Ginning, lint cleaning, fiber length and waste

Authors: Hughs, Sidney; Armijo, Carlos; Foulk, Jonn

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/11/2012
Publication Date: 5/1/2012
Citation: Hughs, S.E., Armijo, C.B., Foulk, J.A. 2012. Ginning, lint cleaning, fiber length and waste. 2003 Beltwide Cotton Conference. Presentation ONLY.

Interpretive Summary: A study was done to determine how the length distribution of raw cotton fiber was changed with different machinery processing at the cotton gin and how this fiber distribution change affected subsequent textile processing. A second part of the study was to determine the quantity and quality of the raw fiber that was lost to the trash during ginning and lint cleaning. Fiber length distribution is important because fibers that are more uniform in length should lead to a lower percentage of short fibers in cotton bales, sliver, and yarn thus producing stronger more uniform yarns that can subsequently be processed at a higher speed. More uniform fiber length and stronger yarns should lead to a reduction in spinning costs, knitting costs, weaving costs, and energy costs. The quantity and quality of fiber lost during ginning could directly affect the cotton producer’s income. In comparing the severity of ginning treatments there was a significant downward shift in the length distribution with the more severe treatment. These data showed that the length shift was a significant decrease of fibers above 2.54 cm (1.0 inch) and a significant increase in fibers between 2.21 and 0.30 cm (0.87 and 0.25 inches). The percentage of fibers in the 2.21 to 2.54 cm (0.87 to 1.00 inch) length range stayed relatively constant. Some relatively long fiber was lost during processing but at least two thirds of the fiber lost to the trash was less than 2.21 cm (0.87 in.) in length and not of great textile processing value. A significant percentage of the fiber lost was relatively short with over 33% being equal to or less than 1.27 cm (0.50 inches) in length. As the fiber length distribution changed with more severe gin processing then measured yarn properties such evenness and strength were adversely affected with additional processing. A priority for future research should be to reduce fiber breakage while maintaining reasonable levels of trash removal during gin processing and cleaning.

Technical Abstract: A study was done to determine how 1) the length distribution of a medium staple upland cultivar was affected by the possible range of ginning and lint cleaning treatments, 2) the length distribution of the fiber lost during increasing levels of lint cleaning changed and 3) changes in ginned fiber length distribution affected textile processing. An upland cultivar that was a reasonable representation of the midrange of U.S. upland cottons in terms of length and strength was used for the study. There was a significant shift towards shorter fibers in the length distribution with saw ginned fiber as would be expected when comparing roller ginning with saw ginning. What was not expected is that the percentage of fibers in the 2.21 to 2.54 cm (0.87 to 1.00 inch) length range stayed relatively constant while the percentage above this range decreased as the percentage below increased as the level of mechanical processing increased. Some long fiber is lost to lint cleaning at all stages but most of that fiber is not of significant textile value. Based on staple length alone, the fiber lost to lint cleaning is worth between 4 to 6 cents less per pound than the baled fiber. Over 33% of the fiber lost at any lint cleaning stage was equal to or less than 1.27 cm (0.50 inches) in length and would be considered waste in the textile process. Subsequent textile processing of the ginned lint showed that the carding operation removed approximately the same amount of total waste from cleanly harvested spindle picked upland cotton regardless of the amount of machining the fiber received during ginning and subsequent lint cleaning. The level of waste in the raw ginned fiber was probably not a significant factor for this test. However, the differing levels of fiber distribution did significantly affect yarn quality. But the change in fiber distribution did not affect dying properties as indicated by white specks in dyed cloth. A priority for future lint cleaning research should be to reduce fiber breakage while maintaining reasonable levels of trash removal during gin lint cleaning.