Analysis of hardness variations in radial and longitudinal directions of bobbins in step precision winding

Abstract

Step precision winding is a widely used bobbin winding method in industry, especially for dyeing bobbins. It is important to adjust winding parameters in an optimum way to obtain optimum hardness variation and best dyeing performance. Main winding parameters are winding pressure, crossing angle and yarn tension. This paper presents a research investigating the effect of main winding parameters on hardness distribution in radial and longitudinal directions of bobbins wound with step precision winding. Bobbins are produced from Ne 30/1 and Ne 10/1 cotton yarns. Bobbin hardness is measured by a new instrument called UNITORQ, which enables the measurement of relative bobbin hardness in radial and longitudinal directions with small increments of distance. It is found that crossing angle affects mainly longitudinal hardness variation while radial hardness variation is determined and affected in a large variation interval by winding tension. Winding pressure is seen to have no significant effect on winding hardness distribution in both radial and longitudinal directions but it determines bobbin hardness level together with winding tension and crossing angle.