THREADLINE INSTABILITY IN THE FALSE-TWIST TEXTURING PROCESS .3. STABILITY OF THE YARN PATH AND SURGING MECHANISMS

An investigation is reported in which the motion of the yarn path on twister surfaces in the surging and post-surging modes was examined by means of highspeed photography. Two types of tension surging, namely, mild and severe surging, are distinguished by the phase difference in yarn tension and yarn rotational speed. The photographic results also show that the yarn path in the post-surging mode is always unstable. Finally, based on the experimental work reported in this series of papers and a theoretical analysis that will be published elsewhere, a discussion on the mechanism of threadline instability is given. © 1990 Taylor & Francis Group, LLC.