Analysis of the characteristics of air–yarn coupling movement in the profiled reed groove of an air-jet loom

The movement characteristics of yarn in the profiled reed groove of an air-jet loom can have a great impact on the performance of the fabric. Unstable yarn movement tends to lead to weft defects, as short wefts or weft breaks may occur, which could deteriorate the quality of the final fabric. In this paper, the characteristics of the yarn movement in a profiled reed groove are numerically studied. The arbitrary Lagrangian–Eulerian method is used to solve the two-way airflow–yarn interaction and the yarn is simulated with the ball–socket model. A fluctuation ratio is defined to characterize the unsteadiness of the yarn movement. Our simulation first investigates the effect of the gap ratio of the profiled reed groove (β) on the yarn movement then compares the movements of different yarn kinds. The simulation results indicate that a larger β not only decreases gas leaks (thus saves gas consumption), but also stabilizes the yarn movement. Our simulation results also show that the movement of the yarn of polypropylene is more stable than the other two weft-yarn materials. An experiment is also conducted to validate our numerical results, which shows a favorable agreement between them. Our numerical results of the yarn movement in the profiled reed groove can provide a valuable insight into the optimization of the weft insertion system of the air-jet loom.

Pengaruh Variasi Timing Opening Angle Terhadap Jumlah Weft Stop pada Pertenunan Kain dengan Anyaman Keper 2/1 1 di Mesin Air Jet Loom

In the weaving process, the process of launching the weft yarn is an important thing to consider. One of the obstacles that often occurs in the process of launching feed using a water jet loom machine is the amount of feed stuck (weft stop). The cause of the weft stop is because the process of opening the warp mouth is not clean and the weft thread slides inappropriately or too fast so that the warp mouth is in a small condition. Variations in timing opening angle of 700, 800 and 900 determine the size of the warp mouth opening, the time the weft will slide and the time the weft will arrive. From the three variations of the timing opening angle, the number of weft stops at the timing opening angle of 800 is smaller than the timing opening angle of 700 and 900, which is namely the number of big loops 0.6 times and end loops 0.8 times per hour.

Optimization of fluid characteristics in the main nozzle of an air-jet loom

As part of the propulsion system, the fluid dynamic features of the main nozzle can immediately affect the stability and efficiency of an air-jet loom. This study aims to optimize the fluid characteristics in the main nozzle of an air-jet loom. To investigate ways of weakening the effect of airflow congestion and backflow phenomenon occurring in the sudden expansion region, the computational fluid dynamics method is employed. Three-dimensional turbulence flow models for a regular main nozzle and 12 prototypes with different nozzle core tip geometry are built, simulated, and analyzed to get the optimum performance. Furthermore, a set of modified equations that consider the direction of airflow are proposed for better estimation of the friction force applied by the nozzle. The result shows that the nozzle core tip's geometry has a significant influence on the internal airflow, affecting the acceleration tube airflow velocity, turbulence intensity, and backflow strength of the sudden expansion region, and other critical fluid characteristics as well. Several proposed models have succeeded in reducing the backflow and outperforming the original design in many different aspects. Models A-60 and C-P, in particular, manage to increase the propulsion force by 37.6% and 20.2% in the acceleration tube while reducing the maximum backflow by 57.1% and 52.2%, respectively. These simulation results can provide invaluable information for the future optimization of the main nozzle.

An investigation of the effects of weave types on surface roughness of woven fabric

The fabrics intended for clothing have more emphasis on their appearance and handling characteristics such as luster, smoothness or roughness, stiffness or limpness, and draping qualities. Nowadays, evaluating fabric touch can be of great interest in the industry to match the quality needs of the consumer and the parameters for the manufacturing process. Throughout this study, the effect of weave types on the surface roughness of cotton woven fabric was investigated and analyzed. Three different weave types namely, plain 1/1, twill 1/3, and sateen 8/3 were investigated. The fabric parameters were 27*20Ne (warp/weft) count of yarn, 38*18 (EPC [Ends per Centimeters]/PPC [Picks per Centimeters]) thread density, and 710 CN/TEX (Cent-newton per Tex) with warp tension was produced by air-jet loom. The findings of this study revealed that the surface roughness values of all the fabrics increased regularly on moving from plain 1/1 weave to sateen 8/3 weave. But, the surface roughness of fabric in the weft direction is higher than in the warp direction. The weave type is statistically significant at a confidence interval of 95% and can effectively be used to describe the surface roughness for both warp and weft direction of woven fabrics. The pairwise comparison reveals that it is statistically significant for weave types in the warp and weft direction of the fabrics. This investigation and analysis of weave types on surface roughness of cotton woven fabrics help textile technologies and manufacturers to consider the weave types during the production of fabrics for different end applications.

PENYETELAN TEKANAN UDARA MAIN NOZZLE PADA PROSES PEMBUATAN KAIN YANG MENGGUNAKAN PAKAN FILAMENT TEKSTUR PADA AIR JET LOOM TOYOTA

Putus benang pakan merupakan salah satu faktor yang dapat mempengaruhi kelancaran proses produksi. Kelancaran proses produksi dapat terganggu apabila terjadi banyak putus pakan sehingga kualitas dan kuantitas produksi yang dihasilkan pun akan menurun. faktor dominan penyebab putus benang pakan diduga adalah tidak tepatnya setelan tekanan udara pada main nozzle yang diberikan pada benang pakan. Permasalahan yang timbul penyebab kegagalam peluncuran benang pakan diantaranya adalah terlalu besar tekanan udara main nozzle yang diberikan kepada benang pakan yang mengakibatkan kegagalan peluncuran pakan yang disebut pakan panjang atau terlalu kecilnya tekanan udara main nozzle yang diberikan kepada benang pakan yang mengakibatkan kegagalan peluncuran pakan yang disebut pakan tak sampai. Setelah melakukan penyetelan main nozzle pada 1 mesin Air Jet Loom dengan menggunakan jumlah variasi penyetelan sebanyak 5 variasi untuk setiap shift maka terlihat adanya perbedaan kegagalan peluncuran benang pakan untuk setiap variasinya baik itu pakan tak sampai ataupun pakan panjang, setelah melakukan perubahan penyetelan main nozzle maka didapatkan penyetelan yang paling efektif adalah pada tekanan 5 bar pada main nozzle, dimana pada tekanan 5 bar dihasilkan kegagalan peluncuran pakan sebanyak 18 kali dalam 1 shift dan jumlah ini lebih sedikit dibandingkan dengan kegagalan peluncuran pakan pada penyetelan yang lainnya. Maka dengan menggunakan tekanan udara main nozzle sebesar 5 bar untuk pakan filament tekstur perusahan dapat mencapai efisiensi produksi yang tinggi.

Thread Breakage in Modern Loom and Efficiency

The study is to find out the relation of thread breakage rate on modern loom to the relative humidity and fabric specifications. This result supports thread breakage rate increased with the choice of rapier loom instead of air jet loom. It also shows that loom width has negative relation towards thread breakage and in the production floor relative humidity has insignificant relation with thread breakage rate. Key part of the study shows that warp and weft breakage rate has interrelation. In the production floor loom types and fabric constructions are studied for thread breakage at floor temperature and found no relation to the relative humidity. But, significant relation of warp and weft thread breakage rate to EPI, loom categories, loom width, fabric length produced, weft count and interrelation between warp and weft breakage rate.

Towards simulation of force and velocity fluctuations due to turbulence in the relay nozzle jet of an air jet loom

This research was aimed at obtaining a first estimation of the effect of turbulent vortices present in the relay nozzle jets of an air jet loom on the weft. To this end a large eddy simulation (LES) model was set up and validated capable of simulating a highly underexpanded jet up to a point sufficiently far from the nozzle exit such that flow features at the weft location could be analyzed. The quality of the LES was evaluated based on several quality criteria as well as by comparing the results with experiments and data from the literature. The results show that for a free jet substantial velocity fluctuations are present at a representative yarn location. By inserting a rigid cylinder at this location, the corresponding force fluctuations on a smooth yarn were also obtained. The research shows that the unsteadiness in the jet is quite substantial, as are the corresponding force fluctuations. These fluctuations could have a profound impact on the yarn motion and should at least be considered when using numerical tools to evaluate the forces on or the motion of a yarn acted on by a relay nozzle jet.