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•The longer staple length of wool , its general
coarseness as a fibre , the presence of the wool scales ,
burrs & remnant trash content, its crimp frequency , the
greater sensitivity of wool with with respect to specific
mechanical stresses causes troubles for rotor spinning of
the wool fibres.
-
• Because its lead to a larger
rotor diameter , lower rotor speeds & comparatively high
twist factors & also more rotor
deposits.
-
•Staple length should be less than rotor diameter.
-
• Spinning is limited to
minimum of 90-120 fibres in the yarn cross section.
-
• There shouldn't be a residual
fat content of 0.5-0.7% in the fed sliver. Also sliver
should content fibres of low crimp frequency.
-
•For this purpose back-washing in a solution of
sodium bisulphite & drying under tension] should be carried
out prior to spinning.
-
• Purity of fibre stock is very
important.
-
•Stretch breaking is an alternative method for
preparing the spinning stock. Normal tops may be used for
rotor spinning if the staple length is reduced by stretch
breaking .
-
•The staple diagram can then be altered by breaking
the longest fibres in several draft zones.
-
•Results have shown that
all other things being equal, broken slivers can be spun
with about 20% less twist than for carded slivers.
-
•The distance between the feed roller & opening
roller has been increased by 40mm.
-
•To avoid damage to fibres.
-
•The opening roller has been widened.
-
•Pinned type opening rollers are used.
-
•The alternative opening process utilizes a fibre
selector [it consists of a cylinder created by staggered
lamellae, each of which takes the form of an equilateral
triangle with rounded corners] in conjunction with a
double-apron draft feed.
-
•The selector cylinder presses against a rubber
covered roller & acts as a draft cylinder , applying
very high draft ratios.
-
• The fibre end is nipped
between the selector & rubber covered & is removed from
the sliver without a hooked configuration.
-
• Rotor with a diameter of
90-100mm., V-shaped groove & without additional surface
coatings were found to give best results. A smooth
doffing tube is also recommended.
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