Influence of Sewing Speed on the Changes of Mechanical Properties of Differently Twisted and Lubricated Threads During the Process of Sewing

Abstract

This paper presents a research into the influence of the stitching speed on changes of the mechanical properties of the polyester core-spun sewing threads, which were twisted by different number of thread turns, and different lubrication method (in apparatus and on the galette). The dynamic loading of the threads arises during the sewing process depend on the stitching speed, that causes greater or smaller changes of the threads‘ mechanical properties. It was found that the expressive changes appear when the sewing process was performed at higher stitching speed, and depend also on the twist intensity and on the lubrication method employed. It was established that with increasing stitching speed increases changes in the breaking tenacity, breaking extension and elasticity modulus of the thread-twisted fibres that provokes also changes of the threads‘ mechanical properties after the sewing process. On the basis of the research of the threads‘ resistance on the dynamic loading during the sewing process at the same stitching speed it was found, that the greatest resistance offer the threads twisted with smaller number of the thread turns and threads treated with apparatus lubrication method.