Causes of Wastage in Carding
Machine:
1. Doffer speed should be maintained as
constant and arrange schedule for checking the same daily.
2. Fluctuation in power, belt slippage,
should be avoided and there should be effective power transmission without any
slip.
3. Apron web doffing should be provided
for the effective doffing of web.
4. Stop motion should be provided to
eliminate excess waste and maintain the production as constant.
5. Auto leveller not only maintain the
evenness of the sliver, also maintain the production as constant.
6. Doffer slow motion drive should be
provided to facilitate the piecing operation & eliminate excess waste.
7. To doff the web effectively from
doffer, roller doffing device should be used to maintain the production rate.
Also, coiler doffing helps to get consistent doffer speed which enable uniform
production Rate. Different types of waste and waste control in card Mote waste:
The angle of mote knives may range from
8. Vertical disposition to about 30 to
the vertical, but the nearer a knife approaches a tangential position. The
greater is the extraction of waste. If the setting is too close, loss of good
cotton may occur and it is too wide, the mote knives operate inefficiently.
9. Under casing waste: Cylinder under
casing to cylinder setting influences air currents and production of fly and
too wider setting causes loss of fibers. Similarly, licker in to cylinder under
casing setting if more, loss of fiber may occur.
10. Closer
setting of taker in to taker in grid increases the fiber extraction with waste.
11. Too
close setting of feed plate with take-in, damage the longer fibers and waste is
increased.
12. Flat
Strips waste: Front top percentage plate control the flat strips waste, this
strips waste ranges about 2. 5 % of the weight fed, depending upon the grade of
cotton, card setting and metallic wire clothing condition of the cylinder. A
flat strip has a fair market value.
13. Wider
setting of top % plate of front plate with cylinder, Increases the flat strips
waste.
14. The
speed of the flat is also directly related to the amount of waste removed in
the form of flat strips, i. e, the higher the flat speed heavier is the flat
strips.
15. If
the flat strip represents the greater loss, they are an important factor in the
cost of making card sliver. Other wastes:
16. Lap
end waste from full lap before they are fed to the running carding-Improved
transport methods and increasing the lap diameter together with strict
supervision, can bring down this waste.
17. Carding
is very much sensitive to temperature and humidity condition which requires to
be maintained in every shift, otherwise rich web and sliver waste is created.
18. Bigger
card cans and box-type springs do help in the reduction of sliver waste at draw
frame.
19. Too
narrow trumpet guide before the calendar roller create web waste.
20. The
pressure between cross rolls require to be checked up and regulated according
to the material, weather condition as these rolls also become a source of
wastages at the card.
21. Over
filling of card can be totally discouraged. General practice is to over fill
and after doffing from the card, turns the top layers of the coils inside the
can to prevent swelling this tends to spoil sliver evenness and create breaks
and waste at later stage.
22. Standard card waste % for
semi-High production cards for given trash content in the lap.
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