Effect of flat heel-toe difference of a card on nep removal

摘要

Effect of flat heel-toe difference (HTD) of a card on neps of card sliver and yarn was studied. The card sliver and yarn were produced under different HTDs, doffer speeds and cylinder speeds. The neps in card sliver and yarn were tested with Premier aQura and yarn evenness tester of PT7000, respectively. Effect significance of HTD on card sliver neps and yarn neps was analysed with SPSS. The results show that HTD has significant influence on both card sliver neps and yarn neps, and 0.42 mm HTD plan is the best in nep removing. The correlation degree between nep numbers of card sliver and yarn was also analysed with SPSS. It is found that nep number in card sliver has a high correlation with that of yarn, and the sequence from high to low is yarn neps (+140%), yarn neps (+200%) and yarn neps (+280%). It is also found that the correlation degree between nep number of card sliver and yarn is higher than that of seed coat neps (SCN) number in card sliver and yarn neps.