A Study of Generating Yarn Thin Places of Murata Vortex Spinning

In Murata vortex spinning, fiber loss is an important cause of the generation of yarn thin areas. In this paper, based on the attenuation law of flow field inside the nozzle block, the force analysis of a separated fiber twined over the top exterior of a hollow spindle in a twisting chamber is carried out, and the movement of a separated fiber affected by a swirling current is discussed. We also present a simple analytical formation that determines the critical angular velocity of the open-end trailing fiber rotating around the hollow spindle, as a function of the length of the core fiber and fiber radius, as well as other parameters. The critical angular velocity can affect whether the leading end of the fiber is pulled out from the yarn trail or not, which can explain the generation of fiber loss and yarn. The critical angular velocity increases with increasing length of the core fiber and decreasing fiber radius. Above a certain nozzle pressure, the fiber radius is larger, there is greater fiber loss and there are a greater number of thin places in the vortex spun yarn. Increasing the nozzle pressure first enhances the yarn tenacity, and then generates more fiber loss and yarn thinning in places, and also causes a deterioration of the yarn properties when the nozzle pressure exceeds the critical point.