Effect of Yarn Draw-off Angle on the Yarn Properties in Friction Spinning

The angle of yarn withdrawal direction when the yarn was being drawn off from the yarnforming zone was varied and yarns were then produced at various friction roller speeds. The yarn tension in the yarn-forming zone and the yarn diameter were determined simultaneously during the spinning process. The optimum draw-off angle was explored for various friction roller speeds by considering the tensile properties and irregularity of the linear density of the yarns. We considered the optimum draw-off angle to produce a yarn at higher efficiency and lower energy consumption. The results of this research show that the yarn tension increased as the negative draw-off angle was increased. Consequently, twist efficiency increased at negative draw-off angles. Hence, it was demonstrated that a yarn of acceptable properties could be produced at lower friction roller speeds with a properly adjusted draw-off angle. The optimum draw-off angles were explored to determine where the desired twist and strength of yarn could be obtained with lower friction roller speeds. It was concluded that a small negative draw-off angle of 0 to–11. was the optimum draw-off angle for various friction roller speeds, at which a yarn having the same strength in comparison with that produced in the straight direction can be produced at about 50% of friction roller rotation.