Fiber Speed and Yarn Tension in Friction Spinning

To investigate fiber speed inside the transport channel, fiber flow and yarn tension are measured at the same time on a friction spinning machine. Fiber speed at the fiber flow detection point is calculated using the number of fibers in a cross section of the channel at the detection area, the number of fibers in the cross section of sliver, and the speed of sliver feeding. The cross correlation method is used to obtain the time lag between the variation of yarn tension and the number of fibers in the channel cross section. The mean fiber speed between the fiber flow detection point and the yarn-forming zone is calculated from the time lag. Fiber speed in both cases is calculated for various levels of suction air pressure. The results of this research show that fiber speed decreases from the beginning to the end of the transport channel, and increases with increasing suction air pressure in the yarn-forming zone. On the other hand, calculating the value of the correlation coefficient demonstrates that there is a high correlation between yarn tension variation in the yarn-forming zone and the number of fibers in the channel cross section.