Some Experimental Investigations Upon the Capstan Friction Properties of Technical Yarns

In this paper some experimental investigations are given upon the capstan static friction properties of technical yarns (2×68 tex glass, 200 tex glass and 168 tex Aramid). Firstly, two experimental works were carried out one of which was to measure yarn to yarn static friction on capstan by covering the capstan device by the same yarns, the other was to measure yarn to metal static friction on the same capstan device. It was seen that yarn to yarn static friction properties could be given by the capstan friction equation based on the Howell’s general friction equation while yarn to metal friction properties could be obtained by adding a metal friction factor, , on the yarn to yarn friction equation. Secondly, the effects of capstan radius of curvatures on the friction properties of technical yarns were investigated experimentally by having 12 different capstan diameters. It was seen that the coefficient of friction was reducing with the reducing capstan diameter. Apart from the above given results; it was observed that metal friction factor, , was affecting after a certain amount of yarn input tension, the parameter, , was bigger for glass yarns and thus the glass yarns would create much more wear on metal surfaces