Thesis Details

Thesis Title: Optimizing fiber length and polyester denier for quality high speed spinning of open-end polyester/cotton yarns
Thesis Author: James Booterbaugh
Abstract: Open-end spinning rotor speeds have been steadily rising over the past few decades, and the trend is expected to continue in the future. Recently, machines have been introduced to the market with production capabilities far exceeding typical commercial production rates. In addition, these new machines utilize extra small (31 mm) rotors. Previous research has proven that yarn quality deteriorates with increases in rotor speed and decreases in rotor size when all else is held constant. Numerous machine adjustments have been made to offset this quality deterioration, but further improvements must be made in optimizing fiber selection for the open-end system. This research was undertaken to develop an understanding of the effect of key fiber properties, and interactions between these properties, on the quality of open-end yarns spun at high speeds on the new generation machinery. To accomplish this work, three polyester deniers, each at two cut lengths, and three cotton varieties of various lengths were blended into 50/50 poly/cotton sliver. Yarns were spun on an Autocoro 240 open-end frame (with an SE-9 spin-box) at 90,000 rpm and 105,000 rpm. Three counts were produced. in all, providing information across the entire count range. Yarn testing was conducted at the Institute, and the yarns containing each experimental condition were ranked based on quality. In addition, select yarns were knitted into fabric to evaluate the appearance of the yarns within fabric. The following general results were noted: 1. Rotor speed did cause significant quality deterioration in yarn properties; however, by choosing the appropriate fiber properties, good quality yarns were produced. Monthly quality overall rankings on yarn properties ranged from 25 percentile to 85 percentile, depending on the fiber properties chosen. 2. For 36/1 yarns, the 1. 0 denier, 1. 5" and the 1. 2 denier, 1.25" polyesters in combination with an 1 1/16" cotton provided the best yarn quality. 3. For the 28/1 yarns, the overall quality level of several fiber blends were good according to the ITT Monthly Quality Check. The best fiber blends included the 1.2 denier polyesters (both lengths) in combination with the 1 1/16" or the 1 3/32" cottons. 4. For the 20/1 yarns, the overall quality level was poor. High numbers of yarn imperfections were present, especially thick places. It appeared that the fibers were not packing well within the rotor. However, one combination, the 1. 2 denier; 1. 5" polyester combined with the 1 3/32" cotton, contributed to high quality yarn. The best poly/cotton blends over the entire count range included: a) 1.2 denier, 1.5" polyester / 1 1/16" cotton, b) 1.2 denier, 1.25" polyester / 1 1/16" cotton, and c) 1.0 denier, 1.5" polyester / 1 1/16" cotton.