共查询到19条相似文献,搜索用时 171 毫秒
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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。 相似文献
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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。 相似文献
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《电子工业专用设备》2006,35(4):63-63
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… 相似文献
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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。 相似文献
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《现代表面贴装资讯》2007,6(4):19-19
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] 相似文献
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Zhu Z. Q. Howe D. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2007,95(4):746-765
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 相似文献
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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. 相似文献
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A Survey of Adaptive Optimization in Virtual Machines 总被引:1,自引:0,他引:1
Arnold M. Fink S.J. Grove D. Hind M. Sweeney P.F. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2005,93(2):449-466
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. 相似文献
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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。 相似文献
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Weihsin Wang Nelson P.C. Tirpak T.M. 《Electronics Packaging Manufacturing, IEEE Transactions on》1999,22(2):137-146
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 相似文献
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Electrical machines for variable-frequency drives 总被引:1,自引:0,他引:1
Slemon G.R. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1994,82(8):1123-1139
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 相似文献