Integrated modelling of a time-pressure fluid dispensing system for electronics manufacturing

In electronics manufacturing the time-pressure dispensing system has been widely used to squeeze adhesive fluid in a syringe onto boards or substrates with pressurised air. For accurate control of the fluid volume, it is vital to have a thorough understanding of the whole process. However, the complexity of the process, which includes air-fluid coupling and their nonlinear uncertainties, makes it difficult to obtain an accurate process model. Using the spectral method, an approximate fluid flow model for both the Newtonian and non-Newtonian fluid can be developed. By taking into account nonlinear flow passing through the valve, attenuation and time delay in the pneumatic lines, syringe chamber dynamics and fluid flow dynamics, a simple but effective model is derived to describe the whole dispensing system with reasonable accuracy. Experiments performed thereafter validate the model.     

机器人贴装涂胶过程建模与时序分析

空间太阳电池帆板的贴装生产过程目前在国内依旧采用单一手工操作,很难保证质量.该文对太阳电池帆板自动贴装机器人的涂胶过程进行了流动特性建模与时序状态分析,确定了机器人单片涂胶周期和串联涂胶周期,得到了机器人任一涂胶拐点处的时序值,及任意时刻机器人对应的涂胶位置坐标.通过对机器人的涂胶过程分析,得到了针管内胶体流动的速度场模型,并确定了胶体流量算式,给出了不同变量条件下涂胶过程的速度场模型及涂胶流量模型,为空间太阳帆板的自动贴装涂胶生产提供了可靠的数据模型.     

BONDING OF MINIATURE PARTS WITH ADHESIVES AND VISION BASED PROCEDURE INSPECTION

Bonding with adhesives is an important technique for building up hybrid microsystems.Some adhesives are tested with capillary dispensing system for microassembly, and volume of dropletsless than 10 nl with good repeatability can be acquired. 1-part UV curing adhesive hardens rapidly andis suitable for bonding of transparent microparts. Light-activated adhesive starts the curing process inan adjustable short period of time after the radiation of visible light, and thus suits bonding ofnon-transoarent microparts. A method is proposed for bonding the guides of a miniature linear motorbeing developed by collaborate research center 516 (SFB516) in Germany.With the method high as-sembly accuracy in the vedical direction can be guaranteed. By making small grooves on the stator forcontaining adhesive, the deterioration of the accuracy due to the thickness of adhesive layer can beavoided. The criteria on deciding the size of the groove are given and analyzed. Vision based inspec-tion method is introduced for aut     

参数自调整非接触式微量试剂分配系统

在高通量的蛋白质结晶操作中,需要对近千种试剂进行快速,微量,精确的试剂分配操作,而且对试剂分配系统的可靠性,灵活性和精确性要求也不断提高。本文研制了一款具有控制参数自调整功能的非接触式微量试剂分配系统。该系统采用精密微电磁阀控制预压液体的流动来实现试剂的分配操作。独特的试剂分配管路设计使电磁阀不易堵塞;非接触式的分配方式减少了试剂污染情况,分配速度更快,更易清洗;自行研制一款MEMS压差式微流量传感器并集成于系统中用于采集试剂分配过程中的流量信息,实现了试剂特性和体积变化时控制参数的自动调整功能,提高了分配精度和灵活性。文中详细介绍了系统的组成结构以及试剂分配过程原理。最后,针对不同粘性试剂进行分配精度的测试,结果表明该系统最小可分配50nl体积试剂,分配精度达8%。在分配试剂体积大于1μl时,重复精度<3%。     

微电子封装点胶技术的研究进展

流体点胶是一种以受控的方式对流体进行精确分配的过程,它是微电子封装行业的关键技术之一。目前,点胶技术逐渐由接触式点胶向无接触式（喷射）点胶技术转变。从微电子封装过程的应用出发,对点胶技术的发展进行了概述;在对比各种点胶方式的同时,重点介绍了无接触式喷射点胶技术,以及其中所涉及的关键技术,并提出了评价点胶品质的标准。     

Application of PCA-based hybrid Taguchi method for correlated multicriteria optimization of submerged arc weld: a case study

Fluid dispensing is a method by which fluid materials, such as epoxy, adhesive, and encapsulant, are delivered in a controlled manner in electronics packaging. This paper presents a brief review of past and recent developments in the modeling and control of the time-pressure fluid dispensing process. In particular, the characterization of the fluid flow behavior is addressed by reviewing several promising models from both time-independent and time-dependent perspectives. In the modeling of the time-pressure fluid dispensing process, various approaches for representing the flow rate of fluid dispensed and the profile of fluid formed on target are examined; and the issues involved are identified. In the control of time-pressure dispensing process, a brief review of various control methods is presented along with their limitations. The challenges associated with this control problem are also discussed. This paper is concluded with the recommendations of research in the future.     

高粘性液体试剂的自动化微量分配系统

在膜蛋白结晶等生物工程领域,常需要对高粘性生物试剂进行精确的分配和转移操作.研制一套液体操作机器人系统,它可以实现纳升级别高粘性试剂的精确分配操作.介绍该系统的结构原理,主要由运动控制模块、分配控制模块和液滴体积检测模块等组成,分别用来实现液滴的精确分配操作和体积检测功能.接下来对影响试剂分配过程的因素进行分析,给出成功实现微量试剂液滴分配操作时,分配头与基板之间高度必须满足的临界高度范围.针对具有不同粘度的三种试剂进行分配试验,验证理论分析结果,结果表明该系统分配精度小于7%,重复精度(用变异系数表示)小于10%.     

跨尺度微管微球三维半自动装配点胶系统

设计和搭建了一个3D半自动装配点胶系统,用于完成跨尺度零件微管与微球的三维装配点胶任务。系统主要由体视显微镜、变焦金相显微镜、发光二极管(LED)背光源、pL级点胶机、微操作手和零件夹持器组成。采用显微镜高低倍转换的方式实现了零件跨尺度特征的检测。基于提出的半自动装配点胶策略,并配合人工引导和显微视觉伺服技术,快速完成了跨尺度零件的半自动高精度对准和插入点胶。在搭建完成的系统上开展微管与微球的装配点胶实验,对提出的方法和装配精度进行了实验验证。结果表明,系统的位置对准误差优于1μm,角度对准误差优于0.5°,可以实现末端直径10μm的微管与孔径12μm的微球之间的装配和胶接,基本满足对该组件的装配精度和成功率要求。     

An empirical approach to modelling fluid dispensing for electronic packaging

Fluid dispensing is a popular process in semiconductor manufacturing industry which is commonly used in die-bonding as well as microchip encapsulation for electronic packaging. Modelling the fluid dispensing process is important to understand the process behaviour as well as determine optimum operating conditions of the process for a high-yield, low cost and robust operation. Previous studies of fluid dispensing mainly focus on the development of analytical models. However, an analytical model for fluid dispensing, which can provide accurate results, is very difficult to develop because of the complex behaviour of fluid dispensing and high degree of uncertainties of the process in a real world environment. In this project, an empirical approach to modelling fluid dispensing was attempted. Two common empirical modelling techniques, statistical regression and neural networks, were introduced to model fluid dispensing process for electronic packaging. Development of neural network based process models using genetic algorithm (GA) and Levenberg−Marquardt algorithm are presented. Validation tests were performed to evaluate the effectiveness of the developed process models from which a multiple regression model and a GA trained neural network with the architecture of 3-15-1 were identified to be the process models of the fluid dispensing respectively for the encapsulation weight and encapsulation thickness.     

高精密点胶螺杆泵的参数分析与性能研究

针对电子封装对胶液分配具有高精度的控制要求,基于单螺杆泵的运动学特性建立边界条件,采用三维计算流体力学软件对精密螺杆泵流场模型进行数值分析,研究了螺距、偏心距、转速和压差等参数对高精密点胶螺杆泵压力和流量稳定性的影响,得到使螺杆泵性能较优的T/D,T/e区间和适宜的转速区间,为确定合理的高精密点胶螺杆泵的结构参数和运行参数提供了理论依据。     

Microdispensing system via the contacting method

This paper presents the development of a microdispensing system based on a contacting method, with an aim to lowering production and maintenance cost. The liquid, to be dispensed, is brought into contact with the work piece, thus dispensing a droplet by making use of the adhesion force between the liquid and the work piece. A piezoelectric actuator is employed as the drive for the system to achieve high precision. The control of the system is accomplished with a PID controller; controlling the dispensing process and trajectory tracking.     

一种适于柔性RFID标签生产的微胶滴检测算法

根据柔性射频识别（RFID）标签批量生产装备对点胶质量严格控制的需求,提出了一种基于胶滴二维图像信息的点胶质量在线检测算法。该算法通过差分、滤波去噪和Blob分析等图像处理过程所得的胶滴图像获取胶滴二维信息,再依据胶滴的面积等参量对点胶质量进行评价。对不同基板和点胶量柔性RFID标签生产进行实际测试实验,实验结果显示,该算法适应性较好、胶滴尺寸波动较小,可对点胶一致性作出定量评价与分析。     

基于机器视觉的四通阀自动钎焊定位系统

为了提高四通阀焊接的速度和精度,提出了四通阀自动钎焊定位技术及系统。运用基于图像处理方法的计算机视觉技术,实现了对空调零件四通阀钎焊坐标的快速准确定位。采用近红外背光源进行照明,实现了对四通阀圆心坐标及侧面高度的自动检测。采用近红外背光源能使成像边缘更清晰易辨,具有环保节能、寿命长等优点。该系统主要通过阈值分割和PCA算法分别实现对四通阀铜柱圆轮廓提取和铜柱高度的水平投影,通过形状匹配和直线拟合获得圆心相对坐标和高度,实现对四通阀钎焊定位的检测。该系统具有速度快、准确率高、系统运行稳定等优点,在工业上的四通阀钎焊中具有较好的应用性和广阔的发展前景。     

微电子封装中的喷射点胶过程建模和控制

针对喷射点胶阀存在点胶一致性差的问题,提出了一种基于体积估计模型的批次PI控制策略。通过对胶体流变特性进行分析,基于胶体剪切应力和剪切速率关系建立了喷射点胶的流量模型,依此推导出体积估计模型。基于建立的模型,运用批次PI算法来实现喷射点胶阀的一致性控制。仿真和实验结果验证了体积估计模型的可靠性,并表明该控制方法能有效地改善喷射点胶的一致性。     

Modeling manufacturing processes using fuzzy regression with the detection of outliers

Empirical modeling, which involves various common techniques such as statistical regression, artificial neural networks and fuzzy logic modeling, is a popular approach to developing models for manufacturing processes. Among those techniques, statistical regression is the most popular one used to develop the explicit type of empirical models. However, if the experimental data and results contain a substantial degree of fuzziness, fuzzy regression is more appropriate for use in developing empirical models based on such data and results. In recent years, attempts have been made to use fuzzy regression to model manufacturing processes. However, it has been recognized that the existence of outliers can have a great effect on the prediction accuracy of a fuzzy regression model. This problem has not been well addressed in the previous studies on fuzzy regression. In this paper, an algorithm for detecting outliers based on Peters’ fuzzy regression is proposed. The application of the algorithm to developing a fuzzy regression-based process model of the dispensing of fluid for IC chip encapsulation is described. Finally, the results of the validation of the models are discussed.     

小流量电液伺服阀叠合量气动测量台的研制

为了提高小流量电液伺服阀叠合量的测量效率,实现叠合量气动测量过程的自动化,分析了电液伺服阀叠合量气动测量方法的原理及特点,采用压力式和流量式气动测量方法实现阀芯自动对中和叠合量自动精确测量。从机械结构设计和控制系统方案上提出了自动化策略,研制了一套小流量电液伺服阀叠合量气动测量台,实现叠合量高精度测量的全过程自动化。通过实验和工程实践验证,该测量台的叠合量测量精度达到±0.5 μm,且重复精度达到±0.5 μm。     

Model-based robust design for time�Cpressure fluid dispensing using surrogate modeling

In industry, the time?Cpressure dispensing system has been widely used to squeeze the adhesive fluid in a syringe onto boards or substrates with the pressurized air. For consistent dispensing of the fluid volume, it is vital to have a robust dispensing system insensitive to operation condition variation. In academia, much dispensing research has been done via modeling and control approach. However, a systematic design approach to determine an optimal operation condition for time?Cpressure dispensing is not available. This paper presents such a method for both line dispensing and dot dispensing, by means of model-based robust design. In particular, all kinds of the quantities involved in the dispensing task is classified into three groups: the design variables (DV), the design environment parameters (DEP) and performance functions, in the framework of model-based robust design. By this approach, the sensitivity analysis can be developed. While the sensitivity for DEP is analytic, whereas the sensitivity function for DV is more complex and have to be approximated by surrogate modeling. Thus the robust design can be used for time?Cpressure dispensing. The results show that dispensing performance robustness can be improved by choosing the appropriate system parameters. Simulations performed thereafter validate the effectiveness of this design method.     

MEMS热电堆芯片固晶工艺参数的优化

MEMS热电堆传感器能够实现对温度的精确测量，固晶工艺是其中关键一环，但目前尚缺乏有效方法精确优化MEMS热电堆固晶工艺参数。本文介绍了热电堆传感器的工作原理，提出了对固晶工艺参数（固晶厚度和爬胶高度）的要求。以固晶工艺要求为导向，初步探究了压力参数对固晶工艺的影响并进行了压力参数的优化。在优化的压力参数下，实验探究了点胶高度和贴片高度对固晶工艺的影响，并缩小了两参数的选择范围。在此基础上，通过有限元ANSYS软件，分析在相同温度下，不同固晶厚度的银浆与芯片接触处的热应力分布，找出最佳的固晶厚度参数，并精确优化了点胶高度和贴片高度。最后，通过实验验证的方式，对此参数下的MEMS热电堆固晶强度给出了检测结果。结果表明：压力参数为0.3 MPa、点胶高度为140 μm、贴片高度为460 μm时，固晶推力均值为43.14 N。其固晶质量最好，能够满足固晶强度要求，有助于提高MEMS热电堆芯片封装的可靠性与成品率。     

空间太阳电池自动贴装系统设计

提出了一种适用于空间太阳电池自动贴装技术的机器人系统,能够自动实现从太阳电池组件到太阳基板的贴装工作.该机器人由直角坐标导轨机构、布贴机构、涂胶机构以及控制系统和气动系统组成,文中详细介绍了机器人的构成原理,实验证明了该机器人进行太阳电池贴装操作的有效性和质量可靠性,能够克服电池碎片率高和胶液污染太阳电池等手工贴装作业的缺点.     

精密点胶螺杆泵胶液流动分析与数值仿真

分析了胶液在精密点胶螺杆泵内的流动过程。把胶液在螺杆泵内的流动分成入口段、螺杆段和针头段三段进行分析;建立三维几何模型,利用流体仿真软件FLUENT对胶液在螺杆旋转条件下的流动过程进行数值模拟,得到了螺杆转速、螺槽尺寸、入口压力和针头大小等参数对挤胶量的影响规律。通过试验验证了仿真结果的合理性。研究结果为确定合理的螺杆泵几何参数及外部条件提供了理论依据。