基于双重网格解耦算法的电火花成形加工 工具电极损耗仿真研究

开发电火花成形加工工具电极损耗仿真系统,模拟加工过程中工具电极的几何形态变化,可有效预测工具电极损耗,从而在保障工件形面精度的前提下,通过合理更换工具电极实现电极成本控制和加工效率提升。现有的工具电极损耗仿真系统的计算效率较低,仅适用于微细尺寸的电极;随着工具电极尺寸的增大,仿真的时间成本迅速升高,甚至超出常规计算机的运算能力。为了预测常规尺寸的工具电极损耗,提出了采用"三角形非均匀网格+方形均匀网格"的双重网格解耦算法。方形均匀网格用于材料蚀除的计算,而三角形非均匀网格用于静电场计算和放电位置的判断。该算法有效提升了工具电极损耗仿真系统的性能与运算能力,为常规尺寸的工具电极损耗预测提供了高效、高精度的解决方法。     

微细电火花伺服扫描加工实验研究

进行微细电火花三维扫描加工时,由于电极损耗相对严重,导致形位公差难以保证和加工效率较低。该研究分析了电火花加工常规的电极损耗补偿方法,提出了基于放电间隙伺服控制进行电极损耗实时补偿的微细电火花三维扫描加工方法。辅助以电极电接触感知工件平面和加工原点,三维结构加工实验显示,采用间隙伺服控制进行电极损耗实时补偿有利于提高扫描加工微三维结构的形位精度和加工效率。     

微细电火花小孔加工过程仿真

微细电火花小孔加工过程中存在的电极损耗问题,严重影响了孔的加工精度.以单脉冲放电理论为基础,改进了微细电火花小孔加工过程的仿真模型,对工具与工件加工形状的变化过程进行了仿真研究.与实验结果相比,模型能较好地预测电极损耗及其对工件形状精度的影响,从而为进一步研究电极离线补偿提供了一种经济、可行的方法.     

提高电火花磨削加工一致性性的新方法

采用块状工具电极的精密电火花磨削加工法是低刚度轴和微细轴类零件电火花加工的主要方法之一，该方法过去采用的径 给方式。由于是损耗的因素，使得工件的形状和尺寸的一致性不好，且对生产率也有影响。本文采用一种新的块状工具电极的进给方式－切向进给方式，利用伺服进给自动补偿电极损耗，大大地提高了成批加工工件的一致性和生产率。     

利用电化学原理降低电火花加工的电极损耗

在电火花成形加工中,如何降低工具电极的损耗是一个比较重要的问题,本文结合生产实践,探讨了利用电化学原理实现使用紫铜电极低损耗加工紫铜工件的途径。     

振动辅助液中喷气电火花加工性能研究

提出了振动辅助液中喷气电火花加工方法。该方法通过工件机械振动改善了极间的放电状态,降低了短路率。通过实验研究了机械振动的频率和振幅对液中喷气电火花加工性能的影响,研究了振动辅助作用下电加工参数、气体压力、工具电极转速对加工性能的影响。结果表明,工件的机械振动可有效提高液中喷气电火花加工的材料去除率,改善加工表面质量,而电极损耗几乎为零。     

利用电化学原理降低电火花加工的电极损耗

在电火花成形加工中，如何降低工具电极的损耗是一个比较重要的问题，本文结合生产实践，探讨了利用电化学原理实现使用紫铜电极低损耗加工紫铜工件的途径。     

电火花加工中多材质电极损耗规律的实验研究

针对电火花加工中多材质电极的损耗和形状变化,在模具钢工件上开展了电火花多材质电极加工实验研究,分析了电极材料、加工极性对多材质电极损耗的影响规律,并以黄铜-模具钢电极、紫铜-铜钨合金电极为研究对象,分析了多材质电极的形状变化规律。结果表明:长度损耗小的电极材料能辅助减小同组其他材料的电极损耗,但通常其角损耗较大;加工中多材质电极结合处形成过渡曲面,当加工进入均匀损耗阶段后,过渡曲面的圆弧半径和圆心角基本恒定不变。     

基于圆锥形端面电极的电火花铣削加工定长补偿方法研究

电极损耗对工件质量的影响显著,为保证电火花铣削加工精度,需要对工具电极损耗给予补偿。定长补偿下配合旋转电极,得到圆锥形电极端面,随后根据定长补偿方法给出了补偿长度的计算公式。实验发现,补偿精度值对工件加工精度有较大影响,随着补偿精度值的增大,加工精度逐渐降低,适当选择较小的补偿精度值,能获得良好的加工效果。     

高速走丝电火花线切割加工中工作液的电解作用

测定了高速走丝电火花线切割加工中添加电解质的工作液电导率与加工效率及表面粗糙度的关系，表明随着电导率增加，工件表面粗糙度下降，加工效率存在最佳值。通过测定电极丝的损耗曲线，证实工作液的电解镀覆作用能减少电极丝的损耗和增加其寿命。     

移动热源作用下电火花线切割加工电极丝三维温度场模拟

往复走丝和“中走丝”电火花线切割机床是中国独创的电加工设备,在模具制造等行业发挥着重要作用.由于其电极丝是重复使用的,因此电极丝损耗是普遍存在的问题.在电极丝与工件之间相对运动的情况下,建立了移动热源条件下的电极丝传热模型,通过有限元分析对单脉冲放电条件下电极丝表面温度场进行了三维仿真,发现当走丝速度增加时电极丝熔融区...     

电火花线切割加工中电极丝的安装

电极丝的安装正确与否,直接关系到加工后工件质量的好坏.只有注意到安装前的检查、上丝、穿丝和电极丝的校正这4个重要环节,才能为后续的工件加工提前做好准备.     

EDM turning using a strip electrode

Turning by electrical discharge machining (EDM turning) is an effective method to machine hard-to-cut materials. Generally, a wire-EDM is utilized in EDM turning because it is not concerned with electrode wear. However, wire-EDM turning has a slow machining speed due to its small machining area, and the wire may break due to overheating electrodes. For these reasons, its machining speed must be limited. In this study, a strip-EDM was created in an effort to overcome the problems in the EDM-turning process. This machining method used a conductive strip as an electrode. The strip was fed continuously, like a wire-EDM; therefore electrode wear was not a concern. One advantage of the strip-EDM was that it increased the material removal rate because of its large machining area and non-breaking electrode. In the experiments, machining characteristics were investigated according to machining conditions, and practical machining was carried out via fabrication of complex shapes on a shaft workpiece.     

Carbon nanofiber assisted micro electro discharge machining of reaction-bonded silicon carbide

Carbon nanofiber assisted micro electro discharge machining was proposed and experiments were performed on reaction-bonded silicon carbide. The changes in electro discharging behavior, material removal rate, electrode wear ratio, electrode geometry, spark gap, surface finish, surface topography and surface damage with carbon nanofiber concentration were examined. It has been found that the addition of carbon nanofiber not only improves the electro discharge frequency, material removal rate, discharge gap, but also reduces the electrode wear and electrode tip concavity. Bidirectional material migrations between the electrode and the workpiece surface were detected, and the migration behavior was strongly suppressed by carbon nanofiber addition. Adhesion of carbon nanofibers to the workpiece surface occurs, which contributes to the improvement of electro discharge machinability. These findings provide possibility for high-efficiency precision manufacturing of microstructures on ultra-hard ceramic materials.     

Probability of precision micro-machining of insulating Si3N4 ceramics by EDM

Electrical discharge machining (EDM) is used as a precision machining method for the electrically conductive hard materials with a soft electrode material. But recently we succeeded to machine on insulating material by EDM. The technology is named as an assisting electrode method. The EDMed surface is covered with the electrical conductive layer during discharge. The layer holds the electrical conductivity during discharge. For micro-EDM, the wear of tool electrode becomes lager ratio than the normal machining. So the micro-machining is extremely difficult to get the precision sample.

In this paper to obtain a fine and precise ceramics sample, some trials were carried out considering the EDM conditions, tool electrodes material and assisting electrode materials. Insulating Si₃N₄ ceramics were used for workpiece. The machining properties were estimated by the removal rate and tool wear ratio. To confirm the change of micro-machining process, the discharge waveforms were observed. The micro-machining of the Ø0.05 mm hole could be machined with the commercial sinking electrical discharge machine.     

石墨电极电火花加工性能的影响因素分析

影响石墨电极电火花加工性能的因素很多，各因素的合理配合对电火花加工特性有重要的影响。分析了主轴性能、脉冲电源及智能控制、工作液、电参数和加工极性选择等对石墨电极加工性能的影响，为生产实践提供了理论依据。