Effect of the Speed Ratio on Surging Phenomenon in False Twisting

Abstract

False twisting machines must operate under a variety of processing conditions involving high-speed production to facilitate mass fabrication. However, high processing speeds increase the likelihood of “surging” events. Surging is a phenomenon in which yarn oscillates unstably, causing the quality of textured yarn to deteriorate. Therefore, the suppression of surging in false twisting machines is an important issue. In our previous paper yarn conditions with and without surging were reported from the perspective of 4T (Twist, Tension, Temperature, Time of heating). However, the causes of surging are not yet to be clarified. In this study, yarn conditions due to changing the speed ratio D / V_d (ratio of tangential disc velocity to delivery roller velocity) were monitored when surging occurred, then revealing the effect of speed ratio D / V_d on surging. As a result, it is found that surging tends to be suppressed owing to the stabilization of the twisting action when the speed ratio is increased. This is because the contact condition between yarn and the disc is improved. Moreover, the results obtained here also indicate that surging is induced by insufficient twisting tension.