Influence of Fiber Morphology and Yarn Spinning Process on the 3D Loop Shape of Weft Knitted Fabrics in Terms of Roughness and Thickness

Abstract

The literature reports the parameters as well as their influence at different levels on the geometric properties of single-jersey fabrics: the main role of stitch length, the medium importance of fabric tightness, the minor influence of yarn physical properties, and the non-influence of the knitting process. This study reveals that even if yarn physical properties and the knitting process have a very small influence on fabric geometric characteristics relative to stitch length and fabric tightness, the effects must not be neglected on fabric roughness and thickness, i.e., the 3D loop shape. Even a very small difference in loop shape can change fabric tactility and quality, and therefore fabric sales. This paper shows experimentally the influence on roughness and thickness of fiber fineness and the yarn spinning process for three different cover factors, i.e., indirectly on the three-dimensional loop shape. In fact, both fiber fineness and the yarn spinning process influence yarn properties and more precisely, bending rigidity. Moreover, the influence of fabric tensile stress during knitting on 3D loop shape properties is discussed. After full relaxation, the loop shape depends on yarn characteristics, stitch length, and tensile stress walewise due to the knitting process. In fact, yarn bending rigidity and the interyarn friction coefficient are very important for loop shape: when bending rigidity decreases and the frictional coefficient increases, tensile stress in the knitting process is more influential.