Analysis of yarn tension in the yarn-forming zone in friction spinning

We have analyzed the tension distribution along the yam tail in the yam-forming zone of a friction spinning machine by considering the effective parameters of the torque applied to the yarn tail. Tension is applied to the yam tail by suction air pressure and rotation of friction rollers. The yam tension in the yam-forming zone is measured for various yarn counts and suction air pressures. The effects of the parameters on yam tension are considered in a theoretical analysis based on tension distribution along the conical yam tail. Theoretical results are compared with the experimental data. The results of this research show that yam tension increases with increasing suction air pressure and yam size in tex, and yam diameter decreases with increasing suction air pressure for the same yam size. Therefore, because of the low tension experienced with fine yarns, it is difficult to properly produce such yarns through friction spinning.