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Abstract:
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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.
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