Determining the tension of complex chemical threads during interaction with guide surfaces

Abstract

This paper reports a study to determine the tension of complex chemical threads made of Kevlar, carbon, polyethylene, and meta-aramid when interacting with the working bodies of knitting machines in the process of forming technical knitwear. An increase in tension after the guide surface of the working body due to a change in the value of the friction forces in the contact zone was established. It has been proven that the tension of the selected complex chemical threads after the guide surface of the working body is affected by the tension of the thread in front of the guide surface of the working body of the knitting machine. Also, the amount of tension is affected by the radius of curvature of the cylindrical guide surface of the working body and the angle of thread coverage of the guide surface of the working body of the knitting machine. This has made it possible to determine thread tension even at the initial stage of designing the technological process of thread processing on knitting machines, during the production of technical knitwear. On the basis of experimental studies for Kevlar, carbon, polyethylene, and meta-aramid complex threads, regression dependences of the stress after the cylindrical guide surface of the working body of the knitting machine were constructed. The analysis of regression dependences made it possible to establish the value of the radius of curvature of the guides when the tension of complex chemical threads before the knitting zone on knitting machines would take a minimum value. This will minimize the stress on complex threads during their processing. So, there are reasons to assert the possibility of directed regulation of the process of changing the tension of Kevlar, carbon, polyethylene, and meta-aramid complex threads during the formation of technical knitwear on knitting machines by selecting the value of the geometric parameters of the guides