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Abstract:
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Yarn manufacturers and knitters are constantly looking for ways to reduce the amount of
lint shedding at knitting. Lint that is shed creates difficulty for knitters by collecting on the
surfaces of the machinery and being transferred into the knitting area of the machine. This
results in lower quality fabric, broken knitting elements, and costly downtime.
These problems originally were caused mainly as a result of natural fibers such as cotton,
which contain more immature and short fibers. As fiber manufacturers began to produce
synthetic fibers, chiefly polyester, with lower pilling tendencies by changing the fiber
structure, the occurrence of lint shedding from yarns made using synthetic fibers began to
increase.
Machinery manufacturers have taken action to reduce the amount of lint shedding by
developing enclosed creels with humidity control to keep the yarn conditions consistently
maintained. Other machinery implementations such as enclosed yarn guides from the creel to
the knitting machine, strategically placed fans to circulate the air, and decreasing the number
of friction points the yarn contacts have helped control the lint. However, no solution has
been found to eliminate the problems caused by lint shedding.
The objective of this thesis was to determine the effects upon lint shedding and yarn
knittability of polyester fiber variants and spinning parameters of open end and ring spun
yarns. The fiber variants under study were fiber length and denier. The open end
parameters were combing roll speed (7500 and 8500 rpm), navel type (ceramic and steel), rotor speed (90,000 and 96,000 rpm), and rotor groove configuration (G and T groove). The
parameters were spindle speed and traveler weight in ring spinning.
To accomplish this work, a 0.9 and 1.2 denier polyester fiber were obtained. Using
three pass drawing, a 45 grain sliver for open end and a 55 grain sliver for ring spinning
were produced. The slivers were spun into 28/1 Ne yarns under various spinning settings.
All yarns were tested for lint generation, knittability, blend analysis, and hairiness. This
data was analyzed using analysis of variance and linear regression. The following general
results were noted:
In open end spinning it was generally found that increasing combing roll speed and rotor
speed had a detrimental effect on the amount of lint shedding exhibited by the yarn. Yarns
spun using G-groove rotors also exhibited a higher percentage of shedding. Open end
spinning using steel navels had a positive influence on reducing lint. The lint shedding from
open end yarns contained nearly 83 % polyester while approximately 18 % polyester resulted
from ring yarns.
Knittability of open end yarns decreased as rotor speed and fiber denier increase. An
increase in fiber length helped reduce the number of knittability stops.
Lower spindle speeds shed more lint than higher speeds but a trend appeared which
showed there may be an increase in shedding as spindle speed continues to increase.
However, spindle speed and traveler weight both affected knittability of the yarns.
In conclusion, slower rotor and combing roll speeds produced yarns of superior quality in
regard to lint shedding and knittability. Conversely, ring yarns result in lower shedding at
higher spindle speeds and better knittability with lighter traveler weights.
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