequential process of yarn manufacturing may be described as follows:
Opening, Mixing and Carding (Blow Room):
Cotton from its constituent bales are blended and mixed at hopper feeder and processed through a series of opening and clearing machines installed in the Blow Room. These machines can be used in various arrangements, which will provide different levels of cleaning. The cleaning lines also include a metal extractor and a central dust filter unit. The cleaning line opens the tufts of fibers and removes dirt, foreign impurities and thus provide cleaning and fiber preparation. Ultimately this opened and cleaned cotton is rolled into laps. Depending on the different grades of raw cotton, their trash-content and degree of cleaning desired, 3-5 cleaning points are used, while the man-made staple fiber is processed in the blow room using only 2 cleaning points with other cleaning points by-passed according to the requirement.
CARDING:
The objectives of carding are to individualize the fibers, remove dust, short fibers and to form uniform sliver. The lap from blow room or chute matt are fed to the cared through feed roller and dish-plate where the fringes of fibers are taken away by the taker-in mounted with metallic wires. After further opening and cleaning at the taker-in region, the fibers are transferred to the cylinder region where the main carding actions take place in between cylinder and flats. Fibers are then transferred to offer by the stripping action and produce a then web. The web is then formed into silver of certain fixed weight per unit length and coiled into silver to the next process.
DRAWING:
The silvers in car are fed doubling at the feed end of the draw frame. At draw frames by doubling and drafting, parallelization of fibers takes place. The end product is regular silver, which is again coiled into silver cans. For processing carded cotton or polyester yarns only 2 passages are required at draw frame and for combed cotton yarn, one passage before Lap former and one passage after combing are required.
SIMPLEX
After finisher drawing the silver is fed to simplex m/c where draft is given to reduce the mass per unit length and twist is given to strengthen the strand so that it can easily fed to the ring frame creel.
RING SPINNING
Finally, yarn is produced ring spinning frame. Maximum draft is given here to produce the required yarn quality. Twist is imparted according to the end use. Here yarn is wound on to a ring bobbin.
AUTOMATIC WINDING
Suitable yarn package is made from the small bobbin. In winding yarn cleaner, waxing, splicing device, foreign fiber detector are there. So the package made in the automatic winding section is export quality.
HEAT SETTING
After spinning process the yarns are Conditioned (Heat setting) in yarn conditioned machine for maintaining high quality and then it will be packed for marketing.
The production flow diagram is shown
Cotton Fibre Spinning Process in Spinning System
Carded Yarn
Raw Cotton
↓
Blow Room (Opening & Cleaning)
↓
Carding
↓
Breaker Drawing Process
↓
Finisher Drawing Process
↓
Simplex
↓
Carded Spinning
↓
Automatic Winding
↓
Heat Setting
↓
Packing
↓
Marketing