Redistribution of Impurity and Visible Foreign Matter in Cotton during Carding

Impurity redistribution during cotton carding was investigated. The content and size of impurity in card sliver,takerin droppings,flat strips,and cylinder screen droppings (including droppings under cylinder screen and cylinder-doffer triangle section)at four taker-in speeds were tested by using USTER AFIS. Results show that both total impurities and visible foreign matter (VFM)weights are increased. Impurities in cotton lap are carded and redistributed in card sliver, taker-in droppings, flat strips and cylinder screen droppings. Impurity percentage in taker-in droppings are the highest,followed by that in card sliver,that in flat strips and that in cylinder screen droppings. Cylinder screen has better dust-removing efficiency than flats. The average sizes of impurities in card sliver and cylinder screen droppings are decreased,whereas those of flat strips are increased and those of taker-in droppings is almost the same,in comparison with cotton lap. The impurity contents of card sliver,taker-in droppings,flat strips and cylinder screen droppings have tendencies to decrease with the increase of taker-in speed.

Change and Redistribution of Immature Fiber Number during Cotton Carding Based on Different Taker-in Speeds

The change and redistribution of immature fiber number after cotton carding were investigated under different taker-in speeds.The immature fiber contents (IFCs) of card sliver,flat strips,takerin droppings and cylinder screen droppings (including droppings under cylinder screen and cylinder-doffer triangle section) produced under different taker-in speeds were tested by using USTER advanced fiber information system (AFIS). Based on these results and relevant data,immature fiber number was calculated. Results show that the carding process makes the immature fiber number increase. After carding, immature fibers are distributed mainly in card sliver,accounting for approximately 90% in their total number. All of the cylinder screen,taker-in and flat have the functions of excluding immature fibers; furthermore,IFC in cylinder screen droppings is the highest,followed successively by those in taker-in droppings,flat strips and card sliver. The IFC of card sliver is the lowest when the taker-in speeds are 1000 and 1400 r/min.