微细电火花加工工艺研究

介绍了在研制的采用蠕动式微进给和线放电磨削走丝机构的微细电火花加工装置上进行的加工工艺实验研究,探讨了微细电火花加工微小轴（工具电极）高深宽比微小孔,非圆截面形状和三维结构成形以及半导体硅材料等的工艺方法。     

微细电火花加工工艺研究

介绍了在研制的采用蠕动式微进给和线放电磨削走丝机构的微细电火花加工装置上进行的加工工艺实验研究。探讨了微细电火花加工微小轴 (工具电极 )、高深宽比微小孔、非圆截面形状和三维结构成形以及半导体硅材料等的工艺方法     

微细电火花加工技术及其应用

介绍了微细电火花加工技术的原理、特点及最新研究成果，简述了微细电火花加工技术的应用及发展趋势。     

超声振动复合微细电火花加工微小孔试验研究

微小孔加工时的放电间隙较小,排屑、消电离状态差,放电效率低,直接影响加工效率和电极损耗;超声振动可改善排屑、消电离状态,能提高放电效率。将超声引入微细电火花加工,通过工件的超声振动,进行超声功率、小孔孔径、脉冲频率的微小孔电火花加工工艺试验研究,结果表明:加工不同孔径时,超声功率及电源频率都存在一个最佳值;加工条件合适时,超声复合微细电火花加工优于常规微细电火花加工。     

高精度微细电火花加工系统的研制

设计并研制了一个微细电火花加工系统。该系统主要由横轴布局V型陶瓷结构旋转主轴系统、带有压电陶瓷的宏、微伺服进给系统、制作微细工具的反拷系统和读数显微镜及电气控制等部分组成，应用该系统已成功地加工出了直径仅为φ4．5μm的微细轴和直径仅为φ8μm的微小孔。     

蠕动式压电驱动微小型电火花加工装置的单片机控制系统

根据电火花微细孔加工伺服性能特点,介绍了一种单片机控制的蠕动式压电驱动电火花加工伺服控制系统。文中叙述了该控制的基本原理,给出了其输入输出通道的电路设计及其软件设计思想,并成功地进行了加工试验。     

微细阵列型孔的冲压与电火花复合加工技术研究

提出一种微细冲压加工和微细电火花加工交叉结合的微细阵列型孔复合加工方法。尺寸较大的过渡型腔采用微细冲压加工，以提高加工效率和保证加工尺寸的一致性；型孔喷口的最小特征尺寸采用微细电火花逐层扫描加工得到。设计制作了专用的微小型腔冲压实验装置，从机构设计上保证加工工艺对微小型腔冲压深度的精确控制。进行了非圆截面阵列微细型孔的加工实验，验证了所提出的工艺方法的可行性和合理性。     

高速旋转电极电火花小孔加工

采用８０３１单片机控制系统，并以３００００ｒ／ｍｉｎ的电极转速及螺旋沟反转送工作液的方法，使电火花小孔加工的生产率和加工深度得以大幅度提高。介绍了高速旋转电极电火花小孔加工设备及应用效果，并讨论了机理。     

蠕动式压电驱动微小型电火花加工装置的单片机控制系统

根据电火花微细孔加工伺服性能特点，介绍了一种单片机控制的蠕动式压电驱动电火花加工伺服控制系统。文中叙述了该控制的基本原理，给出了其输入输出通道的电路设计及其软件设计思想，并成功地进行了加工试验。     

微细电火花加工技术的最新进展及应用实例

介绍了微细电火花加工技术的最新进展，并以一些最新的应用实例反映了该技术的发展趋势和应用前景。     

电火花微孔加工自适应灰色控制

运用灰色控制理论建立了电火花加工过程适时控制的算法，结合短路次数与生产率的关系，形成了控制过程的双环控制。详细地论述了各环控制的原理及实现方法。     

微细电火花加工实验及工艺规律研究

微细电火花加工在当前微细加工中显示出巨大的发展潜力。通过用自行研制的微细电火花加工系统进行的一系列微细电欠花加工实验，对影响微细电火花加工加工效率和加工精度的各种因素(如充放电电容、开路电压和工作介质等)进行了研究，     

Development of peeling tool for micro-EDM

We propose a simple and fast fabricating method of tool electrode for micro-EDM. A ‘peeling tool’, a wire coated with a different material, has been developed as an interim product for a microelectrode. A zinc layer was coated by electroplating on a tungsten electrode of 100 μm diameter. The zinc layer makes both handling and chucking of the electrode easy. Part of the zinc layer is instantly ‘peeled’ by a single discharge, exposing tungsten electrode under the zinc layer undamaged and the exposed electrode can be used in microhole drilling by EDM. Time-resolved imaging revealed the peeling process dynamically.     

A new tool wear compensation method based on real-time estimation of material removal volume in micro-EDM

Owing to the reduced tool area and poor flushing conditions in deep holes, tool wear in micro-electrical discharge machining (EDM) is more significant than in macro-EDM. In micro-EDM drilling, the z-axis of the tool position is monitored as machining progresses. However, due to significant electrode wear, the machined hole depth is not identical to the programmed depth of the hole, and thus this will result in geometrical inaccuracy. This paper presents a new micro-EDM drilling method, in which the material removal volume is estimated as machining progresses. Compensation length is calculated and adjustment is made repeatedly along the tool path until the targeted material removal volume is reached. A real-time material removal volume estimator is developed based on the theoretical electro-thermal model, number of discharge pulse and pulse discrimination system. Under various energy input and machining depth settings, the experimental and estimated results are found to be in satisfactory agreement with average error lower than 14.3% for stainless steel, titanium, and nickel alloy work materials. The proposed drilling method can compensate the tool wear and produce more accurate micro-holes as compared to other methods. Experimental work also shows that the proposed method is more reliable as compared to the uniform wear method. In drilling micro-holes of 900 μm depth, the depth error can be reduced to 4% using the proposed method.     

我国自主研发钛合金现状与进展

根据双团簇模型设计并制备了Ti-Zr-Cu-Ni-Co系非晶钎料,用于真空钎焊TC4钛合金和316L不锈钢,分析了钎料中Co元素含量对钎焊接头界面微观组织形貌、力学性能及断裂行为的影响规律.结果表明,钎焊接头可划分为TC4/扩散区(I区)/钎缝中心区(II区)/界面区(III区)/316L,界面典型微观组织结构为TC4/β-Ti + Ti₂Cu/(Ti, Zr)₂(Cu, Ni) + Ti₂Cu + Ti₂(Cu, Ni) + TiFe/(Fe, Cr)₂Ti + α-(Fe, Cr) + τ + γ-(Fe, Ni) + σ/316L,随着Co元素含量的增加,接头剪切强度先升高后降低再升高,当Co元素含量为1.56%时达到最大310 MPa,不添加Co元素时,接头断裂于钎缝中心区(II区);当Co元素含量为1.56% ~ 6.24%时,接头断裂于靠近316L母材的界面区(III区)附近,断裂模式为典型的解理断裂.

     

基于LIGA技术的微细电火花加工优化研究

比较了活动掩膜法与固定掩膜法得到的PMMA胶结构,实验表明固定掩膜法更适合于多次曝光.结合LIGA技术和微细电火花加工的优点,用LIGA技术制备出具有复杂形状的铜微细工具电极,再用该工具电极进行微细电火花加工,在不锈钢上加工出异形微细孔.并通过进一步调整电火花加工工艺参数,优化了加工尺寸精度和表面粗糙度.     

A study on the machining of high-aspect ratio micro-structures using micro-EDM

Micro-electro-discharge machining (micro-EDM or μ-EDM) has been gaining popularity as a new alternative method to fabricate micro-structures. The main advantages of the micro-EDM method are its low set-up cost, high accuracy and large design freedom. Compared to etching or deposition techniques, micro-EDM has the advantage of being able to fabricate complex three-dimensional shapes with high-aspect ratio. However, there are many operating parameters that affect the micro-EDM process. The fabrication of micro-electrodes on the machine is also an important process to remove the clamping error to maintain high accuracy in the machined micro-structures.

In this paper, the machining of micro-structures is divided into two basic processes. One is the on-machine fabrication of the micro-electrodes with high-aspect ratio, and the other is the EDM of the workpiece in micrometer range. An optical sensor has been developed to measure and control the dimension of the thin electrode during the tool fabrication process. Different methods have been investigated to fabricate a thin electrode into the desired dimension without deflection. The performance of the micro-EDM process is evaluated in terms of the material removal rate (MRR), tool wear ratio (TWR), and the stability of the machining. Influences of the various operating parameters of the micro-EDM process, such as the operating voltage, gap control algorithm, and resistance and capacitance values in the R–C spark control circuit, are discussed.     

Development of a micro-punching machine and study on the influence of vibration machining in micro-EDM

This paper describes the development of a novel micro-punching machine that is capable of producing precision micro-holes. A significant feature of this machine is to fabricate the micro-punch and then the micro-die in the same machine, totally eliminating the eccentricity between the punch and the die when punching is proceeded. By applying vibration machining technique, we can decrease the possibility of electric short-circuiting during the micro-EDM process. The utilization of a proportional solenoid as the power unit of the micro-punching machine and as the source of vibration is found to be a successful attempt. Experiments to punch micro-holes with diameters of 0.1 and 0.2 mm on an SUS 304 stainless steel strip with 0.1 mm in thickness were carried out. The results show that the performance of this machine and the geometry of punched micro-holes are satisfactory.     

Key R&D activities for development of new types of wrought magnesium alloys in China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs： the Key Technologies R＆D Program of China, the National Basic Research Program of China, the National High-tech R＆D Program of China, and the National Natural Science Foundation of China. The key R＆D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.