Effect of Spinning Draft Parameters on Cotton Drafting Efficiency

Abstract

Studies of drafting force in the front drafting zone of the Saco-Lowell MagneCradle 17-B and Tru-Set drafting systems indicate that the MagneCradle 17-B, which uses higher roll pressure, has a greater tolerance for high roving twist, but this theory has not been tested in spinning. In both drafting systems, drafting force increases sharply in the high-force region where occasional hard ends begin to appear in the front roll delivery at a higher roving twist level in the Magne Cradle than in the Tru-Set system. Increasing break draft decreases drafting-force sensitivity to the effects of cradle opening and increases sensitivity to drafting failure, but drafting failure occurs at a higher roving twist level for the higher break draft. A series of yarn spinning studies with a wide range of yarn size shows that drafting force for minimum spinning end breakage decreases nonlinearly as yarn number is increased. Spinning tests show that increasing roving twist multiplier to 1.5 in medium-staple carded roving normally causes reduced spinning performance for the Tru-Set and MagneCradle 17-B systems, and the level of drafting force required to minimize the spinning end breakage is higher for the higher roving twist.