焊膏印刷机制造数据处理软件的设计与实现

近年来, SMT已被广泛地应用在了电子电路制造业。焊膏印刷作为SMT生产工序中的关键步骤,将直接影响到PCB的质量。因此,设计并实现了在生产过程中对焊膏印刷机关键参数实时监控软件,为焊膏印刷机关键参数的分析、可视化处理等提供了途径,推动电子产品向着高质量、高效率、低成本的方向发展。     

基于ACR9000控制器的自动光学检测平台设计 

针对自动光学检测(AOI)平台运行过程中的定位精度控制问题,提出了一种基于速度和加速度前馈控制与PID反馈控制的复合控制算法,该算法对输入量进行跟踪补偿控制以消除系统稳态误差,用于提高AOI平台定位精度;基于开放式的数控系统设计方法设计了AOI平台;在Matlab/Simulink环境下,构建了基于该复合控制算法的定位精度控制仿真模型,仿真结果验证了复合控制算法的有效性;将该复合控制算法作为ACR9000控制器的控制算法,并基于ACR9000控制器进行AOI平台实验研究;应用该AOI平台进行了印刷电路板(PCB)检测实验,实验结果表明文中复合控制算法能够提高AOI平台定位精度,AOI平台的定位精度满足印刷电路板检测要求,可以将该AOI平台用于印刷电路板检测。     

自动光学检测在中国的应用现状和发展

本文首先概括了自动光学检测(AOI)的测试优点,然后结合具体产品讨论了AOI(包括AXI)的最新技术和发展,以及图像处理算法应用概况。接着对国外几家著名公司AOI产品作了简单介绍,并对国内目前AOI产品的研制情况进行了综述。最后介绍了几种基于AOI的电子组装综合检测技术。     

AOI技术在PCB缺陷检测中的设计与实现

随着计算机技术和数字图像处理技术的快速发展,传统PCB缺陷检测技术因技术落后已经无法满足现代PCB质量的要求,而AOI技术以其准确、高效的特点在PCB缺陷检测中的应用越来越受到重视.主要研究了AOI技术在PCB缺陷检测中的实际应用,分别进行了硬件选择和软件系统研究,建立了基于AOI技术的PCB缺陷检测系统,采用基于轮廓对比的数据处理方法进行缺陷检测.实验证明了该系统的可行性与实用性.     

AOI技术在SMT生产上的实施技巧与策略

简要介绍了当今SMT应用的先进自动光学检查技术，通过分析SMT生产方式，有针对性地提出了配合SMT柔性生产模式的实施技巧与策略，并分析了其在SMT生产上的应用时应注意的几个问题和工艺要点。     

基于二值投影的PCB元件安装缺陷检测算法研究

研究分析了适用于AOI设备的PCB表面安装元件的缺陷检测算法.使用二值投影分析方法对2种元件类型的缺陷检测方法进行了研究,包括针对贴片电阻电容类型的chip元件和集成电路芯片类型的IC元件的缺陷检测方法.使用VC++6.0编写MFC程序实现算法,并制作了各种元件图像进行实验测试.实验结果表明,提出的方法能够快速有效的对两种类型的元件安装缺陷进行检测.     

数据驱动的焊膏印刷工艺参数推荐技术

针对印制板焊膏印刷过程中工艺参数制定主观性大、经验依赖性强的问题,提出一种数据驱动的印刷工艺参数推荐方法。首先构建面向每一元器件焊膏印刷质量预测模型,包括面向每一元器件的印刷合格率预测、焊膏相对面积/体积预测、印刷缺陷类型预测3个子模型;其次以每一元器件印刷质量最优为目标,构建印制板焊膏印刷工艺参数推荐模型;最后基于实际印制板的印刷数据中对各模型的正确性进行验证,印刷合格率预测的平均准确度达到98%,推荐出的工艺参数的偏差值与经验值的偏差小于10%,质量预测和工艺参数推荐结果均可满足实际生产应用要求。     

基于Freescale微控制器的AOI多彩照明控制系统

为了检测出高密度印刷电路板(HDI PCB)中的多种焊接缺陷,对用于自动光学检测(AOI)设备的多角度多色彩LED照明装置的控制系统进行软硬件改进,设计了一种以Freescale--MC9H12XS128为微控制器的多彩照明控制系统。控制系统的硬件结构简单,可同时对4组LED阵列进行脉宽调制控制,根据实际图像的提取效果,通过接收主控上位机发出的指令,对不同LED阵列进行颜色选择和256级光照亮度的调节。实验结果表明,该系统能满足AOI设备对照明装置提出的各种要求,使照明系统光照均匀,光强可调,响应快,发热量小。     

国内首台自动光学检测设备研制成功

日前,由中国电子科技集团第45所承担的国际科技合作项目“自动光学检测（AOI）设备技术合作”,通过了国家级验收,技术指标达到了国外同类设备水平,标志着自动光学检测（AOI）设备实现了国产化,填补了国内空白。     

多核并行AOI系统软件框架设计

针对现有自动光学检测(AOI)难以满足大规模高速、高精度和高灵敏TFT在线检测要求的问题,提出AOI混合多核计算机集群体系架构,研究AOI系统的软件框架设计及其关键软件技术。结果表明,采用基于OpenMP, MPI, OpenCV和IPP等技术的并行图像处理融合编程模型及其实现策略可有效克服TFT缺陷检测的性能瓶颈。     

PCB 锡膏图像采集参数的研究

利用图像处理技术对锡膏进行检测是锡膏检测中的一种新方法,图像质量是确保图像检测精度的关键之一。图像采集对于保障图像质量来说有着至关重要的作用,是最终获取图像有用信息所进行的一系列处理步骤中关键的第一步。重点研究了影响锡膏图像采集的焦距、曝光、增益三个主要参数,并通过实验确定了焦距、曝光和增益等三个主要参数的合理取值范围以及快门速度与增益之间的函数关系。为锡膏图像采集参数的调整提供了依据,也为后续研究锡膏图像采集的参数自动调整奠定了基础。     

Design and development of automatic visual inspection system for PCB manufacturing

Inspection of solder joints has been a critical process in the electronic manufacturing industry to reduce manufacturing cost, improve yield, and ensure product quality and reliability. This paper proposes two inspection modules for an automatic solder joint classification system. The “front-end” inspection system includes illumination normalisation, localisation and segmentation. The “back-end” inspection involves the classification of solder joints using the Log-Gabor filter and classifier fusion. Five different levels of solder quality with respect to the amount of solder paste have been defined. The Log-Gabor filter has been demonstrated to achieve high recognition rates and is resistant to misalignment. This proposed system does not need any special illumination system, and the images are acquired by an ordinary digital camera. This system could contribute to the development of automated non-contact, non-destructive and low cost solder joint quality inspection systems.     

SMT锡膏检测中基于Delphi与OpenGL的锡膏三维显示

研究在Delphi下采用OpenGL编程显示锡膏三维形态的方法,并且实现旋转、缩放及根据锡膏厚度显示不同的颜色等功能。实验结果表明：在Delphi7.0平台上采用OpenGL编程实现锡膏三维形态实时动态显示不仅可以避免大量的矩阵运算、减少程序代码长度、提高编程效率,而且能够提高图形的显示效果。     

A neurofuzzy-based quality-control system for fine pitch stencil printing process in surface mount assembly

Surface mount assembly defect problems can cause significant production-time losses. About 60% of surface mount assembly defects can be attributed to the solder paste stencil printing process. This paper proposes a neurofuzzy-based quality-control system for the fine pitch stencil printing process. The neurofuzzy approach is used to model the nonlinear behavior of the stencil printing process. Eight control variables are defined for process planning and control, including stencil thickness, component pitch, aperture area, snap-off height, squeegee speed, squeegee pressure, solder paste viscosity, and solder paste particle size. The response variables are the volume and height of solder paste deposited. The values of the response variables provide indicators for identifying potential quality problems. A 3^8–3 fractional factorial experimental design is conducted to collect structured data to augment those collected from the production line for neurofuzzy learning and modeling. Visual basic programming language is then used for both rule retrieval and graphical-user-interface modeling. The effectiveness of the proposed system is illustrated through a real-world application.     

Experimental design with fuzzy levels

A novel technique is introduced for planning experimental design employing fuzzy rule-based systems. The significant aspect of the proposed experimental design with fuzzy levels (EDFL) is assigning a membership function for each level of variable factors. Consequently, the design matrix and observed responses can be represented in a set of fuzzy rules. Several examples are presented to clarify the proposed idea and the results are compared with the conventional Taguchi methodology. We have specifically planned an L18 orthogonal array EDFL for the solder paste printing stage of surface mount printed circuit board assembly to provide a model for the process and to optimize the selection of variable factors.     

低熔点无铅焊料的研制

现有的Sn-Ag-Cu无铅焊料其关键问题是熔点比传统的Sn-37Pb高34℃～38℃，使得焊接设备和工艺都必须更换。我们在Sn-20Bi焊料的基础上通过添加微量元素并采用快速凝固的方法研制出一种新型的低熔点焊料。该焊料价格远低于Sn-Ag-Cu，其机械性能、热性能、可焊性以及熔点都接近或优于Sn-37Pb。     

A wavelet-based multi-dimensional temporal recurrent neural network for stencil printing performance prediction

The solder paste printing (SPP) is a critical procedure in a surface mount technology (SMT) based assembly line, which is one of the major attributes to the defect of the printed circuit boards (PCBs). The quality of SPP is influenced by multiple factors, such as the squeegee speed, pressure, the stencil separation speed, cleaning frequency, and cleaning profile. During printing, the printer environment is dynamically varying due to the physical change of solder paste, which can result in a dynamic variation of the relationships between the printing results and the influential factors. To reduce the printing defects, it is critical to understand such dynamic relationships. This research focuses on determining the printing performance during printing by implementing a wavelet filtering-based temporal recurrent neural network. To reduce the noise factor in the solder paste inspection (SPI) data, this research applies a three-dimensional dual-tree complex wavelet transformation for low-pass noise filtering and signal reconstruction. A recurrent neural network is utilized to model the performance prediction with low noise interference. Both printing sequence and process setting information are considered in the proposed recurrent network model. The proposed approach is validated using practical dataset and compared with other commonly used data mining approaches. The results show that the proposed wavelet-based multi-dimensional temporal recurrent neural network can effectively predict the printing process performance and can be a high potential approach in reducing the defects and controlling cleaning frequency. The proposed model is expected to advance the current research in the application of smart manufacturing in surface mount technology.     

纳米铜焊膏烧结互连技术研究现状与展望

纳米铜焊膏在低温烧结后可形成耐高温、高导电导热同质互连结构,该互连结构不仅可避免锡基焊料层和烧结银层服役过程中出现桥接短路和电迁移的可靠性问题,还可解决异质互连结构热膨胀系数不匹配的问题,在集成电路和功率器件封装领域具有重要应用价值。近年来,在铜纳米颗粒稳定性和低温烧结性能方面,纳米铜焊膏烧结互连技术取得了重大研究进展。但与纳米银焊膏烧结互连技术相比,纳米铜焊膏的稳定性、低温烧结性能和可靠性仍有较大提升空间。该文从烧结互连机理、烧结工艺调控、铜纳米颗粒表面改性、纳米铜基复合焊膏、互连可靠性和封装应用方面,阐述了纳米铜焊膏烧结互连技术的最新研究进展,并对后续的技术发展和研究思路进行了展望。     

Improving the fine-pitch stencil printing capability using the Taguchi method and Taguchi fuzzy-based model

This paper presents industrial applications for improving the capability of the fine-pitch stencil printing process (SPP) based on the DMAIC framework and using Taguchi-based methodologies. SPP is widely recognized as the main contributor of soldering defects in a surface mount assembly (SMA). An inadequate volume of solder paste deposition or poor printing quality can cause soldering defects and lead to significant reworking and repairing costs. In practice, both the desired amount of solder paste volume (quantitative index) and printing quality (qualitative index) are preferably used to monitor the SPP for the reduction of soldering defects during the statistical control process (SPC), particularly for a fine-pitch solder paste printing operation. To continuously improve SPP capability, the DMAIC framework is followed and Taguchi-based methodologies are proposed under the considerations of single characteristic performance index (SCPI) and multiple characteristic performance indices (MCPI). The SCPI is optimized using the conventional Taguchi method. Then, a Taguchi fuzzy-based model is developed to optimize the SPP with the MCPI property. Optimizing a multi-response problem by the Taguchi method involves the engineer's judgment which tends to increase the degree of uncertainty. The performance of these two approaches is compared through the process capability metric, and the material and factors significantly affecting the fine-pitch SPP performance are reported.     

基于彩色图像分割技术的SMT焊点质量检测

图像分割的策略和方法是SMT焊点图像处理的一项关键技术,也一直是SMT焊点计算机质量检测的瓶颈;以SMT焊点的颜色和几何特征作为分析对象,在灰度图像分割所用二维阈值化的分割方法的基础上,提出一种从颜色直方图的量化级数和二维直方图概率密度不均匀化两个方面改进后的适用于HSV彩色空间图像分割技术,并将其应用于SMT焊点的质量检测;通过其得到SMT片式元器件焊点的图像,对其进行形态学处理后,利用Matlab软件将SMT焊点成功地从PCB板上分离出来,为三维重建提供良好的基础。