Thesis Details

Thesis Title: An investigation of the relationships between polyester fiber properties, ring diameter, and spindle speed and the subsequent effects on yarn quality and dyed fabric appearance
Thesis Author: Peggy Anderson Oscarsson
Abstract: The advent of "high speed" ring spinning-- spinning at 20,000 rpm spindle speed or higher-- has prompted the need for a careful study of this new technology. While frame speeds have been dramatically increased, one limitation of high speed ring spinning is the friction inherent in the system geometry; the heat produced by this friction can melt and fuse any polyester fiber in the yarn. To determine the forces influencing polyester yarn quality and the degree of polyester melting in high speed ring spinning, the relationships of ring diameter, polyester fiber properties, and spindle speed were examined during high speed ring spinning. Three olyester fiber finishes, two fiber tenacities, two ring diameters, two yarn counts, and three spindle speeds were used as variables for the thesis work. While the ring finish fiber yarns performed best in yarn quality and running performance, the number of dark dyeing defects in these yarns were the least desirable of the results. The opposite was true of the low heat fiber finish yarns, with dark dyeing defects bei~g reduced and yarn quality and running characteristics being less satisfactory. The open end finish yarns performed unfavorably in all categories-- particularly in the formation of long thin places-- while the regular tenacity, ring fiber finish yarns had the best dyed appearance and good quality and performance. Spindle speed had little effect on the yarns' quality, production performance, or dyed appearance; however, to avoid ends down, the higher spindle speeds (20,000 rpm and over) had to be approached by incremental increases in speed. These increases were made in 1,000 rpm increments, and full speed could not be attained until the bottom taper of the package had been passed. In some cases, the frame ran at the test speed for only fifteen minutes of a 1 and 1/2 hour doff. A larger ring diameter generally reduced dark dyed fused spots and improved yarn quality because of the faster traveler speeds attendant with the larger ring. A larger ring usually resulted in a stronger and better quality yarn. In summary, fiber finish and ring diameter were the major influences in yarn quality and dyed fabric appearance. While polyester can be spun with some success at high spindle speeds, such production is not practical because of severe traveler wear and failure, lack of efficient traveler technology, and the present requirement of a slow approach to a peak speed rather than a production run at a consistent high speed.