Coefficient of Friction between Yarns and Contact Surfaces

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The nature of the coefficient of friction between yarns and contact surfaces is discussed. The SITRA friction measuring instrument was used for the measurements. The results indicate that the hypothesis by Hansen and Tabor [<i>Text Res J</i>, 27 (1957) 300] that the friction between the yarn and the guide surface is equivalent to the frictional behavior of lubricated journal bearing is true. There is a count-wise variation as well as TPI-based variation of friction. The open-end yarns have lower friction whereas acrylic and wool fibres have higher friction coefficients. A procedure to measure the lateral pressure extended by the moving yarn on a stationary surface is suggested. Thus, the lateral pressure excerted by yarn on knitting and sewing needles could be studied.</span>