Thesis Details


Thesis Title: The effect of draft distribution on state-of-the-art roving and ring spinning technology as it relates to yarn quality
Thesis Author: J. Kelley Edwards
Abstract: Interest in ring spun yarns has increased in recent years. Newer yarn spinning technologies such as air jet and open end rotor have not been able to infiltrate as much of the ring spinning market as was once feared. Machinery manufacturers have increased efforts to improve both the efficiency and quality attainable with the new roving and ring spinning technology. Textile manufacturers have purchased many of these systems; however, research done by I.T.T. suggests that these machines are not being fully utilized. A key consideration when manufacturing yarn on ring spinning technology is the distribution of draft between the roving and ring spinning machines. Many researchers have explored the effects of draft at either process on yarn quality; however, no research was found which quantified the distribution of draft between roving and ring spinning to achieve optimum performance. The object of this research was to determine what effect the distribution of draft between new roving and ring spinning technology has on yarn quality. To accomplish this work, three fiber blends, 100% combed cotton, 50/50 polyester/combed cotton, and 100% rayon, were spun on new roving and ring spinning machinery which utilized the SKF drafting system. Three different roving hanks (1.90, 1.09, and 0.76) were made from each of three different sliver weights (50, 60, and 70 grain/yard). This resulted in nine spinning conditions for each fiber blend. The rovings were then spun into a 38/1 Ne yarn using spinning drafts of 20, 35, and 50 which correspond to the roving hanks of 1.90, 1.09, and 0.76, respectively. All of the yarns produced via the previously mentioned method were tested to determine their quality characteristics. This data was then analyzed using multiple regression and analysis of variance techniques. The following general results were noted: 1. 100% Combed Cotton Increases in the draft index (which corresponds to higher spinning draft) were generally associated with improved yarn quality. This trend was not seen in Classimat minor defects and yarn hairiness. 2. 50/50 Polyester/Combed Cotton a) Increases in the spinning draft were associated with improvements in uster evenness, Uster thins, and single end break strength. b) Increases in roving/spinning total draft were associated with increased evenness variability, lower Classimat minor defects, and increases in single end elongation Vo and Vb' 3. 100% Rayon a) Increases in the spinning draft and draft index were associated with improvements in Uster evenness, Uster thins, and single end elongation Vo' Increased spinning draft also resulted in higher Uster evenness Vb' and higher Classimat major and minor defects. b) Increases in roving/spinning total draft were associated with increased single end elongation Vw' c) Increases in roving draft were associated with lower skein break Vb' In the previous discussion, it is important to note that improvements in quality associated with increased draft does not insinuate that the best quality was always attained using the highest draft. To determine the draft necessary for optimum quality, the reader must refer to the Results and Discussion section of this thesis.