Open-end Rotor Spinning Research Articles

Combination Effects of Open-End Rotor Spun Hybrid Yarns

We have developed a mechanical hybrid yarn spinning system that produces different yam types on a modified open-end rotor spinning frame. In order to improve yam properties and produce novel yams, we investigate the effects of combinations with typical hybrid yams by inserting two filament yarns with varying filament over-feeds. The results are a new rotor spun loop (RSL) yam made by combining two aspects of typical hybrid yarn production into one process, and an RSL yam where a filament yam, fed with a core filament over-feed (CFOF), is located in the center of one yarn and the other filament yam, fed with the effect filament over-feed (EFOF), makes a loop on the yarn surface. The stable conditions of RSL yam production are within a range of EFOF ≧ 4 (m/min) and -6.0 << CFOF << -4.0 (m/min).

Twisting Mechanisms of Open-End Rotor Spun Hybrid Yarns

We have developed a mechanical hybrid yam spinning system that produces different kinds of yam on a modified open-end rotor spinning frame. In order to understand the characteristics of hybrid yam and produce novel yarns, it is necessary to investigate yarn formation and the twisting mechanism in the spinning rotor during yam production. Our results reveal that the rotor revolution generally results in combining the filament yam and the staple fiber strand. The fiber twist angle of the strand in a hybrid yarn is smaller than that of a rotor spun single yam with the same spinning conditions. Although a fed filament yam has a false twist inserted by increasing the filament over-feed, the filament yarn in the hybrid yarn has a smaller level of fiber twist angle in the same direction as the twist of the staple fiber strand due to untwisting of the false twist.

Effects of Spinning Conditions on Structure and Properties of Open-End Cover-Spun Yarns

Critical settings and their effects on the properties of open-end cover spun yams produced by a novel system are explained. The yams are constructed from open-end rotor spun (OER) yarns and textured polyester yarns combined within the yarn formation zone of the rotor during the open-end rotor spinning process. The end result is a textured yarn wrapped as a sheath around an OER yarn core, in which the wraps per meter distribution is uniform, the yarn remains soft, and tensile properties are better than for an equivalent OER yarn.

Two-Dimensional Simulation of Air Flow in the Transfer Channel of Open-End Rotor Spinning Machines

A two-dimensional computational fluid dynamics model is developed to simulate the flow patterns inside the transportation zone of a rotor spinning machine and analyze their effects on yarn properties. The strength and area of recirculation at the inlet of the transfer channel caused by the geometric variation and rotating opening roller are significantly related to fluid flow, and consequently to rotor spun yarn prop erties. Any variation of geometric dimensions of the transfer channel or opening roller velocity affects the air flow pattern, which then alters the configuration of fibers flowing inside the channel. A larger inlet at the transfer channel will lead to a decrease in the inlet mean velocity and will strengthen the primary recirculation zone, which is a potential source for fiber curving and buckling. The ratio of the circumferential velocity of opening roller to mean air flowing velocity is identified as a critical parameter to classify differences in flow patterns. If the ratio is a constant, the flow pattern will not explicitly change, but the drag force will increase with the increase in Reynolds number. Additionally, if the ratio is either too high or too low, the flow is not suitable for maintaining high quality in spun yarns due to the occurrence of strong recirculation at the outer cover side or opening roller side.

43—HIGH-SPEED OPEN-END ROTOR-SPINNING

High-speed open-end rotor-spinning is discussed in relation to the properties of yams spun in the speed range from 30,000 to 100,000 rev/min. The design of the rotor and its modified driving unit is described in detail. The properties of the yarns with respect to strength and strength variation, extension at break, and short-term yarn evenness are discussed.