英语论文翻译

关键词：电子制造 互联网 印刷电路板 表面贴装技术 用户界面 1 介绍

表面组装技术向高密度封装的趋势已经突出了在有这些非常好搭的设备的组装线的固有困难。尽管所有都进步了，在印刷电路板装配技术（PCBA）中各种的缺陷仍然是常见的，并且PCBA的返工是不可避免的而且既然每个组件的成本和PCB本身的话费是几百美元那么必须在PCBA制造地板时必须手动执行。在过去的几年里，包括自动在内的在市场上可以供应的返工站的数量大幅度增长。在电子产品制造中，返工被定义为用那些符合执行标准的组件更换有故障的部件的活动。产品复杂性的增加，组件尺寸的减小以及双面板的使用已经使基于电子制造组件的表面贴装技术更难以组装。PCBA制造技术已经随着完全的自动化，准确组装机器和机器人的使用得到相对的提高。尽管显著改善自动返工也已经由编者之一完成，但事实表明自动返工线还不能产生一个足够可靠地搞得收益比例。这个调查的目的是通过建立一个基于知识的智能系统的电路板缺陷，对表面贴装返工技术做出贡献，这样需要返工操的缺陷可以通过电子制造装配线被检测到。随着这个系统的发展，有缺陷的板的数量将会从PCBA线上最小化，并且那些造成关节水平可靠性问题的PCBA工艺参数将被识别。这些问题的原因将借助于发达的网络系统被发现。 2 通用概述 应用于计算机，军事和电信应用程序的高价值的印刷电路板是21世纪的先进技术的发展的一个关键组成因素。在电子元器件中的小脚印和小特征的SMT技术的增长是这样PCBA的成功产品的巨大的技术障碍。

返工是指在一个印刷电路板过程中消除和替换有缺陷的电路组件。在过去的20世纪的几十年，各种不同的返工方法已经成功开发和测试，但是它也被证明他们没有一个产生最后的可靠地生产联合吞吐量线【1】。现在的新目标是开发替代方法，而不是利用手动，半自动或自动重做系统。那

些已经在调查中在关注如何消除这些制造业的原因问题的技术因为旧的技术联系，在返工是昂贵的，复杂的，需要熟练操作的【1，2】。这个返工操作设计几个步骤：把有缺陷组件清楚，清空组件站点，调剂新锡膏，放置新组件然后回流关节【3】。从图一可以看出，返工流程的功能是从一个完全填充的印刷板而不是破坏性的印刷板本身，周围的组件或是焊点周围的组件删除和替换单个组件。到目前为止，在这个PCBA方向的主要作者已经取得了重大的进展【1】【4,5】。图片2显示了完全自动化的再制造细胞系统通过Fidan创建【2】。

在1990年代中期，一些电子产品制造基本知识已经开发为各种PCBA线条和应用【6-11】。这些研究都没有报道一个集成PCBA工艺规划环境。已经验证的系统也弱化了世纪工业装置。这个调查的目的是通过建立一个基于知识的智能系统的电路板缺陷，对表面贴装返工技术做出贡献，这样需要返工操的缺陷可以通过电子制造装配线被检测到。 3 工艺参数对PCBA质量的影响

与不断小型化电子组件和整体系统互连的PCB和组件——，焊点——也变得小了。接头地方尺寸的减小更要求机械属性的焊料来确保共同的鲁棒性。在除了足迹大小的减少，是一个重点总空间减少，常常导致尺寸的包装硅模具。作为向更小的包装尺寸迁移的SMT技术，每个包装的加工条件的变得更加关键【12】。

在一个包装的显著的差异（从层到层之间或承运人和模具）会引起广泛的内部应力。一旦安装到电路板，焊接头通常必须通过包装的扩装和PCB在热源组来吸收所有的应力。对于SMT设备，如扁平包，引线和焊点提供合规需要弥补不匹配在热膨胀系数的包和PCB。为了让关节变得更小，他们的质量变得更为重要。物理缺陷（如，可怜的可焊性，孔焊，焊料球和桥焊）可以对联合鲁棒性和焊料的收益性有负面影响。

影响PCBA收益的因素可以分为几个主要类别，包括组装材料，多氯联苯和组件以及过程方法和人类的表现【2】。

组装材料的类别可以进一步细分到锡焊膏和通量的相关材料，如应用体积，回流参数，造渣，焊膏沉积方法，以及处理和储存条件。在这个类别最关键的我问题是在回流操作中适当的稀释的附件表面和创造冶金凝固。包含了许多因素的PCB范畴影响整个焊点可靠性，包括电路板厚度，垫大小，基材，通过形成技术，印刷电路板层数，焊接掩膜技术。组件子群参数影响装配可靠性可能包括距大小，销数，包装大小和基材。

PCBA的各个步骤的需求严重影响过程方法的类别。回流方法等因素（对流与红外辐射）和环境条件会影响焊料润湿，共同形成或形状和空隙的存在。接头质量是收到几乎所有装配变量，但是是强烈影响锡膏调剂，元件分布，回流条件。

焊锡膏调剂

在SMT沉积技术中最常见的方法是丝网印刷技术。在这个过程中，焊膏会通过在金属箔上相应的洞沉积到附件垫的印刷板。对于小模数SMT，印刷过程变得至关重要，因为没有足够的空间来拉长的焊料模板孔径。对于0.5毫米的螺距组件来说，实现打印率不到60%并不少见【12】。孔径大小和钢网厚度需要适当调整确保了高转移率（黏贴沉积和孔径卷）【13】。一般来说，光圈相对于附件垫应该是超大号的来增加焊料沉积体积和转移率。然而这可能导致增加焊料球的形成。氮可能在黏贴套印是帮助抵消形成锡球的形成趋势【14】。图片3显示栽培要影响焊点质量的输出的所有可能的数量。

4 新的组件放置

用于在印刷板上放置组建的策略可以分为进入管道，质量，顺序，同时放置【16】。在高容量生产中，专用的顺序或质量可能会执行位置。在大多数情况下，柔性对于适应新产品和组件式非常重要的。通常SMT组装使用顺序元件布局。两个类型的放置设备用于顺序挑拣和放置操作；第一个是一个X-Y龙门式第二个是定头移动表放置机器【12】。头顶的设备提供高灵活性，中放置的速度，精度高，最小加速度或运动的PCB。相比之下，表运动及其（通常旋转炮塔头）提供高位置速度和中等精度额灵活性，但征收高加速度的PCB【17】。

另一个重要特性放置系统映像的是视觉系统的需要【17,18】。一个主要问题是设备的能力来识别功能在黑板上和组件和正确地放置在设备的校准设备导致附件垫在PCB。照明的包从低角度，即侧照明，可以需要防止错误的位置和SMT【19】。 4 联合水平附件

传热机制用于大规模回流焊接过程包括对流，辐射（使用辐射来源）和冷凝（气相）【20】。回流焊的最流行方法是基于强制对流或红外辐射。一些其他的方法的焊料是气相，激光和热棒。处理大规模的回流焊接，PCBA主要往往受到一个波峰焊接操作。在波焊的应用程序中，经过的PCBA一波喊的焊料是吸引所有科室的表面，包括组建领导。波温必须仔细控制预防从燃烧的焊点。在任何回流系统，均匀的温度在PCB和在一个组件是一个主要目标【2,21】。对于一个SMT系统，一个温度梯度是10摄氏度或更少应该保持的防止变形包和确保所有关节正常回流。 5 组建的开发工具

发达的系统由两个主要组件组成。这个组件式面向对象的性质，分别代表一个特定的功能组件的整体。这种形式的编程时声明性的，代表事实和主张而不是程序。

·主要的组件包括测试软件，这将决定是否将输入的值不产生一个可靠地

焊接接头。这是通过使用可扩展标记语言（XML）来完成的。晚间定义了参数进行测试，起约束和依赖以及一个程序模块解释测试。这是一个简单地，非常灵活的文本格式最初是为了满足大规模电子出版的挑战。XML在Web和别处各种的数据交流也发挥着越来越重要的作用【22】。 6 未来研究方向

这种直观的系统将积极消除的主要问题导致表面组装PCB操作。谈话种类与快乐度关系和数目的减少缺陷也将被制作成表格的工具的理由。统计分析焊点的质量输出在这项研究中没有被提出。在不久的将来，完成测试的结果和统计研究不同的组件和流程变量。 参考文献

Internet-based electronics manufacturing troubleshooting tool

for surface mount PCB assembly

Received: 2 March 2004 / Accepted: 6 May 2004 / Published online: 9 February 2005. Springer-Verlag London Limited 2005

Abstract Increasing product complexity, decreasing component size, and using double-sided boards have made surface mount technology (SMT) based electronics manufacturing (EM) component more difficult to assemble. This has resulted in the economic troubleshooting of EM defects being one of the main problems facing all manufacturers. Although the authors have made significant improvements in the EM process, it has been shown that the implemented changes in the automated lines have not yet produced a high enough percentage of reliable finished products. The objective of this current development is to make a contribution towards these EM processes by creating an Internet-based intelligent system of circuit board defect detection so that EM process flaws that necessitate rework operations can be identified prior to manufacturing runs. With the development of this system, the need to rework the defective components will be minimized for any assembly line and assembly line process parameters, which cause some reliability problems (such ass older balls, insufficient solder at joints, burnt joint connections, bridged leads, voids, skewed leads, and unformed joints) will be troubleshot directly, and the rework will be greatly reduced from the EM assembly line. This paper reports the current development and its structure.

Keywords Electronics manufacturing ・ Internet ・Printed circuit board ・ Surface mount technology ・ User interface

1 Introduction

The trend to high-density packaging in surface mount technology assembly has highlighted inherent difficulties in the assembly line of these very fine-pitched devices. A variety of defects is still common in printed circuit board assembly (PCBA) technology despite all of the improvements made, and rework of PCBA is inevitable and must be performed manually in PCBA manufacturing floors since the cost of each component and the PCB itself may be hundreds of dollars. In the last few years, the number of rework stations available on the market has grown considerably including automated ones, but there has still been no significant reduction in the number of defects. In electronics manufacturing, rework is defined as the activity that replaces defective components with those that are acceptable such that the populated board performs to specifications. Increasing product complexity, decreasing component size, and using double-sided boards have made rework more difficult and the economic reworking of PCBA is one of the main problems facing PCB manufacturers .PCBA manufacturing has been relatively improved with fully automated, accurate assembly machines and the use of robots.

Although significant improvement in automated rework has also been made by one of the authors, it has been shown that the outcome of the automated rework line has not produced a high enough reliable yield percentage. The objective of this research project is to make a contribution towards this surface mount rework y creating a knowledge-based intelligent system of circuit rd defects so that the defects that necessitate a rework operation can be detected through the electronics manufacturing line. With the development of this system, the number of defective boards will be minimized from the PCBA line and PCBA process parameters that cause joint level reliability problems will be identified. The causes of these problems will be troubleshot with the help of the developed online system.

2 Generic overview

High value printed circuit boards used for computer, military ,and telecommunications applications are a critical mission sensitive eel e m en t for the 21st century’s advanced technological

developments. The growth of small-footprint and small-feature SMT in electronic components presents enormous technical obstacles to the successful production of such PCBAs.

Rework refers to the general technical problem of removing and replacing defective circuit components on a printed circuit board. A variety of different rework methods have been successfully developed and tested during the last decades of the 20th century, but it has also been proven that none of them has perfectly produced final reliable joint

throughputs out of the manufacturing line [1]. Now the new objective is to develop alternative methods instead of utilizing manual, semi-automated, or automated rework systems. The technology, which has been under investigation now focuses on eliminating the causes of these manufacturing problems since the old technologies practiced in rework are costly, complicated, and require skilled operators [1, 2]. The rework operation involves several steps: removing defective components, cleaning the vacant component sites, dispensing new solder paste, placing new components, and then reflowing the joints [3].To date, major advances have been made in this direction for PCBAs by the authors [1] [4, 5]. Figure 2 shows the fully automated remanufacturing cell system created by Fidan [2]. In the mid 1990s, some electronics manufacturing knowledge bases have been developed for various PCBA lines and applications [6–11]. None of these studies reported an integrated PCBA process planning environment. The validations of the systems were also weakly presented in real industrial settings. The purpose of this research project is to make a contribution towards this surface mount rework and PCBA by creating an interactive knowledge base system of circuit board defects so that defects requiring rework operation can be detected through the PCBA line.

3 The effect of the process parameters on PCBA quality

With the continual miniaturization of electronic components and overall systems, the interconnection of the PCB and the component – namely, the solder joint – becomes smaller as well. This reduction in the size of the joint places more demands on the mechanical properties of the solder to ensure joint robustness. In addition to footprint size reduction, there is an emphasis on total space reduction, often leading to reduced size in the packaging of the silicon die. As SMT migrates toward smaller package dimensions, the processing conditions of each packaging become more critical [12]. Significant differences between properties within a package (from layer to layer or between the carrier and the die) can cause extensive internal stresses. Once mounted to a PCB, the solder joint typically must absorb all strains induced by the expansion of the package and the PCB in thermal excursions. For SMT devices, such as quad flat packages, the leads and solder joints provide the compliance needed to compensate for the mismatch in the coefficient of thermal expansion of the package and the PCB. As joints become smaller, their quality becomes more critical .Physical defects (e.g., poor solderability, voids, solder balls, and bridging) can have a negative impact on joint robustness and solder yields. Factors that affect PCBA yields can be classified into several main categories, including assembly materials, PCBs, and components, as well as process methods and human performance [2]. The assembly materials category can be subdivided further into solder-paste- and flux-related materials, such as applied

volume, reflow parameters, fluxing, and solder paste deposition methods, as well as handling and storage conditions. The most critical issue within this category is the proper fluxing of the attachment surfaces and the creation of metallurgical bonds during the reflow operation. The PCB category contains many factors influencing the overall solder joint reliability, including board thickness, pad size, base material, via formation technology, PCB layer count, and solder mask technology. The component subgroup parameters that influence the assembly reliability may include pitch size, pin count, package size, and base material. The process methods category is influenced heavily by the individual steps in the PCBA. Factors such as reflow methodology (convection versus infrared (IR) radiation) and ambient conditions will affect solder-wetting, joint formation or shape, and the presence of voids. Joint quality is affected by almost all assembly variables, but is influenced strongly by the solder paste dispensing, component placement, and reflow conditions. 3.1 Solder paste dispensing

The most common method for solder paste deposition in SMT is stencil printing. In this process, solder paste is deposited onto the attachment pads of the board through corresponding holes made in a metal foil. For fine-pitch SMT, the printing process becomes critical because there is insufficient room to elongate the solder stencil aperture. For 0.5-mm-pitch components, it is not uncommon to achieve a print efficiency of less than 60 percent [12].

Aperture size and stencil thickness need to be adjusted properly to ensure the highest transfer ratio (paste deposited versus aperture volume) [13]. In general, the apertures should be oversized slightly compared to the attachment pad geometry to increase the solder deposit volume and transfer ratio. However this may lead to an increase in solder ball formation. Nitrogen may help counteract the tendency of the paste to form solder balls during paste overprinting [14]. Figure 3 shows the number of all possible factors in dispensing affecting solder joint quality output.

4 New component placement

The strategies used to place components on boards can be divided into in-line, mass, sequential, and simultaneous placement [16]. In high volume manufacturing, dedicated sequential or mass placement may be performed. In most cases, flexibility is important to accommodate new products and components. Typically SMT assembly uses sequential component placement. Two types of placement equipment are used for sequential pick-and place operations; the first is an x−y gantry style, and the second is fixed-head moving-table placement machines [12]. The overhead equipment offers high flexibility, medium placement speed, high accuracy, and minimal accelerations or movement of the PCB. In contrast, the table movement machines (usually rotary turret

heads) offer high placement speeds and medium accuracy and flexibility, but impose high accelerations on the PCB [17].

Another important feature of the placement system that affects the PCBA is the vision system [17, 18]. A major issue I the ability of the equipment to recognize features on the board

and component and accurately place the device by aligning the device leads to the attachment pads on the PCB. Illumination of the package from a lower angle, namely side-lighting, may be required to prevent erroneous placements with SMT [19].

5 Components of the developed tool

The developed system consists of two major components. The components are object-oriented in nature, each representing a specific functional component of the whole. This form of programming

is declarative, representing facts and assertions, rather than procedural.

• The primary component consists of the testing software which will determine whether the values entered will or will not produce a reliable solder joint. This is accomplished through the use of an extensible markup language (XML) file that defines the parameters to be tested, their constraints, and dependencies/equations along with a program module that interprets the tests. XML is a non-proprietary language for data storage. It is a simple, very flexible text format originally designed to meet the challenges of large-scale electronic publishing. XML is also playing an increasingly important role in the exchange of a wide variety of data on the Web and elsewhere [22]. It allows for verbose definitions, hierarchical relationships, and cross-platform compatibility. It is a tagged language similar to HTML and therefore consists of human readable markers for defining objects, relationships, and their parameters.

6 Future research directions

This intuitive system will positively eliminate the major problems resulting in surface mount PCB operations. Cause-and effect relationships and the reduction in the number of defects will also be tabulated for the tool’s justification. Statistical analysis of the solder joint quality outputs has not been presented in this study. Complete results of the beta testing and statistical studies for different components and process variables will be presented in the near future.

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