微细电解加工实验研究

采用基于电化学腐蚀法制作直径80μm、长度3000μm的微细电极,分别使用微细圆柱电极和微细螺旋电极进行了加工实验,实验研究丧明微细螺旋电极在孔和槽的加工中比微细圆柱电极具有更快的加工速度以及更小的加工间隙.螺旋结构在加工中有助于排出加工间隙内电解产物,显著地提高了加工效率、加工精度及加工过程的稳定性.     

微细电解线切割加工的基础研究

基于电化学原理，讨论了纳秒脉冲电流微细电解线切割加工的机理，建立了微细电解线切割加工数学模型；采用电化学腐蚀原理对微米尺度线电极进行在线制作，建立了微细电解线切割加工试验系统，并进行了微细电解线切割加工试验，切割出带90°直角的微结构，其切缝宽度为30μm。     

超短脉冲电流微细电解加工技术研究

利用电化学腐蚀方法,在自制的电解加工机床上连续实现微细工具电极的制作和工件的加工,通过试验研究了超短脉冲的电压幅值和脉冲宽度对侧面加工间隙的影响。结果表明,减小脉冲宽度,降低加工电压,可以提高微细电解加工的精度。利用优化的加工参数,进行了微小孔加工、微细直写加工以及成形电极微细加工的实验。     

微螺旋电极在改善微细电解加工性能中的应用

改善电解加工的精度和稳定性是微细电解加工中一个重要的研究课题。本文详细分析了影响电解加工性能的因素,电解液采用混合电解液(NaC lO3+H2SO4),工具电极为带有螺旋槽的微螺旋电极。在微螺旋槽旋转所形成的“微螺杆泵”效应作用下,蚀除加工间隙内的产物,加工效率、加工精度和稳定性得到了极大的提高。     

微细孔电解加工控制方法及试验研究

基于微细电解加工的特点，介绍了一种微细电解加工系统。该系统能够将加工间隙控制到几微米到几十微米的范围内。根据电解加工以离子形式对材料去除的特性，进行微细电极、微细群电极的制备研究，并将其用于微细孔、群孔的加工中。试验分析了各工艺参数如电压、溶液浓度、加工间隙、进给速度等对微细孔电解加工精度的影响。结果表明，微细电解加工的侧面间隙随着加工电压的降低、溶液浓度的减小、脉宽变窄和初始加工间隙的减小而减小，改善了加工的定域性，加工精度得到提高。     

高频窄脉冲微细电解加工实验研究

加工间隙是电解加工的核心工艺参数,利用在45钢薄片上打微细孔,通过实验分析来探索高频、窄脉冲微细电解加工中频率、电压和电解液浓度对加工间隙及电极截面和加工稳定性的影响规律。     

高频窄脉冲电流微细电解加工

微细电解加工是微细加工领域很有发展前景的微细加工技术之一。适合于微细电解加工的装置被研制出来, 它包括机床进给机构、线电极电火花磨削在线制作微细电极装置、短路检测模块、脉冲电源及其他一些辅助装置, 其中,高频窄脉冲电源是微细电解加工最重要的核心技术之一。根据微细电解加工的特点,设计了微细电解加工 MOSFET脉冲电源,该微能脉冲电源能很好地满足微细电解加工的要求。运用该微细电解加工装置进行加工试验, 在低的加工电压和低的钝化电解液浓度条件下,利用高速旋转的微细电极加工微小孔和像小铣刀一样进行微细电解铣削加工微结构,得到了满意的工艺效果,因而进一步说明电解加工在微细加工领域很有发展潜力。     

微细电解加工用中空电极的制备

为了改进加工间隙内电解产物的排出条件和加速电解液的更新,提出了一种嵌套式微细中空电极的精确可控焊接制备工艺。仿真分析了电极的过流特性,优化了电极长度,并进行了性能测试及加工实验。通过穿丝、黏结、嵌套尺寸及位置调整和焊接工序,制备出加工段内径为65μm、外径为130μm、长3.25mm左右,后段便于装夹和连通的嵌套式中空电极。在供液压力为1.15 MPa时,其出口流速可达10m/s左右。利用制备的中空电极,开展微细孔电解加工实验,在0.5mm厚不锈钢片上加工出最小入口孔径约为157μm,出口孔径约为133μm的微细孔,并将其延伸应用于微结构加工中,铣削出了长554μm、宽160μm、深224μm的微细T型槽。实验结果表明:制备的微细中空电极有效提高了加工间隙内电解液的流动特性,且连/导通可靠、装夹方便,适用于高深宽比微结构的电解加工。     

电解加工电源的发展与应用

近年来,电解加工(Electrochemical Machining,ECM)在航天、航空、军工等领域中得到极为快速的发展,而电解加工的核心部分是电源,它的频率、波形等输出特性在很大程度上直接影响电解加工的效果.本文介绍了电解加工电源的发展和特点,着重介绍高频、窄脉冲电源的发展现状及应用,展望了其近期的发展方向.     

基于线电极原位制作的微细电解线切割加工

微细电解线切割加工是一种微细加工新方法。从理论上分析了线电极直径大小对微细电解线切割加工精度的影响,提出了原位制作微米尺度线电极的方法,并制作出直径5μm的钨丝线电极。通过电解线切割加工试验,加工出缝宽为20μm左右的微型桨叶结构和曲率半径在1μm以下的微细尖角结构。     

Vibration assisted wire electrochemical micro machining of array micro tools

Micro structures and components are widely used in modern industries, and micro machining has therefore become a popular research topic. As micro tools are essential in micro machining, wire electrochemical micro machining is introduced in the fabrication of micro tools in this paper, and micro square column tool arrays are fabricated using wire cathodes by two steps. In order to improve the machining efficiency and quality, an electrode vibration technique is used, and the effects of bubble behaviour on slit width homogeneity and edge radius are studied through simulations of the electric field. The influences of various machining parameters such as vibration conditions, electrical properties, electrolyte concentration and feedrate on the standard deviation of the slit width and on the value of the edge radius are investigated. In addition, the micro dimple array is fabricated using electrochemical micro machining by employing the micro square column tool array as the cathode.     

电解加工间隙中的传质过程及其对电解加工的影响

这里应用流体力学、传质学和电化学理论,分析了电解加工间隙中处于紊流状态的电解质溶液内的传质过程。在此基础上建立了阳极电流密度的计算方法,并讨论了外加电压、电解质浓度、流速等参数对电解加工的影响。     

微细磨料喷射加工仿真与实验研究

利用流体动力学仿真软件CFX对微细磨料喷射加工中,影响加工效果的喷射压力、喷射距离等影响因素进行仿真,模拟出不同参数下磨料微粒的速度、工件表面所受压力的分布规律,并与实验结果进行对比,验证仿真结果的正确性.     

影响脉冲电化学抛光加工质量的因素研究

在实验研究的基础上,分析了脉冲电化学抛光加工的机理,提出了的影响脉冲电化学抛光加工的主要因素,并对其进行了研究和探讨。     

Precision and efficiency of laser assisted jet electrochemical machining

Laser assisted jet electrochemical machining (LAJECM) is a hybrid process, that combines a laser beam with an electrolyte jet thereby giving a non-contact tool electrode that removes metal by electrochemical dissolution. The laser beam effectively improves the precision of LAJECM as it is able to direct the dissolution to specifically targeted areas. This prevents the machining from unwanted areas due to stray current. This parallel application of a laser beam with the electrolyte jet enables an improvement of machining accuracy, also productivity. LAJECM has shown that machining with laser assistance can effectively facilitate material removal of 20, 25, 33, and 54% for Hasteloy, titanium alloy, stainless steel and aluminium alloy, respectively. There is also a noticeable improvement in the shape accuracy and slight decrease in surface roughness of the holes and cavities produced due to more focused machining (the order of 20%). The measured reduction in taper is of the order of 38, 40, 41, 65% for aluminium alloy, stainless steel, Hasteloy and titanium alloy, respectively.     

Study of the effects of tool longitudinal oscillation on the machining speed of electrochemical discharge drilling of glass

In this study, longitudinal oscillation applied to the cathode electrode during the electrochemical discharge micro drilling of glass and the effects of electrolyte flushing alteration in both discharge and hydrodynamic regimes of the process have been investigated. In this regard, numerous sets of experiments have been conducted using different vibration frequencies and amplitudes. In addition, two geometrically different tools including cylindrical rod and micro drill were used as machining electrode (cathode). In the case of cylindrical rod, two types of longitudinal waveforms including square and sinusoidal ones were applied to the tool. The experiments were resulted in a noticeable improvement in material removal rate (MRR) using square waveform and a slight improvement in the case of sinusoidal waveform. Moreover, the obtained MRR by means of vibrating micro drill has been compared with those achieved by non-vibrating one in several oscillation frequencies and amplitudes. The results showed that the vibration of the micro drill cannot further improve the electrolyte flushing and MRR in comparison with non-vibrating one because of the inherent electrolyte flushing in micro drill through its flutes which is constant in vibrating and non-vibrating cases.     

Fabrication of various shaped tungsten micro pin arrays using micro carving technology

This paper describes a state of the art in micro-structuring high strength metallic materials. Tungsten micro pin arrays in a variety of shapes are fabricated using a micro carving technology, which combines laser beam machining and electrochemical etching processes. First, micro pin arrays were rough-shaped by laser beam machining along a pre-defined scanning path to control their structural shape. The micro pin array in this stage had near-conical shape of structures due to a recast layer. Next, the genuine shape of micro pin arrays came to the surface via electrochemical etching process to elute the recast layer into electrolyte. Quantitative elemental analysis with energy-dispersive spectroscopy (EDS) was implemented to characterize the formation of recast layer on a micro pin structure after the laser beam machining process. The atomic percentage EDS maps indicated that higher percentage of tungsten was detected on the core micro pin structure, whereas relatively large percentage of oxygen was found on the recast layer (O 9%, W 91% in the center area, and O 53%, W 47% in the outer area).     

Investigation of plastic electrode tools for electrochemical machining of silicon

A concept of plastic electrode tools for electrochemical machining is investigated and applied to machining of c-Si. The electrode tools consist of a plastic body with an optimized electrical conductive coating. This concept allows for low cost electrodes which can be even realized by rapid prototyping techniques. The micro electrochemical machining of p-type silicon by these innovative metalized plastic electrode-tools is studied. The technological schemes of the machining and design of metalized plastic electrode-tools are developed. Theoretical investigation of thermal conditions and limitations of the electrode-tools during the machining process are performed. Based on these investigation, recommendations on the minimum thickness of the conductive layer of the electrode-tools from Cu, Ni and Pt are defined. Experimental optimization of the process parameters during the machining is performed and feasibility of the metalized plastic electrode-tools for micro electrochemical machining is demonstrated.     

高频群脉冲电源在微细孔电化学加工中的应用

针对电化学加工的特殊需要所设计的一种新型电源———高频群脉冲电源的设计原理和特征,从理论上分析其对 于传统的直流电源和脉冲电源在微小型零件加工中的优越性;通过微细孔加工对这种新型的电源进行了分析和说明。 结果表明,在微小型加工领域,采用高频群脉冲电源在改善加工精度,提高加工质量方面优于直流电源和脉冲电源。     

An investigation into wire electrochemical micro machining of pure tungsten

Tungsten-based microstructures have attracted great interest in many industrial advanced applications. Nevertheless, with a disadvantageous combination of high hardness, toughness and brittleness, the micro machining of pure tungsten poses significant difficulty. In this paper, an investigation into the wire electrochemical micro machining (WEMM) of pure tungsten at low alkaline electrolyte concentration and small pulse duration is presented. Under the optimal machining conditions, tungsten-based microstructures with a side gap of 4 μm, slit width of 18 μm and aspect ratio of 5.6, as well as with a side gap of 5 μm, slit width of 20 μm and aspect ratio of 15, were obtained. In order to improve productivity in the machining of multi-slit microstructures, multi-wire electrochemical micro machining of tungsten was introduced. Using a 3-wire electrode, a 9-slit microstructure with a slit width of approximately 24 μm was produced and the machining efficiency was improved by a factor of three. The results revealed that it was a promising method for the fabrication of tungsten-based periodic or quasi-periodic microstructures, such as the gratings used in the X-ray absorption contrast system of imaging.