微细电火花机床及其关键技术研究

为了将电火花加工技术应用到微机械制造中,分析了微细电火花加工中的关键技术,开发了微细电火花加工机床.该机床由精密进给装置、主轴、线电极磨削装置、微细电火花加工电源、花岗石工作台、伺服控制系统等构成.该机床具有三轴联动数控功能,各轴的进给分辨率均为0.1μm.主轴的回转跳动<1μm,转速为1 000~25 000 r/m in,可以连续变速.该机床小到可以放在一张桌面上.在这台机床上进行了初步工艺实验,稳定地加工出了直径<15μm的微细轴和25μm的微细孔,还加工出了微三维结构.     

微坑超声复合微细加工试验研究

提出用超声复合电加工方法制作微小结构,并分析微细超声、超声复合电火花、超声复合电解微细加工机理;用微细放电组合技术制作多种截形微细工具电极;完善超声复合电加工试验系统,进行多种材料、形状微结构超声复合加工试验．结果表明：超声复合加工是制作硬脆材料微结构的有效方法;超声复合电火花加工金属材料微结构有良好的精度及稳定性;超声复合电解加工具有效率高、精度好的技术优势．     

半导体硅材料微细电火花加工技术

为了拓展微细电火花加工技术的应用领域,开展了半导体硅材料的微细电火花加工技术研究,从硅材料的抗腐蚀系数、掺杂浓度、掺杂类型以及硅材料的晶向特性等几方面对硅材料的微细电火花加工性能进行研究;在自主开发的微细电火花加工机床上进行了大量工艺实验,研究了不同加工规准下不同掺杂类型硅材料的微细电火花加工工艺规律,并与加工不锈钢材料的工艺规律进行对比分析;阐述了不同工作液类型对硅材料加工后性能的影响;在此基础上进行硅材料的微结构加工实验,给出加工实例.在N型硅和P型硅上分别加工出了最窄梁宽为23μm和12μm的微细梁,并在P型硅上实现了直径为0.15 mm的微半球以及外环直径为4mm,具有24个微型叶片的微型涡轮盘的加工.     

微齿轮轴的微细电火花加工

采用微细电火花铣削与微细电火花线切割组合加工复杂微小零件。以带轴的微小齿轮为例,在分析其结构特点及微细电加工特性的基础上,规划了微小齿轮轴的组合电加工工艺流程,分析了组合加工中的精度和效率,实现了节圆直径为350μm的微小齿轮轴的制造。     

特种加工技术在微小孔加工中的应用

国内外普遍认为机械小孔加工难度较高。采用电火花、电解、激光、超声波、电子束以及复合的特种加工技术,解决微小孔加工难题,可以满足精尖端制品对微、小孔及微细深孔的加工需要。     

微细电解加工及其复合加工技术

结合近几年微细电解加工技术的发展状况,阐述了常规微细电解加工技术、微细电火花电解复合加工技术、微细超声电解复合加工技术、微细激光电解复合加工技术等方面的最新研究进展,研究表明微细电解加工及其复合加工技术是实现难加工材料或具有复杂特殊结构微细金属零件的理想加工制造方法。     

线电极放电磨削(WEDG)技术的研究与应用

为解决微细电火花加工中工具电极的在线制作问题，根据WEDG的技术特点，设计并研制出了一种分体武的新型WEDG装置，采用浮动轮自适应控制张力、齿轮副和滚动轮副的组合结构收丝等方法。系统阐述了其工作原理、设计思想和工艺应用。使用该装置可以稳定地加工出直径φ15μm、长径比40以上的微细工具，在此基础上，进行了微细电火花加工试验，给出了微细轴、孔及微三维结构的加工实例。研究和应用表明，该装置具有结构紧凑、走丝稳定、加工精度高、工艺适应性广等特点。     

微细结构超声电解复合加工工艺研究

利用组合电加工方法制作的多种微细工具阴极,对多种材料进行了微细超声与微细超声电解复合加工的对比试验.结果表明微细超声电解复合加工对于提高微细结构加工效率与成形精度有明显效果.     

微细电火花线切割加工装置及应用

开发了一套微细电火花线切割加工装置.主要由精确可控微小放电能量的脉冲电源、加工状态在线检测与控制系统、基于压电陶瓷驱动的精密伺服控制系统和恒张力走丝系统等关键技术构成.利用直径为30μm的微细电极丝,加工出微小槽的最小宽度<38μm,表明放电间隙≤4μm,并且白层厚度<2μm,表面粗糙度Ra≤0.1μm.给出了微小齿轮以及各种各样的异型孔加工实例,证实该设备具有较广泛的实用性.     

皮焦级超微能电火花加工电源技术研究

为了解决长期困扰微细电火花加工的降低单脉冲放电能量难题,对RC脉冲电源放电特性进行了试验研究.通过一系列实验证实了RC脉冲电源放电时没有电火花维持电压现象,电火花加工可以在低于常规电火花维持电压的低电压下进行,此时的单脉冲放电能量最小可达2.5×10-12J,使微细电火花单脉冲放电能量由过去的微焦耳级剧降到皮焦耳级,为实现超微能的纳米尺度电火花加工奠定了基础.在此基础上设计了一种新型可控的RC脉冲电源,并使用该电源加工出了直径仅为Φ4.5μm的微轴和直径仅为Φ8μm的微孔.     

Experimental study of MWEDM technology

This work deals with an experimental investigation of the machining characteristics of Micro Wire Electrical Discharge Machining (MWEDM). The MWEDM process consists of only one cutting operation yawing with machining conditions. Experimental results show that the peak current and pulse duration have an obvious influence on surface roughness and machining time, and they also have an optimum value for the highest cutting speed. The servo reference voltage influences the surface roughness and machining time as well. In particular,the surface characteristics of work-pieces and a micro wire electrode were analyzed in detail too. Utilizing a micro wire electrode with diameter 30μm, MWEDM can machine a micro slot 38μm wide, which proves that the discharge gap can be controlled not more than 4μm. It can also machine micro gears respectively with a module 40μm, thickness lmm, and a module 100μm, thickness 3.5mm. All kinds of micro shaped holes and complex micro parts can be easily machined as well.     

Effects of mask wall angle on matrix-hole shape changes during electrochemical machining by mask

The influences of the mask wall angle on the current density distribution,shape of the evolving cavity and machining accuracy were investigated in electrochemical machining(ECM) by mask.A mathematical model was developed to predict the shape evolution during the ECM by mask.The current density distribution is sensitive to mask wall angle.The evolution of cavity is determined by the current density distribution of evolving workpiece surface.The maximum depth is away from the center of holes machined,which le...     

Research of micro-EDM and its applications

A Micro Electrical Discharge Machining (MEDM) equipment was developed in this paper,on which the CNC interpolation for 3-axis linkage movement could be realized easily. By this micro-EDM equipment,the fabrication process of microelectrode,micro hole,silicon wafer and complex microstructure was discussed. The process rules of machining efficiency and the relative electrode wear rate as well as the machining mechanism and performance of silicon micro-EDM were also researched. Machining experiments showed that the microelectrode diameter as small as 6 μm and the micro hole with minimum size of 10 μm could be obtained steadily,and the maximum aspect ratios of microelectrode and micro hole were over 25 and 10 respectively. And silicon micro-EDM experiments showed that the micro beam with the aspect ratios over 15 could be obtained easily. And a micro beam with minimum size of 23 μm width on a silicon wafer with 420 μm thickness was achieved. At last,the microstructure machining technology for micro-EDM was also discussed. And a micro-facial sculpture with free space curved surface and size of 1 mm×0.3 mm×0.18 mm was also machined successfully.     

Surface performance of workpieces processed by electrical discharge machining in gas

The surface performance of workpieces processed by electrical discharge machining in gas(dry EDM)was studied in this paper.Firstly,the composition,micro hardness and recast layer of electrical discharge machined(EDMed)surface of 45 carbon steels in air were investigated through different test analysis methods.The results show that the workpiece surface EDMed in air contains a certain quantity of oxide,and oxidation occurs on the workpiece surface.Compared with the surface of workpieces processed in kerosene,fewer cracks exist on the dry EDMed workpiece surface,and the surface recast layer is thinner than that obtained by conventional EDM.The micro hardness of workpieces machined by dry EDM method is lower than that machined in kerosene,and higher than that of the matrix.In addition,experiments were conducted on the surface wear resistance of workpieces processed in air and kerosene using copper electrode and titanium alloy electrode.The results indicate that the surface wear resistance of workpieces processed in air can be improved,and it is related with tool material and dielectric.     

超纯水微细电解加工的可行性研究

针对绿色制造和微细加工的需求,对一种新型微细电解加工方法——超纯水微细电解加工进行了基础研究.在试验原理的基础上,研制了试验装置,研究了阳离子交换膜促进超纯水水解离的机理及其提高电解加工过程中电流密度的因素,并通过工艺试验在不锈钢薄片上加工出微小孔,从而论证了超纯水微细电解加工的可行性.     

硬质合金的超声电解复合加工试验研究

硬质合金材料采用普通切削加工相当困难。试验结果表明,超声电解复合加工和单一的超声加工、电解加工比较可显著提高其加工速度、加工精度及表明质量。     

绝缘材料电火花加工机理探讨

采用辅助电极法，对绝缘性陶瓷材料SbN4的电火花加工进行了实验研究。指出了正常脉冲放电实现除去材料加工，长脉冲放电生成导电膜，正常脉冲放电和长脉冲放电的交替，使电火花加工在去除材料加工和生成导电膜的交替中不断进行，最终使工件成形的绝缘材料电火花加工机理。得出了单位加工时间内正常脉冲比例越大，加工速度越快；单位加工时间内长脉冲比例越大，生成导电膜厚度越厚的结论。     

电解加工技术的应用和发展

结合电解加工技术应用发展的关键,综述了促进电解加工技术进步的重要研究工作,列举了计算机技术在电解加工工艺、阴极设计、控制和设备方面的部分应用实例以及微细电化学加工的研究进展,阐述了复合、组合集成是拓宽电解加工应用范围的有效途径的理念．分析了目前航空、航天、兵器工业对电解加工需求增长以及石油采掘对电解加工的需求异军突起的情况,电解加工技术的日臻完善和新的发展机遇预示着电解加工的春天到了．