COMBER - Page 2


The FEED LENGTH has a direct influence on production rate, noil %, and the quality of combing. High feed
length increases the production rate but cause deterioration in quality. Higher the quality requirement,
feed length should be lower. To some extent , the feed length may be decided by the length of the fibre also.

Detaching length is the distance between the bite of hte nippers and the nip of the detaching rollers.
This distance direectly affects the noil %. More the detaching distance, higher the elimination of noil.
Needles of the top comb have a flattened cross section and are used with a point density in the range of
22 to 32 needles per centimeter. More the needles, more the noil%.

The Depth of Penetration of top comb also affects the Noil %. If the comb depth is increased by 0.5mm,
approximately 2% increase in noil will occur. When the depth is increased , the main improvement in
quality is seen in Neps.Over deep penetration of top comb disturbs fibre movement during piecing which will deteriorate the quality.

Since the web from detaching roller is intermittent because of the intermittent functions like feeding,
combing and detaching, to have a continuous web from the comber,fibre fringes are laid on the top of each other in the same way as roofting tiles. This process is called Piecing. This is a distinct source of fault in the operation of Rectinlinear Combing. The sliver produced in this way exhibits a periodic variation.

As large a lap as possible with adapted lap weight which is as high and as uniform as possible
must be positioned in front of the comber. The better the comber lap is prepared, the heavier the lap weight can be set on the comber and the less the resultant noil waste with the same degree of cleanliness of the yarn.

The higher degree of combing out are used in order to permit final spinning of ultra-fine yarns or
to increase the strength of a yarn. Reducing the lint content improves the medium staple. However, not all cottons meet these requirements. Low degree of combing out , on the other hand, frequently serve to improve purity. When the card sliver is pulled through the needle bars, these separate off foreign bodies, large neps and torn fibres.

Light combing out has also been introduced to a greater extent owing to the impairments in cotton purity influenced by mechanical harvesting. Even when combing with minimum noil percentages, there is a noticeable improvement in fibre parallelsim in the sliver. Even the smoothness and shine of the yarn are improved. It must thus be anticipated that this method will become more and more popular in the future.

Production of the comber is dependent upon the following
N- Nips per min
S- feed in mm/nip
G- lap weight in g/m
K- Noil percentage
A- tension draft between lap and feed roller(from 1.05 to 1.1)
E- efficiency

Production = (E * N * S * G * (100-K) * 60 * 8) / (1000 * 1000 * A *100)  

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