Carding
Carding:
Carding may be defined as the reduction of an entangled mass of fibres to a
filmy web by working between two closely spaced, relatively moving surface
clothed with sharp wire points.
The carding is the heart of the spinning mill & well carded is half-spun-
demonstrate the immense significance of carding for the final result of the
spinning operation. The importance of carding is still greater where new
spinning systems are concerned.
Fiber Sliver
Function/objective of carding:
Why carding is called heart of spinning?
Opening to individual fibres: The blow room only opens the raw mtl to flocks
where as the card opens it to the stage of individual fibres.
Elimination of impurities & dust: Elimination of foreign mtl occurs mainly
in the region of the taker in (T-in). In addition to free dust, which can be directly
sucked away as in the B/R, the card also removes a large proportion of the
micro particles. The card is a good dust removing m/c.
Removing of neps: The card reduces the no. of neps from the B/R. An
improvement in disentangling of neps is obtained by: closer spacing between
the clothing, sharper clothing; optimal speeds of the T-in; low doffer speeds
lower through put.
Elimination of short fibres: Short fibres can only be eliminated if they are
passed into the clothing. Elimination of short fibres in the card must be viewed
in proportion, actually very small, fewer than 1% short fibres.
Fibre blending: The card is the only m/c to process individual fibres. In
formation of the web & with repeated rotation of the fibres on the main cylinder,
intimate fibre with fibre mixing is achieved.
Fibre orientation: It is often attribute the effect of parallelizing. The card can
be given the task of creating partial longitudinal orientation of the fibres.
Sliver formation: To deposit the fibre mtl, to transport it & process it further,
an appropriate product must be formed.
So, carding is called heart of spinning.
Revolving flat card:
Figure: Diagram of revolving flat card
Figure: Diagram of revolving flat card
Machine parts of revolving flat card:
1. Feed roller
2. Licker-in or Taker-in
3. Cylinder
4. Revolving flats
5. Doffer
6. Front Stationary flats
7. Back stationary flats
8. Trumpet
9. Calendar roller
10.Mote knives
11.Sliver
12.Can
13.Cylinder under caging
Specification of revolving flat card:
• Revolving flats 84 pcs
• Front Stationary flats 12 pcs
• Back stationary flats 6 pcs
Total flats: 102 pcs
In action: 30% i.e. 102*0.3= 31 pcs
• Licker-in or Taker-in i) Diameter → 9 − 9.5
ii) Speed → 300-600 r.p.m.
iii) Wire point direction →
Anticlockwise.
iv) Surface speed → 1000ft/min.
• Cylinder i) Diameter → 50 (1280mm)
i) Speed → 250-500 r.p.m.
ii) Wire point per square inch → 550-
650
iii) Surface speed → 2000ft/min.
iv) Total wire point per cylinder →
30lac.
v) Wire point direction → Clock-wise.
• Flat speed i) Wire point direction → Clockwise.
ii) Surface speed → 2-7 inch/min.
• Doffer speed i) Diameter → 27
i) Speed → 30-100 r.p.m.
i) Wire point per square inch → 550-
650
ii) Surface speed → 50 27
inch/min.
• Draft 100+10
• Production 80kgs/hr
Function of Licker-in/Taker-in:
i) Unwind the lap continuous feed with uncontrolled stretching.
ii) To eliminate the impurities.
iii) To transfer the fibres as evenly as possible.
iv) To perform the primary cleaning & opening of cotton fibre.
Function of cylinder and flat:
i) To open the flocks to individual fibres.
ii) Eliminate of remaining impurities.
iii) To eliminate some short fibres.
iv) To remove dust.
v) To disentangle of neps
vi) High degree of longitudinal orientation of fibre.
Function of doffer:
i) To collect the individual fibre from the cylinder and condense them into a
web.
Card clothing:
In carding m/c, different parts (i.e. T-in, Cylinder, Doffer & flats) are covered with
different types of wire which are known as card clothing. To cover the surface of
T-in, Cylinder, doffer & flat of carding m/c with the help of a number of unlimited
fine, closely spaced & specially bented wire is called card clothing. The wire
points are inserted on the m/c surface by means of a base mtl or foundation. Base
mtl may be of textile fabric or may be of some other mtl which is very hard & stiff.
Grinding:
The process of increasing sharpness of the wire points such as cylinder wire, flats
wire, and doffer wire is called grinding. Grinding is done after certain period to get
good carding action.
Why grinding is required:
Due to moving of cotton and waste particle on the surface of the cylinder, doffer
and flats wire points are damaged. Height of wire points are unequal in some
places and sharpness of wire points are reduced. As a result, poor carding action is
occurred and get poor quality of sliver.
Types of grinding apparatus: Two types
1. Long grinding roller
2. Traverse grinding roller (It is better)
Mounting:
Mounting is replacing the old card clothing by new card clothing.
Frequency of grinding and mounting of cylinder, doffer flats and
licker-in:
1st grinding Frequency
Licker-in Not required grinding
Cylinder After completion 200-250 ton
production
Flat After completion 80-120 ton
production
2nd grinding
Cylinder After completion 450 ton production
Flat After completion 240 ton production
Doffer After completion 450 ton production
Mounting
Licker-in After completion 100-200 ton
production
Cylinder After completion 500-600 ton
production
Flat After completion 500 ton production
Doffer After completion 500-600 ton
production
