|Robert Jr, Kearny|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2004
Publication Date: 1/4/2005
Citation: Robert Jr, K.Q., Dunn, M.C., Price, J.B., Cui, X. Method for determining broken fiber in ring spun yarn. CD-ROM. Memphis, TN. National Cotton Council Beltwide Cotton Conference. 2005.
Interpretive Summary: The relationships between the properties of cotton bale fiber and spun yarn are crucial to the definition of cotton bale quality that is relevant to textile manufacturers. Yarn properties, however, do not depend directly upon the properties (such as length distribution) of fiber in the bale. Yarn properties depend upon the properties of fibers in the yarn. Recent technological advances have allowed rapid instrumental measurement of the fiber length distribution of cotton, as well as the powerful mathematical deciphering of these measured distributions to determine the degree of damage done to the fiber by mechanical processing. Fiber breakage is known to have harmful effects on yarn quality. Better understanding of the tolerable limits for damage in yarn should allow us to define the tolerable limits for fiber breakage in bale cotton. These quality limits are presently unknown. In the currently reported work, a method was developed for recovering the fibers from yarns and performing the measurements and analysis on them necessary to compare them to the bale fibers and assess the state of damage to fibers in the yarn. It was found that cotton fiber is substantially damaged by ginning and spinning into yarn. More than half of the fiber mass can be broken by the time the yarn is formed.
Technical Abstract: This project developed out of a more general study in which fiber breakage in cotton was tracked through various processes in yarn production in order to survey the Broken Fiber Content (BFC) in cotton at various stages of production and utilization. The specific task reported here was a student summer project to develop a method for the quantitative characterization of broken fibers in ring-spun yarn. Our approach was to carefully (and tediously) remove the twist from yarns using a twist-measurement device, to recover the individual fibers from the de-twisted yarns in a representative and undisturbed form, and to manually shape the fibers into a sliver suitable for use as a measurement specimen. This manipulation had to be done according to precise unwinding techniques, the development of which was a significant element of this project. The length distribution of the cotton fibers in the hand sliver was then measured by use of the Advanced Fiber Information System (AFIS) length-measurement instrument. A numerical breakage model was applied to the length distribution data to determine the Broken Fiber Content (BFC), or fraction by mass of broken fiber in each unbroken yarn. Preliminary results support the view that the breakage accumulated by cotton during production and utilization processing is substantial, and may often total more than 50% of the mass of the fiber by the time the fiber has been transformed into yarn.