EFFECT OF COTTON FIBER LENGTH DITSTRIBUTION ON YARN QUALITY
International Textile Center, Texas Tech University
The prediction of yarn quality based on the technological characteristics of the raw material has been improved by the use of the AFIS.
Unfortunately, information about distributions of fiber properties that are measured by the AFIS is generally not used. The studies carried out at the ITC show that the AFIS length distribution is variety related. In addition, the percentages of both the shortest and the longest fibers have an important impact on yarn quality.
During recent years, the Uster AFIS (Advanced Fiber Information System) has been increasingly used in the research projects carried out at the International Textile Center (ITC), Texas Tech University. The prediction of yarn quality based on the technological characteristics of the raw material has been improved by the use of the AFIS. The ITC has shown in the past few months the value of AFIS measurements such as the short fiber content or the standard fineness (Ethridge et. al., 1998; Hequet, 1999). Unfortunately, information about distributions of fiber properties that are measured by the AFIS are generally not used, because the data are not available in an electronic file. This makes the use of these data extremely unfriendly. Nevertheless, we decided to investigate the value of the distribution information with a focus on the influence of the fiber length distribution on the yarn quality.
Fourteen USDA (United States Department of Agriculture) standards cottons were used in this first experiment. The following measurements were performed on fiber: . AFIS with 5 replications of 3,000 fibers, . Sutter Web Fiber Array with 3 replications per technician and two technicians, . Peyer AL 101 with 6 replications
Variety evaluation tests were performed at the ITC during the 1998-99 crop year. Eighteen U.S. Upland cotton varieties were represented. Each variety was grown in three locations and two replicated samples were taken at each location. Therefore, a total of 108 cotton samples were collected (18 x 3 x 2). The cotton fibers from each variety were processed through the Short Staple Spinning Laboratory at the ITC and were made into both ring-spun (36 and 50 Ne carded, 50 Ne combed) and rotor-spun yarns (36 Ne carded). The following measurements were performed on fiber and yarn:
. Zellweger Uster HVI 900A: 4 mike measurements, 4 color-grade measurements, 10 length and strength measurements.
. Zellweger Uster AFIS Multidata: 5 replications of 3,000 fibers
. Zellweger Uster Tensorapid: 10 breaks per bobbin and 10 bobbins
. Zellweger Uster UT3: 400 yards per bobbin and 10 bobbins
The printout from the AFIS provides us with a distribution of the length by weight. The histogram is built based upon the percentage of fibers in each of the 40 length categories, from 0 to 2.5 inches with an increment of 1/16th of an inch. In order to get a first look at the data provided on those 108 cotton samples, we limited the number of length categories to 10 by aggregating 4 categories together; therefore, the length category increment became 0.25 inch. A brief statistical summary of fiber properties is given in Tables 2 and 3, showing the mean, minimum and maximum values for each characteristic. An examination of this data reveals that all of the cottons exhibit relatively good fiber properties, with a low short fiber content, good length and maturity and high strength levels. The percentages in the last two AFIS length categories are very low, for this reason they have been aggregated for all the following analysis.
Two commercial cotton bales were selected. A very low amount of ELS cotton was added (2% and 5%) in order to check if the addition of a very small amount of long fibers would increase significantly the CSP. The same measurements used in the second experiment were taken on the fibers and yarns.
Results and Discussion
The first experiment grew out of an anomaly with AFIS measurements. Figure 1 shows a typical AFIS length distribution by weight for Acala- type cotton.
Go to Top of Page