氨基表面组装薄膜的构筑及其微观摩擦学特性

以二乙烯三胺基丙基三甲氧基硅烷(TA)作为分子底层,采用两步组装的方法在单晶硅基底表面制备一系列相同结构不同分子链长的自组装双层薄膜。利用椭圆偏光测厚仪、接触角测定仪、原子力显微镜(AFM)等对薄膜的形成及微观摩擦力进行表征。研究结果表明,低表面能的疏水性末端基团有利于降低薄膜的摩擦力和摩擦因数;组装分子碳链长度的增加有助于形成有序性强和致密度高的组装薄膜,从而减小薄膜表面的摩擦力和摩擦因数。     

基于焊点虚拟成形技术的SMT焊点质量保证技术研究

基于焊点形态理论和焊点虚拟成形技术的表面组装技术焊点质量检测与控制技术的基本思想是,将利用图像获取及处理技术得到的实际焊点形态,与通过焊点虚拟成形技术形成的合理焊点形态进行比较,根据比较的差异,通过智能鉴别得出实际焊点组装故障的类型与产生主因,然后形成调整组装工艺参数的反馈信息对相关组装工艺进行调整控制,以达到提高和保证焊点组装质量的目的。在阐述其基本思想和原理的基础上,结合实例介绍了该技术的实现方法与步骤,对其中焊点图像的获取与处理、焊点质量的分析评价等主要内容与关键技术进行了研究和探讨,并对结果进行了分析验证。     

机械人在组装生产线中最佳配置的探讨

在我国劳动力成本不断上涨的今天,为了降低生产成本、保证产品质量,在生产装配线上采用机械人来替代人工作业是必然的发展趋势。论文阐述了如何在现有组装生产线上,合理配置机械人,以最低的成本使生产线形成人机混合配置的半自动化组装作业这一关键问题。     

基于MDT的组合夹具CAD系统中元件选择及精度计算实现

组合夹具由不同形状、不同规格尺寸的标准元件组装而成。夹具设计过程中工艺人员在组装角度夹具和一些基本功能结构时,通过选取同类元件的多个不同系列尺寸装配形成一个组合尺寸。基于MDT软件和组合夹具CAD系统,开发了夹具设计中组合尺寸元件选择和精度检验的实现方法。     

胶东丘陵花生高产综合配套技术研究与推广

针对花生生产中存在的各种问题,项目组坚持配套技术研究与综合组装相结合,区域试验与大田示范相结合,在组装的基础上创新,在创新的基础上发展,使整套技术不断趋于规范和完善,最终形成了一套系统完整、有效的、适合本地实际生产情况的花生高产配套综合技术方案。     

基于焊点形态理论的SMT焊点实时检测技术

焊点质量与焊点形态有关,在应用表面组装技术进行电子电路模块焊接组装的生产过程中之中,通过对焊点形态的实时检测和分析评价,能及时发现组装过程的焊占故障和故障产生原因,从而形成有效的质量的馈控制信息对焊点质量进行实时控制。     

氨基表面自组装膜成膜及摩擦性能研究

运用原子力显微镜与接触角测量仪研究了3-氨丙基三乙氧基硅烷(APTES)自组装膜不同成膜时间的表面形貌平均粗糙度、接触角,并进行了XPS(X射线光电子能谱)元素分析,表明APTES自组装膜以“岛”状生长,随着反应的时间的延长,岛的数量急剧增加,形成平整光滑的膜,进一步延长成膜时间,可能形成多层膜,从而平均粗糙度先增大再减小然后再增大,表面性质一直变化不大。微摩擦磨损实验研究表明,APTES自组装膜大大降低镀Cr钢球与硅片之间的摩擦因数,摩擦因数从0.71左右降低到0.16左右,在分子级润滑中有广阔的应用前景。     

加工中心底座和鞍座组装的贴塑工艺技术

贴塑技术是数控机床的组装关键技术,它采用耐磨胶带粘贴在工作台的导轨面上,形成金属与塑料的摩擦形式。耐磨胶带是以聚四氟乙烯为基材,添加合金粉和氧化物的高分子复合材料,具有高耐磨性、良好的自润滑性和减振性能。文中介绍加工中心底座和鞍座组装的贴塑工艺技术。     

高密度电子组装新技术之进展

本文概述了高密度电子组装之进展,包括集成电路芯片级组装,厚薄膜混合集成电路、表面安装技术(SMT)电路/组件级组装,以及最近发展的多芯片组件(MCM)、三维高密度组装等分机级、整机级组装新技术。     

蓬勃发展的义乌钟表行业

义乌中国小商品城钟表行业起步于上世纪九十年代初,以代理经销带动组装加工,是义乌市场起步较早的工贸型结构产业。义乌钟表行业在不断发展的进程中,形成了自主设计、开发、生产、     

OPTIMUM DESIGN AND NON-LINEAR MODEL OF POWERPLANT HYDRAULIC MOUNT SYSTEM

6-DOF non-linear mechanics model of powerplant hydraulic mount system is established. Optimum design of the powerplant hydraulic mount system is made with the hydraulic mount parameters as variables and with uncoupling of energy, rational disposition of nature frequency and minimum of reactive force at mount's location as objective functions. And based on the optimum design, software named ODPHMS (optimum design of powerplant hydraulic mount system) used in powerplant mount system optimum design is developed.     

Placement sequence identification using artificial neural networks in surface mount PCB assembly

The widespread use of automation in the printed circuit board (PCB) assembly domain has been dictated by the increasing density of components on PCBs coupled with the continual decrease in component lead pitch, greater product mix, smaller volumes, quality considerations, and the increased cost of labour. However, these advances in technology have also resulted in automated systems that are complex, and solving problems related to these systems requires the efficient use of extensive specialised knowledge.Expert (or knowledge-based) systems have become a widely accepted problem solving methodology for the surface mount PCB assembly domain. Nevertheless, problems in the PCB assembly domains are frequently unstructured, ill-defined, and difficult to communicate. Artificial neural networks provide a novel approach and an advanced technology to deal with the weaknesses and problems associated with expert systems.The surface mount component (SMC) placement process plays a vital and influential part in determining the throughput time of a PCB assembly line. It is important to identify an efficient component placement sequence while considering constraints such as feeder location and tooling and nozzle optimisation. This research studied the use of artificial neural networks as a complement to expert systems in PCB assembly. A prototype decision support system that combined the use of artificial neural networks and expert system techniques to identify a near optimal solution for the surface mount placement sequence problem was designed, implemented, and validated. Artificial intelligence based technologies such as expert systems and artificial neural networks were used in a mutually supportive manner to solve a complex problem within the surface mount PCB assembly domain.     

动力总成悬置系统优化设计及系统稳健性分析

建立动力总成6自由度模型,以能量解耦为优化目标,系统频率分布及悬置各向刚度比值为约束,悬置各向刚度为变量,采用遗传算法对系统进行优化设计。运用Monte Carlo方法对结果可靠性进行验证。最后通过实车测试验证悬置系统的隔振性能。     

基于遗传算法的某车型悬置系统优化设计

悬置系统的设计对车辆NVH性能起着重要作用,影响着整车振动大小及噪声水平。以某车型动力总成悬置系统为载体,基于Virtual.Lab建立的系统分析模型,分别计算了悬置系统固有频率分布、模态解耦率及系统位移量,结果显示:悬置系统固有频率分布不合理,重要方向的解耦率小于80%,且位移量大于10mm,均不满足要求;应用遗传算法,对悬置系统进行优化分析,将系统变量设定为悬置橡胶刚度,固有频率及位移量所要求的范围设定为约束条件,目标为解耦率最大。通过优化悬置橡胶刚度参数,悬置系统的固有频率、位移量可以控制在要求的范围内,并且模态耦合的程度大大降低。     

汽车电子产品表面贴装技术阈值估计研究

随着汽车电子产品越来越精致,对表面贴装技术的要求越来越高。阈值估计是汽车电子产品表面贴装技术的重要组成部分,本文通过用贝叶斯理论对阈值进行估计,得到其估计值,加强锡膏印刷工艺的准确性,提高表面贴装技术成功率。     

载重车动力总成悬置系统隔振性能的仿真分析

利用动力学分析软件ADAMS,建立动力总成悬置系统的六自由度动力学模型。在发动机稳态工况下,以悬置支承处 响应力最小为目标函数,对动力总成悬置系统参数进行敏感度分析,选取敏感度高的几个性能参数作为设计变量,对动力总 成悬置系统进行参数优化,优化结果显示系统的隔振性能得到明显的提高。     

SMT-TAB: A process planning system for PCB assembly using TAB and SMT

Process planning is a critical function in any manufacturing domain. This is especially true in the electronics manufacturing area where substantial heuristic and experiential knowledge is commonly used during process plan development. While research in computer-aided process planning (CAPP) has tended to concentrate in the machining realm, few CAPP systems have been developed for electronics manufacturing applications and more specifically for the printed circuit board (PCB) assembly domain. Besides, the CAPP systems that have been developed for this area have dealt with either insertion mount or surface mount PCB assembly processes only.Tape automated bonding (TAB), though a relatively new technology, is gaining importance in electronics assembly owing to its inherent advantages. The advent of fine pitch technology together with the ever increasing need for more inputs/outputs and greater pin counts in integrated circuit applications has enhanced the use of TAB technology in electronics manufacturing. This trend has been further augmented by the increasing need for compactness in consumer electronics.This research designed and developed a prototype CAPP system for the PCB assembly domain. The system developed generates a process plan for PCBs populated with surface mount and/or TAB components. An artificial-intelligence based expert system approach has been used in the design and development of the CAPP system. Outputs generated by the system are presented along with ideas for future research.     

Reflecting on vision

BI Technologies installed an automated visual inspection system to check the quality of surface mount components mounted on reels. Based on a flexible mechanical design known as CAPVIS, the system was designed around the concept of keeping the mechanical elements as simple as possible and doing the more advanced features in the system control/image processing software. The modular design of the system also enables different camera configurations to be used. The system has evolved with differing customer requirements to now hold as many as twelve cameras     

An adhesive selection advisor for PCB assembly using surface mount technology

The interrelationships that exist in the manufacturing processes associated with the surface mount manufacture of printed circuit boards (PCBs) are complex and varied. Proper understanding of the relationships between the variables in a surface mount technology (SMT) process are critical for achieving effective process control and high yields. One aspect of the complex relationship is the selection and dispensing of adhesives for the wave soldering of surface mount components on a PCB.The quantitative and repeatable dispensing of adhesive dots is critical to providing adequate process control for attaching components including chip resistors, capacitors, and small outline type transistors to the wave solder side of a PCB. Variables that need to be considered include facility temperature, humidity, size and types of components used on the PCB, adhesive properties, type of dispenser used, curing requirements, and the soldering time and temperature,A knowledge-based approach which considers these relationships is described. Developed in PROLOG, this stand alone adhesive selection advisor is capable of guiding the user in the selection of the proper adhesive and providing dispenser related information. The factors considered include facility temperature, material property requirements, productivity measures including yield, and the process used to dispense the adhesive. The system also functions as a database for adhesive related properties and as an on-line installation and maintenance manual for the adhesive dispenser. Twenty-one different commerically available adhesives and two types of dispensers (air over and positive displacement) have been considered in this research.     

SMT产品组装生产系统的组成与控制

介绍了印制板级电子电路模块表面组装生产系统的组成与控制技术,并对其技术的研究现状和发展动态进行了阐述。