Robust design optimization of spun yarn quality characteristics for weft knitted fabric

Abstract

The main objective of this thesis is to design and develop Modal- Cotton blended ring spun yarn used in weft knitted fabric with minimum sensitivity subject to uncontrollable material factor constituent fibre blend ratio and ring frame machine setting parameters. At present because of the competition, the manufacturing sectors have been facing a major problem of variation in performance, during the development and production of yarn. The robust design newlinereduces the variations in the performance of spun yarn due to unforeseen input parameters. In this work, the popular Taguchi parametric design technique has been implemented to find the optimum parameters towards single characteristic optimization of yarn performance measures such as strength, unevenness and hairiness for producing M-C blended spun yarn with different fibre blend ratio and different levels of ring spinning setting parameters namely top roller loading and break draft. Further, the influences of M-C fibre blend ratio and yarn type on performance characteristics namely Comfort and durability of weft knitted fabric that is produced from optimized spun yarn are analysed. Now a days Modal, a regenerated viscose fibre obtained from beach tree has been popularly used either alone or blending with cotton to produce ring spun yarn for weft knitted fabric applications like sportswear, leisure wear and inner wears. Since modal fibre cost is high, blending cotton with modal will help to reduce the fibre cost. Further in order to produce M-C blended yarn and fabric with good quality characteristics, it is proposed to blend cotton at a level equal to newlineor less than 50% with modal fibre. The M-C blended spun yarn is produced in ring spinning system by sliver blending method in draw frame stage. The quality characteristics of blended spun yarn produced with three different blend ratios of M-C fibres are analysed by conducting strength, unevenness and hairiness tests. newline newline