Modern high production carding machine
Developments chute feed system:
Feed system which feeds well opened fiber tufts without compressing them into a lap to a set of cards in becoming a must for high performance carding because a part of increase in production is achieved through a heavier but finally open ban This systern not only eliminate manual efforts in carrying laps from the blowroom to card, but also avoid making clean waste during lap change
Two basic chute feed system need to be considered here
- One-Piece chute without an opening system
- Two-Piece chute with an opening system
The one piece chute, a column of material with height somewhat variable over time is pushed forward the feed roller. This form of chute is simple uncomplicated economical and need little maintenance.
The two piece in more complex and expensive, but delivery a more even batt. The upper half is reverse chamber that serves to receive the material from the blowroom and to separate the material deliver In the lower portion (B), after an opening stage at the opening roller (2). The quality of material is held constant. This material is lightly compressed by the pressurized air or vibrating plates (C), In a continues and a even manner to form an even batt an idea feed stock.
Unidirectional feed
In the new system shown in fig. the feed roller, situated below the feed plate, rotate in reverse direction which enables the feed to be led in the direction of rotation of the Taker- in which results in gentler treatment of fibers and therefore, leads to reduction in nep formation. Where the feed and drum rotation direction are the same, The spacing of the clamping zone is adjusted.
Use of carding segments:-
High performance cards require intensive opening, both in taker in and cylinder flat regions, to deal with higher through put. In the taker in region this can be achieved by increasing the taker in speed or the wire point density of its clothing. Increased taker in speed has been seen 0 to be effective in this regard only to a certain period extent
Use of carding segment around the cylinder:-
On the modem cards, a more effective and simpler arrangement has been developed in where in carding segment are positioned at one or two position around the cylinder as shown in fig. this carding segment generally acts as full-fledged carding units with arrangement for fibers 0 separation through use of carding segment, separation of trash with the help of mot knife, and removal of trash by suction. One of the leading card manufacturer clamps that the knives are more effective in doffing of disc position.
The most effective arrangement has been found where in the first segment is put around the cylinder just before the entry of fibers into the flats and the second unit after the flats above the doffer. These complete carding positions in effect increase a no. of carding zones from one to (one + no. of card segment) adequate fiber individualization is thus mentioned even at very high production rate in also reduction in neps and increase removal of short fiber and trash are achieved. The use of carding segment on the front side(above the doffer) helps in removal of smallest trash and dust particles still remaining in the fibre mass. In the final analysis. therefore one can say that the use of carding segment reduce the loading of the a carding cylinder and flats and thus bring the
following advantages:-
1. Improve dust and dirt climination
2. Improved untangling of neps
3. Increase in production
4. Longer life of card clothing.
5. Possibility of usan he so finer clothing
6. Better yarn quality
7. Less damages to the card clothing.
Apron doffing:-
In the modern high performance card doffer comb sloffing comb would be unable to perform this task Also, the web is freely suspended over a distance of 30-50 cm in conventional cards which would fall a part at delivery speed of 200 to 300 meters per minute used for high performance cards It is the advantageous if these doffing devices can be so manipulated that the web can be taken out for checking of neps
Higher cylinder speed:-
The cylinder diameter used on most of cards is around 1300 mum and the speeds lie between 250-600 rpm in the auest for high for high production on the card the cylinder speed played a central role To maintam an adequate no of wire point per fiber at higher throughput, the cylinder speed is accordingly increased to maintain adequate fibre individualization conversely a higher cylinder speed for a given production rate improves fiber individualization and therefore the yarn quality. A higher cylinder speed is very effective in untangling of neps due to this factor. This is reached cylinder speed 400-500rpm for ring yarn 600rpm above for rotor yam
High performance card wire:-
The first development which made a dramatic change in card productivity was the introduction of a metallic wire in 1965. This not only increase the productivity but also reduced card waste and eliminated frequent card stoppages to strip the cylinder and the doffer the further improvements in the design of the card wire such as optimizing wire bight, wire angle and wire point density lead to further increase in productivity and improvement in yarn quality is especially in reduction of nep level…
Online monitoring neps:-
The neps are a serious blemish in the yarn and need continuous checking. Now some manufacturers have come out with in built device to display the nep count of the card web. Therefore, immediate action can be taken to prevent excessive neps from passing into the card sliver ultimately into the yarn. Looking at the advantages of the devices it is accepted it might became a standard features of card in future.
Auto-leveling at card:-
The card sliver reflects in the variation in the feed in the form of long and medium term variations in its weight. The problem become more acute with chute feed system. In such situation the use of auto-leveling these in regulation in is an accepted features of high performance cards.
Integrated grinding system :-
A mention was made carher about the on-line monitoring of neps in the card web. To go further one can think of not allowing such a thing to happen by keeping the carding clements well ground. This has lead to development of the so called integrated grinding system, incorporated in the Rieter C-50 card automatically grinds the cylinder to maintain optimum sharpness of wire over its entire lifespan. All this takes place when the card is nunning and that too without operator intervention. An associated software determines the need for grinding and o actuates the grinding process.
Conclusion:
Thus we have studied various development in the carding machine.
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