In the first part of this article we discussed the ring spinning and it stages; including, opening and cleaning, carding, drawing, roving, spinning and winding. In this part, the open-end spinning will be discussed.
The Open-end spinning or OE, also called Rotor spinning and Break spinning, has similar but lesser number of stages than the ring spinning. The OE spinning make the yarns from slivers directly unlike the ring spinning, where slivers are first converted to roving; which save time, money and space. The OE process also involve direct winding on the package (cone) thus reducing the number of the stages, comparing to the ring spinning. It is called this way due to the break or discontinuity in the fibres before forming the yarn.
The carded OE yarns can be formed from slivers from card directly or slivers after drawing. On the other hand combed OE yarns formed from combed slivers.
The schematic in Fig (2) explains the process of producing the OE yarns. The sliver (1) is feed to an opening roller (2), covered with teeth/pins by a feed roller (3). The opening roller will separate the individual fibres from the sliver (1). Then the fibres will be transformed by mean of air (pneumatically) to a special groove (4) in the rotor (5) and they will accumulate to form a ribbon of fibres (6).
The fibres are led by the groove inside a rotor by centrifugal force, then they are being peeled off to join the already formed yarn (7). The rotation of the rotor provide the a vacuum that transfer the fibres and centrifugal force that force the fibres to form the ribbon fibres (6) and pull the yarn end (7) into contact with the ribbon (6).
The yarn produced is rotation around its axis and withdrawn through doffing tube (8). For every rotation one twist is inserted in the yarn.
Although the OE spinning is completely different from the ring spinning, it is being called nowadays with the ring spinning as “conventional spinning”. The speed of the OE is 300 m/min (can be higher) and the rotor diameter is ranged between 28 – 56 mm. Electrostatic OE spinning and fluid OE spinning have not been commercialized.
The Use of the OE yarns include coarse cotton yarns, which is used in manufacturing of denim. It also can be produced in finer yarns, but this requires faster turns of the rotor. The claim economical count for OE spinning is between 10 – 100 Tex, it can reach 600 Tex but this will require a lot of energy due to the high speed. The disadvantages of the OE yarn is the lower strength comparing to the ring spinning and the existance of the wrapper fibres.
- Mary Humphries, Fabric Reference, 2003, Prentice Hall.
- Phyllis G. Tortora and Robert S. Merkel, Fairchild’s Dictionary of Textiles 7th Edition, 2007, Fairchild.
- J W S Hearle, L Hollick and D K Wilson, Yarn texturing technology, 2001, Woodhead Publishing Limited.
- S. Gordon and Y-L. Hsieh, Cotton: scince and technology, 2007, Woodhead Publishing Limited.
- Carl A. Lawrence, Fundamentals of spun yarn technology, 2003, CRC Press.