Doffer speed should be maintained as constant and arrange schedule for checking the same daily.
Fluctuation in power, belt slippage, should be avoided and there should be effective power transmission without any slip.
Apron web doffing should be provided for the effective doffing of web.
Stop motion should be provided to eliminate excess waste and maintain the production as constant.
Auto leveller not only maintain the evenness of the sliver, also maintain the production as constant.
Doffer slow motion drive should be provided to facilitate the piecing operation & eliminate excess waste.
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
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.
Under casing waste: Cylinder under casing to cylinder setting influences air currents and prodution of fly and too wider setting causes loss of fibres. similarly, lickerin to cylinder under casing setting if more, loss of fibre may occur.
Closer setting of takerin to takerin grid, increases the fibre extraction with waste.
Too close setting of feed plate with takerin, damage the longer fibres and waste is increased.
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. Flat strips has a fair market value.
Wider setting of top % plate of front plate with cylinder, Increases the flat strips waste.
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.
If the flat strips represents the greater loss, they are an important factor in the cost of making card sliver. Other wastes:
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.
Carding is very much sensitive to temperature and humidity condition which require to be maintained in every shift, otherwise rich web and sliver waste is created.
Bigger card cans and box-type springs do help in the reduction of sliver waste at draw frame.
Too narrow trumpet guide before the calender roller create web waste.
The pressure between cros 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.
Overfilling of card can should be totally discouraged. General practice is to over fill and after doffing from the card, turn 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.
Standard card waste % for semi-High production cards for given trash content in the lap:
