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.     

A backstepping-based control algorithm for multi-span roll-to-roll web system

Multi-layer printing technology is used wisely in printed electronics industry. The small variation of web tension will reduce the quality of production. Thus, web velocity and tension control algorithm play an important role in improving the quality of product in roll-to-roll manufacturing technology. Most algorithms of linearized systems proposed in recent years use PI or PID controllers. Due to the increasing demand of high accuracy in printed electronics industry at micrometer-level, it is necessary to have a precise control scheme of web velocity and tension in the presence of disturbance. In this paper, a mathematical model of modified strict form model is proposed, and a systematic design method of backstepping controller is formulating for this model by using the backstepping based design. By using the proposed theory, a precise control algorithm is proposed for three-span roll-to-roll web control system. The design parameters are chosen optimally by using the modified genetic algorithm. The outcomes of proposed algorithm prove the reliability throughout simulation results in Matlab/Simulink and experimental results.     

无轴传动凹版印刷机的相邻偏差耦合同步控制

针对无轴传动凹版印刷机的同步协调控制,考虑印刷基体张力恒定和套印准确的要求,基于相邻偏差耦合思想提出了一种能同时满足凹版印刷机无轴传动系统完全同步和比例同步特点的控制结构。针对无轴传动系统动力驱动部件非线性、强耦合的特点,设计了2阶自抗扰控制器以实现收放卷牵引单元与印刷色组单元高精度的跟踪控制和扰动补偿。构建了无轴传动凹版印刷机同步控制策略的仿真模型,仿真结果表明,提出的同步控制结构具有较高的同步控制精度和稳定性,设计的自抗扰控制器具有较好的速度跟踪性能和抗扰能力。     

A study on tension behavior considering thermal effects in roll-to-roll E-printing

The mathematical model for tension in a moving web by Shin [1] was extended by considering thermal strain due to temperature fluctuations in the drying of a roll-to-roll system. The extended model describes variations in tension and includes terms that represent the change of the Young’s Modulus, the thermal coefficient, and the thermal strain. In this paper, a new control scheme based on the extended model is proposed for mitigation of tension disturbances due to thermal strain in the drying process. Tension feedback control logic generally is not be applied due to the fact that register errors can be induced by speed alterations that help to compensate for tension disturbances. But in our approach, the thermal strain in the web is compensated for by means of velocity adjustments without adding extra register errors in the steady state. A computer simulation followed by an experimental validation was carried out to confirm the performance of the proposed method. The results show that the proposed model is useful for describing tension behavior and suggest that tension control logic improves control precision for the drying module of a roll-to-roll e-printing system.     

基于多层模糊控制的交叉耦合补偿方法的研究及应用

采用交叉耦合控制能有效地提高复杂曲面轮廓精度,但是传统的交叉耦合控制需要一个确定的数学模型,而且对于大于3轴的多轴交叉耦合控制,由于建模非常困难等原因,现有的研究成果比较少。在加工复杂轮廓时,由于各个轴之间的耦合强度是不同的,所以在前人研究的基础上提出基于多层模糊的交叉耦合补偿方法。该方法根据各个轴之间耦合关系的强弱对耦合层次进行划分,然后设计多层耦合控制器,对实时的轮廓误差进行补偿,更符合实际控制系统的组合规律,所以综合的控制性能更高。最终,将该方法在四轴联动对称加工机床上进行实验研究。     

A study on the tension estimator by using register error in a printing section of roll to roll e-printing systems

The focus of this study is on the development of a mathematical model for estimating tension of a printing section by using the register error in R2R (Roll to Roll) e-Printing systems. In a printing section of conventional R2R printing systems, the tension is generally measured not for controlling but for monitoring, because the tension control may cause the occurrence of a register error. But, for high precision control, the tension in the R2R e-Printing system must be controlled as well as measured for more precise control of the register error. The tension can be measured by the loadcell in the conventional R2R systems. However, installing a loadcell on the R2R systems causes extra economic burden. In addition, the space for adding a loadcell on R2R systems is limited due to many components including dryers, lateral guider, doctor blade, ink supply unit and cooling unit. Therefore, a tension estimator can be another possibility for predicting the tension in a printing section. In this study, a new tension estimation model is proposed. The proposed model is based on the register error model, the equivalent torque equation, and the tension model considering tension transfer. Numerical simulations and experimental results showed that the proposed model was effective in estimating the tension in a printing section. This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo Chang-Woo Lee received a B.S. degree in Mechanical Engineering from Konkuk University in 2001. He received his M.S. and Ph.D. degrees from Konkuk university in 2003 and 2008, respectively. Dr. Lee is currently a researcher at the Flexible Display Roll to Roll Research Center at Konkuk University in Seoul, Korea. Dr. Lee’s research interests are in the area of fault tolerant control, R2R e-Printing line design, and tension-register control. He is the holder of several patents related to R2R e-Printing system. Jang-Won Lee received the B.S. and M.S.degrees in mechanical engineering from Konkuk University, Seoul, Korea. He studied continuous flexible process at the FDRC (Flexible Display R2R Research Center, Project Director: Kee-Hyun Shin), as a reseacher from the concentment to 2008. Since 2008, he has been a Research Engineer with the SKC Films R&D, Suwon, Gyeonggi-do, Korea. Now he is great on the plastic flim mechanics such as a scratch on the film surface, film extruding, winding/slitting mecha-nism and coating processes. Hyunkyoo Kang received the B.S. and M.S degree in 2000 and 2003 res-pectively from Konkuk Uni-versity, Seoul, Korea, where he is currently working toward the Ph. D. degree in mechanical design. He took part in the development of an autoalign guiding system for high-speed winding in a cable winding system, a 3-D roll-shape diagnosis method in a steel rolling system, a design of register controller for high-speed converting machine and real-time control design of electronic printing machine. His research topics include register modeling and control for printed electronics and distributed real-time control. Kee-Hyun Shin received the B.S. degree from Seoul National University, Seoul, Korea, and the M.S. and Ph.D. degrees in mechanical engineering from Oklahoma State University (OSU), Stillwater. Since 1992, he has been a Professor with the Department of Mechanical and Aerospace Engineering, Konkuk University, Seoul, Korea. For more than 18 years, he has covered several research topics in the area of web handling, including tension control, lateral dynamics, diagnosis of defect rolls/rollers, and fault-tolerant realtime control in the Flexible Display Roll-to-Roll Research Center, Konkuk University, of which he has also been a Director. He is the author of Tension Control (TAPPI Press, 2000) and is the holder of several patents related to R2R e-Printing system.     

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.     

Advanced technique for achieving 10-μm-width fine lines in roll-to-roll continuous gravure printing

In roll-to-roll continuous printing, given the limitations in the pattern engraving technique and the need for accurate contact angle control between the ink and substrate, printing fine lines in the 10-μm scale is a major hurdle that needs to be addressed to achieve mass production of printed electronic devices. To address this issue, we propose a novel printing method based on gradation engraving; this method allows for both greater control over the width decrement of printed patterns as well as narrower fine lines than those achieved using an engraved pattern in the printing roll. Our experimental results show that, using the proposed method, printed line widths could be decreased according to the curvature of the sidewall of the engraved cell, even in the same aspect ratio. Furthermore, the width of the printed pattern was decreased by up to 62%, as compared to that achieved via the engraved cell, and a fine printed line narrower than 10-μm could be achieved. The proposed method represents a suitable alternative for the fabrication of 10-μm, or even thinner, fine conductive lines via the roll-to-roll continuous printing process.     

Variable speed compensation method of errors of probes for CNC machine tools

Systematic errors of kinematic touch-trigger probes for CNC machine tools may exceed errors of the machine tool itself. As a result, the machining accuracy is strongly dependent on the probe's accuracy. Numerical correction of probes’ systematic errors can be used. However, it requires executing calculations by the CNC machine tool controller. To avoid this troublesome requirement, a new method of errors compensation is proposed. In this approach, a modification of the probe's pre-travel in a given direction is achieved by modification of measurement speed in this direction. Because all measurement speeds can be calculated offline, the controller does not have to do any calculations. The proposed method has been tested for sample kinematic probes and the error reduction was at least 10-fold.     

Manufacture of face-hobbed straight bevel gears using a six-axis CNC bevel gear cutting machine

Face hobbing is a continuous indexing and double-flank cutting process whose high productivity and precision has made it one of the leading methods for fabricating spiral bevel and hypoid gears. The current method is inappropriate, however, for cutting straight bevel gears (SBGs) because it generates extended epicycloidal flanks. Nonetheless, a mathematical model of a face-hobbed SBG was successfully established in earlier research that enables straight cutting paths to cut straight tooth spaces based on a hypocycloidal straight-line mechanism in which the rolling circle radius equals half the base circle radius. This mathematical model, however, is based on a virtual universal cradle-type bevel gear cutting machine that has not yet been developed. This paper therefore proposes another mathematical model of face-hobbed SBG based on a modern six-axis computer numerical control (CNC) bevel gear cutting machine. The six-axis nonlinear machine settings are derived through conversion from the cradle-type machine settings. Meanwhile, the usage of electric gearbox (EGB) for bevel gear cutting is not revealed because of commercial consideration. Therefore, we also provide a solution to use EGB of Fanuc 16i CNC controller. A cutting experiment validates the proposed mathematical models using our developed six-axis CNC bevel gear cutting machine to cut the face-hobbed SBGs. Finally, a flank topographic correction is made that, according to postcorrection simulated topographic errors, can effectively reduce manufacturing errors. This paper successfully implements a face-hobbing process for manufacturing SBGs on a modern six-axis CNC bevel gear cutting machine.     

VT-Flex100型印刷线退卷张力控制系统的改造

高速印刷生产线的退卷单元的张力控制系统是确保生产连续、稳速进行的关键设备，退卷单元的张力失控将直接影响套印精度，还会引起退卷单元驳接换料失败，甚至会导致印刷单元机件损坏。介绍了VT—Flex100型印刷线退卷张力控制系统的改造项目，结果证明这项技改是成功的。     

高速点阵式脉冲喷射发生器的无传感器控制

为提高标识设备关键部件—高速点阵式脉冲喷射发生器的性能以改善喷印效果,在建立喷射器数学模型的基础上,设计了滑模观测器.通过观测器构成反馈系统,在不增加硬件成本的前提下实现对高速脉冲喷射器的无传感器控制,使其能够准确跟踪理想轨迹,降低阀芯与静铁的冲击速度,并消除振动和噪音.实验结果表明,喷射器工作过程中阀芯与定位静铁的冲击速度由开环控制的0.55 m/s降到了闭环控制的0.02 m/s,振动和噪音基本消失,喷射效果明显改善.对钢铁产品进行的喷码实验显示,设计的喷射器的性能可以满足实际生产需要.研究过程为高速脉冲喷射器控制单元的设计提供了理论基础.     

增材制造工艺匹配性评估的宏微观决策模型

增材制造存在悬空区域难制造、不同结构和不同性能要求零件的可成形性难预测等突出问题,提前评估工艺的匹配性和合理性具有重要意义。提出了一种宏微观一体化综合决策模型,从增材制造工艺角度评估零件的可成形性,根据打印零件的效果推演出最佳的成形策略。宏观决策阶段建立设计需求与制造工艺间的数学模型,从可成形性角度评判工艺的匹配程度;微观决策阶段建立表面粗糙度、支撑结构体积和打印时间的数学模型,从打印质量的角度优化打印工艺。最后,以拓扑优化的梁结构零件为例,利用建立的综合决策模型优化其打印工艺,结果表明,实际打印结果与模拟打印结果一致,验证了数学模型的有效性。     

电容器绝缘套管自动烫印裁切一体机设计

该设备利用伺服和步进驱动实现套管带和烫印纸的定长传送;由气缸控制套管烫印头与裁切刀具的运动;利用多传感器实现烫印纸有无、套管有无、套管的上偏和下偏、生产安全防护等的自动检测;利用可编程序控制器和图形操作终端,实现系统的自动控制、生产工艺参数的设定和调整。整机性能稳定可靠,已在铝电解电容器生产企业得到应用。     

Effect of roll patterns on the Ink transfer in R2R printing process

Ink transfer process from the printing roller to the web was investigated using a CFD technique for the roll-to-roll printing applications. A parametric study was conducted to identify the effects of roll pattern geometry on the ink transfer process. In order to make the present analysis more relevant to the real printing system, 3-D computational configuration was set up using the information obtained from the typical roll-to-roll system. Simplified one-dimensional semi-analytic analysis based on Reynolds equation was also conducted in order to assess the validity of the 3-D CFD results. Pressure information suggests that even a simplified 1-D analysis is reasonably good in capturing the relevant flow physics. 3-D simulation shows that the quality of the ink transfer process is very sensitive to the width of the roll patterns. This sensitivity is believed to be due to the relative importance of surface tension over any other force modes under the 100 micrometer range.     

RFID标签整理机原理设计和Matlab仿真

为了在射频识别（RFID）标签整理机工艺设计的过程中,验证设计思想的正确性,以减少原则性错误,采用Matlab软件进行了仿真分析。首先,对RFID标签和料带做了数学模型的描述定义;然后,从这个数学模型出发推导出了光电的检测模型、RFID的测试模型,以及解决了伺服系统如何驱动料带的难点;又定义了废品选择门的模型和先人先出队列数据结构;最后,对于选择门和先入先出队列数据中断移位算法用STATEFLOW工具箱进行了仿真,从而达到使用Matlab对整体机械工艺完成模拟仿真的目的。研究结果表明,该料带数学模型和整体机械工艺仿真技术在印刷包装领域的新工艺设计阶段具有很大的用途。     

Analysis on the ink transfer mechanism in R2R application

Ink transfer process from the printing roll to the web was investigated using a Computational Fluid Dynamics (CFD) technique for the roll-to-roll (R2R) printing application. A parametric study was conducted to identify the effects of fluid parameters such as viscosity, surface tension and contact angle. To make the present analysis more relevant to the real printing system, a three-dimensional computational configuration for the commercial software was set up using the information obtained from the typical R2R system. Simplified one-dimensional semi-analytic model based on Reynolds equation was compared with the CFD results to assess the validity of the results. Pressure distribution states that 1-D analysis is reasonably good in capturing the flow physics. The 3-D simulation with VOF (Volume of Fluid) shows that viscosity is the most important parameter. Moreover, the larger surface tension resulted in smaller amount of ink transfer.     

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.     

Machining tests to identify kinematic errors of machine tool table rotation axis based on sensitive directions

Machining tests based on homogeneous transformation matrix approach are relatively complex and time resuming in the mathematical modeling and the implementation of measurement and calculation. A new method is proposed to identify the kinematic errors of the rotation axis of machine tool table by machining tests based on sensitive directions. In order to identify the kinematic errors in the sensitive direction conveniently, a simple mathematical model of the kinematic errors is developed by optimizing the coordinate system settings based on basic kinematic transformation, and the sensitive direction vector was adopted to identify the kinematic errors from the machining errors of the finished workpiece. Experimental results demonstrate that the proposed method can reduce the complexity and time resuming substantially.     

高精度数字电子雕刻机控制系统的研究

从现代数字电子雕刻的基本原理出发,对数字电子雕刻机滚筒传动电机与横向丝杠传动电机之间的关联性控制参数进行了研究,并根据高精度凹版雕刻机的要求,研究了基于磁场定向控制交流伺服电机控制器,在此电机控制器基础上实现了高精度电子雕刻机控制系统.雕刻的结果表明,设计的交流伺服电机控制器及控制系统都能稳定而准确的运行,也表明了研究的关联控制参数是正确的,控制的方法是有效的.