Weft Insertion System Research Articles

Design and experimental verification of an S-shaped continuous weft insertion system for soft–hard blended preform narrow channels

To address the limitations of the existing weft insertion technology in inserting carbon fiber bundles into the narrow channels of soft–hard blended preform, a proposed solution is to use a continuous weft insertion trajectory based on an S-shaped path for narrow channels. A weft insertion system that meets the process requirements has been designed. The analysis of the functional requirements for the continuous weft insertion system has identified five key nodes for the system, and the motion paths of each mechanism have been established. Through design methods such as analytical methods, rigid inversion methods, and mechanical analysis, the modular design of the system and the planning of the timing sequence for multiple mechanisms have been completed. Weft insertion experiments have been conducted on a continuous weft insertion system experimental platform, and the results demonstrate that the weft insertion system can effectively introduce carbon fiber bundles into the narrow channels, forming the expected S-shaped continuous weft insertion trajectory. This study verifies the feasibility of the designed weft insertion system and the accuracy of the continuous weft insertion theory, providing a viable solution for continuous weft insertion in the narrow channels of soft–hard blended preforms.

Insertion Performance Study of an Inductive Weft Insertion System for Wide Weaving Machines

Wide weaving machines traditionally enhance the weaving width by increasing the shuttle’s initial velocity. However, this approach introduces challenges like pronounced equipment vibration, elevated noise levels, heightened energy consumption, and a reduced lifespan. Moreover, its efficacy in significantly widening fabric is constrained. Addressing these concerns, this paper proposes a wide-width warp insertion solution that involves driving the high-temperature superconducting shuttle to achieve high-speed horizontal flight through a traveling magnetic field. The inductive weft insertion system structure of wide weaving machines comprises an insertion guideway with an iron core and wound electromagnetic coils. The shuttle consists of a high-temperature superconducting block and a conductive plate, serving as the driving element. By establishing the equivalent circuit of the weft insertion guideway and the suspended shuttle, the calculation formula for the dynamic driving performance of the weft insertion guideway is obtained. Utilizing a transient 3D magnetic field simulation model, the impact of parameters like the current frequency, shuttle conductive plate thickness, and suspension gap on weft insertion performance is explored. Successful wide-width weft insertion motion is achieved by controlling coil input current parameters. Finally, an experimental platform is constructed to validate the correctness of the weft insertion system structure and simulation model through practical experiments.

Design of Weft Insertion System for Ultra Wide and Ultra Thick 3D Flat Loom

Design of Weft Insertion System for Ultra Wide and Ultra Thick 3D Flat Loom

Effect of weft yarn laying on tensile properties of weft-inserted knitted fabrics

To investigate whether the combination of tuck and miss stitches can be used as an alternative method to produce weft-inserted fabrics, in cases where the weft knitting machine is not equipped with a weft insertion system, straight yarns with various densities and arrangements have been inserted in the course direction of rib weft knitted fabrics. The results of tensile tests in the course and wale directions denote that the use of straight yarns increases the tensile strength and tensile strain of the fabric in both directions, while the elastic modulus increases in the course direction. Furthermore, increasing the straight yarn density leads to an increase in the tensile strength and elastic modulus and a decrease in the tensile strain in both directions. Eventually, since the weft yarn arrangement has no significant effect on the fabric tensile strength and elastic modulus, this method can be used as an alternative method to produce weft-inserted fabrics.

Structural Performance Optimization Design of Continuously Accelerating Electromagnetic Weft Insertion System

This paper addresses the problem of low electromagnetic weft insertion acceleration performance of extra-large width automatic looms. Based on single-stage electromagnetic weft insertion and multi-stage intermittent electromagnetic weft insertion, a sectional combined continuous acceleration electromagnetic weft insertion design plan is proposed. First, a new type of weft gripper for electromagnetic weft insertion is designed on the basis of the traditional projectile, and a segmented combined structure optimization design is carried out on the 90 mm single-stage coil. Next, the electromagnetic weft insertion movement model is established to analyze the force and movement speed of the gripper during the movement. The amount of work done by the electromagnetic force of the combined coil determines the exit speed of the weft gripper. Finally, in order to find the best parameters of the combined coil structure to meet the requirements of the launch speed, the steady state and transient performance of the segmented combined continuous acceleration coil are analyzed using Maxwell simulation software. The launch performance of the combined coil with different axial lengths of 45 mm, 30 mm, and 15 mm is compared. The results show that the entire acceleration process is more stable and efficient when the combined coil length is 30 mm, the inner diameter is 18 mm, and the number of turns is 600.

Optimization of the projectile velocity in electromagnetic weft insertion system by genetic algorithm

There are different weft insertion methods used in the weaving machines. Electromagnetic launcher can be used as accelerator to yarn which is attached to the ferromagnetic projectile. For optimization of the projectile velocity in this new weft insertion, the projectile velocity should be obtained by numerous states of inputs (different states of launcher parameters). Experimental tests are very time consuming and costly. Therefore, a validated model (Adaptive Neuro Fuzzy Interface System: ANFIS) which can predict the system behavior accurately and faster than experiments was implemented to predict the projectile velocity. The optimization result of the genetic algorithm shows that achieving the modern weaving machines speed for this weft insertion system is possible by the optimal values of launcher parameters. Also, using the ANFIS model for obtaining the system output is very useful approach. So, the system can be optimized for other desired targets by this procedure.

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.

Simulation of the electromagnetic weft insertion system by adaptive neuro fuzzy interface system

There are different weft insertion methods used in the weaving machines. Electromagnetic launcher can be used as accelerator to yarn which is attached to ferromagnetic projectile. A validated finite element model can predict the system behavior accurately and faster than experiments. For optimization of the new weft insertion, the system outputs should be predicted by numerous states of inputs. Thus, prediction of the system outputs in less computation time is very important. The present study is an attempt to examine the use of an adaptive neuro fuzzy interface system (ANFIS) to simulate this new weft insertion system. The results show that simulation of this weft insertion system by ANFIS can function more efficiently and about 26 times faster than the finite element model.

The effect of launcher parameters on the projectile velocity in laboratory electromagnetic weft insertion system

There are different weft insertion methods in the looms. Electromagnetic launcher can be used to accelerate the yarn which attached to ferromagnetic projectile. In addition to yarn variables and weft insertion system type, weft yarn accelerator parameters strongly affect the weft yarn velocity, yarn pulling force and consequently the fabric quality. Therefore, in this research an experimental coil launcher is implemented and the projectile velocity is calculated by image processing for different states of launcher parameters. Studied parameters are the voltage which is applied to the solenoid, the initial position of the projectile inside the solenoid, the solenoid current-cut-time, the number of coils per centimeter, as well as the solenoid length. The results show that each studied parameter has an optimum value which changes the trend of projectile velocity during acceleration. The results of this research can be used for validation of this new weft insertion system models without experimental cost and time.

Analysis of the magnetic field and electromagnetic force of a non-striking weft insertion system for super broad-width looms, based on an electromagnetic launcher

Weft insertion based on electromagnetic launch technology is a novel and very promising approach for super broad-width (6–12 m) (SBW) looms. There are considerable challenges involved in designing such a system, including analyzing the electromagnetic field while incorporating the effect of a clip weft device, and accurately calculating the electromagnetic and motion parameters of the weft insertion mechanism. In this study, an electromagnetic launch, non-striking weft insertion method for an SBW loom is proposed. The electromagnetic field is analyzed with the finite element method and includes the effect of a clip weft device. Simulation of the motion, analysis of the maximum flight speed of the clip weft device and the work done by electromagnetic force are presented. We also describe an experimental model for electromagnetic launch weft insertion and calculate the electromagnetic force required for weft insertion, using analytical methods and numerical finite element methods. Comparison of the results with measured values shows that this electromagnetic launch weft insertion system has good flexibility. In addition, the weft insertion speed required for different width looms can be obtained by changing the current of the coil or the coil stage number of the launching system.

Study on airflow field in a new type of the main nozzle of an air-jet loom

The main nozzle is a key component in the weft insertion system and the internal airflow characteristic affects the efficiency of an air-jet loom and fabric quality. In order to improvement the weft insertion rate, a kind of new main nozzle is designed by adding a polygon slots inside the needle. In this paper, the transonic/supersonic airflows is numerical simulation with FLUENT software. The distribution of the airflow pressure and axis velocity of the main nozzle are obtained by changing the air tank pressures and geometry of the main nozzle. The numerical results indicated that the velocity along the axis direction is obvious increased by fabricated a pentagon slot inside the needle.

Design and modeling of an electromagnetic launcher for weft insertion system

An electromagnetic launcher can be used as an accelerator for yarn attached to a ferromagnetic projectile. As a result, yarn endures a specific amount of tension. In addition to the yarn variables and the type of weft insertion system, the parameters of the weft yarn accelerator strongly affect the weft yarn velocity, its tension, and consequently the fabric quality. An applicable model that can represent the relationship between input and output parameters of this weft insertion system is very useful for predicting the strike of the projectile. Therefore, in this research a 3D imitating launching model was developed by the finite element method. A coil electromagnetic launcher was employed. An experimental methodology using an image-processing technique was also utilized to measure the projectile velocity. Numerical results were compared with experimental results to verify the numerical procedure. A validated model can be a reliable tool to investigate the effects of many process parameters on the strike of the projectile and to optimize them. Therefore, the system parameters can be scientifically defined by this model to insert a weft yarn.

Characteristics of intersecting airflows in the narrow flow channel

Air-jet loom is a kind of shuttleless loom, which is widely used in textile industries. The weft insertion system is composed of main nozzle, auxiliary nozzles, and profiled dent groove. The jets from the main and auxiliary nozzles intersect in the profiled dent groove. The velocity and stability of the intersecting airflows have a direct impact on the yarn’s motion. In this paper, the commercial software is adopted to simulate the intersecting airflows in the profiled dent groove. The result shows it is reasonable that the distance from the main nozzle to the first dent is 15 mm. The optimal distance from the main nozzle to the first auxiliary nozzle is between 45 and 50 mm based on the criteria of the utilization efficiency of the airflow. According to the standard of airflow stability, when the spray angle of auxiliary nozzle is about 7°, the standard deviation of the radical airflow velocity is the smallest in different cross sections. Therefore, the intersecting airflows are the most stable when the spray angle of auxiliary nozzle is about 7°. The velocity distribution of intersecting airflows in the profiled dent groove is measured using Particle Image Velocimetry (PIV) technique. The research results can provide some useful references for the optimization of the weft insertion system of the air-jet loom.

Construction of a Carbon Fiber Reinforced Weft Guide Bar for a Crochet Knitting Machine

The crochet knitting machine is a warp knitting machine with a weft insertion system placed on a weft guide bar. On standard machines, the weft guide bar is made from aluminum and weighs about 570 g. The single-drive motors, which power the bar, account for 15–20% of the machines total power consumption. The aim of this research was to reduce power consumption by decreasing the mass of the weft guide bar. This was done by constructing the bar from carbon fiber reinforced plastics rather than aluminum, resulting in a mass saving of 260 g.

3D Design and Performance Analysis of Weft Insertion Mechanism of Carbon Fiber Multi-Layer Loom

The design and research of weft insertion mechanism of carbon fiber multi-layer loom which has the great significance for the development of modern 3D weaving equipment. According to the special requirements of carbon fiber multi-layer weaving fabric, a multilayer weft insertion system incidental finding device is designed, which can be satisfied with multi-layer weft insertion according to the change of shedding position and different layers. In order to meet the sword belt and lifting gear running smooth, kinematic and dynamic analysis and static simulation have been done. Analysis results show that institutions satisfy all work requirements, and have important guiding significance for material selection of components.

Research on Electric Weft Insertion Method for the Rapier Loom

This paper, on analyses of the shortages of the traditional rapier loom weft insertion system such as unalterable motion rules and high machining accuracy requirements, introduces a new electric weft insertion method to the modern high-speed rapier loom, which converts single-direction rotation of a motor to linear reciprocation of a rapier with help of the spatial linkage. The new method can satisfy different weft insertion requirements by controlling the speed of the motor rotation, so that it greatly improves the weaving adaptivity of the loom for different wefts. The test results show that this new controlling method not only meets the technical requirements, enabling the gripper head to move without rigid and flexible impact, but also has good high-speed motion characteristics, in line with the requirements of high-speed weft insertion.

Low Cost Tangential Bobbin Creel for Twist-Free Intermittent Reinforcement Fiber Placement

Intermittent reinforcement fiber sheet placement is part of manufacturing high quality composite components (especially carbon fiber reinforcements). In producing mul tiaxial layer reinforcement textiles or in the filament winding process, the reinforcement fibers are subjected to special dynamic conditions during fiber placement. These con ditions are disadvantageous for achieving high quality composite components. There fore, a device is required for feeding twist-free fiber sheets with a constant low fiber tension level, which can be fitted to a filament winding machine or a warp knitting machine with a multiaxial layer weft insertion system. Solutions for twist-free inter mittent reinforcement fiber sheet placement for composite applications can only be realized by complex and expensive mechanical feeding devices. Thus, a new tangential creel has been developed, consisting of a rolling bobbin draw-off frame and a tension reducing accumulator, fulfilling the complex dynamic requirements of composite com ponent production.

New Air-jet Weft-insertion System without an Air-guide and with Double-holed Relay Nozzles: A Study of Double-holed Relay Nozzles

In this paper, a new air-jet weft-insertion system, which does not require any air-guide, such as a confusor or profiled reed, is discussed. Characteristics of the new double-holed relay nozzles, studied by using Pitote-tube measurement and Schlieren photography, are presented. The results of air-velocity and turbulence profiles measured by using a Laser Doppler Anemometer (LDA) are reported. The tensions developed in a stationary yarn are also studied. Schlieren photography and Pitote-tube measurements show that, in many nozzles, the jets are either divergent or parallel with an angular lift Measurements indicate that the air velocity near the jet axis in the weft-insertion direction is much less, with the vertical component of the air velocity accounting for more than one-third of it, and that the main nozzle imparts a higher tension to stationary yarn than the relay nozzles.

Weft Insertion on Air-jet Looms: Velocity Measurement and Influence of Yarn Structure Part II: Effects of System Parameters and Yarn Structure

An investigation of the effects of different weft–insertion–system parameters on yarn velocity is reported. Increasing the air–supply pressure, initial loop length, and running speed decreases the total insertion time and hence increases the average yarn velocity. To examine the effects of yarn characteristics on yarn velocity, several yarns were tested under the same laboratory conditions. For every yarn, relations between total insertion time, yarn velocity, and air velocity and distance were obtained. It was found that open–end–spun (OE) yarns had a higher yarn velocity than ring–spun (R) yarns owing to the bulkier structure. However, R yarns had a higher initial acceleration than OE yarns. Murata air–jet–spun yarns had a higher velocity than R yarns. Increasing the yarn linear density and twist increased the insertion time. Texturing of continuous–filament yarns increased the yarn velocity by comparison with straight continuous–filament yarns.

34—THE ANALYSIS OF GEOMETRICAL CONSTRAINTS ON REED MOTION: PRELIMINARIES

The weft-insertion mechanism, the shed boundary, and any insertion-element guides within the working width have to be suitable aligned during weft insertion in weaving. This requirement constrains reed motion in ways that depend on both the weft-insertion system and the shed geometry, Weft-insertion systems are classified according to whether or not the insertion mechanism has a warpway motion and on the type of insertion-element guide. The constraints are indicated qualitatively for each type at system. There is also a prior constraint duo to the need to form the shed with a reed of limited height, and this is analysed. Expressions for two sets of shed dimensions are also given, those depending only on the motion of the reed, and those depending in addition on that of the healds. A general quantitative method of analysing the constraints due to the required alignments is then indicated.