Al-Al2O3模板阴极法微细电解加工初探

分析了Al-Al2O3模板阴极法微细电解加工材料去除机理,开展了相关试验验证工作。选择陶瓷层厚度为70、150、200μm的铝板作为阴极,工件材料分别为不锈钢和纯钛,进行电解加工试验。结果表明:陶瓷层越厚,侧向腐蚀越小,成形精度越高,但相对加工效率有所降低。采用孔径500μm的Al-Al2O3模板,成功制备出平均孔径554.7μm和575.8μm的不锈钢工件及纯钛工件。     

基于光致抗蚀干膜的掩膜制备及其应用研究

在传统工艺流程中,必须先将干膜贴于工件表面,然后进行光刻,但干膜不可重复使用。现提出一种新型干膜光刻工艺流程,在干膜贴于工件表面之前,先对干膜单独进行光刻试验研究。基于该新型工艺流程,研究了杜邦干膜GPM220的曝光及显影特性。经过对曝光量（曝光时间）及显影时间的参数优化,最终在干膜上获得了平均直径为99.7μm的通孔阵列,并将其作为掩膜应用于微细电解加工,通过选择合理的加工参数,在工件表面获得了平均直径为125μm、平均深度为10μm的微坑阵列。电解实验后的干膜易与工件分离,可实现重复使用,提高了干膜的利用率。     

TC4钛合金转子叶片电解加工试验小结

一、前言钛具有重量轻、强度高以及其他一些优点,因此钛及钛合金在航空、空间工业,已日益得到广泛应用,如航空发动机的低压压气机叶片,以及扩散机匣等零件的材料已为钛合金所代替。对这一类形状复杂的钛合金零件的加工,采用电解加工工艺方法,已引起人们普遍注意。钛属于自钝化金属,在电解加工过程中有其特殊性,它的表面极易氧化,形成氧化物薄膜。这层膜的生成与溶解的不均匀性,直接影响电解加工后的表面质量,因此,摸索钛合金的     

钛合金TC4电解加工表面质量的试验研究

钛及其合金在航空和宇航工业中有重要的作用,但在电解加工过程中存在着特殊性.其特殊性体现在:加工表面易形成钝化膜使加工困难以及非加工表面易形成点蚀影响表面质量.对钛合金TC4进行了电解加工试验,对样件进行了分析、比较并研究了影响表面质量的工艺因素.结果表明:采用脉冲电源,选择浓度合适的NaCl电解液和恰当的电参数加工能获得较好的表面质量.     

NaCl-乙二醇溶液微细电解加工Ti6Al4V实验研究

采用NaCl-乙二醇的有机盐溶液作为电解液,其具有的少、无氧环境可避免电解加工过程中钛合金表面产生钝化膜,且能提高钛合金的可加工性。通过实验对比了加工电压、脉冲频率、占空比、主轴转速对加工缝宽的影响,进而得到最优的加工参数,并在厚度为0.7 mm的Ti6Al4V工件上加工出了微细结构。     

钛合金电解加工特殊性问题的研究与解决

引言钛合金电解加工性能复杂,除共性精度问题外,还存在加工过程不稳定,滲氢严重,表面光洁度差,单面电解二次加工困难,榫头易烧伤度面点蚀等弊病。这些已成为钛合金电解加工工艺关键。研究表明,钛电解的主要障碍是如何在自钝化膜复盖下开始加工,而突破这一障碍的主要关键是电解液。通过长期试验研究,选出了三种低浓度恰当比例电解液:BCE、CCE、NCE经生产考验表明,比较满意地解决了上述特殊性问题。     

微细阵列群电极电解加工关键技术研究

提出了基于阴极优化的微细阵列圆柱凸台群电极电化学腐蚀加工法。根据电化学腐蚀基本原理,通过有限元方法分析计算群电极电化学腐蚀加工过程中的电极表面电场分布,以电流密度分布均匀性为目标,优化设计阴极形状,并进行阵列群电极制备。在制备出直径均匀的阵列群电极的基础上,探索用局部涂胶保护法制备大长径比的盘状阵列群电极,用于微细孔电解加工,进一步提高电解加工的定域性。     

电极侧壁绝缘微细孔电解加工工艺研究

将超声振动技术应用于微细孔的电解加工中,以排除间隙内的加工产物,然而,超声空化现象产生的冲击力会影响电极表面的绝缘层,并加速其破坏。为提高侧壁绝缘电极的使用寿命,采用微弧氧化和阴极电泳工艺在微细钛电极表面形成由陶瓷膜和电泳漆膜组成的双绝缘层。通过超声振动辅助微细孔电解加工实验,对电极侧壁双绝缘层的耐久性进行验证,并分析了超声振动功率、电解液浓度和加工电压对双膜侧壁绝缘电极微细孔加工精度的影响。实验表明:双绝缘层电极在超声辅助微细孔电解加工中显示了很强的绝缘耐久性;当超声振动功率超过一定值后,微细孔电解加工能稳定进行,之后,随着功率的增加,孔的精度改善很小。在稳定加工中,需降低电解液浓度和加工电压,从而减小杂散腐蚀,保证加工孔的形状精度。     

群孔的微细电火花加工技术研究

对微细电火花群孔加工工艺进行了分析和研究。用微细电火花加工机床加工出单电极,并用该电极加工出2×2直径约100μm的阵列孔,在此过程中采用加大加工长度和适度欠补偿的方法,获得了质量较好的阵列孔。用此阵列孔作为工具加工出了2×2直径约100μm的群电极,然后用此群电极一次加工出2×2直径约100μm的群孔,从而实现了微细电火花阵列孔的加工。     

TB6钛合金电解加工过程工艺优化

重点探讨了电解加工过程中的钝化膜和点蚀对电解加工表面成形质量的影响。从电解液种类、浓度以及加工电压三个方面对TB6钛合金进行了电解加工试验,结果表明:采用如Na Cl之类的活性电解液对TB6进行加工时,随着浓度的升高,杂散腐蚀越来越严重,但随着浓度的升高,粗糙度会有所降低;同时,采用较高的加工电压可以使表面粗糙度得到控制。这为今后进一步研究TB6钛合金增材制造件电解加工提供基础数据。     

工件低频振动对微细电解加工材料蚀除速度的影响

基于电化学阳极溶解原理的微细电解加工技术在特种加工技术中占据着重要的地位。然而,微小间隙内电解液更新困难、电解产物难以及时有效排出,一直是制约该技术发展的瓶颈。利用自行设计的低频振动装置,通过工件低频振动辅助的方法进行微小孔电解加工实验,结果表明：该方法改善了加工区域的流场条件,促进了加工区域电解产物的输运及电解液的更新,显著提高了工件材料的蚀除速度。     

电解磨削复合加工精密扩孔研究

研究电解磨削技术应用于9Cr18不锈钢微小孔扩孔工艺,重点分析了加工电压和进给速度对加工质量的影响.实验结果表明,采用电解磨削工艺,选择合适的加工参数可加工出高精度、低表面粗糙度的微小孔.     

A study on micro-hole machining of polycrystalline diamond by micro-electrical discharge machining

Polycrystalline diamond (PCD), with its superior wear and corrosion resistance, is an ideal material for micro-hole parts in the field of microfabrication. This study investigated the micro-hole machining performance for PCDs by micro-electrical discharge machining (micro-EDM). A series of experiments were carried out to investigate the proper machining polarity and the impacts of micro-EDM parameters on machining performance. Experimental results indicate that negative polarity machining is suitable for micro-EDM of PCDs because of the protection brought over by the adhesion sticking to the electrode. An appropriate volume of adhesion on the tool electrode can help to increase the material removal rate (MRR) and reduce the relative tool wear ratio (TWR). By contrast, an excessive volume of adhesion can lead the machining into a vicious circle in which micro-holes are drilled with overlarge diameters. An optimal set of machining conditions was chosen among the investigated ranges of nominal capacitance and electrode rotation speed. An exemplary PCD through-hole, machined under the chosen optimal machining conditions, shows satisfactory machining results.     

Influence of tool vibration on machining performance in electrochemical micro-machining of copper

Electrochemical micro-machining (EMM) appears to be promising as a future micro-machining technique since in many areas of applications, it offers several advantages, including biomedical and MEMS applications. A suitable micro-tool vibration system has been developed, which consists of tool-holding unit, micro-tool vibrating unit, etc. The developed system was used successfully to control material removal rate (MRR) and machining accuracy to meet the micro-machining requirements. Micro-holes have been produced on thin copper workpiece by EMM with stainless-steel micro-tool. Experiments have been carried out to investigate the most effective values of process parameters such as micro-tool vibration frequency, amplitude and electrolyte concentration for producing micro-hole with high accuracy and appreciable amount of MRR. From the experimental results and SEM micrographs, it is evident that the introduction of micro-tool vibration improves EMM performance characteristics. Lower electrolyte concentration in the range of 15–20 g/l reduces stray current effects. Hertz (Hz) range of tool vibration frequency improves the removal of sludge and precipitates from very small interelectrode gap. The 150–200 Hz range of tool vibration frequency can be recommended for EMM, which provides a better electrochemical machining in the narrow end gap. Compared to kHz range, Hz range micro-tool's vibration improves the MRR and accuracy in EMM.     

Electrochemical micromachining of a Zr-based bulk metallic glass using a micro-tool electrode technique

For the first time the possibility of electrochemical micromachining (ECMM) of a Zr-based bulk metallic glass (BMG) using a micro-tool electrode technique is reported. It is demonstrated that the choice of the electrolyte chemistry is substantial for a successful ECMM processing. For the bulk glassy Zr₅₉Ti₃Cu₂₀Al₁₀Ni₈ alloy a concentrated aqueous NaNO₃ standard machining solution is not suitable due to formation of thick and dense corrosion product layers which hinder the machining of structures with high aspect ratio. On the other hand, a commercial methanolic HClO₄ solution is shown to be very promising. In the first experiments with this electrolyte micro-hole structures were machined with aspect ratios of about 1 at depths of ～40 μm. The effect of process parameters such as pulse voltage and pulse length was investigated and their influence on the machined structure morphology is established. In a first approach the potential and challenges of this electrochemical micromachining technique for microforming of multi-component bulk metallic glass surfaces will be discussed.     

CuW90微小孔电火花加工实验研究

利用单因素实验和正交试验法探究了电源电容、电流、伺服参考电压、伺服速度及占空比对CuW90微小孔电火花加工效率和电极损耗的影响。结果表明:伺服参考电压和占空比对加工效率和电极损耗的影响都较大,而电容、电流对其影响较小,最终得到了CuW90电火花微小孔加工的最优参数组合。     

Effect of surface roughness of tool electrode materials in ECDM performance

Electrochemical discharge machining (ECDM) is an emerging non-traditional machining process that involves high-temperature melting assisted by accelerated chemical etching. In this study, the tool electrode (200 μm in diameter) is fabricated by wire electrical discharge grinding (WEDG). After the tool electrode is machined, the surface roughness of tool electrode materials (stainless steel, tungsten carbide, and tungsten) is different because of the physical properties. However, the surface roughness affects the wettability on tool electrode, and also changed the coalesce status of gas film in ECDM. Hence, this study explores the wettability and machining characteristics of different tool electrode materials and their impact on gas film formation. Their machining performance and extent of wear under gravity-feed micro-hole drilling are also examined. Experimental results show that the optimal voltage of different tool electrode can shed light on the machining performance. Moreover, wettability of tool electrode is determined by surface roughness of tool material, which in turn affects the coalesce status of gas film, machining stability and micro-hole diameter achieved. In addition, differences in tool material also results in variations in machining speed. Significant tool wear is observed after repeated gravity-feed machining of 50 micro-holes.     

基于不同加工工艺的微孔节流空气静压轴承的特性研究

随着超精密加工技术和地面微低重力仿真的发展,相关产业对空气静压轴承的性能要求越来越高。由于传统的孔式节流器其结构特点不能完全满足实际使用的需要,节流孔直径与气膜间隙同一数量级的微孔节流空气静压轴承因其良好的刚度和承载特性,越来越受到关注。但在微孔节流器的发展过程中,微孔的加工工艺却限制了其推广应用。针对目前常用的三类微孔加工工艺,进行了理论仿真研究,通过建立不同加工工艺轴承仿真模型,运用双向流固耦合仿真方法,对比分析了基于不同加工工艺的微孔节流空气静压轴承的动静态特性。研究结果表明：锥孔类轴承承载性能优于其他两类,但耗气量大且在小间隙时刚度较差;薄壁直孔类轴承承载性能稍逊,但在大间隙下轴承刚度较佳;嵌套类轴承承载性能较差,但在小间隙下轴承刚度较大且耗气量较低。     

液体辅助激光微孔加工研究进展

随着微孔加工技术的逐渐成熟,激光微孔加工的应用越来越广泛,但依靠单一激光束进行微孔加工仍存在一些问题,尤其是在深孔加工方面,出现了以激光束为主、多能量场辅助的复合打孔技术,并逐渐成为了热点。针对液体辅助激光微孔加工研究领域,总结了水基辅助激光打孔、水基超声振动辅助激光打孔、水基超声?磁场辅助激光打孔和电解液/水射流辅助激光打孔等方法。在水基的基础上,加入了超声、磁场和温度场,使得辅助场变得多元化,在多层面上进行复合加工。介绍了不同辅助加工方法的去除材料机理及加工后材料特性的变化,水起到冷却的作用,但在水层下会形成空化气泡,超声振动可以击溃气泡,磁场和温度场为材料残渣提供了能量,具体表现在热效应、材料去除速率、打孔深度、重铸层及裂纹等方面。影响微孔质量的因素有微孔锥度、深径比、孔的圆度、重铸层厚度、热影响区、微裂纹和粗糙度等,主要对微孔锥度、深径比及其他指标进行了分析,总结了加工方法对微孔质量的影响。     

滤波器腔体压铸技术的研究和应用

滤波器铸件腔体具有共鸣信号柱多而孤立且内腔深的特点,在压铸成形过程中极易产生冷隔、气孔和缩孔,导致加工后,凸柱表面微孔众多,影响产品功能。从滤波器腔体的模具设计着手,优化滤波器型腔信号柱结构,采用挤压销方法,在压铸时,对模具披覆处理,采用抽真空工艺,对部分铸件进行修补处理,使滤波器腔体的共鸣柱加工后微孔得到明显减少,提高了产品的合格率,成功生产出多条相互不连通的共鸣信号柱的深腔滤波器铸件。