Steering guide-based lateral control for roll-to-roll printed electronics

This paper presents the lateral displacement control of a moving web using a steering guide system which can be an important part in roll-to-roll (R2R) printed electronics. In general, R2R systems in printed electronics need a long drying section for the reduction of time and cost by reducing the delay of drying time. However, the lateral web displacement can be a worse problem because the web should be affected by the air blow from the dryer. Therefore, the lateral position control of long span will play a significant role in the R2R production process for better product quality. In our work, PID control method is designed to control the lateral displacement of a moving web by using a steering guide system, and simulations and experiments were performed to test the method.     

Design of roll-to-roll printing equipment with multiple printing methods for multi-layer printing

In this paper, a novel design concept for roll-to-roll printing equipment used for manufacturing printed electronic devices by multi-layer printing is presented. The roll-to-roll printing system mainly consists of printing units for patterning the circuits, tension control components such as feeders, dancers, load cells, register measurement and control units, and the drying units. It has three printing units which allow switching among the gravure, gravure-offset, and flexo printing methods by changing the web path and the placements of the cylinders. Therefore, depending on the application devices and the corresponding inks used, each printing unit can be easily adjusted to the required printing method. The appropriate printing method can be chosen depending on the desired printing properties such as thickness, roughness, and printing quality. To provide an example of the application of the designed printing equipment, we present the results of printing tests showing the variations in the printing properties of the ink for different printing methods.     

Web Tension regulation of multispan roll-to-roll system using integrated active dancer and load cells for printed electronics applications

The mass production of primed electronics can be achieved by roll-to-roll（R2R） printing system, so highly accurate web tension is required that can minimize the register error and keep the thickness and roughness of printed devices in limits. The web tension of a R2R system is regulated by the use of integrated load cells and active dancer system for printed electronics applications using decentralized multi-input-single-output（MISO） regularized variable learning rate backpropagation artificial neural networks. The active dancer system is used before printing system to reduce disturbances in the web tension of process span. The classical PID control result in tension spikes with the change in roll diameter of winder and unwinder rolls. The presence of dancer in R2R system shows that improved web tension control in printing span and the web tension can be enhanced from 3.75 N to 4.75 N. The overshoot of system is less than ±2.5 N and steady state error is within ± 1 N where load cells have a signal noise of ±0.7 N. The integration of load cells and active dancer with self-adapting neural network control provide a solution to the web tension control of multispan roll-to-roll system.     

Design and implementation of adaptive PI control schemes for web tension control in roll-to-roll (R2R) manufacturing

In this paper, two adaptive Proportional-Integral (PI) control schemes are designed and discussed for control of web tension in Roll-to-Roll (R2R) manufacturing systems. R2R systems are used to transport continuous materials (called webs) on rollers from the unwind roll to the rewind roll. Maintaining web tension at the desired value is critical to many R2R processes such as printing, coating, lamination, etc. Existing fixed gain PI tension control schemes currently used in industrial practice require extensive tuning and do not provide the desired performance for changing operating conditions and material properties. The first adaptive PI scheme utilizes the model reference approach where the controller gains are estimated based on matching of the actual closed-loop tension control systems with an appropriately chosen reference model. The second adaptive PI scheme utilizes the indirect adaptive control approach together with relay feedback technique to automatically initialize the adaptive PI gains. These adaptive tension control schemes can be implemented on any R2R manufacturing system. The key features of the two adaptive schemes is that their designs are simple for practicing engineers, easy to implement in real-time, and automate the tuning process. Extensive experiments are conducted on a large experimental R2R machine which mimics many features of an industrial R2R machine. These experiments include trials with two different polymer webs and a variety of operating conditions. Implementation guidelines are provided for both adaptive schemes. Experimental results comparing the two adaptive schemes and a fixed gain PI tension control scheme used in industrial practice are provided and discussed.     

Study on the web deformation in ink transfer process for R2R printing application

Web deformation occurring in the ink transfer process from the printing roller to the flexible web was investigated using a CFD technique for the application in roll-to-roll printed electronics. Analysis for the flow-structure interaction was conducted to assess the deflection and stress distributions of the web. To make the present analysis more relevant to the real printing system, both realistic geometric configuration and ink properties were set up using the information obtained from the typical roll-to-roll system. Fluid properties were found to influence to the shape of the transferred ink and the web deformation. As the line width becomes smaller than 100 microns, the appreciable distortion in the shape of the transferred ink occurred due to a relative importance of surface tension. Non-negligible web deflection occurs in all the cavity geometries considered in the present work but the ratio of the web deflection to the line width gets smaller as the printing pattern width becomes smaller. Thus, the surface and deflection will be important factors for the better printing quality under the 100 micron range.     

Fuzzy decoupling to reduce propagation of tension disturbances in roll-to-roll system

Control of web tension is crucial for maintaining quality of products processed on roll-to-roll (R2R) system. An R2R system can be divided into different tension spans which interact with each other. But converting industries tend to neglect these interactions and use decentralized single-input–single-output (SISO) control approaches to deal with tension control. Multi-input–multi-output approaches have been reported in literatures but are practically not in use. Interaction between the various tension spans is unavoidable as they are all connected by a single web. Disturbances produced in a span tend to travel further downstream along the direction of web travel. When the number of spans is less or the disturbance amplitudes are small, this does not present a big challenge and simple SISO control is sufficient. But when the amplitudes of disturbances produced in processing is large—as is the case with printed electronics—or the number of spans is large or both, then the interactions cannot be neglected. R2R-based offset printers have the potential for mass production of precision-printed electronics. In this paper, a fuzzy logic-based hybrid approach has been followed that specifically targets the printed electronics industry and this method considerably reduces the interactions. The algorithm has been designed such that it takes information from previous span to reduce the propagation of tension disturbances to the given span. This has been achieved through online computation of correlation coefficient and reducing the interaction through fuzzy feedback control.     

Laser sintering of Cu nanoparticles on PET polymer substrate for printed electronics at different wavelengths and process conditions

Frontiers of Mechanical Engineering - This study explores the feasibility of different laser systems to sinter screen-printed lines from nonconductive copper nanoparticles (Cu NPs) on polyethylene...     

Numerical analysis of a radiant drying oven for web applications

During the manufacture of prepregs (composite material made of resin with fiber reinforcement), for the electronics industry, solvent evaporation and product heating are important aspects of the production process. A mathematical model is presented to describe convective and infra-red radiant heating and solvent evaporation from a web (product being processed before being finished as prepreg) in a solvent removal oven. Differential equations are used to model the mass and energy transfers occurring within the oven. Radiation enclosure theory is employed to describe the infrared heat transfer within the oven and use is made of a solvent evaporation model from the literature. Results of temperature distributions in the heated plate (oven component), the web and the air/solvent mixture; the convective and radiant heat transfer rates to the web, the web solvent concentration and the effects of varying the web velocity, heater temperature, heater size and inlet air temperature are in agreement with theory. The results yielded good agreement with a similar study in the literature. Careful analysis of the results of computer simulations under different conditions, such as presented in this study, can be expected to lead to better design decisions prior to building an infra-red oven for web applications.     

多金属3D打印的SLM设备工艺参数库试验研究

针对特定的金属3D打印机,加工不同金属均需反复实验,因此建立成形工艺参数数据库十分必要。以某国产金属打印设备为研究对象,以加工Al Si10Mg合金的工艺方法为例,采用正交试验方法和微观组织分析法验证其选择最佳工艺参数组合的正确性,最终通过多种金属的加工得到该设备的激光功率、扫描间距、扫描速度对打印不同金属的致密度、抗拉强度以及断后伸长率的影响的规律。结果显示选择激光功率时要充分考虑金属的熔点、易氧化、反光率等特性,扫描间距对成形不同金属的力学性能影响敏感度最大,为建立更多金属成形工艺数据库提供了参考。     

国内干燥技术及兰州瑞德干燥设备发展概况

一、国内干燥技术 1.国内干燥技术现状 干燥是工业生产中一项重要的单元操作,在化工、医药、轻工、农产品加工等领域均有广泛的应用.干燥单元的核心设备是干燥机,干燥机分类方法很多,按加热方式可分为对流、传导、辐射、高频和微波等.这些加热方式又可分为直接加热和间接加热两种.按干燥机的结构型式或运行方式又可为管式、箱式、隧道式、回转圆筒式、滚筒式、气流式、流化床、真空干燥、冷冻干燥等.     

Assessment of printability for printed electronics patterns by measuring geometric dimensions and defining assessment parameters

The printability of patterns for printed electronic devices determines the performance, yield rate, and reliability of the devices; therefore, it should be assessed quantitatively. In this paper, parameters for printability assessment of printed patterns for width, pinholes, and edge waviness are suggested. For quantitative printability assessment, printability grades for each parameter are proposed according to the parameter values. As examples of printability assessment, printed line patterns and mesh patterns obtained using roll-to-roll gravure printing are used. Both single-line patterns and mesh patterns show different levels of printability, even in samples obtained using the same printing equipment and conditions. Therefore, for reliable assessment, it is necessary to assess the printability of the patterns by enlarging the sampling area and increasing the number of samples. We can predict the performance of printed electronic devices by assessing the printability of the patterns that constitute them.

     

Effect of taper tension profile on the telescoping in a winding process of high speed roll to roll printing systems

Winding is an integral operation in almost every roll to roll system. A center-wound roll is one of the suitable and general schemes in a winding mechanism. In general, the quality of wound roll is known to be related to the lateral displacement error and starring defect of a wound roll. Especially, a telescoping within a center-wound roll can cause damages such as misalignment between layers, folding, wrinkle, etc. Taper tension is known to be one of the major factors which affect the shape of a wound roll. It is therefore necessary to analyze the relationship between taper tension profile and telescoping within the center-wound roll to prevent winding failure and to sustain high quality of the printed materials. It is hard to compensate for undesirable winding roll shapes such as telescoping, because a winding is commonly a final process in roll to roll systems and has no feedback control mechanism to correct winding roll shape directly during winding operation. Therefore, an optimal taper tension profile and the accurate control of it in a winding section could be one way to shape the fail-safe of a wound roll. Through the correlation between taper tension profile and telescoping in a winding process, a mathematical model for the telescoping due to tension distribution in cross machine direction was developed, and verified by experimental study. A new logic to determine the proper taper tension profile was designed by combining and analyzing the winding mechanism which includes nip induced tension model, relationship between taper tension profile and telescoping, relationship between taper value and telescoping. Numerical simulations and experimental results show that the proposed method is very useful for determining the desirable taper tension profile during the winding process and preventing defects of winding roll shape such as telescoping.     

自动拆卸电路板电子元件装置的设计

物理机械法对废弃印刷电路板上的电子元件实现自动拆卸是现在废弃电路板处理技术的发展趋势.本文针对已有的螺旋拆卸装置对电子元件拆除破坏性较大、拆除率不高等缺点,设计了一种带有通过式连续加热炉的自动拆卸设备,利用带有夹具传送装置和自动入料装置实现自动入料、自动拆卸、自动出料的功能,最后通过试验表明该装置拆卸电路板电子元件高效、可靠、安全,且电子元件损坏率低.     

晶闸管可控整流对卷绕式镀膜机张力控制的影响

介绍用品闸管可控整流器控制直流电机时对卷绕式镀膜机张力控制的影响，并对引起张力不稳定的原因进行分析、提出解决方案。     

变压法在大型电力变压器干燥过程中的应用

水分是影响大型电力变压器寿命的重要因素之一,常规的干燥方法容易使绝缘表层毛细管萎缩,影响绝缘深层水分的蒸发,同时,由于受蒸汽压力和干燥罐真空度等等多方面的影响,PID控制器参数难于整定,经常产生很大的超调。采用变压法后,控制器执行器采用可编程控制器,人机界面采用在工控机平台下的组态软件,系统运行后稳定可靠,变压器干燥取得了很好的经济和社会效益。     

瓶颈工序影响下汽车电子生产车间排程研究

针对汽车电子生产车间作业排产面临的在制品(Work In Process,WIP)堆积、生产周期长和订单准时交付率低等问题,梳理汽车电子零/部件生产车间排程逻辑,依托于约束理论(Theory Of Constraint,TOC)和“鼓-缓冲-绳子”(Drum-Buffer-Rope,DBR)方法,识别瓶颈工序,以完工期限最早优先(Earliest Due Date,EDD)和提高产出率为原则,引入交付紧迫系数,建立了瓶颈工序影响下的订单优先排产计划模型。以某汽车电子零/部件企业的印刷线路板(PCBA)生产车间实际生产数据为例,结合订单优先排产计划模型对PCBA订单进行作业时间排程,验证了该模型的有效性,为汽车电子生产车间排程提供了一种新的可行方案。     

可卸式防尘盖工装设计分析

叙述了可卸式防尘盖采用两道工序的工装设计适用于中大型防尘盖加工，采用一道工序的工装设计适用于中小型防尘盖的加工。通过对比，分析了两种工装设计的优缺点。     

微波干燥过程数学模型建立与分析

介绍微波的定义、应用现状以及微波干燥的特点,通过一系列数学推导给出微波干燥过程的数学模型,并对其中的一些问题进行讨论.     

An application of ESD technology for the R2R printing process

The conductive coating method is used for various industrial fields. For example, the sputtering process is used to coat the ITO layer in LCD or OLED panel manufacturing process and fabricate a base layer of substrate of an electric printing device. However, conventional coating processes (beam sputtering, spin coating etc.) have problems in the industrial manufacturing process. These processes have a very high cost and critical manufacturing environment as a vacuum process. Recently, many researchers have proposed various printing processes instead of conventional coating processes. We propose an ESD printing process in ITO coating layer and apply to fabricate a conductive coating film. Furthermore, the effect of the nozzle and also the applied voltage on different configurations of the nozzle head was also studied for better understanding of the electro static deposition process.