卷筒料印刷装备收卷张力系统解耦控制研究

目的 为了保证卷筒料印刷装备收卷张力系统的性能,提出一种适用于收卷张力系统的自抗扰（ADRC）解耦控制器。方法 在收卷张力系统数学模型基础上,结合卷筒料收卷系统的工作原理,基于ADRC控制技术设计收卷张力系统的ADRC解耦控制器,并利用Simulink软件对所提出的控制策略进行仿真研究。结果 在相同的阶跃输入下,研究结果表明,PID控制器调整时间为2.4 s,而ADRC解耦控制器调整时间为0.7 s;在PID控制下,收卷基材张力出现超调和震荡,而在ADRC解耦控制下,基材张力无超调和震荡现象;采用PID控制器,收卷牵引跨度张力变化引起收卷跨度张力波动,而采用ADRC控制器则没有波动。结论 提出的卷筒料印刷装备收卷张力系统ADRC解耦控制器实现了高精度张力控制,具有比传统PID控制器更好的控制性能。     

玻璃布包装中锥度收卷的内张力分布及其参数确定

介绍了玻璃布包装过程中收卷张力控制系统的工作原理,并针对在该包装收卷过程中易产生折皱的问题,分析了包装收卷过程中的张力变化规律及其影响因素.从弹性理论出发,给出了锥度张力收卷后卷装的内张力分布公式,通过这些研究,可对不同锥度系数下的包装收卷情况进行估计.最后,给出了不同卷装条件下避免折皱的锥度系数的确定方法.     

软包装复合膜收卷张力的优化

目的 为了改善软包装复合膜在生产过程中出现的复合皱折问题。方法 在现有薄膜收卷张力模型的基础上,对薄膜收卷的内张力进行分析,建立以卷径Ri=1.5R0为分界点的分段张力收卷模型。结果 按照该模型设置收卷张力可以很好地避免现有收卷张力模型存在的具有张力薄弱点和内部张力过大等问题,可以有效减小设备、材料等不稳定因素产生的影响,从而有效减少复合皱折问题。结论 利用这一优化的张力收卷模型,通过长期、大量的生产实践,统计出复合皱折损耗率从平均5%下降到低于1%,复合皱折问题得到明显的改善,给公司带来超过200万元/年的经济效益。     

滑模变结构在收卷张力控制系统中的应用与仿真

为精确研究卷筒纸印刷机的收卷张力特性及控制策略,通过对无轴传动多机组印刷机实验平台收卷运动的分析,建立了一个较精确的收卷张力动力学模型。利用MATLAB构造了一个以交流永磁同步电机为执行机构的张力控制仿真系统,根据其非线性,设计了滑模变结构控制器,并与传统的PID控制进行了实验比较,结果表明滑模控制改进了张力控制系统的动静态特性。仿真模型综合考虑了多个张力扰动因素,更加接近实际印刷机系统,为将先进的控制理论引入印刷机收卷张力系统,搭建了一个更精确、便捷的仿真平台。     

FFS重膜印刷机收卷部双锥度张力控制方法

目的解决FFS重包装膜在高速印刷过程中带卷过大所引起的卷膜中心处皱折和端面不齐等产品质量问题。方法提出一种双锥度张力控制方法,通过对收卷张力和辊筒压力分别采用锥度张力控制来有效控制卷膜内部张力的分布,令卷膜内部张力分布更加均匀。基于等效张力的概念,对卷膜中的单元体进行受力分析,得到卷膜受力和卷膜自身张力的变化规律。建立卷膜张力的数学模型,对双锥度控制方法的性能进行理论分析。结果通过集成到设计的平台上,对所提出方法的有效性进行验证,实验结果表明该方法使收卷张力更加稳定,可减少卷膜内层抓心变形,产品合格率提高至98%以上。结论实验结果验证了所提出方法和研制装置的有效性,可有效解决产品出现的质量问题。     

S7300控制系统及G120变频器在薄膜收卷机上的应用

本文主要介绍西门子S7-300控制系统及G120变频器在薄膜收卷机上的应用,包括PLC硬件组成,软件结构,收卷机,张力控制,变频力矩控制,以及profinet网络应用等,收卷机结构上主要由牵引辊,接触辊,中心动力辊等部件组成,中心动力组件通过电机与堵头连接驱动膜卷运转,传动部分均采用变频调速,结构如下图:收卷机电气控制主要由S7-300PLC,G120变频器,张力传感器,张力放大器,人机界面等组成,主控制器为CPU325-2PN/DP,采用ET200分布式I/O系统,系统使用PROFINET现场总线网络,将变频器,人机界面及PLC等连接在一起,实现实时控制与信息交换。     

基于改进模糊控制的印刷机卷纸张力均衡器设计

目的为了提高印刷机收卷系统张力平衡控制性能,结合模糊控制和PID控制设计一种卷纸张力均衡器。方法以无轴传动多机组卷纸印刷机为例,介绍其工作原理并建立收卷张力数学模型。在模糊控制的基础上,加入调整因子,用于实时调节PID控制器的关键参数比例、积分、微分系数。基于ARM控制器STM32F103RC搭建收卷张力控制系统。通过仿真和实验验证所述方法的可行性和有效性。结果实验结果表明,采用改进模糊控制器后,其线速度和张力曲线平滑、收敛速度较快、超调量较小。结论所述控制方法能够有效抑制非线性因素导致的抖振等问题,可满足印刷工艺要求。     

BOPP薄膜跑边的机械因素分析和解决方法

本文主要分析BOPP薄膜在收卷过程中出现跑边现象的机械影响因素。着重讨论滑架的水平度和平行度、牵引压辊、扩展轮、收卷张力和压力、收卷间隙和收卷机驱动和传动部分等对其影响比较大的几个方面。并结合生产实际,提出解决方法。     

复合机铝箔换卷中的速度损失研究

目的减少铝箔复合机换卷时的速度降幅及变化,改善降速换卷中容易断幅的问题,从而提高设备的综合效率(OEE)。方法通过对实验数据的5W1H和张力分析,建立复合机铝箔换卷时铝箔张力的动力模型,探讨了张紧辊张力、压辊压力、铝箔偏心度、运动离心力方向角和速度差等影响铝箔张力的因素,并对实际操进行了实验改进。结果铝箔在换卷时速度变化得到改善,改善了断幅的问题。结论调整影响铝箔张力等一系列因素,综合效率(OEE)达到92.1%,提高了生产效率。     

恒转矩张力控制器在包装机械上的应用

张力通俗的讲就是引起拉长的两个平衡力之一。张力的应用极为广泛,在有些场合我们需要张力恒定不变,有些场合又要求转矩输出不变,而在有些场合却需要张力随卷径增大而增大随卷径的减小而减小,也就是我们说的锥度张力控制。在许多包装机械设备上,如分切机、印刷机、复合机等在卷材的生产加工过程中,在收卷或放卷的过程中,卷     

表面张力作用下抗粘附的微齿轮结构设计原理研究

粘附是微机械中最常见的一种失效现象,一般的微机械结构都极力避免粘附的出现．表面张力是引起微结构粘附的最主要原因．深入研究了表面张力作用下使构件产生粘附的物理机理．以多晶硅微齿轮为例,考虑其在表面张力作用下发生的粘附现象,推导出表面张力作用下抗粘附多晶硅微齿轮结构参数设计公式．结果表明,微齿轮产生粘附与材料特性（弹性特性、表面特性）、微齿轮结构参数（半径、齿宽）、微齿轮与基体之间的间隙有关．     

Surface tension and viscosity of industrial alloys from parabolic flight experiments — Results of theThermoLab project

The surface tension and the viscosity of a series of industrial alloys have been measured by the oscillating drop technique with an electromagnetic levitation device under reduced gravity conditions in several parabolic flights. It was demonstrated that the 20 seconds of reduced gravity available in a parabola were sufficient for melting, heating into the liquid phase, and cooling to solidification of typically 7 mm diameter metallic specimen. The surface tension and the viscosity were obtained from the frequency and the damping time constant of the oscillation which were evaluated from the temperature signal of a highresolution pyrometer. Alloys processed included steels, Ni-based superalloys, and Ti-alloys which were supplied by industrial partners to the project. Three to four parabolas were sufficient to obtain the surface tension and the viscosity over a large range in temperature.     

Surface tension of the 60%Bi-24%Cu-16%Sn alloy and the critical temperature of the immiscible liquid phase separation

In order to control the core-shell structure of bimetallic lead-free solder balls, the surface tension and the critical temperature for the phase separation of two immiscible liquid phases are required. In this study, the temperature dependence of the surface tension of the 60%Bi-24%Cu-16%Sn alloy was measured using the constrained drop method. The temperature dependence of the surface tension was changed at the critical temperature due to phase separation and corresponding modification of the atomic structure of the surface layer. This simple and new procedure enables us to determine the surface tension and the critical temperature for the separation of two immiscible liquid phases simultaneously.     

Prediction of the Surface Tension of Refrigerants and Their Binary Mixtures

The use of scaling principles for the prediction of surface tension was studied. The temperature dependences of the capillary constant, density difference on the saturation line, and surface tension were investigated. New relations containing only a few constants were proposed, which made it possible to calculate the capillary constant and surface tension. On the basis of theoretical and experimental studies, equations have been determined for the calculation of the surface tension of poorly studied refrigerants over wide regions of the state parameters. Relations are also proposed that may be used for calculating the surface tension of binary mixtures at specified compositions of the liquid phase. An equation of the surface tension for reduced isotherms was proposed. Results of investigations of the surface tension of binary mixtures, R116/23, R22/14, R134a/152a, and R22/142b, are presented.     

A Comparison of Surface Tension,Viscosity, and Density of Sn and Sn–Ag Alloys Using Different Measurement Techniques

This work is aimed at comparing several methods for the measurement of physical properties for molten Sn and Sn–Ag alloys, namely, surface tension, density, and viscosity. The method used for viscosity in this work is the modified capillary method. For surface tension and density, the data used for comparison were previously measured using the maximum bubble pressure method and the dilatometer technique, respectively, for four Sn–Ag alloys having (3.8, 32, 55, and 68) at% Ag. The results are compared with those obtained using a new method based on a fluid draining from a crucible under the influence of gravity, designated the Roach–Henein (RH) method. This new method enables the determination of these three physical properties in one set of measurements. Liquid Sn was used as well as two liquid Sn–Ag alloys having (3.8 and 34.6) at% Ag with the RH method. It was determined that the RH method may be used to simultaneously obtain surface tension, viscosity, and density and that the errors associated with these measurements were similar to those obtained using traditional and separate techniques. Comparisons of the measured viscosity and surface tension to those predicted using thermodynamic models will also be presented. Finally a comparison of mixing model predictions with the experimentally measured alloy surface tension and viscosity is also presented.     

CFRP-PCPs复合筋嵌入加固钢筋混凝土梁裂缝试验及计算方法研究

通过5根嵌入不同张拉控制应力的碳纤维增强塑料预应力混凝土棱柱体(CFRP-PCPs)复合筋加固钢筋混凝土梁受弯试验,对比分析试验梁的裂缝分布与发展,得到最大裂缝宽度与平均裂缝宽度在静力荷载作用下的变化特性。结果表明: 嵌入CFRP-PCPs复合筋能有效的减少被加固钢筋混凝土梁的裂缝宽度和高度。在试验基础上,根据国家现行混凝土规范,对平均裂缝间距和最大裂缝宽度计算公式进行参数修正,建立了CFRP-PCPs复合筋嵌入加固钢筋混凝土梁最大裂缝宽度计算公式,计算值与试验值吻合较好。     

Effect of different loading conditions on the mechanical behavior of [0/±45/90]s woven composites

The main objective of this paper is to investigate the behavior of [0/±45/90]_s woven FRP composites under tension, bending, and combined bending/tension loading conditions. First, the mechanical properties of the composite were determined experimentally using the ASTM testing standards. Bending properties were determined using 3-point and 4-point bending tests. The results showed that the woven composites performed better under bending loading than under tension loading. Finally, special test fixtures were designed to facilitate the study of the effect of the combined bending/tension loading. The bending moments were applied using offset shims of various thicknesses placed between the plane of the specimen and the loading axis. At the beginning, the load–strain diagrams at the specimen center showed the domination of bending strains, tension on one surface and compression on the other. With the advance of the loading process, the tension strain dominated and the strain on both sides were almost equal. The failure under combined bending/tension loading was due to the high stresses near the fixture. However, in pure bending, the material failed at the center because of the excessive delamination on the compressive side.     

流动聚焦微气泡流型分布及控制参数实验

介绍了一种基于毛细管流动聚焦方法制备微纳米量级气泡的流动聚焦微流控芯片．以水和空气为工质,在一定的压力和流量下,利用高速摄影技术研究微气泡的尺寸、发生频率和形成过程．分析了表面张力、气体压力、液体流量等参数对微气泡直径和发生频率的影响．实验结果表明,该微流控芯片可以稳定产生直径微米量级的微气泡,操作简单,在微反应器和生物、医药等领域有良好的应用前景．     

EHD喷印技术相关参数数值分析

目的对基于电-液耦合动力学原理(简称EHD)喷印技术的相关参数,进行锥射流和滴落模式下的数值分析研究。方法在锥射流模式中,对毛细凝结加热液体喷射的物理模型进行调整,以适用于EHD喷印;对滴落模式的液滴沉积过程,引入表面张力概念进行数值分析。运用数值法得到了锥射流的轮廓图,集中讨论了流量和净高度对射流直径的影响;重点研究了液滴直径与电压频率和液体表面张力之间的关系,并将理论结果与实验和经验数据进行了比较分析。结果锥射流模式在一定条件下,射流直径随着流量和净高度的增大而增加;在滴落模式中,得到的液滴直径随电压频率和流体表面张力的增大而减小,且数值分析得到的结果与实验结果相一致。结论对相关参数进行数值分析是对实验研究的补充,为EHD喷印技术研究提供了理论参考。     

Dynamic surface tension measurements on a molten metal-oxygen system: The behaviour of the temperature coefficient of the surface tension of molten tin

In order to point out the interactions of oxygen with a liquid metal and to study the influence of the actual operating conditions, dynamic surface tension measurements of a liquid test metal (tin), were performed under vacuum conditions by using the large drop method. This classical method has been improved by applying a new experimental procedure which allowed to obtain reliable surface tension measurements at high temperature as a function of time and varying the oxygen content. Further, complementary information on molten metal-oxygen interactions can be obtained. In particular, in this work, the trend of the surface tension temperature coefficient has been analysed as a function of different operative parameters, highlighting some crucial points such as the dependence of the temperature coefficient on the accuracy of the surface tension experimental data and the influence of the dissolved oxygen. It was demonstrated that the surface tension and its temperature coefficient do not depend on the quantity of dissolved oxygen when this is inside a certain range of values.