This study compares the effects of different levels of ginning and lint cleaning, raw cotton quality factors, and yarn quality factors on the level of dyeing imperfections in finished cloth. Seven cotton varieties were included in the test; all were both saw and roller ginned, and processed through both zero and two stages of lint cleaning. All test treatments were processed into carded 16/1 yarn used to make corduroy cloth and combed 40/1 yarn used to make broadcloth. A statistical analysis showed that neither the yarn nor most of the fiber quality measurements were useful in predicting levels of neps in finished cloth. What relationships did exist between raw fiber quality measurements and dyed cloth nep levels, while statistically very significant, resulted in statistical models that left a great deal of the variability in cloth dyeing imperfections unexplained. Including variety and gin treatment in the statistical analysis decreased the level of unexplained variability, but still did not result in a useful predictive model. The conclusion was that there are one or more fiber parameters that have a large effect on cloth nep levels, but these are not currently being measured. One possibility is that the level of small motes from unfertilized ovules or other sources may be partially responsible for the observed levels of cloth dyeing imperfections.

The interactions between picking dates, locations, and varieties were studied to evaluate the effect of growth period on neps in ginned lint, yarn, and fabric. Five harvest intervals were selected, and the cotton yield increments between intervals were used to provide five levels of maturity. Neps in raw cotton were measured by the USDA-AMS web nep test and microscopic examination of card web, imperfections in the yarn ascertained by the Uster instrument, and neps in woven fabric counted by dyeing procedures. Results showed that growth period has a significant impact on the number of neps and other imperfections found in lint and manufactured yarns and fabrics. As a general rule, cotton grown early in the season will produce yarns and fabrics with a lower number of imperfections than cotton grown late in the season from the same field.Neps are small knots of tangled fibers created during the harvesting, ginning, and yarn manufacturing phases of production. They occur in varying numbers in most cotton yarns and cause considerable concern to most persons interested in yarn and fabric quality. Neps may be a source of trouble in manufacturing, may detract from the appearance of the woven fabric, and may not dye properly [4,9]. Seedcoat fragments, along with neps, affect not only the quality of the finished product but are also probably responsible for some of the &dquo;ends down&dquo; in spinning [6].There is some evidence that the number of neps in yarn increases with increasing fiber length, decreasing fiber weight per inch, and increasing percentages of thin-walled fibers [5]. Ginned lint from machine-picked defoliated cottons may have more neps than the lint from undefoliated cottons, and fibers from late harvested cotton are more susceptible to nepping than fibers°from early harvested cotton [3]. This has been attributed to the likelihood that the defoliated and late harvested cottons are more immature.Field studies of boll development during [1977][1978][1979][1980] showed that air temperature was the primary environmental variable controlling the relative rate of cotton lint accumulation, with a smaller but signi6cant moisture stress influence for the range of conditions encountered. Fiber micronaire was chiefly dependent on temperature, but plant moisture stress decreased the sensitivity of micronaire to temperature. Fiber strength was strongly influenced by temperature, with a sipificant temperature-genetic interaction [10].In new experiments, we studied the interactions between picking dates, locations, and varieties to evaluate the effect of growth period on neps in ginned lint, yam, and fabric. We sought this information to help control to some degree the number of neps created during harvesting, ginning, and mill processing and to aid breeders in developing varieties with a low potential for neppiness.

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A new, high-speed, automated instrument for measuring foreign matter including microdust and trash in bale or processed fiber is described. The method uses aero- mechanical release and separation and electro-optical sensing for microdust, trash, and lint. Data are provided proving the correlation of an experimental prototype gin monitor's readings with readings of other methods. Example data for both microdust and trash are given for both gin and textile mill cleaning machinery performance.

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