Hollow Spindle Research Articles

Effect of different knitted structure on the mechanical properties and damage behavior of Flax/PLA (Poly Lactic acid) double covered uncommingled yarn composites

Double faced plain and rib knitted fabric (DFPKF & DFRKF) were produced by using double covered uncommingled yarn (DCUY), where the flax fiber is used as reinforcement and PLA (Poly Lactic acid) as matrix. DCUY was fabricated by the hollow spindle spinning machine with a flax core yarn, which were wrapped around PLA sheath yarns. DFPKF & DFRKF fabrics were produced by flat knitted machine. Composites were fabricated with film stacking technique by hot pressing machine from DFPKF & DFRKF. Flexure and Izod impact test were carried out for DFPKF & DFRKF reinforced composites. Fractography examination was done by digital camera. The influence of different knitted structures on the mechanical properties of the composites is demonstrated in this research work.

Experimental Study on the Fiber Motion in the Nozzle of Vortex Spinning via High-Speed Photography

Vortex spinning is a novel process for spinning short-staple yarns with high production rate and quality. The dynamics of the fiber in the nozzle plays a key role on the properties of the resultant yarn. In this paper, the images of fiber motion in the airflow inside the nozzle of vortex spinning are captured using a high-speed photography technique. The nozzle is magnified according to the Reynolds number similarity. Based on the high-speed photographic results, the effects of some parameters – the nozzle pressure, yarn delivery speed, and distance between the nozzle inlet and the hollow spindle – on the motional characteristics of the fiber are investigated.

Monodisperse Mesocrystals of YF3 and Ce3+/Ln3+ (Ln=Tb, Eu) Co‐Activated YF3: Shape Control Synthesis, Luminescent Properties, and Biocompatibility

A family of monodisperse YF(3), YF(3):Ce(3+) and YF(3):Ce(3+)/Ln(3+) (Ln=Tb, Eu) mesocrystals with a morphology of a hollow spindle can be synthesized by a solvothermal process using yttrium nitrate and NH(4) F as precursors. The effects of reaction time, fluorine source, solvents, and reaction temperature on the synthesis of these mesocrystals have been studied in detail. The results demonstrate that the formation of a hollow spindle-like YF(3) can be ascribed to a nonclassical crystallization process by means of a particle-based reaction route in ethanol. It has been shown that the fluorine sources selected have a remarkable effect on the morphologies and crystalline phases of the final products. Moreover, the luminescent properties of Ln(3+)-doped and Ce(3+)/Ln(3+) -co-doped spindle-like YF(3) mesocrystals were also investigated. It turns out that Ce(3+) is an efficient sensitizer for Ln(3+) in the spindle-like YF(3) mesocrystals. Remarkable fluorescence enhancement was observed in Ce(3+)/Ln(3+) -co-doped YF(3) mesocrystals. The mechanism of the energy transfer and electronic transition between Ce(3+) and Ln(3+) in the host material of YF(3) mesocrystals was also explored. The cytotoxicity study revealed that these YF(3) -based nanocrystals are biocompatible for applications, such as cellular imaging.

Preforms and composites manufactured by novel flax/polypropylene cowrap spinning method

In the past decade, natural fiber composites with thermoplastic matrices have been embraced by many composite manufactures for its properties such as lightweight and low cost. Reinforced cowrap spinning yarns and thermoplastics offer a potential for low-cost manufacturing of complex-shaped and good, drapable composite parts, due to reduced impregnation times and resin flow distance during processing. In this article, the cowrap spinning yarns were produced by cowrap spinning method with flax and polypropylene (PP) and then woven to fabric preforms. The natural flax fibers were twistless in yarns and preforms, and PP served as a carrier for flax and prevented damage to flax fibers during processing, and became the polymer matrix in the final composites. To get an even distribution of fibers and thermoplastic resins in preforms and different flax fiber content, the main spinning parameters (hollow spindle twist and hollow spindle rotational speed) were analyzed and optimized. Besides fabric structure, the parameters affecting the mechanical properties of flax/PP preforms and composites were investigated. The fabric density, fabric structure (including plain, twill, and basket weave), and yarn tensile orientation (at 0°, 90°, and 45°) had a great influence on the tensile strength and elongation of preforms. Different pretreatments on flax/PP were investigated, and the microstructure and mechanical properties of thermoplastic composites showed improved wettability of impregnation and good adhesion and bonding interface between flax fiber and PP matrix in composites.

Electromagnetic shielding characteristics of woven fabrics made of hybrid yarns containing metal wire

In this study, electromagnetic shielding characteristics of woven fabrics made of hybrid yarns are investigated. For this purpose, initially the hybrid yarns containing stainless steel wire are produced with hollow spindle covering technique, and then eight different fabric samples are produced using these hybrid yarns. Electromagnetic shielding values of fabric samples are determined by a test set up based on enclosure measurement technique. Measurements are made in the frequency range of 30 MHz-9.93 GHz. Test results show that woven fabric samples investigated in this study have 25–65 dB electromagnetic shielding effectiveness for incident frequency. It was also shown that the direction, density and settlement type of conductive hybrid yarn in fabric structure are important parameters affecting electromagnetic shielding characteristics of woven fabrics.

Electrical circuit model of elastic and conductive yarns produced by hollow spindle spinning

<title/>The implementation of electronic textiles which are capable of being applied as electrodes, sensors or heating elements is crucial in several fields of application, ranging from automotive to sports, from rehabilitation to art and design. However, current electronic textiles often suffer from poor mechanical properties, low drape and unstable electroconductive characteristics. One possibility to overcome these shortcomings is to introduce the electroconductive properties at a fibre or yarn level by combining traditional fibres and yarns with metal wires or metalised yarns. In this paper, we describe the production of multicomponent yarns which combine electroconductive properties with elasticity, drape and mechanical strength. We discuss the electroconductive properties of the yarns produced with hollow spinning technology. An electrical model based on Kirchhoff’s law was designed and validated with the abovementioned measurements.

Investigation on the Dynamic Behavior of the Fiber in the Vortex Spinning Nozzle and Effects of Some Nozzle Structure Parameters

Vortex spinning, which adopts high speed airflow to insert twist into the yarn, is one of the most promising technological innovations in the textile industry. In vortex spinning, the dynamic behavior of the fiber inside the nozzle, which involves fiber-airflow interaction and fiber-wall contact, plays an important role in the twist insertion process. This paper investigates the airflow characteristics and the fiber dynamic behavior inside the vortex spinning nozzle via a two-dimensional numerical model with the fiber-airflow interaction and fiber-wall contact included. The fiber is assumed to be isotropic, elastic material. The airflow inside the nozzle is assumed to be turbulent, viscous and incompressible. The numerical results show that two vortices with momentarily changed sizes are created upstream of the jet orifice outlets. The imbalance of the pressure around the fiber causes the fiber to move and deform. The trailing end of the fiber rotates with wave shape within the nozzle chamber for several periods to insert twist into the yarn. Based on the model, the effects of three nozzle structure parameters – the jet orifice angle, jet orifice diameter, distance between the nozzle inlet and the hollow spindle, on the dynamic behavior of the fiber, and in turn, the yarn structure and tensile property are investigated. The results show that the appropriate jet orifice angle for obtaining the best yarn tenacity is 70°. The optimal jet orifice diameter is 0.4 mm. The spun yarn has the highest tenacity when the distance between the nozzle inlet and the hollow spindle is 14 mm.

Electro-conductive and elastic hybrid yarns – The effects of stretching, cyclic straining and washing on their electro-conductive properties

Electro-conductive yarns can be produced in various ways and can obtain very different properties in terms of conductivity, touch, as well as strength and elasticity. In this research, it was focussed on manufacturing elastic and electro-conductive yarns (el2-yarns) via hollow spindle spinning. All yarns comprised elastic core yarns, based on rubber, around which electro-conductive winding yarns, based on silver, copper and stainless steel, were wound. This paper presents the yarn’s electrical characteristics while stretching and after exposure to cyclic straining and washing. Analyzing the el2-yarn’s electro-conductive properties upon elongation, revealed that their electrical resistance remains constant over elongation levels up to 100%. Furthermore, it is shown that both, cyclic straining and washing, decrease the yarn’s electrical performance.

Optimization for Spindle of Jade Carving Machine Based on Fuzzy Reliability Theory

In machines working under the effect of alternating stresses, the fatigue bending deflection occured occasionally. On the basis of the Fuzzy Reliability Theory and with full consideration of the fuzzy factors during mechanical process, the paper studied the fuzzy reliability optimal design for the hollow spindle of multi-functional jade carving machine and improved the design quality of the jade carving machine spindle by probing into the combined model constructed by the random variables and fuzzy variables. The design was approved to be advanced, reliable and practical in service and provided a new way for the design of multifunctional jade carving machine spindle and other mechanical products.

FANCY YARNS - AN APPRAISAL

Abstract The great interest in fancy yarns area was noticed at the textile market all over the world as well as in science area. That interest may be the consequence of liberalization in trade with countries like China. Due to liberalization in fancy yarns sector trade between Europe and Asia, the main Asian producers of fancy yarns compete with each other to offer more and more sophisticated products. The production of fancy yarns has been differentiated and enriched in such scale that makes almost impossible to catalog and standardized all the produced types. However, certain activities has been taken up at The Technical University of Lodz with cooperation of the University of Gent to investigate the area from scientific point of view, mainly by tests based on fancy cotton yarns e.g. spiral, loop and bunch as well as fancy elastic yarns e.g. spiral, bunch and flame yarns. The aspects of fancy yarns implementation into fabrics will be considered as well as positioning those scientific activities at the European level with connection to the global policy. Therefore, the aim of this paper is bringing closer the matters concerning fancy cotton yarns and fancy elastic yarns from scientific point of view on a base of chosen examples carrying out a comparison of physical properties of those fancy yarns, the introduction of those yarns as wefts into fabrics. The aesthetic aspects and behaviour at wear of final products will be considered. The first experiment concerns the production, on the ring twisting frame, of three types of fancy cotton yarns, spiral, loop and bunch which were differentiated in respect of twist, linear density, the angel of lap of pegs by yarn on the slat of ring-twisting frame (the input only for spiral yarns) and the frequency of rocker's action in ringtwisting frame (the input only for bunch yarns). All obtained yarns were analysed in respect of real value of twist (t/m), linear density (tex), breaking force (cN/tex), elongation during breaking (%), air index (m/sec), bending rigidity (cN*cm) and width of hysteresis from bending rigidity test (cN*cm/cm). The fancy cotton fabrics were analysed in respect of mass surface (g/m2), friction-mass loss (g), piling, flexural rigidity (mg*cm), tearing (N), creasing, breaking force (cN/cm) and elongation while breaking. The second experiment concerns the production, on the hollow spindle, of three types of fancy elastic yarns, loop, bunch and flame yarns which were differentiated in respect of twist (t/m), linear density (tex), the value of stretch given to the elastic component (%) and preparation of the bobbin - precise and normal. All obtained yarns were analysed in respect of real value of twist (t/m), linear density (tex), breaking force (cN/tex), elongation during breaking (%), air index (m/sec). The fancy elastic fabrics were analysed in respect of mass surface, flexural rigidity (mg*cm), creasing, breaking force (cN/cm) and elongation while breaking (%) and dimensional stability. All the statistical analyses were carried out with usage of multiple regression module.

STUDY THE EFFECT OF COMMINGLING PARAMETERS ON GLASS / POLYPROPYLENE HYBRID YARNS PROPERTIES

Abstract The objective of this paper is to discuss effect of commingling parameter on characteristics of Glass/Polypropylene commingled hybrid yarns to get homogenous mix of matrix and reinforcement elements in the final yarn. A commingling machine developed to produce hybrid yarn using two techniques viz. mingling technique and hollow spindle wrapping technique using single machine is highlighted .The machine can run at speed upto 800 meters/min and for hybrid yarn it can go up to 200 meters/min. To study the effect of parameter three variable namely Air pressure, Overfeed and Take-up speed are take in to consideration and the Box-Behanken design is used for experimental setup. The hybrid yarn samples have been evaluated to investigate the influence of process variables the commingling characteristics of hybrid yarn viz. nip frequency; nip stability and nip regularity have also been studied. 'MINITAB' software is used for the analysis of test results. It was observed that effects of individual parameter as well as interaction effects are equally important in deciding final yarn quality. The structural analysis of hybrid yarn is done using SEM (Scanning electron microscope). To study the mixing behaviour of glass/polypropylene hybrid yarn three different methods have been used to prepare hybrid yarn viz. Friction spinning, hollow spindle wrapping, commingling. Its was clearly observed that commingled process gives better homogenous mixing of glass and polypropylene filaments compare to other two method. This yarn is used to make final laminate sample using hot press.

Study on the Principle of Yarn Formation of Murata Vortex Spinning Using Numerical Simulation

In Murata vortex spinning (MVS), the principle of yarn formation is closely related to the flow field inside the nozzle. This paper presents a numerical simulation of the flow characteristics inside the nozzle of the MVS machine. A three-dimensional grid and the realizable k-ε turbulence model are used in this simulation. The numerical results of pressure distribution and velocity vectors inside the nozzle are shown. A streamline starting from the nozzle inlet is also acquired. Based on the simulation, the principle of yarn formation of MVS is discussed. It is shown that a negative pressure zone exists in the center of the twisting chamber. The collision between the air currents entering the twisting chamber through the nozzle inlet and the yarn passage of the hollow spindle occurs in the vicinity of the spindle inlet, resulting in a reverse flow and a vortex. The disturbance of the flow helps to separate fibers. In addition, the simulation results have well supported the principle of yarn formation of MVS claimed by the spinner makers.

Analysis of the Fiber Spatial Trajectory in Vortex Spun Yarn

The principle and the process of yarn formation determine fiber migration and twist radial distribution in a yarn. Usually tracer fiber technology is introduced to discuss fiber configuration in the yarn body. There are few studies on fiber spatial configuration based on the principle and the process of yarn formation. In this paper, we discuss fiber spatial trajectory in vortex spun yarn from the viewpoint of the principle and the process of yarn formation. Based on the fiber movement rule, the parameter equations of fiber spatial trajectory in vortex spun yarn were established. The fiber spatial configuration and its influenced factors were analyzed. The research results showed that the fiber spatial configuration in vortex spun yarn consisted of the core fiber and the migration wrapper fiber as well as the regular wrapper fiber. The fiber spatial configuration in vortex spun yarn was affected by the following factors: delivery speed, distance from the front roller nip point to the hollow spindle, mean angular velocity for the open-end trailing fiber, fiber length, and vortex spun yarn diameter.

Effect of Manufacturing Parameters of Covered Yarns on the Geometry of Covering Components

This study deals with numerical simulation of structure of covered yarns produced on a double covering machine. Four manufacturing parameters of covered yarns such as delivery speed of covered yarn, rotational speed of two hollow spindles, and core stretch ratio during wrapping were used to simulate coil length indices of both covering components. Coefficient of evenness of semi-manufactured product as a function of delivery speed of covered yarn and rotational speed of first hollow spindle was also computed. The influence of the above-mentioned process variables on the geometry of covering components was shown by means of analysis of corresponding relationships. To evaluate the intensity effect of each variable, the comparable partial differences of the proposed functions were computed. The computations were made for covered yarn structures composed of polyurethane elastomeric multifilament core wrapped with two viscose (CV) multifilament covering yarns.

A Study of Generating Yarn Thin Places of Murata Vortex Spinning

In Murata vortex spinning, fiber loss is an important cause of the generation of yarn thin areas. In this paper, based on the attenuation law of flow field inside the nozzle block, the force analysis of a separated fiber twined over the top exterior of a hollow spindle in a twisting chamber is carried out, and the movement of a separated fiber affected by a swirling current is discussed. We also present a simple analytical formation that determines the critical angular velocity of the open-end trailing fiber rotating around the hollow spindle, as a function of the length of the core fiber and fiber radius, as well as other parameters. The critical angular velocity can affect whether the leading end of the fiber is pulled out from the yarn trail or not, which can explain the generation of fiber loss and yarn. The critical angular velocity increases with increasing length of the core fiber and decreasing fiber radius. Above a certain nozzle pressure, the fiber radius is larger, there is greater fiber loss and there are a greater number of thin places in the vortex spun yarn. Increasing the nozzle pressure first enhances the yarn tenacity, and then generates more fiber loss and yarn thinning in places, and also causes a deterioration of the yarn properties when the nozzle pressure exceeds the critical point.

A Study of the Twisted Strength of the Whirled Airflow in Murata Vortex Spinning

In Murata vortex spinning, the highspeed whirled airflow twists the open-end trailing fibers converged at the inlet of the hollow spindle into a yarn. The twisted strength acting on the vortex spun yarn by the whirled airflow was investigated by an analytical model based on simulating the flow field inside the nozzle block. The results showed that the twisted strength acting on the vortex spun yarn by the vortex could be regarded as the following functions: (1) the number of jet orifices, the jet angle, the inner diameter of the jet orifice and the nozzle block; (2) the distance from the inlet of the nozzle block to the inlet of the hollow spindle; (3) the projecting height of open-trail-end fibers twined over the top exterior of the hollow spindle; (4) the vortex spun yarn diameter; and (5) the velocity at exit of the jet orifice (i.e. corresponding to nozzle pressure). Increasing the velocity at exit of the jet orifice increased the strength twisted by the whirled airflow. The strength twisted by the whirled airflow increased with decreasing inlet diameter of the nozzle block, and was enhanced with increasing outer diameter of the hollow spindle. The strength twisted by the whirled airflow was weaker when the distance from the inlet of the nozzle block to the inlet of the hollow spindle was bigger. The numerical results validated the effectiveness of the analytical model.

A Numerical and Experimental Study on the Effect of the Cone Angle of the Spindle in Murata Vortex Spinning Machine

To study the effect of the cone angle of the hollow spindle in the nozzle of Murata vortex spinning (MVS) on yarn properties, the k‐ε turbulence model is employed to simulate the airflow patterns inside the different nozzles with different spindle cone angles. A set of corresponding spinning experiments is designed to verify numerical predictions. The simulation results show that some factors, such as the counter-rotating vortex pair (CVP) over the spindle, high supersonic zone in the inlet of the swirling chamber, and the distribution of wall shear stress (WSS) along the outer wall of the spindle caused by variation of the cone angle of the spindle, are significantly related to fluid flow, and consequently to MVS yarn properties. A rational cone angle (Case 2) can form an axisymmetric CVP and high WSS, which can ensure sufficient twisting of the yarn and produce high quality yarn. The experimental results, which yarn properties spun using 100% cotton, 100% polyester, and polyester 70∕cotton 30 blends with different nozzles, are well consistent with the numerical study.

New type motor for tough hard disk drive

A new type fluid dynamic bearing spindle motor has been developed for use in a small hard disk drive for mobile applications. Classified as an untied type motor in its basic construction, the new motor is constructed so that it prevents oil leakage and enhances the rigidity of the hard disk drive chassis. The characteristic structural feature of the motor is a hollow rotary spindle through which a stationary shaft is installed. The stationary shaft does not interfere with spindle rotation. Since the stationary shaft is secured between the top cover and base chassis, the motor enhances hard disk drive chassis rigidity, which is an advantage that cannot be achieved by the conventional untied type motor. Although measuring small and thin, the motor has excellent rotational accuracy and shock resistance.

Characteristics of Rotor Spun Cotton/Spandex Composite Yarns

Spandex fibers have superior stretch and elastic recovery ability, which is why clothes containing spandex fibers fit well and are comfortable. The most common methods of producing elastic yarns are core-spun on a modified ring frame and hollow spindle technique. Rotor spinning has many advantages over ring spinning and has been adopted worldwide. In this paper, a method of producing the cotton/spandex composite yarns on a modified open-end rotor spinning is introduced. By changing the draft ratio and linear density of spandex filaments, different kinds of cotton/spandex composite yarns are produced on a modified rotor spinning frame, and their appearance and properties are tested and analyzed at the same time. The results show that the spandex draft ratio has great influence on the appearance and properties of rotor spun cotton/spandex composite yarns. The linear density of spandex filaments also has influence on the properties of composite yarns.

A general algorithm for profiling and dressing grinding wheels when using a grinding spindle on a CNC lathe

Remarkable progress is being made in the technology for grinding complicated geometrical parts. Today, some factories are considering adding a grinding spindle to a turning lathe to save buying an additional expensive new grinding machine. The grinding spindle will be interchangeable with a turning boring bar and it will need two types of software. First is a program and subroutine to control the machine movement during the grinding profile of the work-piece. Second a program and a subroutine are needed to profile the new grinding wheels according to the grinding profiles of the work-piece, as well as dressing the grinding wheels after usage. In the case of a very small depth of cut, a long program will be required. Each different shape of grinding wheel will require different software. There are no detailed descriptions for this problem in the literature or machine manuals. This paper presents a general algorithm to make the profiling and dressing programs for grinding wheels easier. The programmer will use this algorithm for creating a subroutine suitable for the machine dressing system. This algorithm can be used on grinding machines as well as on an additional grinding spindle on a hollow spindle lathe. This subroutine will be used for profiling and dressing the most common shape of grinding wheels. The programmer will then only need to fill in the parameters which describe the contour of the grinding wheels. This algorithm has been applied on a hollow spindle lathe equipped with a numerical Sinumeric 840C control. Several grinding wheels have been profiled and dressed using the proposed approaches, and satisfactory results were obtained.