基于VayoPro—SMT离线编程的贴装效率研究

文章主要讨论了如何通过优化的手段编制合理的贴装程序来缩短贴片机的贴装时间,提高贴片机的贴装效率。贴片机的种类繁多,专业用途各不相同,文章按照贴片机的机械特征和贴装方式对贴片机进行了分类,然后按照分类找出对应的主流优化算法,分析各自的优缺点和用途,通过VayoPro—SMT离线编程软件进行试验,论述试验过程和分析试验结果,提出SMT生产工艺过程中如何编程以及工艺改善的方法,并提出贴装效率优化的思路。     

基于蚁群算法的贴片机贴装最短路径问题的研究

贴片机贴装路径与表面组装生产线的装配效率紧密相关。为了提高贴片机的生产效率,对贴片机的贴装路径进行了优化,提出一种改进的蚁群算法。该算法考虑了在寻求最短路径过程中信息素的更新,使算法不易陷入局部最优解,并且能较快地收敛到全局最优解。理论分析和实际仿真实验,都证明了此算法优于传统的贴片机贴装路径的优化算法。     

基于免疫算法的拱架式贴片机贴装过程优化

提出一种免疫算法来优化带多头的拱架式贴片机贴装过程。通过设计合理的问题编码、免疫算子以及参数,对贴装过程进行优化求解,并与遗传算法进行比较。以4贴片头的贴片机为例,对13个案例进行计算,得到免疫算法解的质量均要比遗传算法提高5%~10%,且每个实例的平均计算时间减少10%~25%。结果表明免疫算法比遗传算法更加有效。     

SMD与贴片机

以典型的表面贴装元器件及典型贴片机为例,针对表面贴装元器件的贴装和贴片机作简要论述,希望对ＳＭＴ设备使用厂家的选型有一定的参考价值。     

应用于贴片机贴装顺序优化的遗传算法的比较和改进

元件贴装顺序优化是决定贴片机生产效率的关键问题,传统的解决贴装顺序优化问题的方法有遗传算法,蚁群算法,SS(伞布搜索法)等。使用较多的还是遗传算法。遗传算法中包含选择算子、交叉算子、变异算子,且编程思想简单,但容易出现局部最优,过早收敛等情况。在此,通过对遗传算法在贴装顺序优化应用的结果比较找到一种更适合的遗传算法,使之拥有较快的收敛速度和全局优化性。     

环球仪器新型贴片机内置转塔技术

环球仪器(UniversalInstruments)近日推出全新Quadris-S四拱架(four-gantry)贴片机。据介绍,这款新型贴片机采用内置转塔技术以及先进运动控制装置,在同类设备中可实现最大单位面积产量。该款拱架结构高速贴片机可贴装尺寸范围广泛的元件而无需更换贴装头。此外,Quadris-S具备100×10-6最终贴装性能的灵活性和高产量,将速度和通用性与高利用率和重复性融为一体。Quadris-S集80,000cph贴装性能、0201(44mm×44mm)元件贴装范围、支持带式和盘式送料器(包括双磁道送料器)以及生产效率优化程序(包括送料器料垅间印刷电路板自动对中、快速联…     

基于改进SUSAN算法的片式元件角度识别

元件角度识别是贴片机元件视觉检测的关键,其参数的精确获取直接影响贴片机进行元件贴装的准确性.SUSAN算法是一种基于图像灰度比较的算法,不涉及梯度的计算.讨论了该算法的模板和门限的选取方法,继而提出一种改进的SUSAN边缘检测算法对矩形片式元件进行边缘检测,并通过试验比较了该算法与传统的几种边缘检测算法的优劣.试验证明改进的SUSAN算法能更好地提取复杂成像条件下元件图像的边缘,提高了贴装过程中元件角度识别的精度和稳定性.     

转盘式贴装头设计与检验研究

转盘式贴装头作为多轴贴装头主要适用于较小型片式电子元件的贴装。12轴一次图像处理,节省了多次拍摄和计算处理的时间。在一个工作循环内连续抓料,连续贴装,减少了抓、放料移动的时间,能够大大地提高贴片效率。同时,利用贴片机自身的视觉系统在线精度测试与补偿能够有效地提高贴装精度。     

贴片机可视化运动仿真系统设计与实现

贴片机在制造过程中,需要进行贴装测试工作,进行这项工作不仅需要消耗基板、元件而且费时费力,对贴片机的调试工作也很麻烦。为了解决以及更多的了解这方面的技术问题,从可视化动态仿真的角度提供新的思路,通过建立贴片机三维模型、实现贴片机可视化运动仿真、对仿真系统进行测试与优化几个方面对贴片机技术进行研究设计,实现了贴片机的可视化运动仿真,使贴片机的工作流程清晰形象的展现出来。     

FUJI-XPF高速多功能贴片机

XPF系列是FUJI公司最新推出的一款创新型的高速多功能复合型贴片机，分为XPF—L通用型和XPF—S省空间型两款机型。XPF在生产过程中，实现了世界首创的动态更换贴装头，包括12吸嘴的高速贴装头，吸取QFP、BGA、连接器的多功能贴装头以及点胶头，因此XFP完美的将高速和多功能的特点集合在一台贴片机上，使整线中各台贴片机的性能得到了平衡，实现最佳的生产线优化和机器间无浪费运转，最大限度的提高了贴装的品质和生产线的效率。[第一段]     

Electrical Machines and Drives for Electric, Hybrid, and Fuel Cell Vehicles

This paper reviews the relative merits of induction, switched reluctance, and permanent-magnet (PM) brushless machines and drives for application in electric, hybrid, and fuel cell vehicles, with particular emphasis on PM brushless machines. The basic operational characteristics and design requirements, viz. a high torque/power density, high efficiency over a wide operating range, and a high maximum speed capability, as well as the latest developments, are described. Permanent-magnet brushless dc and ac machines and drives are compared in terms of their constant torque and constant power capabilities, and various PM machine topologies and their performance are reviewed. Finally, methods for enhancing the PM excitation torque and reluctance torque components and, thereby, improving the torque and power capability, are described     

Dynamic modeling of a horizontal washing machine and optimization of vibration characteristics using Genetic Algorithms

In this work, a 2D dynamic model of a horizontal axis washing machine is derived regarding the rotation plane in order to examine the vibration characteristics of the spin-cycle and improve the design proposing a new optimization scheme based on Genetic Algorithms (GA). The dynamic model is numerically simulated and the outputs are validated using experimental vibration data acquired from a test-rig including the drum and the motor of a horizontal-axis washing machine. The measurements are performed using piezo-transducers and a novel measurement scheme is used to obtain displacement values from acceleration data as well as estimating the instantaneous frequency of the rotation with appropriate signal processing. This study has two main contributions: (i) a new method for design improvement applying GA to optimization of vibration characteristics for the horizontal-axis washing machines, and (ii) a novel measurement method yielding the displacement in 2D and instantaneous frequency of vibration from acceleration data. While the GA is contributing to passive improvement methods in the field, the novel measurement method opens the way for low-cost diagnosis and active-vibration control of washing machines.     

A Survey of Adaptive Optimization in Virtual Machines

Virtual machines face significant performance challenges beyond those confronted by traditional static optimizers. First, portable program representations and dynamic language features, such as dynamic class loading, force the deferral of most optimizations until runtime, inducing runtime optimization overhead. Second, modular program representations preclude many forms of whole-program interprocedural optimization. Third, virtual machines incur additional costs for runtime services such as security guarantees and automatic memory management. To address these challenges, vendors have invested considerable resources into adaptive optimization systems in production virtual machines. Today, mainstream virtual machine implementations include substantial infrastructure for online monitoring and profiling, runtime compilation, and feedback-directed optimization. As a result, adaptive optimization has begun to mature as a widespread production-level technology. This paper surveys the evolution and current state of adaptive optimization technology in virtual machines.     

基于包簇框架的云计算能耗优化算法

文中针对以虚拟机为中心的云计算分配模式中结构复杂、分配困难等问题,采用了一种基于包簇结构的分配框架。在此基础上提出了一个有效的能耗模型,并将二进制粒子群算法进行改进,通过调节自适应的权重,提高了包簇分配算法的速度和准确性。实验表明,改进的二进制粒子群算法在收敛速度和寻优能力方面更加优于传统的二进制粒子群算法。相较于以虚拟机为中心的分配算法,基于包簇框架下的改进二进制粒子群分配算法提升了CPU使用率,有效降低了能耗,更加绿色节能。     

电子组装中焊接设备的选择(待续)

再流焊设备与波峰焊设备是自动化电子组装工艺中的主要焊接设备,无铅化工艺对焊接设备提出了许多新的技术要求,相应的对焊接设备的选择也有了新的标准,从无铅化焊接工艺角度出发,分析了两种焊接设备选择中应考虑的问题.     

电子组装中焊接设备的选择(续完)

再流焊设备与波峰焊设备是自动化电子组装工艺中的主要焊接设备,无铅化工艺对焊接设备提出了许多新的技术要求,相应的对焊接设备的选择也有了新的标准,从无铅化焊接工艺角度出发,分析了两种焊接设备选择中应考虑的问题.     

Optimization of high-speed multistation SMT placement machinesusing evolutionary algorithms

Surface mount technology (SMT) is a robust methodology that has been widely used in the past decade to produce circuit boards. Analyses of the SMT assembly line have shown that the automated placement machine is often the bottleneck, regardless of the arrangement of these machines (parallel or sequential) in the assembly line. Improving and automating the placement machine is a key issue for increasing SMT production line throughput. This paper presents experimental results using genetic algorithms to optimize the feeder slot assignment problem for a high-speed parallel, multistation SMT placement machine. Four crossover operators, four selection methods, and two probability settings are used in our experiments. A penalty function is used to handle constraints. A comparison of genetic algorithms with several other optimization methods (human experts, vendor supplied software, expert systems, and local search) is presented, which supports the use of genetic algorithms for this problem     

Electrical machines for variable-frequency drives

The paper presents a perspective on the various types of motors which are currently in use or proposed for application in variable speed drives. One focus is on motors for industrial and commercial use, reflecting the large and expanding market arising from concerns about energy saving and system optimization. A second focus is on high-performance motors capable of rapid response in speed and position control systems. The machine types considered include commutator, induction, synchronous and switched permanent magnet, and synchronous and switched reluctance. Each machine type is introduced from first principles to establish a basis for comparison and also as an aid to readers who have not recently refreshed their knowledge of electric machines