基于非共振固有振荡的微细电火花加工脉冲电源的研究

实现微细电火花电源微能放电并提高脉冲电源的频率一直是理想之选,但由于受到电源电阻、电容、电感自带杂散电容和杂散电感的影响,使提高脉冲电源频率遇到了瓶颈。通过对电火花放电电路和联接线路的分析,提出了依靠电火花机床和连接线路的固有振荡制作微细电火花脉冲电源。通过理论计算和电路仿真,放电电路的振荡周期可控制在1.176 ns,脉宽低于650 ps,这为皮秒级电火花脉冲电源的制作和微细电火花纳米级加工提供了理论支持。     

基于CPLD的多模式微能脉冲电源设计

根据微细电火花加工对脉冲电源的要求,设计了以CPLD为控制核心的多模式微细电火花脉冲电源,介绍了该电源主放电回路的实现方法,并对电源的脉冲控制部分进行了仿真分析.     

微细电火花加工用脉冲电源技术的基础研究

在微细电火花加工中，使用RC放电回路容易得到数十至数百纳秒的窄脉宽电流，但RC放电回路由于向电容器充电所需时间而不能得到很高的放电频度，严重影响其加工效率。为此，本研究开发了微细电火花加工用晶体管式脉冲电源，并对其加工特性进行了评价，找出了适合于微细电火花加工的晶体管式脉冲电源。实验结果表明，自振式晶体管脉冲电源因其加工速度慢并不适于微细放电加工。通过开发等脉宽晶体管脉冲电源，可实现脉宽80ns的放电电流，与传统的RC放电回路相比，加工速度可提高2至3倍。     

微细电火花加工多模式脉冲电源的研究

根据微细电火花加工的特点及其对脉冲电源的要求,设计了以单片机和FPGA为控制核心的多模式微细电火花脉冲电源.介绍了该脉冲电源关键回路的实现方法,实验研究表明该电源可实现多种形式的脉冲放电加工.     

超声振动复合微细电火花加工微小孔试验研究

微小孔加工时的放电间隙较小,排屑、消电离状态差,放电效率低,直接影响加工效率和电极损耗;超声振动可改善排屑、消电离状态,能提高放电效率。将超声引入微细电火花加工,通过工件的超声振动,进行超声功率、小孔孔径、脉冲频率的微小孔电火花加工工艺试验研究,结果表明:加工不同孔径时,超声功率及电源频率都存在一个最佳值;加工条件合适时,超声复合微细电火花加工优于常规微细电火花加工。     

应用线电极磨削法的电火花微孔加工

在微细电火花微孔加工中,微细工具电极的制作精度是决定微孔加工质量的关键。本文介绍了作者研制的微细电火花加工样机。该机床应用了线电极电火花磨削法制作微细轴,并在同一台机床上用制作的微细轴作为工具电极加工微孔;同时为提高微孔的加工质量,采用了主轴横轴布局结构。该机床还采用了微能放电电源、去离子水工作液等加工工艺。经过实验加工,获得了高质量的微细轴以及微孔。     

一种用于微细电火花加工的甚高频微能脉冲电源

作为微细电火花加工的关键技术之一,微能脉冲电源性能的优劣直接影响放电加工的精度、效率、稳定性等。从减小放电脉冲能量、增大放电间隙、可持续加工的需求出发,探索了一种基于电路共振原理的甚高频(频率在30~300 MHz)微能脉冲电源,突破了现有电火花脉冲电源的工作模式,能产生脉宽极窄、频率极高的脉冲波形,具有纳米级放电蚀除特性,提高了微细电火花加工的极限蚀除能力。放电频率为65 MHz时,相对于传统的微能脉冲电源,加工的孔边缘几乎没有重铸层,极大地减轻了在加工过程中的热损伤、重铸层和热影响区等常规缺陷,改善了工件加工的表面质量,实验结果证明所设计的甚高频微能脉冲电源具有良好的放电蚀除特性。     

低电压下微能RC脉冲电源放电波形研究

RC脉冲电源是微细电火花加工中常用的电源,低开路电压下的微能RC脉冲电源可实现更加微细和精密的电火花加工.针对低开路电压下的微能RC脉冲电源放电波形进行观测,对不同充电电容和开路电压下的充电电容两端电压、放电间隙两端电压及放电回路的电流波形进行了对比和分析.研究发现:由于回路中寄生参数的影响,充电电容两端电压与放电间隙...     

一种微小孔电火花加工机床的研制

介绍了一种面向工业应用的微小孔电火花加工机床及其技术开发，兼顾加工效率和加工精度两方面的要求，推进微细电火花加工的实用化。内容涉及摩擦传动微进给机构、高频脉冲放电电源、微小电极的旋转进丝机构、加工状态检测与控制系统等关键技术。     

应用线电极磨削法的电火花微孔加工

在微细电火花微孔加工中，微细工具电极的制作精度是决定微孔加工质量的关键。本文介绍了作者研制的微细电火花加工样机。该机床应用了线电极电火花磨削法制作微细轴，并在同一台机床上用制作的微细轴作为工具电极加工微孔；同时为提高微孔的加工质量，采用了主轴横轴布局结构。该机床还采用了微能放电电源、去离子水工作液等加工工艺。经过实验加工，获得了高质量的微细轴以及微孔。     

Influences of pulsed power condition on the machining properties in micro EDM

Micro EDM is one of the most powerful technologies which are capable of fabricating micro-structure. However, there are many operating parameters that affect the micro EDM process. Since the EDM is basically a thermal process, the supplying electrical condition can be an important factor. The conditions generally consist of several parameters such as electrical current, voltage, pulse duration, spark gap, and others. Those are decisive in removal rate, wear rate, and machining accuracy, which are characteristics of EDM. In this study, the influences of EDM pulse condition on the micro EDM properties were investigated. Voltage, current, and on/off time of the pulse were selected as experimental parameters based on a simple equation for the material removal rate. The pulse condition is particularly focused on the pulse duration and the ratio of off-time to on-time, and the machining properties are reported on tool wear, material removal rate, and machining accuracy. The experimental results show that the voltage and current of the pulse exert strongly to the machining properties and the shorter EDM pulse is more efficient to make a precision part with a higher material removal rate.     

A plate capacitor model of the EDM process based on the field emission theory

The electrical discharge machining (EDM) process is, by far, the most popular amongst the non-conventional machining processes. The technology is optimum for accurate machining of complicated shapes in hard materials, required in the modern industry. However, although a lot of EDM machines are widely applied for many years, fundamental knowledge of the process is still limited. The complex nature of the process involves simultaneous interaction of thermal, plasma temperature and electromagnetism factors, which makes the machining process modeling very difficult. In this paper, based on the analysis of the electric discharge machining (EDM) process, a plate capacitor model is constructed to describe the discharging process in a pulse time. The whole EDM process is divided into four stages, successively as interelectrode electric-field establishment, electric discharge channel formation, stable EDM and deionization, the interaction of each stage and the distribution function of EDM energy are deduced using the field electron emission theory. For the purpose of analyzing the effect of the single factor, a set of machining through-hole experiments were carried out and investigated. The study shows that critical electric-field intensity and the effective discharging time rate play major roles on the improvement of machining efficiency; the model can explain the differences of machining efficiency using different materials of tool pole and different EDM parameters; and the theoretical results are concordant with the experimental data well.     

微细喷油孔电火花加工机床控制系统研究

在对微细喷油孔电火花加工机床的结构特点和加工原理进行分析的基础上,研究开发了该机床的控制系统,详细介绍了该控制系统的设计原理及其硬件与软件组成,并对其控制方法、抗干扰等关键问题进行了分析研究.实验结果表明,该控制系统能实现微细喷油孔的高效、高精度的电火花加工.     

冷等离子体射流中微细电火花加工特性研究

采用晶体管脉冲电源,在氧气辅助氮气等离子体射流、氮氧混合等离子体射流及外部压缩空气辅助氮气等离子体射流等不同冷等离子体介质中进行了微细电火花加工特性的实验研究,以期确定加工过程稳定的工艺条件,达到提高加工效率和加工质量的目的。在氧气辅助氮气等离子体射流实验中发现,随着氧气流量的增加,材料去除速度和表面粗糙度值均有增大趋势;采用压缩空气辅助氮气等离子体射流的电火花加工在表面质量、边缘质量方面均优于氧气辅助氮气等离子体射流加工。     

微小齿轮模具的微细电火花线切割加工研究

介绍了微细电火花线切割加工微小齿轮模具的方法，其关键技术包括：晶体管可控微能量RC脉冲电源、间隙放电状态检测系统、基于压电陶瓷电机驱动的精密伺服机构和偏开路加工控制策略。使用微细电火花线切割加工机可一次切割出厚度为1mm、模数为0．04和厚度为3、5mm、模数为0．1的微小齿轮模具，表明由微细电火花线切割加工出的微小齿轮模具能满足微成形加工的技术要求。     

超声振动磨削放电复合加工SiCp／Al试验研究

针对SiCp／Al的加工,提出一种超声振动磨削放电复合加工的方法．从加工效率、加工稳定性及表面质量等方面与电火花加工进行了对比试验研究。分析了两种加工方法的脉冲宽度和峰值电流对加工速度和表面粗糙度的影响,结果表明：电火花加工的表面粗糙度平均值为尺04．5μm,超声振动磨削放电复合加工的表面粗糙度平均值为Ra2μm：超声振动磨削放电复合加工的稳定性比电火花加工好,但加工速度较低。通过扫描电镜对两种加工方法下零件表面形貌和重熔层进行了观测,对试件表面进行了X射线衍射分析,表明采用超声振动磨削放电复合加工SiCp／Al复合材料可获得较好的表面质量。     

Ultrasonic and electric discharge machining to deep and small hole on titanium alloy

Being a difficult-to-cut material, titanium alloy suffers poor machinability for most cutting process, let alone the drilling of small and deep holes using traditional machining methods. Although electric discharge machining (EDM) is suitable to handle titanium alloys, it is not ideal for small and deep holes due to titanium alloys’ low heating conductivity and high tenacity. This paper introduces ultrasonic vibration into micro-EDM and analyzes the effect of ultrasonic vibration on the EDM process. A four-axis EDM machine tool which combines ultrasonic and micro-EDM has been developed. A wire electric discharge grinding (WEDG) unit which can fabricate a micro-electrode on-line, as well as a measuring unit, is set up on this equipment. With a cylindrical tool electrode, made of hard carbide, which has high stiffness, a single-side notch was made along the electrode. Ultrasonic vibration is then introduced into the micro-EDM. Experiments have been carried out and results have shown that holes with a diameter of less than Ø0.2 mm and a depth/diameter ratio of more than 15 can be drilled steadily using this equipment and technology.     

压电自适应微细电火花加工电极损耗率实验研究

针对电火花加工技术的特点,开发、研制了新型的压电自适应微细电火花加工装置,分析了该装置的加工原理.该装置有别于常规的微型电火花加工装置,可实现放电间隙与放电状态的自适应调节,促进排屑,能有效控制提弧及短路现象的出现,并能实现短路自消除,从而大幅度提高加工效率.通过大量实验,分析了各参数对电极相对损耗率的影响.实验结果表明:电极相对损耗率随开路电压和电容值的增大而增大,限流电阻R1和R2对电极相对损耗率有一定的影响.     

基于CPLD的钛合金电火花加工脉冲电源的研究

设计一种以CPLD作为脉冲发生器的电火花加工脉冲电源.利用CPLD产生两种模式脉冲波形,即等电流脉宽模式和等电压脉宽模式,设计了脉冲发生单元和功率转换电路,并用该脉冲电源对钛合金进行加工试验.通过对比两种脉冲模式加工钛合金的效率,发现等电流脉宽模式加工钛合金效率较高.     

基于FPGA的电火花加工脉冲电源设计

为更好地满足电火花的加工要求,提出一种基于FPGA的电火花加工脉冲电源的实现。研究电火花加工脉冲电源的工作原理,脉冲电源的核心部件高频脉冲发生器采用IP软核实现,其输出信号的脉宽和脉间精细可调,能与上位机有效通信。该方法的有效性通过仿真和电路测试得到验证。