ABSTRACT
Open-end spinning is a process in which fibrous material is highly drafted, ideally to the individual fiber state, creating a break in the continuum of the fiber mass. The individual fibers are subsequently collected onto the open end of a yarn that is rotated to twist the fibers into the yarn structure to form a continuous yarn length. Rotor spinning, usually referred to as open-end spinning, was commercially introduced during the late 1960s and is second only to ring spinning in terms of short staple yarn production. The rotor spinning machine is fed with draw frame sliver, which converts it into yarn and subsequently into yarn package, eliminating the roving process. With this spinning method, twisting and package building are separated by employing the false-twist principle. The major components of the rotor spinning machine are shown in Figure 9.1. The first rotor spinning machine suitable for industrial use was presented in 1967 by the name BD200 at the ITMA exhibition.1 The current share of rotor-spun yarn is around 20% of total staple fiber yarn production, and it is increasing steadily. In summary, open-end spinning has the following major advantages compared with ring spinning:
• Elimination of roving stage • High productivity and low energy consumption • Large package size
Open-end spinning systems are designed to overcome some of the problems associated with ring spinning. Twist insertion in ring spinning requires the rotation of the whole yarn package. In open-end spinning, only an end of the yarn is rotated to insert twist, which consumes much less energy than rotating a yarn package. In open-end spinning, the fiber supply is reduced, as far as possible, to individual fibers, which are subsequently carried forward by an air stream as free fibers. This gives rise to the technique called “free-fiber spinning.” These fibers are then progressively attached to the tail or “open end” of the already formed yarn. Hence, this is called as “open-end spinning.” The interruption in the fiber supply accounts for the alternate name to the process, called “break spinning.” The characteristic advantages of rotor-spun yarns are listed in Table 9.1.
