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Abstract:
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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.
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