微细电解加工中空电极侧壁绝缘层的制备工艺研究

针对孔径100～200μm高深宽比微细孔电解加工中,电极侧壁绝缘层在电解液冲击和气泡撕裂中易损伤/脱落等问题,本文提出一种丙烯酸环氧树脂电泳法的中空电极侧壁绝缘制备工艺。通过优化工艺参数并开展加工实验,比较加工孔尺寸及形貌、加工后电极表面形态,结果表明丙烯酸环氧树脂电泳法制备的中空电极侧壁绝缘层,具有较高的致密性、均匀性、耐久性和一致性。最后,在500μm厚304不锈钢片上加工出入口180.6μm、出口173.8μm、深宽比约为3的微细阵列孔,其锥度比非侧壁绝缘电极加工的孔减少了约70%以上,基本为直孔,可满足实际需求,进而验证了本方法的应用可行性。     

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。     

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。     

双极性电泳法的微细中空电极侧壁绝缘层制备

针对孔径(100～200)μm高深宽比微细孔电解加工中,电极侧壁绝缘层在电解液冲击和气泡撕裂中易损伤/脱落等问题,提出一种基于丙烯酸环氧树脂双极性电泳法的微细中空电极侧壁绝缘制备工艺.通过工艺参数优化后,利用所制备的侧壁绝缘电极,开展加工对比实验,结果表明双极性电泳法所制备的侧壁绝缘层,具有较高的致密性、均匀性、耐久性...     

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。     

电解加工在微细制造技术中的应用研究

电解加工是利用阳极金属电化学溶解原理来去除材料的制造技术,这种微去除方式使得电解具有微细加工的可能,这里着重探讨了高频窄脉冲微细电解加工技术、电液束微细电解加工技术和利用电解制备微细电极的工作原理,技术特点,应用领域和加工精度,并详细的讨论了目前微细电解加工脉冲电源和加工设备的研制和发展。     

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。     

电极丝前置式射流电解加工铣削微槽试验研究

射流电解加工广泛应用在航天、军工、汽车、电子等制造领域,多用来进行工件表面微结构的加工,是一种高效低成本的方法。电极丝前置式射流电解加工利用液束中的电极丝将电场集中约束在主要加工区域,相比于传统射流电解有着更高的加工效率和质量。通过搭建试验平台并在不锈钢工件表面进行微槽铣削试验,验证了该方法的实际加工效果,初步得到了电压、电极丝直径、单次进给量等参数对加工结果影响的工艺规律。当选用直径100μm侧壁绝缘的电极丝时,扫描5次可以得到槽宽最小为400μm,槽深120μm的直槽。试验结果表明,电压和加工间隙影响电流密度的大小,主要决定了加工效率和质量,而电极丝和液束的状态则决定了特征的精度和形貌。     

带双极电极的电解加工

如何降低加工间隙中气体密集度的问题,目前已引起电解加工行业的极大关注。这是因为加工过程中析出的气体,对于加工精度、生产率、耗电量以及表面质量等电解加工工艺特性,都将产生不良的影响。而加工间隙中气体浓度不均匀以及阴极附近的超高浓度乃是导致这种不良影响的主要原因。这样将使电解液的导电率降低和电流密度沿加工间隙通道长度的相应分配。当加工长尺寸     

Novel structure of a sidewall-insulated hollow electrode for micro electrochemical machining

Adopting the sidewall-insulated hollow electrode (SIHE) is an ideal approach to achieve electrolyte-refresh and stray corrosion inhibition functions in micro electrochemical machining (ECM) processes. Most of the traditional SIHEs are made of metal substrate and non-metal thin films. The insulating film has poor durability, and the preparation approach of the traditional SIHE is complex and has limited repeatability. This research presents a novel structure of a SIHE with an insulated substrate and an internal conductive film. The machining performance of the novel SIHE is primarily verified by a potential distribution analysis in the numerical simulation. According to the concept of the novel SIHE, a silver-plated glass tube electrode (SPGTE) is presented: the glass tube acts as the insulated substrate, and the plated silver layer acts as the working cathode. Then, a fabrication process for the SPGTE is proposed. Silver layers are tightly bonded on the glass tube surface by electroless plating. The thickness of the silver layer is approximately 3.5 μm, and its electrical resistivity is approximately 5 × 10−5 Ω cm. In micro ECM experiments, microstructures with steep sidewalls with taper angles of <5° are machined, which is attributed to the stray corrosion inhibition of the insulated substrate. Micro holes with an aspect ratio of approximately 3 are machined. There is no accumulation of electrolytic products and short circuits, which verifies the excellent electrolyte-fresh performance. Compared with the traditional SIHEs, the novel SIHE could provide a simpler and more reliable way of fabricating sidewall-insulated electrodes. The proposed electrode structure can further inspire new electrode preparation schemes based on new substrate materials and film preparation approaches.     

电火花加工多材质电极制备方法及试验研究

随着电火花加工技术的不断发展,利用多材质电极来实现微小复杂曲面的电火花成形加工,具有加工速度快、一次成形等特点而被广泛应用.针对多材质电极的制备,以黄铜、紫铜、铁、钼及铜钨合金等材质电极在模具钢上进行了加工试验,以研究的电极损耗及形状变化规律为基础,根据复杂曲面加工需求设计多材质电极,运用热镀法制备多材质电极,通过扫描...     

多工位组合电极电火花成形微凹槽结构

针对具有复杂微尺度凹槽结构的高硬度模具钢型腔难以加工的难题,提出了一种多工位组合电极电火花成形的新方法。以某种聚合物微流控芯片模具型腔为研究对象,选用NAK80模具钢为型腔材料,铜钨合金(W75%)为相应的微凸起结构电极材料并经由高速铣削加工。为降低加工难度及保障加工质量,对复杂微凸起结构进行分解,形成2组4工位组合电极;采用周铣、端铣交替进行的工艺使微凸起上表面的毛刺连续发生塑性变形从而减小和去除微凸起结构顶端的加工毛刺。最后,利用制备好的多工位组合电极,采用变换工位代替更换电极的加工方式,通过精密电火花成形,依次完成粗、半精与精加工。结果表明:加工的凹槽侧壁与底面垂直度较好,宽度、高度误差在3μm以内,根部圆角在15μm以内,可以满足成型聚合物微流控芯片的使用要求。     

用高转速微电极电解钻削深小孔

针对难切削材料的深小孔加工,提出一种有效排屑、迅速补充电解液的新工艺——高转速微螺旋电极电解钻削加工工艺,并对该工艺进行了机理分析与试验研究。研究了电极转速、电压、脉冲频率、进给速度等工艺参数对深小孔电解钻削加工精度和稳定性的影响,提出合理匹配上述参数可在较高加工效率下获得高的加工精度和加工稳定性。基于硬质合金微螺旋电极用自行研制的高精度微细电解系统成功地在高温镍基合金GH4169上加工出了一组孔径小于0.5mm、深径比大于10、形貌较好,锥度较小,侧壁陡直,进出口边缘锐利的深小孔。试验结果表明,高速电解钻削加工工艺在深小孔加工方面很有潜力。     

Design of ECM tool electrode with controlled conductive area ratio for holes with complex internal features

The design method of electrochemical machining (ECM) tool electrode with controlled conductive area for the machining of holes with given complex internal features was presented in this paper. Such holes were difficult to machine with traditional mechanical machining methods. In authors’ previous work, it has been proved that electrochemical machining (ECM) using tool electrode with controlled conductive area ratio was effective to machine many kinds of complex holes. However, it is considered that the inverse problem, i.e., designing of suitable tool electrode for given internal feature is of great importance for practical application. Therefore, in this work, the proposed ECM process was modeled to investigate the electric potential and current distribution in the electrolyte and on the electrodes’ surface, and the evolution of inner hole profile. Then, the relationship between conductive area ratio and the machining depth was investigated by a set of fundamental simulation experiments. Simulation result showed that suitable tool electrode with specific helical conductive area can be designed for the machining of hole with given internal feature. A prototype tool electrode with non-uniform conductive area ratio from its tip to the root was fabricated and used in the verification experiment. The machining result showed that a free-formed hole was successfully shaped and the inner hole profile is in well accordance with the given internal feature.     

不同流场构型对微细螺旋孔电解加工的影响

为了研究微细螺旋孔电解加工中不同流场构型对加工效果的影响,首先介绍了一种微细螺旋孔电解加工（ECM）用工具电极的制作工艺方法;然后,通过改变电极绝缘层厚度构造不同的螺旋孔电解加工流场构型,并对其进行了数值分析;最后,通过电解加工实验对分析结果进行了验证。研究结果表明,在其它条件不变的情况下,涂层厚度越厚,加工效果越好。     

Research on ECM process of micro holes with internal features

Micro holes with internal features are widely used as spray holes and cooling holes nowadays, which are usually required to be with high aspect ratio and shape accuracy, as well as good surface quality. An electrochemical machining (ECM) process is presented to machine these micro holes with diameter <200 μm. A quantitative relation between micro-hole diameter and machining parameters including voltage, duty ratio and feedrate is obtained through orthogonal experiments. According to the designed shape of internal features, change rules of machining parameters for varied diameters in different depth are obtained, and then micro holes with internal features are shaped precisely. Taking reverse tapered hole as an example, ECM experiments by varying parameters of voltage, duty ratio and feedrate (called varying voltage machining, varying duty ratio machining and varying feedrate machining, respectively) are carried out. Micro holes with inlet diameter of 178 μm and taper angle of 1.05° are shaped on a 1.0 mm-thick workpiece of 18CrNi8. The deviation of inlet is <3 μm and the taper-angle error is <0.1° in varying voltage machining. The corresponding dimensional accuracy of taper angle is improved by 51% than that of varying duty ratio machining under the same efficiency. The machining efficiency of varying voltage machining is increased by 36% compared to the efficiency in varying feedrate machining. In addition, the micro holes with complex features of funnel shape and bamboo shape are machined.     

叶片电化学加工过程多场耦合仿真

针对叶片电化学加工过程难以预测、实验参数修正周期长的问题,建立与温度相关的叶片多场耦合仿真模型,基于COMSOL Multiphysics平台对叶片电化学加工过程进行多场耦合仿真,仿真分析了不同加工电压和不同进液流量对法向平衡间隙的影响。结果表明：加工电压越大,间隙也相应增大,且间隙分布越不均匀;进液流量越大,间隙分布越均匀。采用其中一组仿真参数进行工艺实验,仿真与实验的对比结果表明,叶片轮廓曲率变化缓慢处的仿真结果和实验结果比较贴合,而轮廓曲率变化较快处的仿真值与实验值差别相对较大,但两者的变化趋势相同。     

基于环形电极的曲孔加工方法

探讨利用直柄和弧柄环形电极电火花加工曲孔的方法,可加工任意横截面的曲孔,通过加工实例,讨论其加工原理,分析了特别影响环形电极曲孔加工的工艺因素,包括电极形式、环形部分制作、芯料支撑方式、工作液方式和加工状态等,并就其加工特点进行了总结。     

基于气液两相流模型的电解加工多场耦合仿真

针对电解加工产生的气泡影响加工精度的问题,引入Euler Euler双流体模型对电解加工中气液两相流场进行描述,并耦合电场和温度场相关模型,分析了工具阴极、工件阳极表面气泡率、温度、电导率和电流密度的分布规律;通过调整加工电压、入口压力和出口压力,对工件阳极表面气泡率和电流密度分布进行仿真优化。仿真结果表明：在流速相同的条件下,减小加工电压、增加出口压力能够改善电导率分布,使阳极表面电流密度分布更加均匀。实验结果表明：仿真得到的阳极表面电流密度分布与工件轮廓高度误差分布吻合;采用优化后参数加工出的工件轮廓精度得到提高。