OPC技术发展综述

OPC（OLE for Process Contr01）基金会成立以来,OPC技术的发展经历了三个阶段,即经典OPC、OPCXML-DA和OPCUA（OPCUnifiedArchitecture）。OPC技术从依赖微软的COM和DCOM技术到采用WebServices、XML和IrrrP等标准和协议,实现了从依赖单一平台到平台无关的跨越。为了保持OPC技术的兼容性,OPC基金会提供了从经典OPC到OPCUA的迁移策略。最后。展望了OPC技术的发展前景。     

基于车铣复合加工的微小型结构件工艺研究

随着产品小型化、微型化的发展趋势,微小型零件尤其是微小型结构件的需求越来越广泛,微小型复杂、异形、高强度、多尺度金属结构件对加工提出了更高要求,基于车铣复合加工的微细切削技术在加工微小型结构件方面有独特优势.首先对微小型结构件的工艺特征进行了总结和分析,指出微小型结构件加工机床的工艺特点,然后介绍了微小型车铣加工中心的结构布局和工艺能力,并对典型微小型结构件的加工工艺进行了试验研究,结果表明:基于微小型车铣加工中心,采用车、铣、钻、车铣复合工艺加工微小型结构件,能够一次装夹定位实现完整加工,提高了加工精度和加工效率,通过快速调整加工工艺,能够实现微小型结构件的柔性加工,是一种高效实用的加工方法.     

Mastercam在车铣复合加工中的应用

随着数控机床的广泛应用,CAD/CAM软件成为提高数控编程效率,解决特殊和复杂工件数控编程的重要工具.在对加工实例进行工艺分析的基础上,提出了利用Mastercam软件进行车铣复合加工自动编程的思路,阐述了该软件的车铣复合功能,详细介绍了其工作流程和实现方法.     

风力发电技术综述

我国风能资源十分丰富,21世纪风能利用的主要领域是风力发电.主要介绍了风力发电的优缺点和风力机的组成与分类,对我国风力机设计中面临的技术难点进行了分析,指出高质量叶片的研究是风电工作者的重要方向.     

An overview of JIT

The term JIT (Just in Time), when used as a manufacturing control system, has become very confusing over the past few years. Everyone wants to claim they are users of JIT systems and because of this a variety of systems creations, all claiming themselves to be JIT systems, have sprouted up, none of which look anything like what Japan uses. This article attempts to clear up some of this confusion by showing four different variations of JIT and comparing them to the traditional MRP/MRP II environment.     

Microcutting using a micro turn-milling machine

A turn-milling machine, which is a device having two spindles that rotate a tool and workpiece, can be used to fabricate various shapes by cutting. However, little progress has been made in microcutting using a turn-milling machine. Therefore, a micro turn-milling machine designed especially for microtools was developed and used to fabricate micropins with various cross sections. Cemented tungsten carbide microtools, which are useful both as a milling cutter and as a turning tool, were processed by electrical discharge machining and employed for microcutting. As a result, various micropins were successfully fabricated, including not only cylindrical pins but also those with cross sections having square, triangle, and cross shapes. These noncylindrical micropins have the smallest reported cross-section dimensions for pins fabricated by cutting to the best of our knowledge. Furthermore, cutting characteristics such as the machined shape and surface quality were investigated, which showed that better micropin shapes were obtained by up-cut turn-milling than by down-cut turn-milling or by turning. In contrast, turning was superior to turn-milling in terms of the surface quality.     

Research on rotary surface topography by orthogonal turn-milling

As a new technology in manufacturing, turn-milling broadens the application ranges of mechanical processing, wherein both cutting tool and workpiece are given a rotary motion simultaneously. The objective of the present work is to study workpiece surface topography during orthogonal turn-milling process. This study begins with two mathematical models, which describe theoretical surface roughness and topography of rotationally symmetrical workpiece. The models are built with the establishment of locus function according to orthogonal turn-milling principle. Then based on these models, the influence law of surface topography affected by various cutting parameters is found by some simulation methods. The law also matches with orthogonal turn-milling surface roughness and topography experiments. By analyzing the experimental results, some parameter selection criteria during orthogonal turn-milling processing are also proposed qualitatively and quantitatively. The comparison between the simulation and experimental results shows that a better surface quality and tiny oil storage structure can be obtained if the cutting parameters are chosen in reason. This conclusion provides a theoretical foundation and reference for the orthogonal turn-milling mechanism research.     

A web-based virtual system for turn-milling center

This paper presents a three-dimensional, web-based, interactive simulation system for turn-milling center. To overcome the disadvantages of transferring files over the Internet and depending on expensive computer-aided design (CAD)/computer-aided manufacturing (CAM) softwares, the system is developed by virtual reality modeling language (VRML)/JavaScript interaction. The system files produced by machining simulation have small size, and could be transmitted on the web easily. Firstly, a dynamic interactive technology based on VRML and JavaScript, which is essential to a web-based simulation system, has been presented in this paper. Secondly, the geometric and kinematic model is created for representing the turn-milling center motion. Then, the key technologies for machining simulation including material removal, NC codes compiling and collision detection are studied. Finally, to validate feasibility of the proposed system, the virtual machining process for a stepped shaft in the machine tool is carried out. Since the system realizes multiple dynamic demonstrations of virtual machine tool, users can comprehensively understand the product performance. The research for the web-based virtual system of turn-milling center has important research value and application prospect.     

Machinability of damage-tolerant titanium alloy in orthogonal turn-milling

Frontiers of Mechanical Engineering - The damage-tolerant titanium alloy TC21 is used extensively in important parts of advanced aircraft because of its high strength and durability. However,...     

正交车铣螺杆钻具数控加工的研究

对5LZ165螺杆钻具端面曲线进行了数学建模,在对内摆线建模的基础上求出了螺杆钻具端面曲线的极坐标方程.根据正交车铣加工原理,求出了正交车铣螺杆钻具时球头铣刀刀具中心轨迹的极坐标方程,利用宏程序进行数控编程,在Mazark车铣加工中心上实现了5LZ165螺杆钻具模型的加工.     

超声车铣圆环斜槽传振杆设计

针对超声波车铣加工,设计了一种谐振频率30 kHz的圆环斜槽传振杆,阐述了30 kHz圆环斜槽传振杆纵扭共振的基本原理。利用有限元分析方法,计算了圆环斜槽传振杆的尺寸和斜槽的位置以及力学特性,并比较了有限元分析结果和理论结果。有限元分析结果比理论值结果小,是由于将圆环斜槽传振杆作为理想的模型。用阻抗分析仪对圆环斜槽传振杆进行了测试,并比较了测试结果和有限元分析值,偏差较小,相对偏差符合要求。实验测试结果表明,测试参数和设计结果一致。     

Variable eccentric distance-based tool path generation for orthogonal turn-milling

This study proposes an algorithm for maximizing strip width in orthogonal turn-milling based on variable eccentric distance. The machining error model is first established based on the local cutting profile at the contact line. The influencing factors of the strip width are then investigated to analyze their features and determine an optimizing strategy. The optimized model for maximum machining strip width is formulated by adopting a variable eccentric distance. Hausdorff distance and Fréchet distance are introduced in this study to implement the constraint function of the machining error in the optimized model. The computing procedure is subsequently provided. Simulations and experiments have been conducted to verify the effectiveness of the proposed algorithm.     

Swept area modeling and cutter wear study in turn-milling

In turn-milling machining, we found the cutter wear concentrated on a small section around the corner of the cutter and affect the cutter life. In this paper, the idea of swept area is proposed firstly based on the analyses for cutter wear, and it can indicate the cutter wear. Balance of swept area will lead to balanced wear along cutting edge, and expressions of swept areas of infinitesimal elements on the cutting edge are given. Secondly, the cutting depth and cutting angle, which are the key parameters in calculating the swept area, are analyzed based on different contact situations between the cutter and workpiece, and the detailed calculating method is given. Then, the optimization model to balance swept areas along the cutting edge is established, and the cutting parameters including cutter offset and machining length are optimized. Finally, the orthogonal turn-milling machining experiments with different cutting parameters are conducted; the result shows that turn-milling with optimized parameters can actually balance the cutter wear and increase the cutter life.     

诊断信息流模型的综述

在系统测试性分析领域,信息流模型是系统建模方面的主要方法之一,本文通过一个示例,给出了建立诊断信息流模型的整体框架。文章首先介绍了信息流模型的提出背景和国内外应用研究现状,然后在叙述模型的基本要素和诊断推理的相关概念的基础上.对一示例推理图进行了建模以及模型处理,最后提出了在国内研究该模型的必要性。     

基于自适应采样距离场的车铣复合加工中刀具—工件接触几何计算

基于自适应采样距离场提出了对车铣复合加工中刀具—工件接触几何的计算方法。针对车铣复合加工中典型的运动形式,分析了加工过程中刀具—工件接触几何的特性。采用八叉树边界体积结构对初始工件的距离场进行自适应采样,并计算采样点在扫掠体积的距离场中对应的距离值,通过对上述各个采样点处对应的两个距离值进行布尔运算确定加工中工件的距离场并对其进行重建。采用三线性插值法计算运动中刀具的表面采样点到加工中工件的距离,根据距离值判定接触区域内的点,由这些点即可获得刀具—工件接触的相关参数。对所研究方法得到的刀具—工件接触几何所得的刀具—工件接触的对比结果表明,所研究的内容为车铣加工中刀具—工件接触的计算提供了一种高效率高精度的方法。     

微小型车铣加工表面粗糙度正交试验研究

铣车转速比、工件转速、轴向进给量以及切削深度是车铣加工中相对独立的四个重要切削参数.运用正交试验法研究微小型零件车铣加工表面粗糙度与上述四因素的关系.试验数据分析结果表明,该四因素对表面粗糙度的影响程度从大到小依次为:铣车转速比、轴向进给量、工件转速、切削深度.而且转速比的提高对粗糙度值的影响是单调的,转速比越高粗糙度越低.这一结论也与单因素试验结果相吻合.由试验结果分析还得到各切削参数的优化匹配关系.     

主动轮廓模型综述

主动轮廓模型(也称为snake模型)是在由轮廓自身特征决定的内部能量和图像特征决定的外部能量共同作用下能量极小化的轮廓曲线,可用于边缘检测、运动跟踪、图像匹配、计算机视觉和三维重构等图像处理领域.从snake模型的数学模型出发,介绍了两种常用的snake模型--气球力模型和GVF模型,阐述了近十年来基于经典snake模型的能量改进算法,对比说明了对当前求解snake能量极小的算法,并对未来的研究方向进行了讨论和展望.     

生成式对抗网络研究综述

深度学习领域一个十分活跃的分支—生成式对抗网络（GAN）已经成为人工智能学界一个热门的研究方向。生成式对抗网络采用无监督的学习方式,自动从源数据中进行学习,在不需要人工对数据集进行标记的情况下就可以产生令人惊叹的效果。阐述了GAN的背景、基本思想,对其相关理论、训练机制和应用研究进行了梳理,总结了GAN的常见网络构架、训练技巧与模型评估标准,还进行了GAN与其他生成模型VAE、衍生模型的对比,最后进行分析总结,指出GAN的优缺点并对未来发展方向进行展望。     

Analysis of the tool tip radial stiffness of turn-milling centers

Modern industry requires high-precision machines and processes. This requirement implies the determination and reduction of all possible sources of error. For turning, a main error is related to machine–tool–workpiece deformation caused by cutting force. On the other hand, current turning centers are structurally more complicated than conventional lathes. However, stiffness values for this kind of machine are not described yet in literature. Thus, the aim of this work is to provide stiffness values for this type of machines clamping a common workpiece. To obtain this information an experimental methodology to measure static stiffness along kinematic chain of the turning center is proposed. The method may be useful for both users and machine manufacturers in order to consider this factor in the general error budget of the turning process. At the same time, stiffness values for lathes with a Y-axis incorporated in a three-axis turret and equipped with living tools are registered.