2. The primary functions of a comber are three:
 Remove fiber hooks and parallelize the fibers
 Bring about fiber-to-fiber separation
 Remove short fibers.

3.  The comber waste also contains a large number of neps
and some foreign matter particles.
 Combing, therefore, results in a considerable reduction
of nep content and in some cleaning of cotton also.
 However, a higher percentage of waste need not
always mean more removal of short fibers and neps.

4.  The high cost of removing even one percent extra
comber waste makes it imperative that a mill should
carefully choose the optimum level of comber waste for
each mixing.
 Then exercise a strict control on all combers to
maintain the waste at the desired level.

5. For an effective control of short fibers, retention of long
fibers and removal of neps, the following considerations
are important.
 The card trailing hooks are longer and more numerous
than the leading hooks. They are removed when fed as
leading hooks by keeping an even number of reversals
between card and comber.
 The waste at comber can be reduced by increasing
precomber draft upto certain limit without effecting
the resultant yarn quality.

6.  The proper place for controlling neps is carding and not
combing. It is often more economical to run card at
somewhat low production rate than to take out extra
comber waste.

7.  The minimum level of comber waste which gives the
desired
 Yarn quality,
 Yarn appearance and
 End breaks at ring frame depend on nature of fiber
length distribution in the cotton or mixing.

8. Nature of fiber
length distribution
of mixing
Short fiber %
(by number)
Mean length Approximate level
of comber waste
%
(by weight)
Triangular >20% 26mm No optimum
(waste%~quality)
Flat <18% 26mm 0.5*S.F%

9.  An increase in comber waste results in improvement in
yarn quality till most fibers below 15mm length are
removed.
 For e.g. for a cotton with short fiber content of 22%, one
can take trials with 10%, 11% and 12%.
 The minimum level which gives the desired yarn quality
and minimum end breakage rate in spinning gives should
be adopted for large scale production.

10. ROUTINE CHECK OF COMBER WASTE
The waste at comber need to be checked and controlled due to
the following reasons.
 More waste than the nominal means financial loss.
 Less waste than the nominal could lead to unacceptable
yarn quality performance.
 Between comber waste variation could contribute to
between lea count variation.

11. The numerous experiments conducted in the industry
have brought out the following facts.
 Head waste CV exceeding 6% calls for attention.
. Comber waste CV in excess of 4% calls for attention.
. For a well set and maintained comber , the difference
in the level of comber should not exceed 3% from the
average.

12. PROCEDURE FOR DETERMINING COMBER WASTE
 Remove noil from the back of each head and break the sliver
just beyond the coiler.
 Collect head wise noils and comber sliver from the can by
breaking just after the coiler.
 The overall comber waste and head wise waste are then
calculated as follows:
Wt. of noils from all heads * 100
Overall comber waste (%) = ...........................................................
(Wt. of sliver+Wt. of noil from all heads)
Wt. of noil from a head *100
Head wise waste (%) = ...............................................
1/n (Wt.of sliver+Wt.of noil from all heads)

14. Feed rollers move the lap by 4-6.5 mm .

15. Upper nipper plate Z 0 is lowered and the fibers are nipped

16. Combing segment k combs the fiber fringe and Carries away those fibers not held by
nippers

17. Nippers open again and move towards the detaching rollers.

18. Detaching rollers rotate backwards and bring back a part of the material

19. The new fiber (B) fringe is placed over the returned material (V)

20. Detaching rollers reverse the direction and draw the clamped fibers out of sheet W.

21. The top comb thrusts its single row of needles into the fibe fringe.

22. Nipper assembly moves back. Top comb is withdrawn and new cycle begins. Combing segment
is cleaned by the brush roller.