Thesis Details

Thesis Title: The Effects of Open-end Machine Parameters and Fiber Length on Spinning Stability, Yarn Quality, and Hand of Woven Fabric Using Viscose Rayon
Thesis Author: JoDee Hannon Dailey
Abstract: Currently, open-end yarn manufacturers produce viscose rayon yarns at speeds approximately 20 percent below maximum machine capability. Based on previous research, the inability to spin at higher speeds is attributed primarily to insufficient yarn quality and spinning stability (ends-down rates). In this research, the quality of yarns produced from two combing rolls (OB20/4 DN and OS2116 DN) at four combing roll speeds (7100, 7600, 8100, and 8600 rpm) was analyzed. Fiber length (1.1 dpf, 1.25 inch and 1.50 inch), rotor speed (105,800, 110,900, 116,000, and 120,500 rpm), rotor diameter (30 and 32 mm), rotor finish (boron and diamond/nickel), and navel type (8-groove, ceramic and 6-groove, silicium carbide) were altered to determine their influence on spinning stability and yarn quality. Fabric hand testing on the Kawabata Evaluation System for Fabrics was conducted to determine if changes in the research variables resulted in changes in fabric hand. The general results are noted below. 1. The OB20/4 DN combing roll produced yarns with comparable or better quality than the OS2116 DN combing roll. 2. Increases in combing roll speed deteriorate yarn tensile properties but improve yarn Uster properties. 3. Due to excessive ends-down rates, use of a 1.1 dpf, 1. 50 inch rayon fiber is not feasible with 30 mm, diamond/nickel rotors; however, it is possible with 30 mm, boron rotors. 4 ... In'some'instances;decreasing 'fiber length from 1.50 to 1.25 inches resulted in lower yarn elongation and worse Uster properties. 5. An overall deterioration in yarn quality resulted when rotor speeds were increased. 6. Decreasing rotor diameter from 32 to 30 mm improved some yarn properties. 7. At high rotor speeds, diamond/nickel rotors produced yarns with fewer U ster imperfections than boron rotors. 8. Yarns produced with the 8-groove, ceramic navel were superior in quality to yarns produced with the 6-groove, silicium carbide navel.