Effects of Gin Machinery on Cotton Quality

Authors: Hardin Iv, Robert; BARNES, EDWARD - Cotton, Inc; Valco, Thomas; MARTIN, VIKKI - Cotton, Inc; CLAPP, DAVID - Cotton, Inc

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2018
Publication Date: 6/5/2018
Citation: Hardin IV, R.G., Barnes, E.M., Valco, T.D., Martin, V.B., Clapp, D.M. 2018. Effects of Gin Machinery on Cotton Quality. Journal of Cotton Science. 22:36-46.

Interpretive Summary: Ginning practices affect both the economic returns to cotton producers and the quality of fiber produced for textile mills and, ultimately, consumers. Because of the recent shift from a primarily domestic to an export market for U.S. cotton and the loss of textile market share to synthetic fibers, production of high-quality cotton is critical to maintaining the competitiveness of the U.S. cotton industry. A review, focusing on recent research using state-of-the-art methods for measuring fiber quality, of the effects of ginning on cotton quality was conducted to develop best practices for gin managers to maximize bale value and fiber quality. Higher fiber moisture content during processing, with an optimum of 6-7%, better preserves fiber length and strength, but reduces the efficiency of seed cotton and lint cleaners; therefore, a fiber moisture content of 5-6% may be needed for efficient cleaning. Control systems should be used for seed cotton drying systems to maintain optimum moisture levels for processing as incoming moisture levels and feed rates can change rapidly. Moisture restoration immediately before the gin stand can minimize fiber damage, while maintaining a high level of seed cotton cleaning efficiency. Seed cotton cleaners are effective at removing larger foreign matter particles and cause minimal fiber damage; therefore, these cleaners should only be bypassed with relatively clean cotton. Lint cleaners are efficient cleaners and necessary for removing seed coat fragments and other small particles created in the gin stand; consequently, at least one lint cleaner should be used. However, lint cleaners break some fibers, create neps (fiber entanglements), and remove some good quality fiber with the foreign matter. The decision to use one or two stages of lint cleaning is based on maximizing bale value, according to the tradeoff between leaf grade and weight loss, and will depend on color grade and other quality factors. Real-time control systems have been developed to select the number of stages of lint cleaning based on measurement of leaf and color grade. To maximize fiber quality, gins should encourage producers to grow high-quality cultivars and follow recommended harvesting practices. Modules need to be stored and handled properly. Gins should use the minimum amount of drying and lint cleaning that maximizes bale value. Avoiding contamination, particularly plastic, is vitally important to upholding the U.S. cotton industry’s reputation as a supplier of high-quality cotton. The cleaning machinery at gins does not effectively remove plastic. Furthermore, the yarn produced from contaminated bales will likely contain some plastic, if a costly contamination detection system is not used at the mill. Research is underway to develop sensing technology during ginning to remove plastics. For now, the best method of preventing plastic contamination is to keep the plastic out of the cotton in the first place by removing plastic from fields, turnrows, and gin yards.

Technical Abstract: Ginning practices affect both the economic returns to cotton producers and the quality of fiber produced for textile mills and, ultimately, consumers. Because of the recent shift from a primarily domestic to an export market for U.S. cotton and the loss of textile market share to synthetic fibers, production of high-quality cotton is critical to maintaining the competitiveness of the U.S. cotton industry. The objectives of this review were to summarize the effects of ginning on cotton quality and provide best practices for gin managers to maximize bale value and fiber quality. This review focused on recent research, with fiber properties measured using HVI and AFIS, which are currently used by industry. Higher fiber moisture content at the gin stand, with an optimum of 6-7%, better preserves fiber length and strength, but this moisture level reduces both seed cotton and lint cleaning efficiency; therefore, a fiber moisture content of 5-6% may be needed for efficient cleaning. Seed cotton cleaners are effective at removing larger foreign matter particles and cause minimal fiber damage. Lint cleaners are efficient cleaners and necessary for removing seed coat fragments and other small particles created in the gin stand. However, lint cleaners break some fibers, create neps, and remove some good quality fiber with the foreign matter. To maximize fiber quality, gins should encourage producers to grow high-quality cultivars and follow recommended harvesting practices. Modules need to be stored and handled properly. Gins should use the minimum amount of drying and lint cleaning that maximizes bale value. Avoiding contamination is vitally important to upholding the U.S. cotton industry’s reputation as a supplier of high-quality cotton.