Effect of Suction Air Pressure in Friction Spinning on Yarn Properties

Self Cite

The divergent channel in friction spinning causes fiber deceleration and inferior orientation in the transport channel. A convergent channel is designed, and the properties of yarns made by it are compared with conventional channel yams. The position of the convergent transport channel relative to the suction slit is a very important factor in improving yarn properties. The results of our research show that yams made by the convergent channel positioned 15 mm from the beginning of the suction slit are the strongest. The mechanical properties and structural parameters of friction-spun yams made by conventional and convergent channels are investigated at various suction air pressures. The results clearly indicate that the strength of yams made by the convergent channel is about 22% higher with no significant difference in elongation compared with yams made by the conventional channel at a suction air pressure of 2000 mmAq. Yarn twist at the various suction air pressures has no significant impact on yarns made by the two channels, meaning that the convergent channel provides the same twist efficiency as the conventional channel. We also find that yarns made by the convergent channel have a higher proportion of long effective fiber lengths and a lower proportion of short effective fiber lengths in which the total fiber extent is about 54.1 % compared to about 48.6% for conventional channel yams. We conclude that the superior strength of yarn made by the convergent channel is due to differences in its structure.In yam formation by friction spinning, fiber speed decreases from the beginning to the end of the channel [5]. Fiber speed in the channel depends on many parameters such as the air flow, channel shape, and fiber properties. The cross-sectional area along the channel is one of the most important parameters that influences air speed and fiber speed inside the transport, channel [15,16].The behavior of fibers in an air stream has been studied elsewhere [2,15,16]. Edberg [2] found that parallelization of cotton or rayon staple fibers is possible using high-speed air in a convergent tunnel. Smith and Roberts [16] described the tendency of fiber configuration in a convergent air flow in a tapering tube. They considered two ducts with different convergence angles and analytically specified air speeds. They indicated that crimped and hooked fibers have a tendency to be straightened in a convergent flow with sufficient acceleration. In a conventional friction spinning machine, there is a divergent flow based on the structure of the system. Obviously in a divergent flow, air speed and fiber speed decrease, so fiber configuration inside the channel has a tendency to buckle. A yarn's structure has a significant influence on its properties and performance. Structural parameters of various yarns produced on different spinning systems and under different conditions vary, and studies of yarn structure are numerous [1,3,13]. The structure of friction spun yarn is different from ring spun and rotor spun yarns, possessing inferio...

Section: Tensile Propertiesmentioning

confidence: 80%

Section: Fiber Feeding Onto the Yarn Tail In Friction Spinningmentioning

confidence: 99%

Fiber Feeding onto the Yarn Tail in Friction Spinning

Merati

Okamura

2000

Self Cite

“…A higher suction air pressure through the friction drums leads to increased frictional forces between the fibre assembly (sleeve) and the friction drum surfaces, thereby increasing the torque acting on the fibre sleeve. 15 As a consequence, the rotational speed of the fibre sleeve increases, resulting in higher twist in the sheath. 16 In DREF-2000 friction spinning, a core yarn (i.e.…”

Section: Resultsmentioning

confidence: 99%

Electro-mechanical properties of friction spun conductive hybrid yarns made of carbon filaments for composites

Hasan

Diestel

Cherif

2011

Textile-reinforced composites are a leading trend in lightweight structure design. The demand for additional function integration in lightweight structures made from textile-reinforced composites is growing rapidly. This article reports on the production of functional yarns made with friction spinning using carbon filament yarn as the core component and polypropylene fibres as the sheath component. The suitability of these yarns was tested with regards to mechanical properties for use in textile-reinforced thermoplastic composites. Their ability to perform additional functions such as structural health monitoring and signal transfer was also tested. Differences in the electro-mechanical and mechanical properties of hybrid yarns made from different types of carbon filament yarn core and polypropylene sheath were investigated with respect to different spinning parameters used to produce the yarns. Optimum processing parameters have been suggested that improve the functional properties of these yarns.

“…We considered the relationship between yarn tension and yarn diameter variations using the cross correlation method [7]. The high correlation between them ( r = 0.65) demonstrates that the yarn diameter influences yarn tension in the yarn-forming zone.…”

Section: Resultsmentioning

confidence: 99%

“…Twist efficiency is expressed as a percentage of yam turning in contact with the friction rollers without slipping [7]. As Figure 13 shows, there is a significant reduction in twist efficiency of the 37-and 32-tex yarns, because their diameters are smaller than the gap between the friction rollers.…”

Section: Resultsmentioning

confidence: 99%

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

Merati

Konda

Okamura

et al. 1997

Self Cite

We have analyzed the tension distribution along the yarn tail in the yarn-forming zone of a friction spinning machine by considering the effective parameters of the torque applied to the yarn tail. Tension is applied to the yarn tail by suction air pressure and rotation of friction rollers. The yarn tension in the yarn-forming zone is measured for various yarn counts and suction air pressures. The effects of the parameters on yarn tension are considered in a theoretical analysis based on tension distribution along the conical yarn tail. Theoretical results are compared with me experimental data. The results of this research show that yarn tension increases with increasing suction air pressure and yarn size in tex, and yam diameter decreases with increasing suction air pressure for the same yarn size. Therefore, because of the low tension experienced with fine yarns, it is difficult to properly produce such yarns through friction spinning.