综合改善微细电解加工精度的工艺研究

电解加工的阳极电化学溶解原理使其在微细加工领域具有巨大的发展潜力,但杂散腐蚀和流场条件恶劣制约加工精度的提高.分析了影响微细电解加工的主要因素,提出综合改善微细电解加工精度的工艺途径.理论分析和实验研究均表明:将LIGA工艺制备高质量微细阵列电极、电极侧壁绝缘、高频脉冲电流及非线性电解液加工、电极间歇回退伺服控制等方法有机结合,能有效约束电场、改善流场,提高微细电解加工的精度.     

微细电加工应用技术研究

微细电加工要达到工业应用的目的,需兼顾加工效率和加工精度两方面的要求.以微细孔、微细三维结构的加工为目标,进行了微细孔电火花加工、三维微细结构电火花伺服扫描加工及微细电化学加工技术的研究开发.设计出微细电极的损耗补偿进给和导向机构,开发出三维微细结构的电火花伺服扫描加工工艺,研究了采用阵列微细电极的微细电化学加工方法.微细孔电火花加工可连续加工直径小至100 μm的孔.伺服扫描电火花加工可便捷地在小于1 mm2区域内加工出三维微细结构.提出的微细电化学加工技术路线拟将微细电解加工应用于阵列微细孔和三维微细结构的加工.     

超声扰动电解液的微细孔电解加工精度研究

根据法拉第定律、间隙内流场的特性以及超声扰动参数的影响,探讨了采用超声扰动电解液方法进行微细孔电解加工的机理,对微细电解和超声扰动电解液下的微细电解加工工艺试验进行了比较,结果表明超声扰动电解液加工时,加工间隙减小,加工的定域性得到改善,加工精度得到提高.     

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。     

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。     

提高微细电解加工精度的研究

对影响微细电解加工精度的因素进行了详细的分析，提出了改善加工精度的方法，如以循环进刀代替直接进刀方式、采用脉冲加工电源、改善阴极的结构设计以及采用非线性电解液等。最后，结合实验对这些方法的可行性与有效性进行了验证。     

微细电解加工机理探讨

介绍了微细电解加工技术的原理和特点，通过对其加工工艺的分析，简述了在微细电解加工过程中，影响其加工速度、精度、效率的主要因素，并通过对这些因素的综合分析，总结了制约微细电解加工技术应用的因素和进行微细电解加工应具备的基本条件。最后，针对微细电解加工技术的现状，对其发展提出了新的展望。     

电火花摇动加工微细阵列轴和孔的试验研究

针对微细阵列轴和孔的电火花加工,提出了利用数控电火花加工机床摇动功能的摇动加工微细阵列轴和孔的方法.此法是基于电火花反拷贝加工的原理,先用丝电极在薄平板(中间电极)上按要加工的阵列轴和孔间距或数倍间距加工阵列小孔(直径0.1 mm以上),然后用加工的薄平板(中间电极)作电极,电火花摇动加工微细阵列轴(电极),最后用此微细阵列电极加工阵列孔.进行了电火花摇动加工微细阵列电极试验,得到了单电极直径为50 μm、长径比为16的3×3阵列电极,并用此电极在70 μm厚的不锈钢板上加工出单孔直径为70 μm的3×3微细阵列孔.试验结果表明,电火花摇动加工方法可实现微细阵列轴和孔的加工.     

变参数微细电解加工变截面孔的实验研究

为提高微细电解加工高深宽比变截面孔的形状精度,通过仿真分析加工过程中不同的参数变化时间间隔对变截面孔形状精度的影响,设计并实现了一种变参数加工控制方法。在1 mm厚的18CrNi8工件上进行变参数微细电解加工实验,加工出孔径200~320μm(深宽比约为5)的变截面孔。结果表明:参数变化时间间隔为1 s时,形状平均误差为9μm,相比于其他时间间隔,其平均误差减小约85%,较好地满足了设计要求,也验证了该变参数加工控制方法的有效性。     

微细孔、阵列孔及微细三维型腔的超声加工研究

利用自行开发的微细电火花与微细超声复合加工装置,对微孔超声加工中效率随孔深的变化、磨料颗粒尺寸对精度的影响等进行了实验研究,并采用恒加工力控制方式,在单晶硅100晶面实际完成了直径18μm圆孔和28μm×28μm方孔的超声加工、微细十字孔与阵列孔的超声反拷加工以及微细三维型腔的工具均匀损耗补偿分层铣削超声加工.     

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.     

Advancement in electrochemical micro-machining

Electrochemical micro-machining (EMM) appears to be very promising as a future micro-machining technique, since in many areas of applications it offers several advantages, which include higher machining rate, better precision and control, and a wide range of materials that can be machined. In this paper, a review is presented on current research, development and industrial practice in micro-ECM. This paper highlights the influence of various predominant factors of EMM such as controlled material removal, machining accuracy, power supply, design and development of microtool, role of inter-electrode gap and electrolyte, etc. EMM can be effectively used for high precision machining operations, that is, for accuracies of the order of ±1 μm on 50 μm. Some industrial applications of EMM have also been reported. Further research into EMM will open up many challenging opportunities of improvement towards greater machining accuracy, new materials machining and generation of complex shapes for effective utilization of ECM in the micro-machining domain.     

光刻胶掩膜微细电化学加工参数的试验研究

对光刻胶掩膜微细电化学加工参数进行了试验分析研究，发现光刻胶厚度、开口角度、咏冲电源频率、脉宽及电解液配方对加工质量都有影响，在此基础上提出改善加工质量的可行性方案。     

微细电化学加工研究新进展

结合国内外微细电化学加工技术的最新进展，系统地综述了微细电化学加工在多个方面的研究情况和工艺特点，例如LIGA工艺、用电化学隧道显微镜(electmchemical STM)的针尖进行纳米级尺寸的电化学加工、用超短脉宽脉冲电压微细电化学加工等。微细电化学在未来的微纳加工中必将大有作为。     

Experimental investigation into electrochemical micromachining (EMM) process

Due to several advantages and wider range of applications, electrochemical micromachining (EMM) is considered to be one of the most effective advanced future micromachining techniques. A suitable EMM setup mainly consists of various components and sub-systems, e.g. mechanical machining unit, micro-tooling system, electrical power and controlling system and controlled electrolyte flow system etc. have been developed successfully to control electrochemical machining (ECM) parameters to meet the micromachining requirements. Investigation indicates most effective zone of predominant process parameters such as machining voltage and electrolyte concentration, which give the appreciable amount of material removal rate (MRR) with less overcut. The experimental results and analysis on EMM will open up more application possibilities for EMM.     

五轴数控机床非线性误差建模及补偿方法

针对五轴数控机床后置处理中由于平动轴和旋转轴的联动产生的非线性误差,提出一种基于误差建模的非线性误差在线预测与补偿方法.根据任意两个相邻刀位数据点产生的非线性误差,获得误差的分布特征,建立起误差分布模型;利用最小二乘法求解出非线性误差的数学表达式,经与误差许用值相比较来确定新的刀位点,从而实现非线性误差的在线预测及补偿...     

A review on spindle thermal error compensation in machine tools

Thermal error caused by the thermal deformation is one of the most significant factors influencing the accuracy of the machine tool. Among all the heat sources which lead to the thermal distortions, the spindle is the main one. This paper presents an overview of the research about the compensation of the spindle thermal error. Thermal error compensation is considered as a more convenient, effective and cost-efficient way to reduce the thermal error compared with other thermal error control and reduction methods. Based on the analytical calculation, numerical analysis and experimental tests of the spindle thermal error, the thermal error models are established and then applied for implementing the thermal error compensation. Different kinds of methods adopted in testing, modeling and compensating are listed and discussed. In addition, because the thermal key points are vital to the temperature testing, thermal error modeling, and even influence the effectiveness of compensation, various approaches of selecting thermal key points are introduced as well. This paper aims to give a basic introduction of the whole process of the spindle thermal error compensation and presents a summary of methods applied on different topics of it.     

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.     

复合式镗铣加工中心铣削部分空间误差建模研究

基于多体系统运动理论,结合复合式镗铣加工中心铣削部分的结构布局,阐述了多体系统的拓扑结构、低序体阵列和相邻体间特征矩阵的创建方法,分析基于多体运动学原理的复合式镗铣加工中心铣削部分空间误差模型的建立。     

加工过程中各类误差项对圆柱零件的影响研究

车削加工中,分析了影响被加工零件的误差源,然后利用齐次坐标变换原理建立各种原始制造误差的数学模型,利用差分法计算被加工零件受力变形引起的加工误差,得出车削过程中各项误差对被加工圆柱零件的影响,并以实例说明加以验证。