Open-end Friction Research Articles

A Comparative Study of Hooks in the Ya Rns Produced by Different Spinning Technologies

Abstract This article presents a comparative study of hooks’ characteristics of ring, rotor, air-jet and open-end friction spun yarns. Hook types and their extent, spinning in-coefficient and mean fibre extent in the yarns produced on different spinning technologies are investigated. The results show that the hook extents for open-end friction spun yarn are the highest followed by rotor, ring and air-jet spun yarns. Ring and air-jet spun yarns have higher percentage and extent of trailing hook as compared with leading hook, whereas, rotor and friction spun yarns show the reverse trend.

Influence of process parameters on properties of open-end and core-sheath friction spun acrylic yarns

The present paper is concerned with the influence of opening roller speed, difference in drum speed and suction air pressure on properties of acrylic open-end and core-sheath friction spun yarns. The results show that opening roller speed and suction air pressure have significant influence on properties of open-end friction spun yarns. In the case of core-sheath yarns, suction air pressure has influence on yarn tenacity and hairiness. However, yarn unevenness and imperfection are not significantly influenced by experimental variables. The results also show that core-sheath friction spun yarns have significantly higher yarn tenacity, modulus and work of rupture and have a lower level of yarn unevenness, imperfections, hairiness, and breaking elongation than open-end friction spun yarns.

Hairiness of spun yarns and their reduction using air-nozzle in winding

Using ring, rotor, air-jet, and open-end friction spinning, viscose yarns of same count were spun and compared for hairiness in terms of types of hair and hair-length distributions. Hair-length distributions present on as-spun yarns, regular wound yarns, and yarns wound passing them through an air-vortex nozzle were obtained using microscope and instrument. Hairiness of Dref-II yarn is the maximum followed by ring, air-jet, and rotor yarns. Rotor and Dref yarns have higher proportion of looped hairs followed by air-jet and ring yarns. Contribution of looped hair to hairiness is predominant followed by leading or trailing hair. Smaller hair (class interval of 0–1 and 1–2 mm) are major contributors to the total number of hairs on all the yarns. Hairiness of all these yarns increases by winding without the nozzle and hairiness decreases by winding with nozzle and this is found for all types of hairs. The total number of hairs ≥ 3 mm (i.e. S3 values) for nozzle-wound yarns is about 16–30% less than that observed for the corresponding spun yarns. When many hairs are present on the yarns before feeding into the nozzle, a higher percentage reduction in hairiness is achieved by nozzle-winding. An empirical equation has been proposed based on exponential distribution to characterize the hair-length distribution present on various yarns. The number of longer hairs counted by the instrument is higher compared to that estimated by the equation and opposite is the case for the shorter hairs.

Influence of modified transport duct profile on air flow, yarn structure and properties: Part II

The present work is concerned with the modification of transport duct inDREF-III machine. This article deals with the design of the duct and its influence on air flow inside the duct and on yarn properties. By modifying the design of the transport duct, air flow inside the duct as well as arrangement of fibres in the yarn and yarn properties can be improved. The transport duct having curved profile of 15-mm length (modified duct) leads to improved yarn structure and properties for open-end and core-sheath friction yarns. However, this improvement is more significant for open-end friction spun yarns. In core-sheath friction spun yarns, the improvement in yarn tenacity is more for 50:50 core-sheath ratio and also for the higher linear density.

Influence of process parameters on migrational characteristics of open-end and core-sheath friction spun yarns

The migration characteristics of open-end and sheath fibres of core-sheath friction spun yarn have been studied using the tracer fibre technique. In open-end friction spun yarns, migration parameters were studied in both two-dimensional and three-dimensional projection methods. From the analysis, it has been observed that three-dimensional studies give higher mean fibre position (MFP), root mean square (RMS) deviation and mean migration intensity (MMI) than two-dimensional studies. The results show that fibres from first sliver feeding position have significantly higher MFP, RMS deviation and MMI than fifth sliver feeding position. The results also show that trailing half of fibres for first sliver feeding position has higher MFP, RMS deviation and MMI than leading half of fibres for both types of yarns. The migration parameters are mainly influenced by suction air pressure followed by opening roller speed and difference in drum speed for both open-end and core-sheath friction yarns. In open-end friction yarns for first and fifth sliver feeding positions, the experimental variables show different trends for MFP and RMS deviation.

Twist structural characteristics of friction spun yarns

The present work is concerned with the study of the twist structure of open end and core-sheath friction spun yarns. The process variables chosen are opening roller speed, difference in spinning drum speed, suction air pressure and sheath sliver feeding position. A three-variable factorial design method proposed by Box and Behken has been used. The influence of sheath sliver position on twist structure is also studied. An analysis of the twist level and helix angle at both the trailing and leading half of the individual fibre has been carried out to quantify the twist structure of friction spun yarn. For both types of yarns the leading half of the fibres has less twist than the trailing half. Under similar conditions of spinning, the twist level of open-end friction spun yarns is significantly higher than that of core-sheath friction spun yarn. In core-sheath friction spun yarns, the core fibres have a low level of twist but have significantly higher twist near the trailing end in Z-direction.

Analysis of Spun Yarn Failure. Part II: The Translation of Strength from Fiber Bundle to Different Spun Yarns

A generalized mathematical model has been developed for predicting the strength of spun yarns produced by ring, rotor, air-jet and open-end friction spinning systems. The model is based on the translation of fiber bundle tenacity into the yarn tenacity and it is applicable to all spun yarns. The model describes the failure behavior of spun yarns. Experimental strength results are compared with the predicted ones on the basis of theory, and a satisfactory agreement is reached. The limitations of the model are also analyzed.

Analysis of Spun Yarn Failure. Part I: Tensile Failure of Yarns as a Function of Structure and Testing Parameters

The phenomenon of spun yarn failure is strongly dependent on the yarn structure namely, the configuration, alignment and packing of the constituent fibers in the yarn cross-section. The structure of yarn is solely determined by the methods of consolidating the fibers into yarns. In the present study, ring, rotor, air-jet and open-end friction spun yarns were produced from identical fibers and their structural parameters; namely, mean fiber extent, spinning-in-coefficient, helix angle of the fibers, percentage of different hooks and their extents, number of fibers in yarn cross-section and yarn diameter were measured. These yarns were subjected to uniaxial loading on the tensile testers with a large range of gauge lengths (0 to 500 mm) and strain rates (5 to 400 m/min). The results showed that the strength of yarns largely depends on the structure of the yarns, gauge lengths and strain rates. A combined effect of fiber extent in the yarn and gauge length influences the yarn strength. At high strain rates the yarn failure is dominated by the breakage of fibers rather than the slippage of fibers. Furthermore, the analysis of the region of yarn failure provides more direct evidences of the influence of yarn structure and testing parameters on the strength of different spun yarns.

Effect of opening roller speed, drums speed difference and suction air pressure on properties of open-end friction spun polyester and acrylic yarns

The present paper is concerned with the influence of opening roller speed, drum speed difference and suction air pressure on properties of polyester and acrylic open-end friction spun yarns. The results shows that the opening roller speed and the suction air pressure have considerable influence on the characteristics of polyester and acrylic open-end friction spun yarns. In case of polyester yarns the unevenness, imperfection and hairiness decreases and the yarn tenacity increases with the increase in opening roller speed and suction air pressure. However for acrylic yarns the unevenness and imperfections decreases and tenacity increases with the increase in opening roller speed and suction air pressure.

Stress–strain characteristics of different spun yarns as a function of strain rate and gauge length

The influence of strain rates and gauge lengths on the characteristics of the stress–strain curves of ring, rotor, air-jet, and open-end friction spun yarns is investigated. A modified form of Vangheluwe's model is used in describing the stress–strain characteristics of spun yarns. The proposed model can fairly well replicate these characteristics.

Effects of yarn constitutions and fabric specifications on electrical properties of hybrid woven fabrics

Abstract This paper reports a fabrication method for conductive open-end friction core-spun yarn (OFCY), which, as described, are constructed from open-end friction spun yarn (OFSY) and core stainless steel wire (SW) combined within the yarn twisting zone of the friction drum during the open-end friction spinning process. To facilitate weaving of SW and reduce the material cost, initially, the sheath stainless steel (SS), Kevlar (KS) or rayon (RS) staple fiber and core stainless steel wire are combined to form the OFCY yarn by using a DREF III open-end friction spinning method. The OFCY yarns were successfully woven into a variety of woven structures produced from a semi-automatic loom. The primary objects of this research are to develop new conductive yarns and fabrics, which could be suitable for shielding home electronic devices, electrical appliances from electromagnetic fields. Such fabrics could be incorporated into prepreg systems used for composite manufacture. In these fabrics, SW is used as a core component that is wrapped around a sheath SS and KS or RS to form an OFCY yarn in which OFCY yarn strength remains the same and electrical properties are better than for an equivalent OFSY yarn. Stainless steel staple fibers (SS) and wire (SW) are incorporated as conductive fillers to enhance the electromagnetic shielding properties of the woven fabric. The electromagnetic shielding effectiveness (EMSE) of various woven fabrics was obtained using a coaxial transmission line holder in the frequency range of 300 kHz–3 GHz. The variations of EMSE, the surface and volume resistivities of the woven fabric structure, and blend ratios of the OFCY yarns are also described.

Friction core-spun yarns for electrical properties of woven fabrics

This paper reports a study to develop a spinning method of open-end friction core-spun yarn (OFCY) and its conductive fabric for shielding the electrostatic discharge and electromagnetic applications. To facilitate weaving of stainless steel (SW) and to reduce the material cost, initially OFCY yarn was made from SW core and polyester (PET) and stainless steel staple (SS) fibers, produced by a DREF III open-end friction spinning method. The core-spun yarns were woven into a variety of woven structures, which are made from semi-automatic loom, successfully. The conductive fabrics could be suitable for shielding home electronic and electrical appliances, cellular phones, and digital devices from electromagnetic fields. The variations of EMSE, and ESD of the woven fabric structure, and blend ratio of stainless steel yarns are also described. It has been shown that the EMSE and ESD attenuation of the woven fabric can be tailored in a number of ways including fabric structure, density, and the amount of conductive filler material.

Production and Electromagnetic Shielding Effectiveness of the Knitted Stainless Steel/Polyester Fabrics

This paper describes a study on the development of stainless steel/polyester knitted fabrics for electromagnetic shielding applications. To facilitate knitting of stainless steel wires and to reduce the material cost, initially blended yarns of staple stainless steel and polyester fibers were fabricated by using the ring and open-end friction spinning methods. The stainless steel/polyester produced by ring and open-end friction spinning methods, and their knitted fabrics made from 14G flat knitting machine were developed successfully. Using a coaxial transmission line holder set-up, the electromagnetic shielding effectiveness (EMSE) of various knitted fabrics was carried out in the frequency range from 30kHz to 3000MHz. The variations of EMSE with the knitted structures, yarn type, and the blend ratio of stainless steel fiber and wire to the polyester fiber in the yarns are discussed. The results indicate that the proposed knitted fabric having higher EMSE can be used for the purpose of EMI shielding, as well as for some electronic and electrical applications.

Effects of Opening Roller Speed on the Fiber and Yarn Properties in Open-End Friction Spinning

The opening roller system for fiber separation in an open end spinning process is known to cause considerable fiber breakage. We have investigated fiber breakage at different opening roller speeds and the relationship between breakage and the properties of friction spun yams made from cotton, polyester, viscose, and acrylic fibers. A high level of fiber damage caused by the opening rollers occurs at high speeds. The level of damage differs from one sort of material to another. There is a great deterioration in properties when yams are processed at high opening roller speeds.

The Surface of the Tail in Open-end Friction Spinning

The Surface of the Tail in Open-end Friction Spinning