压力棒牵伸区中的纤维数量分布模型

Fiber distribution model in pressure bar drafting zone

牵伸区中纤维的运动状态受与其接触纤维状态的影响,为研究牵伸区中纤维的运动状态,对上托式压力棒牵伸区中各类纤维的数量分布进行了研究。分析了牵伸区中各类纤维的理论分布,测量了牵伸区中的各类纤维数量分布,简化了纤维数量分布曲线。再通过均匀设计,测试了不同牵伸参数下的变细曲线,建立了变细曲线与牵伸参数之间的回归方程,最终得到了牵伸区中的纤维数量分布模型。结果表明:牵伸区中各类纤维的数量分布受牵伸倍数、罗拉握持距、纤维长度、压力棒位置等牵伸参数的显著影响,纤维的数量分布可基于总纤维、前纤维和后纤维的数量分布得到。回归方程的平均拟合误差在7%以内,所建立的纤维数量分布模型适用于涤纶和粘胶纤维。

Objective Drafting is a key process in spinning and has attracted much attention due to the recent development of virtual spinning technology.The drafting process is essentially a process by which the fibers redistribute and rearrange in sliver or strand.To accurately predict the fiber distribution and better control the fiber movement during drafting,the distribution of fibers in the drafting zone was investigated by analyzing the changes in the weight of fibers along the length direction of sliver or strand.Method In order to analyze the fiber distribution in the drafting zone theoretically,cutting and weighing method was used to obtain the attenuation curve and the distribution of front-roller and back-roller fibers,from which the distribution of floating fibers,fast-floating fibers,slow-floating fibers,fast-moving fibers,and slow-moving fibers from the theory were expected to be derived.in addition,attenuation curves under different draft parameters were obtained based on the uniform design and a fiber distribution model in the drafting zone.Results The fiber distribution in the drafting zone with a pressure bar was analyzed and measured.It was shown that in the drafting zone,the distribution of the total fiber,the front-roller fiber,and the back-roller fiber was needed to confirm the distribution of the floating fiber,the fast-floating fiber,the slow-floating fiber,the fast-moving fiber,and the slow-moving fiber.The distribution curves were simplified.For simplicity,man-made fibers of equal length were discussed in this paper.The distribution curves of the front-roller and back-roller fibers in the form of diagonal lines,and the thinning curve could be expressed as a folded line.According to the simplified distribution curves,it was only necessary to determine the attenuation curve.The experiment was carried out by uniform design,the attenuation curve under different drafting parameters was tested based on the cut-off weighing method,and the regression equation between the turning point of the thinning curve and the drafting parameters such as the drafting multiple,the roller grip distance,the fiber length,the position of the pressure bar was established,and the coefficient of determination R^(2) was 0.97.The fitting error within the fitted group was 5.66%.The measured results showed that the larger the drafting multiple,the farther away roller-setting,the shorter the fiber length,and the higher the height of the pressure bar,the farther the turning point of the thinning curve was from the back nip.And the position of the pressure bar in the drafting zone did not have a significant effect on the turning point.To verify the accuracy and applicability of the regression equation,polyester and viscose slivers in the drafting zone were cut and weighed respectively,then the tested results were used to identified for comparison with the calculated values,and the average fitting errors were 5.44% and 6.70%.A calculation model of the fiber distribution in the drafting zone was finally derived based on the above analysis and measurement,which can effectively predict the fiber distribution,according to drafting multiples,roller-setting,fiber length,and height of the pressure bar.Conclusion The accuracy of the model is illustrated by comparing the measured and predicted values,and the model allows the determination of fiber distribution based on drafting parameters,which can effectively predict the fiber distribution,reduce the number of related measurements,and provide a basis for the study of fiber arrangement and movement.The distribution of fibers in the drafting zone is the main factor affecting the evenness of the strip.Mastering the fiber distribution not only predicts the alignment of fibers after drafting but also improves the quality of sliver formation.The fiber distribution equations presented in this study can provide a basis for drafting process simulations and smart textiles.