Dissertations / Theses on the topic 'Twisted yarn'

A new perspective in the field of actuators was opened by the demonstration of multiwall carbon nanotube based actuators by Foroughi et al, in 2011. The approach involves applying a high degree of twist to create large torsional actuation in carbon nanotube yarns, and more recently in coiled nylon filaments. In this thesis torsional actuation is further studied in nylon, and extended to shape memory alloys (SMA). Torsional actuation is demonstrated using 25 μm diameter micro strands of shape memory alloy (SMAs) that are twisted together. These form yarns with Young’s modulus of 13.5 GPa in the Martensitic phase and 18 GPa in the Austenite state. In torsion, the SMA yarns show more than 8,000 rpm peak rotational speed with 11 reversible rotations for an 8 cm long yarn. This is observed upon applying 0.47 W/cm electrical input power. Providing more than 5 N.m/kg torque, SMA yarns may be of interest in biomedical and other applications. The mechanical behaviour of coiled nylon actuators is studied by testing elastic modulus and by investigating tensile stroke as a function of temperature. Loads that range from 35 MPa to 155 MPa were applied. For the nylon and the coiling conditions used, active thermal contraction totals 19.5 % when the temperature is raised from -40 ⁰C to 160 ⁰C, with most contraction above the glass transition temperature. Introducing various cooling methods was shown to enable increased rate of actuation up to several Hertz. Nylon coiled actuators potentially provide affordable and viable solutions for driving mechanical devices as recently demonstrated in robotic hands and arms. A new biomimetic arrangement of the nylon actuator is presented that imitates the human pennate muscle in structure, including the ability to vary stiffness by a factor of 9 and to increase isometric force from 19 N to 37 N by recruiting additional fibers.
Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate

The idea underlying the present study was to apply twisting in order to introduce different levels of transverse pressure. The modified structure affected both the bonding level and the evolution of the damage in the yarn. In order to isolate this effect in a broader context, additional parameters were included in the experiment design, namely effects of loading rate, specimen length and filament diameter (directly linked to the fineness of the yarn). These factors have been studied in various contexts by several authors. Some related studies on involved factors will be briefly reviewed.

碩士
逢甲大學
紡織工程所
93
This thesis is to research and investigate the process, characteristics and fabric touch of the polyester imitating the natural fiber of Ramie yarn; thus the yarn can be widely used in daily commodities. JAPAN MURATA 33H friction false twisted texturing machine is used to experiment processes with varied drawing ratios (DR), twister velocity ratio (VR), heating temperature (H1), yarn speed (YS) to produce poly (ethylene terephthalate) Ramie like yarn out of polyester (Partially Oriented Yarn)(POY). Experimental results show that when the heating temperature is raised, the yarn produces more SHARI touch and Ramie touch, especially when the heating temperature is between 240℃ and 250℃, the Ramie touch is the best. As yarn speed gains higher and higher, the put in twist tension (T1) and put out twist tension (T2) get looser and looser until the yarn tension remains shaking and can''t be measured. Experiments show that yarn speed between 400 m/min and 500 m/min suits most for false twisted texturing process. The crimp elasticity improves with the higher twister velocity ratio value. The friction disk gives the yarn much more texture twist and torgue curly, which results in better SHARI touch. The increased drawing ratio enhances the orientation of molecular; the uniform arrangement of molecular contributes to higher fiber strength but cuts down SHARI touch. Therefore, to get better SHARI touch during tight spot texturing process, the drawing ratio should be low not high. To sum up, in order to improve and get the best texture yarn SHARI touch during tight spot texturing process, the most favorable texturing parameters are 450 m/min for yarn speed, 1.36 for drawing ratio, 245℃ for heating temperature , 1.82 for twister velocity ratio . The test of sampled texturing yarn and woven fabric for Kawabeta Evaluation System fabric touch shows that it is similar to nature Ramie yarn in surface friction and roughness. Such made Polyester Ramie like yarn has the characteristics of SHARI and stiffness, which can be widely applied to knit fabrics, shirts, underwear, suits, household clothing and so on.

碩士
國立臺灣科技大學
纖維及高分子工程研究所
88
In this paper, we have selected poly(ethylene terephthalate) (PET) thick＆thin yarns, partially oriented yarns, cross-section of trilobal fully oriented yarns, and proceeded to the frictional false-twisting of three conditions. We also investigated the influence of false-twisted yarns of morphological structures, physical properties, and heat behaviors of filaments and twisting conditions. PartⅠ：The experiment process begins with the overlapping of two filaments by air pressure and then frictional false-twisting at different draw ratio and primary heater temperatures. The result shows that knots of textured yarns are obviously at low primary heater temperature, but almost unable to perceive at 240℃. At same time, tenacity decreases tremendously due to broken filaments. Elongation and tenacity decreases with draw ratio or as primary heater temperature increases. Heat Behaviors are directly proportional with the amorphous volume fraction and amorphous orientation of textured yarns. PartⅡ：We discuss the structure formation of slub yarns, which is produced by phase difference and insertional spindle false-twisting process. We then studied the formation process of thick sections by utilizing the phase difference twisting motionless state simulate experiment. The result shows that there are four steps to the motionless state twisting formation process; and the formation of three different twisting structures are of the right order. It matches actual slub yarns, which are wrapped around by three orders of different twisting structures. The physical property of slub yarns is determined by the degree of Crystallinity. We found that the thick sections are much lower than the thin sections, resulting in thick sections dyed darker and nature linen-like hand-feeling. Besides, there is different external color effect of slub yarns. PartⅢ：The condition of false-twisting process occurs with the overfeed ratio of two filaments are 1.01 and 1.07, increased throughput speed occurs, as well as proceeding simultaneous composite frictional false-twisting. The result shows that there are no significant special changes of the textured yarns.

碩士
逢甲大學
紡織工程學系
88
The study deals with the effects of process parameters on the physical properties of Nylon 6 texturing yarns. The texturing process was processed with a Murata No. 33H Crimp Texturing Machine. The materials used in the study were 86d/34f and 86d/24f Nylon 6 partial oriented yarns (POYs). In order to obtain the optimal yarn quality, the Taguchi methods of was applied for evaluating the effects of twister belt crossover angle (θ), primary heater temperature ( T1 ), yarn speed ( YS ), draw ratio ( DR ) and twisting velocity ratio ( VR ). The physical properties of draw texturing yarns were tested; in addition,the statistical reproducibility of optimize parameters was evaluated for reaching the desired replication. The experiments were processed with the orthogonal arrays of Taguchi methods. There are three factors of parameter for every experiments. The experimental parameters in the study were twister belt crossover angle ( 100°,105°,110°), primary heater temperature ( 165 ℃, 175 ℃, 185 ℃ ), yarn speed ( 500 m/min ,600 m/min, 700 m/min ), draw ratio ( 1.20 ,1.25 ,1.30 ), and twisting velocity ratio ( 1.35 ,1.45 1.55 ). 27 experiments were carried out in the study and the related physical properties of draw texturing yarns were also tested. The yarn physical properties in testing were tenacity, elongation, crimp rigidity, and boiling water shrinkage. The optimal parameters for 70d/34f of texturing yarn lies in 105°of twister belt crossover angle, 165 ℃ of primary heater temperature, 600 m/min of yarn speed, 1.20 of draw ratio and 1.55 of twisting velocity ratio, as referred to the experimental results. The related physical properties of 70d/34f texturing yarn were 5.92 g/d of tenacity, 29 % of elongation, 30 % of crimp rigidity and 6.1 % of boiling water shrinkage. The reproducibility under three conditions were reliable and saticfactory. Furthermore, the similar results for 70d/24f texturing yarn were 105°of twister belt crossover angle, 165 ℃ of primary heater temperature, 500 m/min of yarn speed, 1.20 of draw ratio and 1.55 of twisting velocity ratio, as referred to the experimental results. The related physical properties of 70d/34f texturing yarn were 5.32 g/d of tenacity, 27.5 % of elongation, 28 % of crimp rigidity and 7.3 % of boiling water shrinkage.

碩士
中國文化大學
紡織產業碩士專班
105
As the towel fabric need to have excellent moisture absorption and drying properties, so it is important to select materials and weaving structure for the towel fabric. Therefore, this study select the single yarn, the ply yarn and the untwist yarn to text the physical properties. Such as twist of yarn, the diameter changing after moisture absorption and so on. And weaving into a towel fabric to text saturated water absorption, moisture absorption rate, drying rate and strength for the analysis. The experiment uses the 100% cotton yarn to be made into the towel fabric. There are, Ne16 single yarn, Ne32 / 2 ply yarn, Ne16 untwist yarn and Ne16 / 2 ply yarn, four kinds of yarns. Comparison of different yarn structure and Ne impacts the towel fabric moisture absorption, drying and strong. According to the experimental results, the maximum saturated moisture absorption of the untwist towel fabric is 742.68%, the vertical wicking high of the wrap is 10.6cm, and the remnant water rate is 85.64% at 40 minute. As the towel fabric that be made of the untwist has the best properties.

碩士
國立臺灣科技大學
纖維及高分子研究所
86
With the elevation of industrial technology and life horizon, manufacturing industries are replacing human workers with automatic artifices gradually for benefits like higher efficiency and lower costs. Recently, the production of synthetic fiber in Taiwan expands vigorously especially that of polyester texture yarn, which has become number 1 in the world in terms of quantity. Most of the false twist texturing factory have been highly automated, but all of them encounter a bottleneck of complete automation, for inspecting the appearance of yarn packages still requires human labors to examine each product one by one. This task is not only non-objective but also greatly heighten up the cost of labor in the process. Moreover, the wage in Taiwan has been higher and higher today, so that modification of this process has become a problem that is eagerly needing to be solved. Hence we designed an inspection station specially for the appearance of false twist yarn packages, combining techniques of machine vision and digital control. To finish this task in an automatic manner is expected. Some skills of image processing including convolution filtering, image segmentation, curve fitting, signature extraction and morphological operation, are implemented with programming language. The size of a package, discoloration, formation and overthrow at the bottom of package are inspected. We integrated the algorithms with two CCDs, rotating plate driven by a servo motor and illumination equipment with a personal computer, following the concepts of visual inspection system. Thus a practicable, low-cost and automatic visual inspection system was exploited in this study. This system can turn the indeterminate concepts into explicit representation by extracting index for each characteristic of the package. These results were used to grade the products using theories of statistical pattern recognition. After the accomplishment of the construction, several samples were examined to test the functions and effects. According to the data obtained, the result diagnosed by the system meet the fact, providing a standard for classification. Comparing to traditional method of human labor, it is more precise and performs a more regular classification.

博士
逢甲大學
紡織工程研究所
84
ABSTRACTYarn strength and yarn elongation are the two most important physical properties for the assessment of plied yarn. In addition, they are the main judging factors in the industry. Therefore, it is essential to study the influencing factors for the yarn strength and the yarn elongation in the field of yarn doubling. This research concerns the influencing factors for the yarn strength and the yarn elongation of the plied yarns using rotor twister which was developed in this research since 1994. Two kinds of plied yarns including doubling and wrapping process were ivestigated. In this thesis, four main parameters were adopted for their influences on the yarn physical properties and spinning performance: rotor speed (10000, 12500, 15000, 17500, 20000 rpm); twist propagation length (36, 40, 44, 48 cm); length of rotor (98, 132, 166 mm); twist direction (S, Z). Moreover, the analysis of the possibility was made for the twisting of loom selvage with rotor-wrapping twister.According to the experimental results, it was found that the twist C.V% and twisting tension were increased with the rotor speed during twisting. On the contrary, the yarn strength and yarn elongation were reduced when the rotor speed is increased. According to our observations, the yarn strength 6% and the yarn elongation drops about 8% for every increasement of rotor speed per 5000rpm from 20000 rpm to 30000 rpm. For a plied yarn with long twist propagation length, the yarn strength and the yarn elongation are directly proportional to the yarn twist before the maximum twist limit is reached. The optimal twist propagation length for the plied yarn occurred at 40cm within 36~48cm; 11.84~13.88cN/tex of the optimal yarn strength as well as 4.24~5.84% of the yarn elongation could be achieved. For the length of rotor, apparently, the optimal length of rotor was found to be 132mm, at which length a better yarn strength (14.88~13.96cN/tex) and yarn elongation(6.51%~4.96%) can be obtained. This results in 7%~30% increase in yarn strength and 17~44% in yarn elongation in comparison with rotor length at 98mm. Similarly, it results in an increase of 7~14% of yarn strength and 9~39% of yarn elongation when compare with the rotor length of 166mm. In the case of the length of rotor at 132mm, the yarn strength was 14.67~11.53cN/tex which has an increase of 8%~13% and 16%~38% in comparisons with rotor length of 98mm and 166mm, respectively; the yarn elongation was 6.35%~4.93% that was 19%~54% and 10~40% higher in comparisons with rotor length of 98mm and 166mm, respectively. The plied yarn could achieve a better yarn strength and yarn elongation as well if the assembly yarn has an identical twist direction before the maximum twist limit. For an assembly yarn with Z- twist direction, the yarn strength was 33~59% higher and the yarn elongation was also increased if the plied yarn twist direction has the same direction as the assembly yarn. These two types of the rotor twisters are capable of making plied yarns, special cover yarns, elastic cover yarns, spun-like filament yarns, cover yarns of shuttless loom selvages, and cover yarns of selvage of spun-bonded nonwoven fabrics etc. Independent of S-twist or Z-twist, those cover yarns of selvage evidently improve the yarn strength, the yarn elongation and the friction resistant. It had been proved that this twister provides a possibility to recycle the wastes of selvages. The new born yarn of this selvage can be used for woven or knitted fabrics.Through this contribution, we had opened a new era for the recycling of selvages. We attributed this success to the research and development of our new twister.

博士
逢甲大學
紡織工程所
92
In this study, it is important the process of functional elastic composite yarn is developed and the mechanical properties of the yarn are investigated, and then the yarn will be used in daily commodities and industrial products. Core-spun elastic yarn was produced with spandex filaments and polyester or polyester/rayon staple fibers using a ring spinning frame and a multi-section drawing frame. Elastic wrapped yarn was manufactured with spandex filaments and textured nylon filaments using a rotor twister and the multi-section drawing frame. The results show that when the main drawing ratio of the spandex filaments is either 2.2 or 2.7, the maximum breaking tenacity and elongation of the core-spun elastic yarn are maximized. When the rotor speed is 4000-8000 rpm and the wrapping count of the textured nylon filaments is either 2.5 or 3.0 turns/cm, the maximum breaking tenacity of the elastic wrapped yarn with the spandex filaments of 78 dtex exceeds that of the yarn in any other processing conditions. However, when the rotor speed is 4000 rpm, the breaking tenacity trend of the elastic wrapped yarn with the spandex filaments of 940 dtex is not significant when the wrapping count increases. The maximum breaking tenacity of the elastic wrapped yarn increases with the increasing drawing ratio of the spandex filaments. As the wrapping count of the textured nylon filaments is 3.0-4.0 turns/cm, the drawing ratio of the spandex filaments is 2.0-3.5 and the rotor speed is 4000 rpm, the maximum breaking tenacity of the elastic wrapped yarn with the spandex filaments of 78 dtex is maximized. The elastic yarn is flexible and could be applied for pantyhose, underwear, jeans, sportswear, socks for medical use, bandages, girdles, warp-knitted fabrics, and so on.

碩士
國立臺灣科技大學
纖維及高分子工程研究所
87
Industry automation is a trend of all trades and professions. In the present, false twist yarn package are classified by people, but the result may affect by personal equation, and automatic package classification is more economical and effectively, so we are going to build a system of false twist yarn package automation classifier. We may use the CCD camera and some digital image process like “Mask Operation”, “Threshold Process”, “Edge Extraction”, “Curve Fitting” and “Run Length” to extract the defect of yarn package, such as “Size”, “Discoloration”, “formation” and “Cross Over”, and then build these defect feature index. We use these defect feature indexes to be the input of Neural Networks to training it. After training, we can have a system of false twist yarn package automation classifier. In the Last, we combined the image process and the networks. The result shows accurate.

碩士
中國文化大學
化學工程與材料工程學系奈米材料碩士班
101
The high-strength polyester fiber are often used in rubber reinforcement materials, but there has a phenomenon when polyester heating over the glass transition temperature Tg, the molecular chain would change from folded to stretched, the molecular chain become crystallization and forward. At the same, it slide by force then stretch. In this situation if we give tension to let the fiber not to stretch or compress to much. Polyester fiber surface has hydrophobic so how to treatment the interface become a key point. In this study, we use different tension and temperature to get the best elongation and shrinkage of the ply yarns. Under those conditions to use different pre-dealing by adding 1-8% isocyanate compounds, and dipping in RFL. Then after hot pressed rubber become ply yarns has better bonding strength. By increase the ply yarns absorb the RFL, and using fiber surface analysis, heat shrink, elongation, tensile fracture strength analysis to prove in different temperature, tensile has different effect. Ply yarns and rubber’s layer stripping strength. We used the polyester filament to produce a variety of filament fold yarnswith the different of twist number. By using the tensile, through the six-level heat treatment system. We analysis the properties on strength, twist shrinkage, heat shrinkage of polyester ply yarn. It is found the twist shrinkage increase by twist number, but the heat shrinkage decrease. According with the twist level, the rate of heat shrinkage keep in 0% to applied 1-1.5kg force at the 125℃, 150℃, 175℃. The best to applied more than 1.5kg force at the 200℃, 225℃, 250℃.In 0kg force, the best tensile strength is 64.26kgf in 2 of twist number in first twisting and 1 of twist number in second twisting. In 0.5kg, 1kg, 1.5kg force, the best tensile strength are 67.53kgf, 65.08kgf, 65.61kgf in 4 of twist number in first twisting and 3 of twist number in second twisting.Pre-dipping, add 2% isocyanate compounds by far-infrared radiation treated and untreated joint stock index results in a higher rate on the drug, and its rate of 17.57% on the drug RFL and 17.44%. Bonding strength in the isocyanate compound concentration of 2%, the bond strength 23.48kgf, improved 17.40%; untreated isocyanate compound concentration of 2%, bond strength 22.88kgf, improved 14.40%.