2012 Annual Report 1a.Objectives (from AD-416): Roller ginning, when compared to saw ginning, does the least amount of damage when separating the fiber from the seed. Roller ginning produces a superior fiber with excellent spinning potential. Currently, roller ginning is used primarily to gin the Pima cotton crop (about 3% of the total U.S.), and a smaller niche market of high-quality Acala upland cotton in California. The objectives of this research are to determine if roller ginning can remove only the longer and more desirable fibers off of upland cottonseed in a primary ginning process, and then remove the shorter fibers left on the cottonseed in a secondary ginning process. The improvements in fiber length obtained with differential roller ginning may earn a substantially higher price as well as open up new markets for better-quality upland fiber. 1b.Approach (from AD-416): Theoretically, differential roller ginning selectively removes only the longer fibers off of upland cottonseed by controlling the dwell time and proximity of seed cotton at the ginning point on the gin stand. This may be accomplished with newly designed rotary and stationary knives. Modifications may be needed at the feeder to separate the partially ginned seed cotton prior to the secondary ginning process, and at the lint cleaner to ensure precise feeding and loading of lint onto the cleaning cylinder. Formal experiments will determine the performance of the experimental rotary and stationary knives, and of any machinery changes at the feeder and lint cleaner. 3.Progress Report: Preliminary testing was done on a newly designed roller gin lint cleaner feed works. The feed works may improve the cleaning efficiency of roller gin lint cleaners by feeding individual tufts of fiber (as opposed to a batt of fiber) to the lint cleaner. The new feed works would complement improvements in fiber length obtained with differential roller ginning. Results showed that the paddle brush cylinder that transfers lint between the high speed separator cylinder and lint cleaner did so in clumps rather than individual tufts. The brush cylinder was also very noisy due to pulsing of the individual paddle brushes. Some of the paddle brushes did not stay attached to the cylinder core. Work began on designing a full-face brush cylinder to replace the paddle brush cylinder. This research will be the basis for a future journal publication. Communication between the Lummus Corporation and the ARS PI occurred by e-mail and/or telephone once a week.