工艺参数对微小方孔的微细电解加工精度的影响

微小方孔结构是航空航天、兵工、仪器仪表等领域中常用的结构且加工困难。为了提高金属材料微小方孔结构的加工精度,在分析微细电解铣削加工原理和实验系统基础上,进行了一系列镀镍不锈钢微小方孔(50μm×50μm)的微细电解铣削加工正交实验,探讨了加工电压、电解液浓度、进给速度、脉冲宽度等参数对微细电解铣削加工精度的影响。结果表明:在合理参数范围内采用较低的工作电压、较低浓度电解液、较高进给速度和较小脉宽电源有利于提高镀镍不锈钢材料微小方孔的微细电解加工精度。     

微细硅工具电极的制备及其微细电解加工实验

提出了一种采用重掺杂单晶硅作为工具电极基体、二氧化硅/氮化硅作为绝缘层的硅工具电极用于微细电解加工。设计了利用体硅湿法腐蚀实现电极基体成形,化学气相沉积制备绝缘层的微细硅工具电极制备工艺。初步实验得到电极加工部尺寸约为100μm,绝缘层厚度为800 nm的硅工具电极。利用高速旋转的微细硅工具电极在18Cr Ni8材料上加工出了微细沟槽结构和微细通孔。实验结果验证了侧壁绝缘层对杂散腐蚀抑制作用的有效性。经过96 min的持续加工实验,电极绝缘层保持了可靠的绝缘效果。     

基于高速铣削的微细电极加工方法

微模具型腔的高效、高精密加工,一直是制约微模具制造技术发展的瓶颈问题.以微细 电火花加工用的圆柱阵列结构微细电极为对象,研究了应用高速铣削加工技术,实现微细电极的高效、高精密加工方法.通过优化分析微细电极结构和高速铣削加工参数及刀具路径,获得了尺寸和形状精度及表面质量均满足要求的阵列结构微细电极,并以制得的微细电极进行...     

三维微结构微细电火花和电解组合加工实验研究

提出一种微三维结构的微细电火花和微细电化学组合加工工艺,利用三维伺服扫描微细电火花加工快速去除三维型腔材料和微细电解铣削加工形成高精度和高质量三维型腔轮廓表面的互补优势,实现三维微结构的高效率和高精度加工。该组合加工工艺可在同一台微细电加工装置上进行。以在四方体型腔内形成设计尺寸为400μm×400μm×180μm四棱柱结构的加工为例,实验加工出尺寸为410μm×406μm×181μm的四棱柱结构,加工材料的去除速度分别为微细电火花加工31 182μm3/s,微细电解加工11 017μm3/s,得到了加工效率和加工精度的优化组合。     

微细电解铣削加工技术研究进展及展望

微细电解铣削加工技术具有工具电极无损耗、加工柔性高、与工件材料硬度无关等特点,在金属微结构器件制造领域展现出极具诱惑力的应用前景。通过综合国内外文献资料,按照不同的电解液供给方式介绍微细电解铣削加工技术的研究进展,分析微细电解铣削加工相关技术研究中存在的不足,并展望该领域的未来发展趋势。     

微流控芯片注塑模具的微细电解加工

基于电解加工电极不损耗的优势,研究了一种微细电解加工微流控芯片注塑模具微结构的工艺,针对微小V型槽和微孔,解决微细电极在线制备和测量、微结构成形精度、群微结构加工等关键问题。加工实验结果表明:该工艺可实现曲线V型槽和群微结构加工,通过微细电解加工的模具具有较高的形状精度和表面质量。     

基于可重构方法设计的多功能微细电加工系统

简要介绍了可重构制造系统的概念和可重构机床的特点。基于可重构机床模块化的设计方法,设计了一套可进行微细电火花加工和微细电解加工的多功能微细电加工系统。在多功能系统中利用在线电解的方法制备微细钨电极,并用此电极进行电火花微细孔加工试验。     

微细电火花铣削电极运动轨迹加工工艺实验

在微三维结构微细电火花铣削过程中,电极运动轨迹的规划直接影响产品的加工效率和工具电极的损耗。针对钛合金微三维结构进行了不同铣削方式的加工工艺实验,选取了最佳电极运动轨迹,其加工时间和电极损耗均明显低于其他铣削方式。     

微细盘状电极制备及其微细电解加工研究

基于电化学腐蚀加工方法,提出了一种微细盘状电极的制备方法。先采用平板阴极电化学腐蚀法,将毛坯加工成圆柱状微细电极,再对圆柱电极端部进行绝缘保护,进一步腐蚀制备得到微细盘状电极。利用微细圆柱电极、盘状电极和盘状群电极,在厚1 mm的304不锈钢片上进行电解加工对比实验,结果证明采用微细盘状电极电解加工微小孔,其加工定域性有明显改善,侧壁间隙减小,且降低了孔锥度。     

微细电解加工微电极成形工艺研究

微细电极的形状是影响微细电解加工尺寸与质量的重要因素。通过理论分析得出电源、电压、占空比、浸入深度等影响电极成形的规律,并验证其正确性。结果表明,在一定加工环境下可加工出形状和尺寸较理想的电极,并用不同形状的电极进行了电解钻孔实验,对比了电极的加工性能。     

Impact of the shape of electrode-tool on radical overcut of micro-hole in electrochemical micromachining

To make use of the full capability of electrochemical micro-machining (EMM), a meticulous research is needed to improve the material removal, surface quality and accuracy by optimizing various EMM process parameters. Keeping this in view, an indigenous development of an EMM machine set-up has been considered to carry out a systematic research for achieving a satisfactory control on the EMM process parameters to meet the micromachining requirements. In this study an EMM machine has been developed and experiments were conducted to study the influence of some of the major process parameters such as the machining voltage, electrolyte concentrations, the pulse-on-time and the machining current on the machining rate and accuracy. The effect of the shape of the tool electrode tips on EMM has been investigated experimentally with 304 stainless steel sheets. The machining rate and the overcut are significantly influenced by the shape of the tool electrode tip.     

发动机缸体后端面粗铣机床的设计

为了快速加工发动机缸体的上端面,按照客户要求设计出一套卧式粗铣机床。根据发动机缸体的结构、加工部位的特点,确定定位面及卡紧位置;由缸体的加工精度和缸体材料的性质,选定铣刀的型号和对应电机的型号;根据力的大小确定夹具的夹紧方式和定位方式,计算出合理的夹紧力。同时为了适应产品更新换代速度越来越快的趋势,在加工过程中缩短工艺流程,提高加工精度,在整体机床设计中选用通用件,以降低成本,增加收益。     

燃气弯管弧面结构电解铣削加工特性研究

液氧煤油火箭发动机燃气弯管具有尺寸较大、形状特殊的三维空间弧面结构,利用传统拷贝式电解加工技术难以获得理想的加工形貌.针对弧面结构燃气弯管的加工难点,研究采用电解铣削技术进行加工,基于新一代液氧煤油火箭发动机燃气弯管的尺寸等比缩小样件,试验了具有弧面结构的316L不锈钢在NaCl溶液中不同工艺参数下的电解铣削加工特性....     

Micro electrochemical machining for complex internal micro features

In this paper, the application of micro electrochemical machining (ECM) for the micromachining of internal features is investigated. By controlling pulse conditions and machining time, micro features are machined on the side wall of a micro hole. These methods can easily machine a micro hole with larger internal diameters than the entrance diameter, which is very difficult to do by the conventional processes. A micro disk-shaped electrode with an insulating layer on its surface is also introduced to machine microgrooves inside the hole. This method is similar to the turning lathe process. The purpose of this study was to confirm the various possibilities of making complex internal structures in a micro hole by micro ECM.     

Transitions of micro-EDM/SEDCM/micro-ECM milling in low-resistivity deionized water

Owing to its slight conductivity, deionized water has been used as a bi-characteristic fluid to combine micro-EDM and micro-ECM milling in a unique machining process which has been named as SEDCM milling. To attain both electrical discharge and electrochemical reaction during machining, selection of machining parameters such as feedrate and layer depth has been empirically observed to be of prime importance. This paper presents an analytical model to identify the critical conditions for transitions of material removal mechanisms in this hybrid machining process. The criteria for three distinct machining modes micro-EDM/SEDCM/micro-ECM milling are determined based on the thickness of material layer that electrochemical reaction could dissolve when the electrode scans over the surface. The critical feedrate for transitions of material removal mechanisms are then predicted using double layer theory, Butler–Volmer equation and Faraday's law of electrolysis. Experimental tests were also performed to validate the proposed model. It has been established that the SEDCM milling is only attained at moderate feedrate. For high feedrate, machining mode is changed to micro-EDM milling alone when the thickness of material layer that electrochemical reaction could dissolve is smaller than the roughness of micro-EDMed surface. On the contrary, for low feedrate, material removal mechanism is converted to pure micro-ECM when the thickness of layer dissolved by electrochemical reaction is higher than the preset layer depth. In addition, it is also found that lower feedrate is required for SEDCM milling when higher layer depth is used because more material needs to be removed by the sparks in every feed.     

Effect of machining fluid on the process performance of electric discharge milling of insulating Al2O3 ceramic

Wire electric discharge machining (WEDM) and electrical discharge machining (EDM) promise to be effective and economical techniques for the production of tools and parts from conducting ceramic blanks. However, the manufacturing of insulating ceramic blanks with these processes is a long and costly process. This paper presents a new process of machining insulating ceramics using electrical discharge (ED) milling. ED milling uses a thin copper sheet fed to the tool electrode along the surface of the workpiece as the assisting electrode and uses a water-based emulsion as the machining fluid. This process is able to effectively machine a large surface area on insulating ceramics. Machining fluid is a primary factor that affects the material removal rate and surface quality of the ED milling. The effects of emulsion concentration, NaNO₃ concentration, polyvinyl alcohol concentration and flow velocity of the machining fluid on the process performance have been investigated.     

Development of a reversible machining method for fabrication of microstructures by using micro-EDM

A new micromachining method for the fabrication of micro-metal structures by using micro-reversible electrical discharge machining (EDM) was investigated. The reversible machining combines the micro-EDM deposition process with the selective removal process, which provides the ability of depositing or removing metal material using the same micro-EDM machining system. From the discharge mechanism of micro-EDM, the process conditions of micro-EDM deposition were analyzed firstly. Using the brass and steel materials as a tool electrode, the micro-cylinders with 200 μm in diameter and height-to-diameter ratio of more than 5 were deposited on a high-speed steel surface. Then the machining procedure was transformed easily from deposition to selective removal process by switching the process conditions. Different removal strategies including micro-EDM drilling and micro-EDM milling were used in the machining. Micro-holes with 80 μm in diameter are drilled successfully in the radial direction of the deposited micro-steel cylinder. Also, a brass square column with 70 μm in side length and 750 μm in height, and a micro-cylinder with 135 μm in diameter and 1445 μm in height are obtained by using micro-EDM milling. Finally, the characteristics of the deposited material were analyzed. The results show that the material components of a deposited micro-cylinder are almost the same as those of the tool electrode, and the metallurgical bonding has been formed on the interface. In addition, the Vickers-hardness of 454Hv of the steel deposited material is higher when compared to the hardness of 200Hv of the raw steel electrode.     

Machining performance of silicon carbide ceramic in end electric discharge milling

A new process of machining silicon carbide (SiC) ceramic using end electrical discharge milling is proposed in this paper. The process is able to effectively machine a large surface area on SiC ceramic with good surface quality and low cost. The effects of machining conditions on the material removal rate, electrode wear ratio, and surface roughness have been investigated. The surface microstructures machined by the new process are examined with a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The results show that the SiC ceramic is removed by melting, evaporation and thermal spalling, the material from the tool electrode can transfer to the workpiece, and a combination reaction takes place during end electric discharge milling of the SiC ceramic.     

镍基高温合金短电弧加工工艺参数优化

为了对短电弧加工镍基高温合金材料过程中的材料去除速度,表面质量和电极损耗等工艺目标进行综合评价,在新型数控短电弧铣床设备上对峰值电流、脉冲宽度、占空比和电压等可调工艺参数进行正交试验,并运用灰色理论进行试验数据的分析。将复杂多变的多工艺目标转换为单一评价指标,即灰关联度。该方法很大程度地简化了试验过程,最终得到最优工艺参数组合方案。试验结果表明:得到的参数组合能够在保证表面质量的前提下提高短电弧加工效率并降低电极损耗率。     

A study of three-dimensional shape machining with an ECμM system

This paper presents an electrochemical micromachining (ECμM) system developed with a machining gap control system. As a preliminary, electrochemical machining (ECM) experiments are carried out. The optimum machining condition of ECM is determined in terms of machining voltage, machining pulse length, amplitude of the electrode for flushing out contamination, and electrolyte concentration. After the preliminary ECM experiments, three-dimensional shape micromachining is carried out under the optimum condition. First, a prismatic electrode with a 200-μm square as the base shape is machined by ECM. Next, three-dimensional shape micromachining is carried out by scanning the prismatic electrode. A three-dimensional shape with sub-millimeter range is successfully machined.