Impact of progressive yarn extension on fibre helix twist in cross-sectional and longitudinal direction of yarn

The multicoloured tracer fibre technique has been used to study the helix twist in concentric cylindrical zones and along the length of fibre of ring spun yarn at different level of yarn extension. Twist is being calculated from the triplets of Cartesian co-ordinates obtained from the 3D path of tracer fibre. A continuous reduction in helix twist of yarn was noticed with the increase of yarn extension. The intermediate zone of yarn cross-section retained the machine twist. Helix twist was not found to be uniform across the yarn cross-section. A reduction in helix twist was observed in all the segments along the length of fibre with the increase in yarn extension.