织物折皱回复性能建模研究

基于纺织材料的弹性回复性能及织物的内摩擦作用,研究织物在较小折皱力作用下的折皱弯曲与回复性能,通过简单的模型及公式表征织物回复过程中的重要性质,分析毛及毛涤织物在折皱回复过程中回复力与折皱弯曲形变的关系。利用KES-FB3压缩仪设计折皱弯曲测试试验,用所得数据计算模型参数,能较好地反映出织物折皱回复规律,理论计算值与实测值吻合程度较好。     

粉煤灰在农村公路路面建设中的运用

以荥阳市农村公路改造工程为例,对粉煤灰混凝土的配合比设计进行了介绍,对路用水泥混凝土掺入粉煤灰的可行性进行了研究,实践表明,在水泥混凝土中适当掺入粉煤灰,提高了路面的抗折强度,在提高公路质量的同时,取得了良好的社会经济效益。     

Objective evaluation of multidirectional fabric creasing

Creasing is one of the most important properties of textiles for apparel application. Most fabrics are regularly evaluated by means of etalons, that is, visual standards. Nevertheless, due to the disadvantages of visual evaluation, which is unreliable and time consuming, several objective methods were developed. In this article, a new objective method of multidirectional evaluation of creasing is described. We have proposed the test method of angle recovery using image processing. The specimen of the fabric was of a circular shape and it was measured by the method of angle recovery in various directions. We compared the results obtained from our method with the method described by Sommer and by the hollow cylinder method also. We found good conformity between the results obtained from our method and the method described by Sommer.     

蜂窝纸板折叠回弹特性研究

以回弹力作为蜂窝纸板易折叠性能的评价指标,设计了一种测试回弹力的方法。试验结果表明:随着压痕深度的增加,回弹力呈现先降后升的趋势;当压痕深度与纸芯厚度相等或比纸芯厚度稍大时,回弹力最小,此时蜂窝纸板保持压折状态的能力最好;对于孔径为6,15,20 mm的蜂窝纸板,钢刀刃口半径分别为1.0,1.5,2.0 mm时,其回弹力最小,故应随着蜂窝孔径的变化而调节压痕钢刀刃口半径,随着蜂窝孔径的增大,压痕钢刀刃口半径也应相应地增大。     

薄刀式分切压痕机控制系统的设计

薄刀式分切压痕机是生产包装纸箱所用瓦楞纸生产线中重要的设备,其产品的质量主要是由设备的控制系统优劣决定的。由于传统分切压痕机使用继电器-接触器的控制系统,存在诸多缺点,我们设计了基于PLC的控制系统。首先分析了薄刀式分切压痕机的工作原理及工艺过程,其次进行了控制系统硬件和软件的设计。实践证明:这种控制系统克服了传统控制系统的缺点,从而提高了纸板的整体质量,特别是对包装纸箱生产线上后序印刷质量带来了较大的提高。     

数字刀式压痕机定位辊实时相位测量系统

定位辊实时相位测量精度是决定数字刀式压痕机压痕精度的关键.本研究提出了一种数字刀式压痕机输纸定位辊的实时相位测量系统.系统采用正交编码器和高速数字信号控制器实现对定位辊转角相位的实时显示与数据采集.实验结果表明,该系统检测实时性强,并具有较高的测量精度,可以实现对数字压痕机压痕精度的检测.     

A Productivity Study of Digital Printing in the Packaging Industry

In this study, the suitability of digital printing is evaluated in short runs in packaging industry. The image quality of digital printing is high enough to be used in packaging. The advantages of digital printing and modern converting processes include e.g. the possibilities of using variable data, on‐demand manufacturing and cost‐effectiveness within short print runs. The limitations may include a smaller colour gamut compared to traditional presses, format size, productivity and lower printing speed. In addition, the variety of substrates for use is smaller than in traditional printing. The productivity of the world's first integrated digital printing line designed for short runs was tested by simulating various packaging runs in production. For further analysis, an MS Excel calculation tool was developed. In the calculations, the productivity of a digital packaging line was compared with that of a standard packaging line based on an offline offset printing technique. The cost advantages to be achieved by digital printing techniques in short runs are discussed in two scenarios. The scenarios address the subjects' break‐even point and inline production process. The results of the study show that it is possible to achieve significant cost savings using the inline digital printing and converting systems when compared with traditional offline manufacturing systems in short runs. However, as there are numerous variables included to the production process, it is impossible to present any exact numbers for the break‐even point. In this study, the break‐even point calculated is estimated to be in the range of 4000–8000 packages, depending on the package and sheet sizes. The greatest difference in price per package occurs when the runs are below 2000 packages. Based on the calculations, the inline process itself can decrease the payback time for the machine line as much as 20–35%. One significant factor to be mindful of is that when digital printing is used in the short runs, it often releases machine time from the traditional presses. This part of the analysis has not been included in this study, but using the calculation tool, it is easy to simulate different scenarios and perform further analyses on the systems. Copyright © 2011 John Wiley & Sons, Ltd.     

基于神经网络的织物折皱回复性能预测

探讨了将神经网络理论用于织物折皱回复性能的直接预测。根据研究对象特征,通过选取织物原料组成、经纬密度、抗弯长度、织物厚度及重量等重要影响因子作为神经输入元,将折皱回复角值作为输出目标,比较了径向基函数RBF、BP和广义回归GRNN 3种神经网络对织物折皱回复角的预测结果。试验结果表明,通过神经网络方法对织物的折皱性能预测具有较好的满意结果,且在预测织物的整体折皱回复性能时,BP模型与GRNN网络模型的预测值与实测值之间的相对误差要比RBF的小。利用输入神经元织物参数进行折皱回复性能的预测更有利于工艺与织物结构设计优化与质量控制,通过对输入神经元试验与优化有望达到满意的预测结果。     

Experimental quantification of differences in damage due to in-plane tensile test and bending of paperboard

Creasing is an essential process to convert paperboards into packages since it enables folding along well-defined lines. The creasing process relies on purpose-made damage that is initiated in the paperboard structure: delamination. However, creasing might also cause in-plane cracks, which must be avoided. In this laboratory study, three paperboards were creased at six different depths, respectively. Two mechanical tests were performed to characterize the creases at standard climate (23°C and 50% RH): 2-point folding, to examine the bending force and short-span in-plane tensile test to evaluate the strength. The results were normalized with the values for the uncreased boards, which gave the relative strength ratios: relative creasing strength (RCS) and relative tensile strength (RTS). When the relative strengths were evaluated against the normative shear strains, a creasing window was formed. This window has an upper limit given by the RTS values, corresponding to the in-plane cracks, and a lower limit given by the RCS values, corresponding to the delamination damage initiated in the paperboard during creasing. It was observed that both the RCS and RTS values exhibit a linear relation against normative shear strain. From this, it was concluded that performing tests at two creasing depths might be sufficient to estimate the lower, and upper, limits for the creasing window in future studies. Finally, the effect of moisture was investigated by creasing, folding and tensile testing at 23°C and 90% RH, which showed that moisture had no clear effect on the RCS or the RTS values.     

技术创新与技术扩散的非技术因素影响分析初探

技术创新和技术扩散能力不仅取决于企业的知识积累和人材结构，还在很大程度上受政策环境和技术创新组织结构的影响。为此，本文分析了政策工具与组织结构对Pearl增长曲线的影响，以及对技术创新和技术扩散的作用，并就长征系列运载火箭的技术创新作了案例浅析。