Analysis of Yarn Tension in the Yarn-Forming Zone in Friction Spinning

Najar

Etrati

et al. 2012

Self Cite

The aim of the present study is to produce elastic core/cotton spun yarns in a friction spinning (Dref-II) system and then to investigate the effect of spandex filament draw ratio on the physical and mechanical properties of produced yarns. First, a positive feed device was designed and developed to adjust the spandex draw ratio and then mounted on the friction spinning machine. To maintain a constant yarn count at various draw ratios, the proportion of cotton sheath fibers should be increased. The yarns with larger proportions of cotton fibers showed lower twist. The elastic core spun yarns have lower hairiness in comparison with 100% cotton yarns in the present experiments. The theoretical and experimental results indicate that the tenacity of elastic core spun yarn increases as the spandex draw ratio increases. While the elongation of the elastic core spun yarns is the same as 100% cotton yarn at low spandex draw ratios of less than 3.75, when the spandex draw ratios exceed 3.75, the elongation of the elastic core spun yarn increases sharply.

Section: Resultsmentioning

confidence: 92%

Effect of spandex filament draw ratio on elastic core spun yarn properties in friction spinning

Najar

Etrati

et al. 2012

Self Cite

“…As we explained earlier, producing fine tex yarns on the friction spinning machine is very difficult [ 1,4]. On the other hand, producing the core yarn in friction spinning is easy, and the existence of a filament in the yam-forming zone prevents yam end breaks during spinning.…”

Section: Resultsmentioning

confidence: 97%

“…The production of thin yarns has been limited in friction spinning because of the structure of the machine and the yarn production method [1,4]. In friction spinning, where the yarn diameter is less than the gap between the friction rollers, the yarn may pass through the gap due to the tangential forces on both rollers created by the airflow.…”

mentioning

confidence: 99%

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Limits of Hollow Yarn in Friction Spinning

Okamura

2003

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In hollow yarn spinning, the yarn is spun with a PVA filament in its core in the yarn-forming zone, which provides enough dynamic strength to the yarn during spinning. Therefore, the dynamic strength of the yarn is not so important a factor in spinning. In order to measure the spinning limit of a hollow yarn, we measure the strength and irregularity of the hollow yarns after extracting the PVA. The results show that the high PVA percentage hollow yarns do not show good tensile properties and irregularity. Both spinning and PVA extraction increase the irregularity of the cotton component in the yarns or hollow yarn products, while the effect of PVA extraction can be minimized by treating the yarns when they are formed into fabrics. We conclude that the PVA percentage should not exceed 40%. We also conclude that the middle count yarns (20 tex and thinner), which are not spinnable as conventional yams, can be spun on a friction spinning machine using the hollow yarn spinning technique.

“…In friction spinning, the fibers are transferred from the supply to the yarn tail by the transport channel (Figure 1 ) [11][12][13]. The position of fibers in the yam depends on the landing point of fibers on the yarn tail and their shape inside the transport channel.…”

Section: Fiber Landing On the Yarn Tailmentioning

confidence: 99%

Fiber Feeding onto the Yarn Tail in Friction Spinning

Okamura

Marui

2000

Self Cite

Air and fiber flow patterns and fiber landings are two important parameters we discuss in this paper. We use tracer filaments to study the effect of various parameters such as combing roller rotation, friction roller rotation, and suction air pressure on the fiber flow pattern in the transport channel. We also use staple fibers to consider the mechanisms of fiber landing and the manner of fiber capture by the yam tail. Our results show that although the rotation of combing and friction rollers affects the flow in the channel, the most important parameter is suction air pressure. One of the most important results is the small size of the flow outlet, about 25 mm, when the main parts of the machine are running, while the outlet of a conventional channel is 115 mm. This means that most of the fiber supply may land on the yam tail at the flow outlet of the channel. Although considering fiber motion within the transport channel is a difficult problem, the body of the flow is found by tracing the shape of a filament in the channel. The results of fiber landing experiments show that there are two kinds of landings: "drawing" by the yam tail and the fiber "trapping" by itself on the yam tail surface. The landing and capturing phenomena depend on the fiber position in the transport channel and the yam-forming zone. Both drawing by the yam tail and the fiber trapping by itself may occur as the fibers pass through the transport channel. Most of the fibers fed from the upside of the transport channel will be drawn by the yam tail, while the probability of both drawing and trapping is almost equal for fibers fed from the downside of the channel.