Weaving with a new warp yarn break detection system using contact linear image sensors instead of drop wires

Abstract

A thin metal plate called a drop wire is placed on warp yarns during a weaving process in order to stop the loom in case of a broken warp yarn and to fix it. Drop wires are placed on each warp yarn to ensure the flow of warp yarns at a certain tension level and to stop the loom when a warp yarn is broken. In some cases, the drop wire may not fall due to dirtiness or abrasion of the drop wire and the weaving process continues with a broken warp yarn which is an unwanted situation. In this study, an alternative method to detect broken warp yarn is proposed based on contact image sensor. Therefore the need for drop wires is eliminated. The contact image sensor is not at full scale of the weaving machine, it can only acquire a linear image only a small portion of the total warp yarns, therefore a carrier module is implemented on the machine to carry the sensor and cover all the warp yarns. A complete image is then formed at the end of each cycle, and the total number of warp yarns is evaluated. If this value is less than the expected number of warp yarns, a broken warp yarn is detected, and the system generates an alarm. The system is implemented on an industrial scale weaving machine and the warp yarns are detected with 99% performance.