-
•Selection of raw materials : the
selected cotton fibres should have following
fibre properties:
–A] average fibre fineness = 1.7 dtex;
–B] effective fibre length = 32 mm.;
–C] fibre breaking length = 26-28 km. ;
–D] percentage of ripe fibres in excess
of 80 %.
-
•The requirements of sliver
preparation : sliver
preparation should be done keeping in mind that
the impurity level in fed slivers
could not exceed
3mg/g of sliver.
-
• The more parallel
the fibre orientation in the sliver , the better
will be the fibre arrangement in the rotor
groove & ultimately in the yarn.
-
• This means a
minimum two draft passages , possibly three , if
combed sliver is used.
-
• Special attention
should be paid to the careful mixing .
-
• The number of
doublings in the drafting passages are more
significant.
-
• Fine slivers are
readily subject to the
draft faults such as the
splitting of the web or licking up of of fibres
which ruins the desired final assembly of the
fibre mass.
-
• Hence the number
of draft passages has to be limited to the point
beyond which splitting could occur.
-
• For the same
reason , the delivery speed of drawframe must be
reduced for very fine slivers .
-
• Speed should not
exceed 300 m/min. For a sliver linear density of
up to 3 ktex, & care should be taken in coiling
the sliver into sliver cans.
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