Optimum drafting conditions of bamboo charcoal-modified fiber blended yarn obtained by drafting behavior analysis

In this work, the effect of optimum drafting condition on the drafting behavior and yarn quality of the bamboo charcoal-modified fiber blended spun yarns were studied. We measured the drafting force and drafting force variance, CV% of the bamboo charcoal-modified Polyester/Cotton (BCP/C) blended roving and bamboo charcoal-modified Rayon/Cotton (BCR/C) blended roving to examine the influence of the roller gauge and drafting ratio on drafting behavior and yarn quality. We understand that the drafting force of the bamboo charcoal-modified fiber blended roving follow the same trend as that for the regular P/C and R/C blend roving. However, the drafting force presents some difference in characteristics between these bamboo charcoal-modified fiber blended rovings. To correlate the drafting force variation, CV% and the bamboo charcoal-modified fiber blended spun yarn properties, we evaluated the yarn quality and investigate the yarn quality index in conjunction with the break drafting ratio. Therefore, in this work, we can obtain the best optimum drafting conditions for bamboo charcoal-modified fiber blended spun yarns; for the 19.7 tex of BCP70/C30 blend spun yarn was under the roller gauge of 54 mm at the draft ratio of 1.3, whereas, for the 19.7 tex of BCR40/C60 blend spun yarn was under the roller gauge of 54 mm at the draft ratio of 1.2.     

High performance flame-retardant composite yarns with oxidized fiber

This study employed a SKF draft system equipped with an additional spreading device to form a high performance flame-retardant composite yarn. For mixing the spread Technora® filaments and Stretch-Broken oxidized fibers, nip of the front rollers was arranged for best dispersion. The yarn unevenness (CV %), strength, abrasion-resistance, and Limited Oxygen Index (LOI) of the composite yarn were evaluated. The cross-sections of the actual composite yarn were observed to assess its structure and the effect on yarn performance. The experimental results showed that the yarn CV% is worse as the yarn count (Tex) tend to be finer. This would be an optimum condition adopting 30 TM for the yarn evenness and yarn strength. After abrasion test, the residual strength of composite yarns remains above 80 %. The LOI value depends on the coverage degree of oxidized fiber outside the yarn surface, and there tended to be a lower LOI value with finer yarn count (Tex). Overall, the T/O composite yarn with uniform distribution structure can provide high performance and flame-retardancy.     

Study on Spinning triangles in the common ring spinning and Super draft ring spinning systems

In the paper, one kind of super draft ring spinning frame with four drafting rollers and corresponding three drafting zones were introduced. The yarn qualities spun by the super draft ring spinning frame were analyzed by studying the shape of spinning triangles. Using the high speed camera system OLYMPUS i-speed3 and one kind of transparent front top roller, the spinning triangles were captured, and the geometry size of spinning triangle were measured. Then, according to the theoretical model of fiber tension in the spinning triangle, fiber tension distributions in the spinning triangles were presented by using Matlab software. Using the combed roving of 350 tex as raw material, three kinds of cotton yarns, 27.8 tex (21^S), 18.2 tex (32^S) and 14.6 tex (40^S), were spun in the common ring spinning frame with three different suitable spindle speeds, travelers and twist factors. Using the combed roving of 350 tex and 500 tex as raw material, 14.6 tex cotton yarns were spun in the super draft ring spinning frame with three different drafting ratios at back zone. It is shown that with the increasing of spindle speed, a more asymmetric shape of spinning triangle would be produced, and lead to worsen yarn evenness. With the decreasing of traveler weight, the height and horizontal deviation of the spinning triangle is decreased, and may lead to better yarn evenness and less long hairiness. By taking suitable large yarn twist factors, the comprehensive qualities can be improved. Comparing with the common ring spinning, the spinning triangle is larger in the super draft ring spinning. That is, in the super draft ring spinning, the fibers in the strand in the front roller nip are more dispersed, and not benefit for yarn qualities. Therefore, the compact device was introduced into the super draft ring spinning, and the cotton pure yarns and blend yarns were spun, and the yarn qualities were measured and analyzed.     

Properties of wool/spandex core-spun yarn produced on modified woolen spinning frame

Spandex has been successfully applied on modified worsted spinning system to produce spandex core spun yarn. However it’s difficult to produce wool/spandex core-spun yarn on woolen spinning system with the same modified device because the drafting device of the two systems is quite different. A new method is introduced to apply spandex on woolen spinning system in this paper. Core-spun yarn produced in this way has good appearance and quality by comparing with normal yarn. A series of experiments were carried out to study the influence of spandex drafting ratio and yarn twist factor on tensile properties and elasticity of core-spun yarns. The results indicate that core-spun yarn with spandex drawing ratio of 2.5 and twist factor of 13.63 has highest value of tenacity and breaking elongation.     

Processing parameters optimization of multiple quality characteristics of open-end rotor spinning process for Bamboo charcoal and CVC blended fibers

In the field of yarn spinning engineering, the importance of the processing parameters taken depends directly on the quality characteristics of the yarn. This study aimed to find the optimal processing parameters for an open-end rotor spinning frame at work to identify its multiple quality characteristics for yarn. In this study, Bamboo charcoal and cotton 70 %/polyester 30 % (CVC) blended fibers were adopted as the materials, and the open-end rotor spinning frame was used to spin the yarn. In order to identify optimal conditions of an open-end rotor spinning frame, the Taguchi experimental method was applied to design open-end rotor spinning experiments, and the L₉ orthogonal array was chosen in accordance with nine sets of experiments and contained four control factors and three levels. Furthermore, a response surface methodology (RSM) was used to obtain the models of significant processing parameters for the strength, unevenness, I.P.I, and hairiness. Based on experiments designed to obtain an open-end rotor spun yarn Ne 30, the strength, unevenness, imperfection indicator/km (I.P.I) and hairiness were then chosen as the quality characteristics. In addition, grey relational analysis integrated the optimal processing parameter of multiple quality characteristics, and a confirmation experiment was performed. In conclusion, the optimal processing parameters under steady spinning conditions were a rotor speed of 88000 rpm, a feed speed of 0.392 m/min, and a winding speed of 39.466 m/min.     

牵切苎麻在棉纺设备上的纺纱初探

对苎麻长麻纺（复精梳）工艺中的苎麻预并条和头道精梳条进行牵切,然后分别将其在棉纺设备上进行并条、粗纱和细纱加工。探讨牵切纱断裂强度与捻系数的相互关系,并对比分析牵切纱与常规纱的质量。结果表明,牵切纱临界捻系数αt 在405左右,苎麻牵切精梳纱的条干、粗细节、棉结及3 mm以上的毛羽与苎麻常规精梳纱的接近,且断裂强度优于苎麻常规精梳纱的。     

A study on siro-jet spinning system

Nowadays, there is ever increasing interests regarding with the nozzle usage in spinning systems and also winding process. In this study, an air nozzle was attached on to the sirospun spinning system and the system was called as siro-jet. Sirospun is a spinning system combining spinning and doubling in one operation and a yarn like a two fold is produced. The principle of the siro-jet system is based on the placement of the nozzle at the exit of drafting unit on sirospun spinning system and pressurized air was fed into the nozzle by the compressor during the spinning. In literature, air nozzle application in this manner is not common and hence the system is very less known. For that reason, siro-jet and siropun yarns were produced with different fibre types, material qualities and yarn counts, and the properties of the yarns were compared. At the end of the study, it was determined that siro-jet spinning system truly improves the yarn hairiness in comparison to sirospun spinning system. Even, the siro-jet yarns are less hairy after winding process. Interestingly, hairiness results of siro-jet and sirospun yarns produced with short, non-uniform fibres showed that siro-jet spinning system allows working with low cost raw materials while maintaining yarn quality. Therefore, siro-jet can be considered as an innovative spinning system regarding with less hairy yarn production opportunity.     

Multiple response optimization of rotor yarn for strength,unevenness, hairiness and imperfections

In this study, a multiple response optimization model based on response surface methodology was developed to determine the best rotor speed and yarn twist level for optimum rotor yarn strength and unevenness, and minimum yarn hairiness and imperfections. Cotton yarn of 30 tex, was produced on rotor spinning machine with different twist levels (i.e. 500, 550, 600 and 700 tpm) at different rotor speeds (i.e. 70000, 80000, 90000 and 100000 rpm). Yarn quality characteristics were determined for all the experiments. Based on the results, multiple response optimization model was developed using response surface regression on MINITAB® 16 statistical tool. Optimization results indicate that with the quality of raw material selected for this study, top 50 % quality level, according to USTER® yarn quality benchmarks, can be achieved with 100 % desirability satisfaction for all the selected yarn quality parameters at rotor speed of 77,800 rpm and yarn twist of 700 twists per meter.     

The analysis of the influence of fiber length distribution on the theoretical and additional unevenness of yarn

Fiber length distribution has an impact not only on the theoretical unevenness of yarn caused by random fiber alignment, but also upon the additional unevenness caused during processing, especially in drafting. For a given fiber length distribution, there is a discrepancy between the theoretical unevenness of yarn which is calculated with Martindale’s equation and the actual unevenness tested by instrument. In order to reflect the effect of fiber length distribution on the theoretical unevenness of yarn, in this research, a kernel function was used to estimate the probability density function of fiber length, therefore, calculation of Suh’s model for theoretical unevenness was realized. On this basis, the theoretical and additional unevenness of yarn were calculated. The statistical influence of fiber length parameters on yarn unevenness was discussed. It can be concluded that decreasing the values of effective length, length irregularity and 16 mm SFC by weight would improve the uniformity of yarn.     

An experimental study of influence of filament and roving location on yarn properties during embeddable and locatable spinning

This study was focus on the influence of filament and roving location on yarn properties during embeddable and locatable spinning (ELS). ELS composite yarns were produced with various filament and roving locations on an experimental ring spinning frame. Besides yarn formation zone configurations, ELS yarn properties were compared including yarn hairiness, unevenness and tensile properties. Results showed that spinning triangles became larger; however, the reinforced composite spinning strand length kept constant. With a constant filament-roving spacing on each side of ELS, Filament spacing variations caused no significant changes of spun yarn hairiness, tenacities, imperfections and unevenness CV. For roving location variations with constant filament spacing, the reinforced strand length became longer as the roving spacing increased. Hairs exceeding 3 mm were lower for ELS yarn spun with 4 mm and 10 mm roving spacings than that spun with 6 mm, 8 mm and 12 mm roving spacings. Roving spacing variations had a trivial influence on ELS yarn unevenness; whereas, yarn tensile index variation coefficients fluctuated dramatically due to hairiness variations for different roving spacings.     

Real-time estimation and irregularity control of the sliver draft system

High regularity is important in manufacturing spun yarn. Among controllers used in regularity control, existing PID controller is suitable for linear time-invariant systems but not for the control of sliver draft systems with non-linear characteristic. Thus, the present study designed a knowledge-based fuzzy controller in consideration of disturbance and non-linear characteristic of sliver draft systems. RLS (Recursive Least Squares) was used as an estimation algorithm to formulate a model used in computer simulation for implementing the controller, and real time estimation was made using real data from draft systems to get a model close to actual systems. This research used a estimation model in designing a knowledge-based controller that minimizes the variation of control response to the sliver linear density of the system, and the result of linear density control was used to prove the superiority of the controller in control performance through CV%.     

Vorticity analysis associated with drafting cylinders for pneumatic spinning

Traditional spinning systems have reached profitability limits in developed countries due to high production costs and low system productivity. Pneumatic spinning is seen as a developing system, because productivity is much higher than conventional systems. This study evaluates one of the main problems to increase productivity in pneumatic spinning, where air mass-flow is dragged by the drafting cylinders. This flow interacts with the incoming fibres deviating them from their expected path. Via laser anemometry, airflow velocity distribution around drafting cylinders has been measured and it has been found that vorticity is created at the cylinder’s inlet. Extensive CFD simulation on the air flow dragged by the cylinders has given a clear insight into the vortex created, producing valuable information on how cylinder design affects the vorticity created. Several drafting cylinder designs have been tested without giving any improvement in productivity. However, the use of a drafting cylinder with holes in it produced good results to the problem of air currents, strongly reducing them and therefore allowing a sharp increase in yarn quality, as well as an increase in productivity. An extensive study on vortex kinematics has been undertaken, bringing with it a better understanding of vortex creation, development and breakdown.     

A new mathematical expression of yarn limit unevenness

With the development of spinning process, it was found that Martindale’s theory on yarn limit unevenness in staple fiber yarns has no longer been valid in the case of high yarn count. Martindale’s theory was based on the assumption that fibers had the identical length. Taking fiber length distribution into consideration, this paper has developed a new model on fiber random arrangement of ideal sliver. By applying mathematical probability method to analyze this model, a new mathematical expression of yarn limit unevenness has been obtained. Compared with the values from tested and calculated by Martindale’s theory, the value of new yarn limit unevenness is reasonable to reintroduce the index of irregularity in the case of high yarn count.     

Yarn engineering using hybrid artificial neural network-genetic algorithm model

This work aims to manufacture cotton yarns with requisite quality by choice of suitable raw materials for a given spinning system. To fulfill this aim, a hybrid model based on Artificial Neural Network (ANN) and Genetic Algorithm (GA) has been developed which captures both the high prediction power of ANN and global solution searching ability of GA. In an attempt to achieve a yarn having predefined tenacity and evenness, a constrained optimization problem is formulated with the ANN input-output relation between fibre and yarn properties. GA has been used to solve the optimization problem by searching the best combination of fibre properties that can translate into reality a yarn with the desired quality. The model is capable in identifying the set of fibre properties that gives requisite yarn quality with reasonable degree of accuracy.     

Reducing ring spun yarn hairiness via spinning with a contact surface

In this study, spinning with a contact surface was introduced as a simple and energy-saving method to reduce spun yarn hairiness. Theoretical analysis indicated that yarn hairiness could be reduced via a sufficient long contact surface applied in other part of yarn formation zone in addition to spinning triangle. Then, a simple contact apparatus was installed on ring frame to validate the theoretical analysis. Results proved that yarn hairiness was reduced via a contact surface in the yarn formation zone. However, unevenness was deteriorated for most yarns spun with contact apparatus during the spinning, which might be due to fiber mass concentration. Most of yarns spun with contact apparatus had a lower strength than the conventional yarns. This might be because evenness deterioration to decrease yarn strength overpowered hairiness reduction to increase yarn strength for most yarns spun with a contact surface.     

Prediction system of open-end rotor spinning process based on LM-neural network for bamboo charcoal fibers

In line with the environmental protection trends of the 21st century, bamboo charcoal fiber is invented to meet the requirements of the fields of science and technology. Its special functionalities, namely, antistatic, moisture adsorptive, perspiring, antibacterial, deodorizing, anti-radiation, and far infrared properties make it extremely suitable for applications in medicine, sports, and recreational fields, as well as an important breakthrough for environmentally-friendly textile materials. To achieve rapid manufacturing, this study processes bamboo charcoal fibers by open-end (OE) rotor spinning. The Taguchi orthogonal array is applied to the design of this experiment, and the significant factors of fibers quality are obtained through ANOVA in order to facilitate the follow-up processes of quality control. The process prediction system is built based on the test data, and is combined with the back-propagation neural network and the Levenberg-Marquardt (LM) algorithm in order to establish an OE rotor spinning process prediction system. The rotor speed, feed speed, and winding speed are set as the network input parameters, while the yarn strength, the hairiness, the unevenness, and the imperfections indicator (I.P.I.) are the output parameters. Through network learning and training, this system reports a prediction error below 5 %, proving that this prediction system has excellent predictability.     

Investigation on the physical and structural properties of melt-spun multifilament yarns,drawn yarns and textured yarns produced from blend of PP and oxidized PP

In the present study, effect of OPP (oxidized PP) fraction on the mechanical and structural properties of produced fibers is investigated. Polypropylene powder without antioxidant materials was oxidized at the suitable thermal condition. The various fractions of OPP were blended with PP in the chips shape, and employed as starting material in a melt spinning machine for production of filament yarn. Then as-spun filaments were drawn and finally textured. Structural properties including density, birefringence and FTIR and physical properties consisting of shrinkage, tensile properties and crimp properties were measured. Results show that blending of OPP with virgin PP reduces tacticity and crystallinity, but it hasn’t any effect on orientation. Physical properties of drawn yarns and textured yarns were reduced with increasing of OPP fraction. Moreover, increasing of OPP fraction in blend, reduce crimp properties of textured yarn.     

The influence of fiber length distribution on the accelerated points in drafting: A new perspective on drafting process

The distribution of the accelerated points of fibers in roller drafting is the key to the evenness of the drafted slivers. The fiber length distribution is believed to affect the accelerated points. This approach is trying to give a quantitative expression of the influence. A parabolic density function is introduced for the expression of density functions and a generalized method is presented. The experiment shows that the parabolic-type density function is a better explanation for the distribution of the accelerated points in the drafting zone in terms of the consequent yarn unevenness. The statistical test verifies the distribution type. The analysis helps to understand the mechanism of the roller drafting and can be used in the optimization of the parameters in roller drafting.     

Effect of two separate fibre feed systems in rotor spinning on yarn properties

Opening of the fibres in all industrial rotor spinning units is being done by an opening roller, which intakes the fibres from one feed point. Increasing number of feed rollers from one to two may improve fibre opening on the opening roller by gradual loading of the opening roller, which may improve fibre orientation in the final yarn and yarn properties. In this research a modified SE-8 rotor spinning unit of Suessen was used in which two separate fibre feed systems were employed. Raw material used was 38 mm, 1.7 den viscose fibre, to spin a 40 tex yarn. Yarn properties produced with this unit, were compared with that of the original yarn. Yarn properties tested were tenacity, extension, work of rupture, mass irregularity and imperfections, abrasion resistance and hairiness, which were measured on Shirley (SDL) and keisokki yarn testing machines. Test results were analyzed by ANOVA for any difference between the means, and Tukey and Duncan for classification and ranking of the yarn properties. Test results showed that, tenacity, extension and work of rupture of the modified yarn increased in comparison to the original yarn. Its mass irregularity, number of thin places and neps, and hairiness decreased. Number of thick places and yarn abrasion didn’t change. According to the test results, it was concluded that increasing the number of feed rollers on the opening roller from one to two has improved yarn properties.     

An experimental investigation of yarn tension in simulated ring spinning

Yarn tension is a key factor that affects the efficiency of a ring spinning system. In this paper, a specially constructed rig, which can rotate a yarn at a high speed without inserting any real twist into the yarn, was used to simulate a ring spinning process. Yarn tension was measured at the guide-eye during the simulated spinning of different yarns at various balloon heights and with varying yarn length in the balloon. The effect of balloon shape, yarn hairiness and thickness, and yarn rotating speed, on the measured yarn tension, was examined. The results indicate that the collapse of balloon shape from single loop to double loop, or from double loop to triple etc, lead to sudden reduction in yarn tension. Under otherwise identical conditions, a longer length of yarn in the balloon gives a lower yarn tension at the guide-eye. In addition, thicker yarns and/or more hairy yarns generate a higher tension in the yarn, due to the increased air drag acting on the thicker or more hairy yarns.