Study of carding machine may be broadly classified into the following three heads.
licker in section
Carding section
Condensing section
Taker-in (or) licker in section
The main objects of this sections are:
i) To unwind the lap and pass the sheet of cotton at a constant
rate.
ii) To open the cotton into very small tufts.
iii) To extract the seed bits, sand and other vegetable, trash
particles from cotton.
iv) To transfer the cotton into the cylinder surface and
distribute the fibres as envely as possible both transversely and
longitudinally on the cylinder surface.
Taken-in section include the following topics: i) Feed unit & lickerin ii)Mote knives iii)Licker in under grid iv) stripping action between licker in and cylinder.
Feed unit & licker-in
It consists lap stand, lap roller, feed plate & feed roller. Lap roller rotates at slow speed and lap is unwound by the friction of lap roller.
Sheet of cotton now passes over the feed plate and pass under the feed roller which is heavily weighed to grip the cotton. Lap roller ( 6 inch dia) is driven by feed roller (2.5 inch dia) and feed roller is driven by doffer, so rate of unwinding of lap, supply of material from feed roll to licker-in are all kept under control. Feed roller feed the sheet of cotton to the action of fast revolving Licker-in
Grooved surface of the licker-in is clothed with saw tooth wire. Lap is now well opened into very small tufts by the beating action of fast revolving Licker in. Mote-knives and licker - in under grid
In order to retain the cotton on lickerin and yet permit dirt to be separated from it, the underside of the lickerin is enclosed by one or two mote knives and lickerin undergrid. To opened fibre tufts are carried by lickerin against Mote knife and over the under grid.
Mote is a particle of seed, leaf, boll, shale or stem. Due to the resistance of the mote knives, heavily vegetable impurities known as "Motes and sand are removed and falls down through licker-in under casing. "Mote knives to Takerin Setting -Upper Knife -0.010 inch
Bottom Knife -0.0012 to 0.015 inch
Three types of mote knives are available. In the first type the angle and setting with respect to taker-in are fixed. In the second type the angle is fixed while the setting can be altered. In the third type both angle and setting can be altered.
The angle of mote knives may range from vertical disposition to about 30 degree to the vertical but the nearer a knife approaches a tangential position, the greater is the extraction of waste. If the setting is too close- loss of good cotton may occur, if it is too wide-the mote knife operate in efficiently. Licker-in under grid:
The object of the licker-in under grid is to hold the good fibres on the licker-in and to permit the short fibres, dust, dirt particles to fall down, and collect outside the licker in grid through spacing of under grid
Licker- in under grid consists number of spaced bar and perforated metal sheet.
Setting between licker-in to grid-5/16" close setting increases the fibre extraction with waste.
Stripping action between licker in and cylinder
Stripping action takes place between cylinder and lickerin.
In between licker in & cylinder, the direction of the both lickerin and cylinder wires are inclined in the same direction. This is called point to back arrangement. Stripping action is made possible due to the following reasons:
* Point to back arrangement of the wires facilitates stripping of fibres from the lickerin by the cylinder.
*The surface speed of the cylinder is twice that of lickerin.
*The close setting of 0.007 inch from lickerin wire to cylinder helps to transfer the fibre effectively.
*Air current close to the cylinder helps the transfer of fibres, from licker in to cylinder.
