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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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