微三维结构电火花铣削关键技术研究

Research on Key Techniques of 3D Micro-EDM Milling

为解决电火花方法加工微三维结构时工具电极的制备、测量和损耗补偿问题,研究了块反拷法和线电极磨削法(WEDG)相配合的电极加工工艺,设计了通过4点接触感知实现的电极在线测量系统,提出了由数控系统对放电状态进行实时监测、统计并根据统计结果预测电极损耗状况的自动补偿策略。此技术方案在计算电极加工路径时无需作任何补偿考虑,因此可选用普通金属铣削CAM软件生成加工代码,特别适合复杂自由曲面微结构的加工。综合采用此技术设计了专用微细电火花数控系统,制备了直径30μm,长度3mm的工具电极,使用此电极加工出1mm×0.3mm×0.18mm的雕塑头像。

Fabricating, measurement and wear compensation of the tool electrode are the key problems in 3D microEDM milling. The techniques of fabricating micro-electrode by reverse EDM block and WEDG are presented. The online measuring system by 4points contact sensing is designed. The strategies of automatic electrode compensation by NC system on realtime monitoring and counting discharge state are proposed. Because no compensation is considered in calculating electrode trace before machining and common metal milling CAM software can be used to generate machining code, this method is especially practical in the machining of complex free curved surface microstructures. With these methods, a dedicated microEDM NC system is designed and a head sculpture, 1 mm×0.3 mm×0.18 mm in dimensions, is machined with an electrode 30 μm in diameter and 3mm in length.