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Abstract:
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Two major functions performed by high-draft retrofits
for short staple ring spinning include: superior control
over short fibers and parallelization of the fiber bundle.
The high-draft retrofit investigated in this thesis is an
apron device which was sUbstituted for the top front roll
of the drafting system. The brushing action and short
fiber control performed by the apron enabled the fiber
bundle to be drafted more evenly. Resulting yarns possessed
improved quality when compared to yarns produced on the
same equipment without the retrofit. In pursuit of high
quality yarns, an additional advantage of a high-draft
retrofit would be the easy installation of the retrofit to
existing spinning frames at a substantially lower cost than
replacing machines with newer equipment.
During this thesis work, the development of the
high-draft retrofit for short staple was based on the long
staple version manufactured by Monsanto. Various counts of
yarn were spun from 100% cotton; 50/50 polyester/cotton,
coarse and fine roving with and without the retrofit in
order to determine quality changes in yarns as a result of
the device. The tensor pin angle was found to vary the
amount of control and brushing action of the apron on the fiber bundle moving through the drafting zone.
Four roving constuctions were spun on a conventional
Casablancas drafting system as well as the retrofitted
system. The retrofit was tested three times, each with a
different tensor pin angle. Evaluation of the yarns
produced from the different systems was based on Adjusted
Break Factor of skeins, Single End Strength, Single End
Elongation, Uster CV%, Uster Imperfections, Shirley
Hairiness, Appearance, and ends down rate in spinning.
Based on the results of this thesis research, the following
general results were noted:
1. The best yarns were produced from retrofitted
systems with tensors set at the 0 and 45 degree.
2. Significant quality improvements included:
Adjusted Break Factor increased 8 percent
Uster CV% decreased 2.5 points
Uster Thin Places showed a 75 percent reduction
Uster Thick Places decreased 45 percent
Uster Neps decreased 25 percent
Single End Tenacity increased by 1.0 gram/tex
Ends down rate dropped 50 percent
3. Retrofitted yarn hairiness increased 20-25 percent
over conventionally spun yarns.
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