CARDING - Page 2
The treatment for opening and cleaning imparted by Taker-in is
very intensive, but unfortunately not very
gentle.Remember that around 60% of the fibres fed to the main cylinder is in the form of individual fibres.
The circumferential speed of Taker-in is around 13 to 15 m/sec and the draft is more than 1000.It clearly
shows that fibre gets deteriorated at this opening point. Only the degree of deterioration can be controlled
by adjusting the following
the thickness of the batt
the degree of openness of the rawmaterial
the degree of orientation of the fibres
the aggressiveness of the clothing
the distance between the devices
the rotational velocity of the taker-in
the material throughput
Latest TRUTZSCHLER cards work with three
licker-ins compared to one liker-in.The first one is constructed
as needle roll. This results in very gentle opening and an
extremely long clothing life for this roll. The other two
rollers are with finer clothing and higher speeds, which results
in feeding more %of individual fibres and smallest tufts
compared to single lickerin, to the main cylinder. This allows
the maing cylinder to go high in speeds and reduce the load on
cylinder and flat tops. There by higher productivity is achieved
with good quality. But the performance may vary for different
materials and different waste levels.
between the taker-in and main cylinder , the clothings are in the doffing disposition. It exerts an influence
on the sliver quality and also on the improvement in fibres longitudinal orientation that occurs here.
The effect depends on the draft between main cylinder and taker-in.The draft between main cylinder and taker-in should be slightly more than 2.0.
The opening effect is directly proportional to the number of wire points per fibre. At the Taker-in
perhaps 0.3 points/ fibre and at the main cylinder 10-15 points /fibre.If a given quality of yarn is required,
a corresponding degree of opening at the card is needed. To increase production in carding, the number of points per unit time must also be increased. this can be achieved by
more points per unit area(finer clothing)
higher roller and cylinder speeds
more carding surface or carding position
speeds and wire population has reached the maximum, further increase will result in design and technological problems. Hence the best way is to add carding surface (stationary flats). Carding plates can be applied at
under the liker-in
between the licker-in and flats
between flats and doffer
Taker-in does not deliver 100% individual fibres to main cylinder. It delivers around 70% as small flocks
to main cylinder. If carding segments are not used, the load on cylinder and flats will be very high and carding action also suffers. If carding segemets are used, they ensure further opening, thinning out and primarily,
spreading out and improved distribution of the flocks over the total surface area.carding segments bring the following advantages
improved dirt and dust elimination
improved disentanglement of neps
possibility of speed increase (production increase)
preservation of the clothing
possibility of using finer clothings on the flats and cylinder
better yarn quality
less damage to the clothing
In an indepth analysis, all operating elements of the card were therefore checked in regard to their
influence on carding intensity. It showed that the "CYLINDER-FLATS" area is by far the most effective
region of the card for.
opening of flocks to individual fibres
elimination of remaining impurities(trash particles)
elimination of short fibres( neps also removed with short fibres)
untangling the neps
high degree of longitudinal orientation of the fibres
The main work of the card, separation to individual fibres is done between the main cylinder and the flats
Only by means of this fibre separation, it is possible to eliminate the fine dirt particles and dust.
When a flat enters the working zone, it gets filled up very quickly. Once it gets filled, after few seconds,
thereafter , hardly any further take-up of fibres occurs, only carding.Accordingly, if a fibre bundle does
not find place at the first few flats, then it can be opened only with difficulty.It will be rolled between
the working surfaces and usually leads to nep formation
In principle, the flats can be moved forwards or backwards, i.e. in the same direction as or in opposition
to the cylinder. In reverse movement, the flats come into operative relationship with the cylinder
clothing on the doffer side. At this stage, the flats are in a clean condition. They then move towards
the taker-in and fill up during this movement. Part of their receiving capacity is thus lost, but sufficient
remains for elimination of dirt, since this step takes place where the material first enters the flats.
At this position, above the taker-in, the cylinder carries the material to be cleaned into the flats. The
latter take up the dirt but do not transport it through the whole machine as in the forward movement system.
Instead , the dirt is immediately removed from the machine. Rieter studies show clearly that the greater part of the dirt is hurled into the first flats directly above the taker-in.
Kaufmann indicates that 75% of all neps can be disentagled, and of these about 60% are in fact
disentagled. Of the remaining 40% disentaglable nep
30-33% pas on with the sliver
5-6% are removed with the flat strips
2-4%are eliminated with the waste
The intensity of nep separation depends on
the sharpness of the clothing
the space setting between the main cylinder and the flats
tooth density of the clothing
speed of the main cylinder
speed of the flat tops
direction of flats with reference to cylinder
the profile of the cylinder wire
The arrangement of the clothing between the cylinder and the doffer is not meant for stripping action,
It is for CARDING ACTION. This is the only way to obtain a condensing action and finally to form a web. It has both advantages and disadvantages. The advantage is that additional carding action is obtained here and it differs somewhat from processing at the flats.
A disadvantage is that leading hooks and trailing hooks are
formed in the fibres , because the fibres remain caught at one
end of the main cylinder(leading hook) and some times on
the doffer clothing(trailing hook).
There are two rules of carding
The fibre must enter the carding machine, be efficiently carded and taken from it in as little time as possible.
The fibre must be under control from entry to exit
Carding effect is taking place between cylinder and doffer because, either the main cylinder clothing rakes through the fibres caught in the doffer clothing, or the doffer clothing rakes thro the fibres on the main cylinder.
Neps can still be disentangled here, or non-separated fibre bundles can be opened a bit in this area and can be separated during the next passage through the flats
A disadvantage of web-formation at the card is the formation of hooks. According to an investigation by
morton and Yen in Manchester, it can be assumed that
50% of the fibres have trailing hooks
15% have leading hooks
15% have both ends hooked
20% without hooks
Leading hooks must be presented to the comber and trailing hooks to the ring spinning frame.
There must be even number of passages between card and comber and odd number between the card and ringframe.
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