Design Of The Draft Control Device And Spinning Performance Of Yak And Cotton Co-spinning

When spinning yarns from fibers with very different lengths,it is difficult to adjust the gauge setting in the drafting zone to properly control the different fibers.Either the long fibers may be broken or the short ones are not controlled during ring spinning,leading to poor spinning performance and inferior yarn quality.In this study,three accessories were developed to adjust the effective gauge setting by changing the roving path in the drafting area.The three accessories were used as rear pressure bar in conjunction with slip drafting.Both laboratory experiments and mill trials were conducted to co-spin Yak/cotton rovings on cotton ring frames,and the yarn properties were evaluated.The main research content is as follows:(1)Designed an H-shaped rear pressure bar based on the conventional double rear zone pressure bar.This H-shaped rear pressure bar was used with corresponding pin and slip drafting mechanism to control fiber movements during drafting.Yak/Cotton(50/50)yarns of 23 tex were spun with five kinds of pin components.These five kinds of upper pin component used different pressure bars,namely without pressure bars,conventional pressure bars,10 mm groove depth H-shaped rear pressure bar,13 mm groove depth H-shaped rear pressure bar,and 16 mm groove depth H-shaped rear pressure bar.The yarns were tested for hairiness and other properties for the five groups of experiments.The results showed that compared with pin components without pressure bar,the yarn had worse CV and better breaking elongation property.And the H-shaped rear zone pressure bar with groove depth of 13 mm had a better effect on the yarn performance.However,the adjustment of groove depth in the spinning process is not flexible.As a result,the cost of the early exploration is high.(2)Designed a gauge adjuster based on the H-shaped rear pressure bar.Compared with the H-shaped rear pressure bar,the gauge adjuster changed the shaft to a flexible gauge bar.This gauge adjuster was used with corresponding cotton spinning pin and slip drafting assembly to form the pin components.Yak/cotton yarns of 18 texwith different blend ratios,Y/C(45/55),Y/C(50/50),Y/C(55/450),were spun with the five kinds of pin components.These five kinds of upper pin component used different pressure bars,namely conventional pressure bars,12 mm groove depth gauge adjuster,16 mm groove depth gauge adjuster,20 mm groove depth gauge adjuster,and 24 mm groove depth gauge adjuster.The yarns were tested for hairiness and other properties of the fifteen groups of experiments.The results showed that the impact of gauge adjuster on improving yarn quality was not significant.The reason is that,due to the installation of the gauge adjuster,an excessive friction and a smaller angle increased the internal tension and shearing force of the yarn,and made it difficult to spin the yarn.As a result,gauge adjuster had an unsatisfactory effect on yarn quality improvement.(3)Designed a pulley-gauge adjuster based on the gauge adjuster.Compared with the gauge adjuster,the pulley-gauge adjuster was installed a pulley on the adjusting shaft to reduce the frictional resistance of the yarn and the length of the surrounding arc.Two pulley-gauge adjusters were used with corresponding cotton spinning pin and slip drafting assembly to form the pin components.One was installed in the front draft zone and its groove depth was 2 mm.Another was installed in the back draft zone and it had five kinds of pin components.Yak/cotton yarns of 18 tex,with different blend ratios of Y/C(45/55),Y/C(50/50),Y/C(55/450),were spun with the five kinds of pin components.These five kinds of upper pin component used different pressure bars,namely conventional pressure bars,10 mm groove depth pulley-gauge adjuster,14 mm groove depth pulley-gauge adjuster,18 mm groove depth pulley-gauge adjuster,and 22 mm groove depth pulley-gauge adjuster.The yarns were tested for hairiness and other properties of the fifteen groups of yarn.The results showed that the pulley-gap adjuster significantly improved yarn quality and the yarn had the best quality with the 14 mm groove depth pulley-gauge adjuster...