Further, back zone bottom roller setting is reduced from 51 to 44mm. As a result of these actions the strand takes a V-shaped path as twist in roving is broken down. The strand width is reduced leading to improved inter fibre friction in the main drafting zone. Detailed studies show that thick and thin places and U% of yarn are significantly reduced in cotton counts with offset drafting. The improvements are more prominent in carded counts from short staple cotton and at high ring frame draft.

COMPACT SPINNING

In traditional ring spinning, fibres in the selvedge of strand emerging from front roller nip do not get fully integrated into the yarn because of the restriction to twist flow by the spinning triangle. These fibres show up partly as protruding hairs or as wild fibres. The spinning triangle is because of higher width of the strand as compared to final yarn diameter. Further the fibres are tensioned to varying extent depending upon their position in the spinning triangle. As a result full realization of fibre strength is not achieved in the yarn. The hairiness gives a rough feel to the yarn. Variation in hairiness is a source of weft bars and warp way streaks in the fabric. Long protruding hairs from the yarn contribute to multiple breaks in weaving and fabric faults like stitches and floats.

The length of the spinning triangle depends upon the spinning geometry and upon the twist level in the yarn. If the spinning triangle is too short, then the fibres on the edge must be strongly deflected to bind them in. This is not possible with all fibres, and lost as fly. Thus with shorter triangle, smaller weak point resulting into fewer end breaks but makes the yarn hairy. On the other hand, a long spinning triangle implies a long weak point and hence more end breaks giving smoother yarn and less fly.

In Compact Spinning, incorporating a condensing zone after main drafting zone, thereby overcoming the drawbacks of conventional spinning, eliminates spinning triangle. This will be clear from a comparison of mode of yarn formation in the two systems as shown in figure.