模具电火花—机械复合加工中心的开发

当前,产品更新加快,市场竞争激烈,对于模具生产,既要求提高精度、降低成本,又要求提高生产率、缩短制造周期。但是,由于模具制造工序繁多,需要在不同的机床上加工,这对精度、工效、周期都不利。长期以来,人们都积极寻求在一台机床上完成多种加工工序。加工中心虽能部分满足这一要求,但模具的型腔大多需要电火花加工,因此如果能将电火花加工功能组合到加工中心中去,无疑对模具加工就更有效。另一方面,目前的金属切削加工机床和电火花加工机床均已实现高度数控化,并装备了工具自动交换装置(ATC),两者的硬件和软件又非常接近,这就为研制具有电火花加工功能的加工中心带来有利条件。国外早在80年代中期就开始研究具有多种加工功能的复合加工机床。例如:机械与电火花复合加工机床、电火花与电解复合加工机床、电火花与线切割复合加工机床、机械与电火花和线切割复合加工机床等。目前又进一步研制了具有电火花加个功能的复合加工中心,进一步缩短模具总的加工周期并提高加工精度。在加工中心上进行电火花加工的优点可归纳如下:(1)可减少使用设备的数量和占地面积,这对加工大型模     

精密电火花加工机床四轴三联动数控系统的研制

论述了精密电火花加工机床数控系统软、硬件的设计。该系统以一台 ４８６ 系统机为主机和４ 片 ８０３１ 单片机为从机组成主从式控制系统实现四轴三联动功能, 并采用步进电机细分驱动技术,在电火花机床上实现了小于 ０．１μｍ 的脉冲进给。该机床还具有多种摇动功能, 可修光或加工锥面和球面。因而可用于各种难加工零件的精密电火花加工。     

在普通电火花成形机床上加工斜齿轮模具型腔

由于普通电火花成形机床是一种单轴(主轴Z)控制型机床，在工作中一般只能利用主轴的上、下移动来完成电极形状的拷贝加工，其加工工艺范围较为狭窄。如何拓宽普通电火花成形机床的加工工艺范围，使其更好地满足客观生产的需要，一直是广大普通电火花成形机床用户所关注的现实问题。以下基于笔者多年的实际工作经验介绍在普通电火花成形机床上加工斜齿轮模具型腔的方法。     

电火花加工精密凹凸球面的新方法

本文论述了电火花磨削加工精密凹，凸球面的新工艺，可用于制造凹，凸透镜的注塑模具和其它特珠需要。该方法可以采用电火花线切割机床或小型车床，铣床，工具磨床等经过简单的改装来实现。因此具有一定的应用前景和经济效益。     

分流阀窄槽改数控加工

介绍了将传统微型孔（槽）电火花加工工艺改为数控铣的加工方法，摸索了微型槽、孔的数控加工参数，将先进的铣削刀具和高速高精度小孔加工机床应用到喷嘴加工作出了有益的探索。     

数控电火花加工多型孔模具编程

数控电火花加工在模具制造中的应用越来越广泛,其中编写加工程序是其技术的关键。目前数控电火花加工机床都提供了自动编程模块,可自动生成ISO代码。但自动编程模块的功能往往具有局限性,如果能够灵活运用手工编程,就可以进行各种复杂工件的加工,实现用户的个性化操作,最大限度地发挥数控电火花加工机床的功能。     

电火花加工中的模糊控制技术

在阐述了以模糊理论建立电火花加工状态的模糊临别模型基础上，着重介绍了为提高电火花成形加工机床的适应控制功能，模糊控制控制技术在电火花加工的状态鉴别和多参数自适应控制中的应用。     

模糊控制在电火花加工技术中的应用

本文在阐述以模糊理论建立电火花加工状态的模糊鉴别模型基础上，着重介绍了为提高电火花成形加工机床的适应控制功能，模糊控制技术在电火花加工的状态鉴别和多参数自适应控制中的应用。     

空气中微细电火花沉积与去除可逆加工技术研究

论述了一种新的电火花加工方法。它使用通用的电火花成形加工机床,利用常见的电极材料,在空气介质中,通过脉冲放电在工件表面上沉积生长电极材料,再通过反转极性和适当的轨迹控制对所生成的沉积材料进行有选择的去除加工,进而实现材料的生长与去除可逆加工。通过对电火花加工理论的研究,预测和论证了实现这一新加工方法的可能性和实现条件。通过试验成功地将钢、铜和钨三种电极材料沉积到工件上,形成直径为 100~240 mm、高度为1 000~2 500 mm的微小圆柱体。并对沉积物进行了选择去除,实现了在同一设备上的可逆电火花加工。对沉积材料的致密性、硬度及其与工件的结合强度等进行了系统的分析,表明沉积物组织致密、坚硬,可以满足功能材料的要求。     

对当前电火花加工机床的发展建议：中国数控机床展览会特种加工机床评述

CCMT 2000集中展示了我国数控机床近年来开发的新品和精品,特种加工机床(主要是电火花加工机床)也同样展示了近年来的发展成就。本次展览会共展出电火花加工机床25台(见表)。其中电火花成形机     

“炮塔铣-电火花”数控成型组合机

将模具加工主设备垂直炮塔式铣床与电火花机组合成一台机,既能作多功能铣削,又能作电火花精密成型加工,既降低了设备成本,又扩大了设备功能,是模具制造业的一种新型设备.     

用Hauseman方法研究EDM石墨电极研具的磨损与堵塞问题

理论与实验相结合的方法，深入研究EDM石墨电极Hauseman研磨研具的磨损与堵塞问题。首先分析研具磨损的形式和机理、研具堵塞的类型和形貌，接着分析研究影响研具堵塞的因素，最后提出改进措施。     

电极圆形平动补偿系统的开发

针对电火花成型加工中由于电极圆形平动产生的加工误差,提出了圆形平动补偿修正原理,开发了电极圆形平动补偿系统。实验证明,该系统有效减少了加工误差,提高了加工精度。     

Analysis of the machining characteristics of EDM as functions of the mobilities of electrons and ions

Electrical discharge machining (EDM) is a process that can be used effectively to machine conductive metals regardless of their hardness. In the EDM process, material removal occurs because of the thermal energy of the plasma channel between the electrode and the workpiece. During EDM, the electrode as well as the workpiece is abraded by the thermal energy. Tool wear adversely affects the machining accuracy and increases tooling costs. Many previous studies have focused on mitigating the problems of tool wear by investigating various EDM parameters. In this study, the tool wear problem was investigated on the basis of the mobilities of electrons and ions in the plasma channel. The material removal volumes of both the electrode and the workpiece were compared as functions of the gap voltage. The material removal difference according to the capacitance was also investigated. The tool wear ratio was calculated under different EDM condition and an EDM conditions for reducing the tool wear ratio was suggested.     

A method to predict possibility of arcing in EDM of TiB2p reinforced ferrous matrix composite

Electrical Discharge Machining (EDM) is very popular for machining conductive metal matrix composites (MMCs) because the hardness rendered by the ceramic reinforcements to these composites causes very high tool wear and cutting forces in conventional machining processes. EDM requires selection of a number of parameters for desirable results. Inappropriate parameter selection can lead to high overcuts, tool wear, excessive roughness, and arcing during machining and adversely affect machining quality. Arcing leads to short circuit gap conditions resulting in large energy discharges and uncontrolled machining. Arcing is a detrimental phenomenon in EDM which causes spoiling of workpiece and tool electrode and tends to damage the power supply of EDM machine. Parameter combinations that lead to arcing during machining have to be identified and avoided for every tool, work material, and dielectric combination. Proper selection of parameter combinations to avoid arcing is essential in EDM. In the work, experiments were conducted using L27 design of experiment to determine the parameter settings which cause arcing in EDM machining of TiB₂p reinforced ferrous matrix composite. Important EDM process parameters were selected in roughing, intermediate, and finishing range so as to study the occurrence of arcing. Using the experimental data, an artificial neural network (ANN) model was developed as a tool to predict the possibility of arcing for selected parameter combinations. This model can help avoid the parameter combinations which can lead to arcing during actual machining using EDM. The ANN model was validated by conducting validation experiments to ensure that it can work accurately as a predicting tool to know beforehand whether the selected parameters will lead to arcing during actual machining using EDM. Validation results show that the ANN model developed can predict arcing possibility accurately when the depth of machining is included as input variable for the model.     

电极直线平动补偿修正的研究

在电火花成型加工中,电极直线平动产生了加工误差,笔者研究了误差产生的机理,提出了直线平动补偿修正原理,实验证明,该原理能有效减少加工误差,提高加工精度。     

Influence of flushing on performance of EDM with bunched electrode

The existing applications of electrical discharge machining (EDM) for bulk material removal are restricted by their comparatively low material removal rates. The bunched-electrode EDM proposed in this study, using the powerful multi-hole inner flushing, is an effective way of being released from this restriction. This paper investigates the mechanism by which flushing (flushing modes and flushing parameters) influences machining performance indices, i.e., material removal rate and tool wear rate, using experiments and simulations. Based on an investigation conducted, compared with traditional solid electrode with mono-hole inner flushing, a bunched electrode with multi-hole inner flushing endures higher peak current and results in larger material removal rate and higher relative tool wear ratio because of a more effective flushing process. By properly choosing inlet velocity and electrode effective-area ratio, a higher material removal rate is achieved and relative tool wear ratio is kept at a lower level.     

EDM石墨电极快速研磨成型研具的开发研究

简介Hauseman研磨研具的特点、制造要求和制造方法;对研具配方进行深入的理论分析,在此基础上,通过实验获得研具制造的最佳配方,并进行了研磨实验给予验证。     

微细电火花成形加工设备关键技术研究

基于微细电火花加工的要求,对微细电火花成形加工设备中的关键技术进行研究,成功研制了一套高精度的微细放电加工设备产品,包括一台微细电火花加工机床和一台精密脉冲电源。优化机床关键零/部件的结构后,机床的变形小,运动精度高;电源放电稳定,控制精确。经加工试验表明,该设备加工效果较好,加工精度和稳定性较高,加工出的窄槽工件的尺寸精度可达到5μm,加工直径为300μm的小孔,其圆度误差达到3μm,可满足微细电火花加工的要求。     

Investigating and removing the re-sticky debris on tungsten carbide in electrical discharge machining

Electrical discharge machining (EDM) is an excellent method to machine tungsten carbide with high hardness and high toughness. However, debris from this material produced by EDM re-sticking on the workpiece surface remarkably affects working efficiency and dimension precision. Therefore, this study investigated the re-sticky phenomenon of tungsten carbide and how to reduce the debris re-sticking on the workpiece surface. In general, the polarity in EDM depended on the different electrical parameters of the machine input and the different materials of the tool electrode. The first item of investigation observed the re-sticky position of the debris to study the effect of different polarities during the EDM process. Next, the tool electrode was set at different conditions without rotation and with a 200 rpm rotational speed to evaluate the rotating effect in EDM. Finally, different lift distances of the electrode and different shapes of electrode with rotation were utilized to investigate the improvement for reducing debris re-sticking on the machining surface. The results showed that only negative polarity in EDM could cause the re-sticky phenomenon on tungsten carbide. On the other hand, debris would notably re-stick on any machining position when the tool electrode was not rotated in EDM. Besides, debris significantly stuck on the center of the working area with rotation of the electrode. Additionally, a larger lift distance of the tool electrode could reduce debris re-sticking on the working surface, but this process would decrease material removal rate in EDM. In the end, a special shaped design of the tool electrode resulted in the re-sticky debris completely vanishing, when the electrode width was 0.6 times the diameter of this cylindrical electrode.