Automatic in-line moisture control system for weft package on a weaving machine

The competitive woven fabric production moves from shuttle weaving to shuttleless weaving in order to acquire higher production rates in tact with good quality. The efficiency of the loom production not only depends on the loom speed but also on the rate of loom stoppages during the weaving process. The loom stoppages can be occurred due to various reasons and the frequency of such occurrence will determine the rate of loom stoppages. In addition to the reduction in efficiency, loom stoppages seriously affect the fabric quality as startup marks and differential dye take up are appeared on the fabric as defects. The ambient conditions in the vicinity of the weaving machine is subjected to vary over the day due to the heat dissipation from weaving machines and many other reasons such as sunlight and prevailing weather conditions. In the weaving preparational process, warps ends are generally sized so that they can withstand various stresses encountered in weaving process. However, weft yarn is not sized to retain greater flexibility and hence it is much susceptible for damages. The possibility of damaging the weft yarn is further influenced by the variations of surrounding conditions and hence these conditions are much sensitive for the weft yarn breakages during weaving process. In this paper, authors attempted to analyze the effect of surrounding conditions to weft breakages in weaving and device an automatic in-line moisture control system for weft package in weaving machine. Based on the experimental evidences, authors verified the effectiveness of the automatic moisture control system and their strong industrial implication in existing weaving machines

Designing of tension control Device to minimize tension variation across Weaver’s beam

The tension variations across the width of the weaver’s beam cause uneven tension in the fabric formation zone. As a result of the tension variation, the woven fabric tends to have fabric defects, such as non-uniform fabric density and differential dye take–up at various places on the fabric. As the warp ends are continuously subjected to varying tensions, warp breakage frequently occurs. As a result, the quality of the fabric produced suffers and there is reduced loom efficiency. However, uniformity in the fabric density is crucial, especially for technical and smart textiles. In this paper, the authors have attempted to model the varyingtensions across different segments of a warp sheet under a set of assumptions and derived a linear model. Furthermore, a prototype of an automatic tension control device is instrumentedwith two different positions which are located one meter apart and allows the tension variations across the warp-sheet to be practically observed. The measured average tension shows that variations in the internal tension on different segments of the warp-sheet can be minimized or even completely eliminated over time. With the implementation of a related experiment, the authors have shown the effectiveness of this automatic tension controller and its strong implications for the industry

Development Of mathematical model to select best technological parameters In sizing

The sizing process does not add value to the grey fabric, but it is critical to the improvement of weaving efficiency especially for cotton and cotton blend fabrics. With the advent of technology, weaving speeds have been greatly ameliorated and the significance of correct size applications has been thoroughly explored. Since the correct size application is primarily characterized by the size percentage, the technological parameters for proper sizing were chosen through experimental trials and acquired prior knowledge. Thus, a scientific approach to determining the technological parameters is essential to the textile industry. To fulfill the aforementioned need, the authors have developed a mathematical relationship that relates technological parameters involved in size applications. The practical utility of the derived equations were also highlighted. Experimental trials, carried out with poly/cotton yarn on a single yarn sizing machine, confirm the validity of the model developed. Furthermore, empirical findings published in internationally renowned reference books on sizing were also in accordance with the analytical results established. The mathematical relationships developed can be exploited to calculate the optimum parameters of the sizing machine and to obtain the required quality of sized yarn.This approach does not require carrying out costly trials and therefore has positive industrial impacts. Keywords—Mathematical model

6-REXOS: Upper limb exoskeleton robot with Improved pHRI

Close interaction can be observed between an exoskeleton robot and its wearer. Therefore, appropriate physical human-robot interaction (pHRI) should be considered when designing an exoskeleton robot to provide safe and comfortable motion assistance. Different features have been used in recent studies to enhance the pHRI in upperlimb exoskeleton robots. However, less attention has been given to integrating kinematic redundancy into upper-limb exoskeleton robots to improve the pHRI. In this context, this paper proposes a six-degrees-of-freedom (DoF) upperlimb exoskeleton robot (6-REXOS) for the motion assistance of physically weak individuals. The 6-REXOS uses a kinematically different structure to that of the human lower arm, where the exoskeleton robot is worn. The 6-REXOS has four active DoFs to generate the motion of the human lower arm. Furthermore, two flexible bellow couplings are attached to the wrist and elbow joints to generate two passive DoFs. These couplings not only allow translational motion in wrist and elbow joints but also a redundancy in the robot. Furthermore, the compliance of the flexible coupling contributes to avoiding misalignments between human and robot joint axes. The redundancy in the 6- REXOS is verified based on manipulability index, minimum singular value, condition number and manipulability ellipsoids. The 6-REXOS and a four-DoF exoskeleton robot are compared to verify the manipulation advantage due to the redundancy. The four-DoF exoskeleton robot is designed by excluding the two passive DoFs of the 6- REXOS. In addition, a kinematic model is proposed for the human lower arm to validate the performance of the 6- REXOS. Kinematic analysis and simulations are carried out to validate the 6-REXOS and human-lower-arm model

Design and fabrication of an automatic tension monitoring and regulation system for needle thread

A matched needle and bobbin thread tensions is a major requirement of a seam and also to the quality of garment. This paper describes an attempt on the development of an automated needle thread tension regulating system for single needle lock stitch sewing machine. Historically, several experiments have been carried out to measure the thread tensions of both needle thread and bobbin thread of a lock stitch machine. However, no evident in favour of the development of a device to adjust the needle thread tension automatically. Despite a cyclic variation of the needle thread tension, a needle thread regulation system is developed to maintain an average needle tension during the cycle at a predetermined level. The developed system can be installed on an existing single needle lock stitch machine and capable of maintaining the required correct thread tension profile for sewing. The needle thread tension regulation system is a closed loop system and with a load cell as a sensing device and a geared DC motor adjusts the compression of the spring of the thread tensioner. A visual display of thread tension is indicated on a 16X4 LCD display and the required needle thread tension is set by 4x4 keypad. An Arduino board controls the electronic equipment in the system

Warp tension analysis of narrow fabric weaving and designing of tension compensator to avoid start up marks

Start up marks are one of the major defects on woven fabric and this defect occurs when loom restarts after stoppages due to warp tension variation at the time of start. This defect is more prominent in high speed looms and it is critical in manufacturing elastic tapes. In this paper, formation of start-up in elastic tape on a narrow fabric loom was analyzed mathematically and provided a practical technical solution to the problem. In mathematical analysis both continuous operational condition and stopping condition of a narrow fabric loom was taken into consideration and the developed mathematical model established a quantitative relationship between excess warp yarn length fed and the tension variation of warp yarn at the point of starting the loom. A system simulation was carried out using the model developed and compared with the experimental results to show the accuracy of the model. A tension compensating device was proposed to avoid formation of the startup marks. The effectiveness of the proposed solution was proven practically with a prototype developed

Modeling of compressed air requirement for different weft yarns on air jet weaving

Although air-jet looms run faster than mechanical weft insertion looms such as rapier or shuttle looms, but their production cost can be higher when their air usage is not optimized. The amount of air required for weft insertion varies greatly for each yarn type and also depends on several key factors. One of these factors is the yarn’s air friendliness, which is the measure of how easy it is to project yarns across a web with an air column. In practice, the same air pressure is applied to all yarn types since determining the optimum air pressure for each yarn type is laborious and time intensive. Consequently, a considerable amount of air is wasted and the weaving efficiency of the loom is compromised, especially when weaving with air friendly yarns. A scientific approach that predicts the best pressure for main nozzle and sub nozzles for each yarn type can mitigate the waste of compressed air usage. Thus, a mathematical model that can be applied to optimize the compressed air usage is presented