流动磨料电解研磨复合工艺的研究

本文介绍并分析了流动磨料电解研磨复合镜面加工工艺获取镜面的机理，针对SUS304不锈钢的镜面加工研究了各工艺参数对加工过程的影响规律，得出了在多因素影响的情况下表面粗糙度参数值Ra与各工艺参数之间的关系式。     

电解电火花复合研磨加工法

本文简述了电解电火花复合研磨加工(MEEC)的基本原理和新的发展,即在进行MEEC加工的同时,对磨轮进行电火花修整。这种方法对陶瓷等不导电材料可进行加工,效率是传统方法的五倍。本文称该方法为新MEEC法。     

超精密平面研磨加工参数对精度的影响

通过分析超密度平面研磨加工中放射线结构和螺线结构研磨轮的运动数学模型可得出如下结论，在通常加工条件下，放射线结构研磨轮受加工动压的影响小于螺线结构研磨轮。文中通过对两种结构研磨轮不同加工参数的研磨加实验表明，采用放射线结构研磨轮可以提高工件的形状精度及减小表面粗糙度值。     

流动磨料电解研磨复合工艺对不锈钢加工的研究

分析流动磨料电解研磨复合镜面加工的机理,通过试验验证了复合加工的效果绝非电解作用与研磨作用的简单迭加,而是加工机理质的变化,总结并验正了复合加工中电解作用与研磨作用的匹配是获取镜面粗糙度的关键.     

电解研磨复合加工对表面残余应力的影响

本文就电解研磨复合加工对表面残余应力的影响在理论分析的基础上通过试验进行了验证。     

磁性研磨加工

从理论上分析了磁性研磨的加工机理,对导磁材料进行了外圆磁性研磨试验研究,探讨了磁性研磨中各工艺参数对加工效果的影响。     

流动磨料电解研磨复合镜面加工中电解—研磨平衡关系的试验研究

流动磨料电解研磨复合镜面加工中电解——研磨平衡关系的试验研究哈尔滨工业大学赵家齐，张文峰一、理论分析由流动磨料电解研磨复合镜面加工的选择性阳极溶解一机械整平说分析可知，在该工艺中金属的去除主要是由电解作用完成，小的表面粗糙度参数值由磨粒的剖膜作用和整...     

微细群缝的精密电解加工研究

以某辐射状分布微细群缝结构的电解加工为研究对象，讨论了电解液、工件材料、加工速度等因素对加工精度的影响，结合研制的加工电极设计流场分布，优化加工参数，实现了以较高的效率加工出缝宽小至0．27mm的微细群缝结构，缝宽一致均匀，加工稳定性和重复性均好。     

电解研磨复合加工

电解研磨复合加工是近几年发展起来的一种高效率、高精度的加工方法,特别适于不锈钢、钛合金刚、耐热钢、纯钢、铝、电工纯铁等难加工材料的超精加工。这种加工方法是把电解抛光、研磨和超精磨削加以结合起来的超精加工方法。     

Electrolytic-abrasive mirror finishing

Using the electrolytic-abrasive mirror finishing method, large workpieces of stainless and ordinary carbon steel can be easily mirror-finished in a short time and with high efficiency, resulting in a surface roughness of up to 0.01–0.02 μm Rz. This method is based on the fact that the electrolytic effect is assisted by the removal action of abrasive grains within an appropriate current density range by the use of neutral salt-type electrolytes. In the past, the actual implementation of this method in the field of high-precision machining was not clearly defined and many unsolved technical problems remained. This paper clarifies the combined effects of the electrolytic dissolution and polishing action of abrasive grains in this method. It also describes the results of the experimental analysis of the surface roughness formation mechanism and the process for forming the required surface shape.     

Generating complicated surface with electrolyte jet machining

In the electrolyte jet machining (EJM), the electrolytic current is supplied between the anodic workpiece and the cathodic nozzle via the electrolyte which is ejected from the minute nozzle. Only the workpiece material exposed to the jet is removed due to the anodic dissolution, because the electrolytic current is restricted to the limited area by the jet. In this study, an electrolyte jet machining system which can be used to process the complicated three-dimensional surface was constructed. This system is composed of an XY stage, a rotating axis and a high-speed bipolar power supply, all of which are cooperatively controlled by a personal computer. An algorithm was developed to obtain the scanning path and speed of the nozzle to process complicated shape by superimposing simple patterns. The optimized path and speed were thus obtained so that the summation of the squared difference between the superimposed and the required patterns at every checking point becomes minimal. In order to verify the effectiveness of the developed algorithm, simulation and experiment were carried out and the machining accuracy was analyzed. The good agreement between the simulated and produced shapes with the required one proves that the algorithm meets the purpose properly. Besides, the effect of machining conditions, especially the current density on surface roughness of produced patterns was examined. It was clarified that a high current density is not only necessary to reduce machining time but also to improve the surface roughness.     

硬质合金刀具磨料电解刃口钝化工艺试验

本文将磨料电解加工工艺应用到硬质合金刀具的刃口钝化中,并对钝化工艺方法做可行性实验研究。结果显示,新工艺可以实现刀具的刃口钝化,获得光滑的圆弧形刃口,切削刃得到明显改善。对于硬质合金刀具,磨料电解工艺的去除效率高于毛刷式钝化机2.3倍。     

The importance of current density ‘focusing’ in STM image resolution

In a previous paper we incorporated Tersoff and Hamann's model of an STM tip into Lang's transfer Hamiltonian result for the tunnelling current density and applied the resulting simple expression to Tersoff's six-plane-wave model of a monolayer of graphite. In this paper the results for a more realistic model of a graphite surface and a more complete selection of tip positions are presented. They support the previous conclusions that the normal component of the current density takes on both positive and negative values in a complex flow pattern and that its lateral falloff away from the (projected) tip position is much slower than expected from the extraordinary lateral resolution (～1 Å) evident in the best STM images of graphite. This shows that sharp ‘focusing’ of the current density directly under the tip is not a necessary condition for high lateral resolution.     

High Tc ceramic superconductors: Introduction,background, and challenges to the electron microscopist

This introductory article reviews the recent developments in high T_c superconducting ceramics. Particular emphasis is given to the structural and chemical aspects of these compounds that may be of interest to the electron microscopist. Included are some of the contributions made by electron microscopy techniques over the last 10 months. The applications of electron microscopy to solving practical problems associated with these exciting new materials are also discussed.     

轻合金板材超塑成形中的脉冲电流加热方法及其宏微观分析

为提高轻合金板材超塑成形过程中的加热效率,降低能耗,提出一种脉冲电流快速加热方法。通过电热学理论及脉冲电流加热试验,系统研究电流密度对不同材料升温速率及最终加热温度的影响,并采取在电极处布置阻热片的措施,提高板材加热时温度场的均匀性;此外在微观层面,利用电热耦合有限元法及金相显微分析方法,简要分析加热过程中脉冲电流对轻合金板材内部裂纹、孔洞等缺陷及板材晶粒尺寸的影响。结果表明,由于加热时间极短,有效地避免板材内部晶粒的过度长大,并且高密度的脉冲电流可对板材原有缺陷起到一定的抑制作用。以AZ31镁合金超塑成形工艺为例进行试验验证,确定合理的脉冲电流加热参数,试验结果表明,与传统加热方法相比,采用脉冲电流直接加热方法,可有效提高加热效率、降低能耗。     

用数理统计方法评估特种加工表面形貌

本文通过对特种加工零件表面粗糙度进行测量，将实测数据输入计算机，运用数理统计方法，分别求出每个零件的幅度密度函数、自相关函数和功率谱密度函数，并绘制出轮廓图和函数图，对这些函数与其图进行综合分析；评估特种加工表面的形貌。     

交变磁场测量系统数值仿真分析

利用有限元分析软件，建立了交变磁场测量系统的数值仿真模型。基于这个模型，分析了检测位置对确定缺陷大小和分布的影响，发现检测路径离裂纹中心越近，检测到的磁场分布信号越好；检测平面与工件表面间隔越小，Bz曲线越准确，但过小的间隔却可能增大Bz曲线的噪声。同时研究了缺陷几何尺寸与表面磁场分布的对应关系，进一步验证了表面磁场曲线极值间隔与缺陷长度的对应关系；以及在确定缺陷长度的基础上，缺陷深度与Bz曲线极小值之间的一一对应。以上结论为识别缺陷特征专家系统的实现提供了理论依据．     

一种基于面密度概念的数据简化方法

提出一种基于面密度概念的数据简化方法,并给出了算法的步骤.从应用实例上看,该算法达到了预期的效果,实现了简化后数据点随被测曲面的形状特征自适应分布.     

A study of the characteristics for electrochemical micromachining with ultrashort voltage pulses

Electrochemical micromachining (EMM) has traditionally been used in highly specialized fields, such as those of the aerospace and defense industries. It is now increasingly being applied in other industries, where parts with difficult-to-cut material, complex geometry and tribology, and devices of microscopic-scale are required. EMM, which is not normally considered as a precision process, is presented in this paper. The application of voltage pulses between a tool electrode and a workpiece in an electrochemical environment allows the three-dimensional machining of conducting materials with micrometer precision. In this paper, tool electrodes (5 μm in diameter, 1 mm in length) are developed by EMM and microholes are manufactured using these tool electrodes. Microholes with a size of below 50 μm in diameter can be accurately achieved by using ultrashort voltage pulses (1–5 μs).