三元流闭式叶轮组合电加工技术研究Ⅱ——数控电解预加工

Research of Combined Electrical Machining of 3D-flow Closed Impeller Ⅱ—Numerically Controlled Electrochemical Machining for Pre-processing

数控电解预加工是组合电加工技术中不可或缺的关键工艺,本文专题论述了三元流闭式叶轮数控电解预加工中阴极及其运动轨迹设计等关键技术。提出了采用多个阴极分区域加工流道的方法,利用先层切再叠加的方法将三维问题简化为二维问题处理而实现阴极加工型面的数值求解。在完成阴极结构优化设计专用工装夹具设计和数控加工程序编制的基础上,以某型三元流闭式叶轮为研究对象进行了加工工艺试验,并加工了符合设计要求的三元流闭式叶轮。试验研究表明,采取数控电解预加工工艺方案能够满足实际生产要求,可提高效率40%,降低电火花加工的电极损耗50%。

Numerically controlled electrochemical machining （NC-ECM） for the pre-processing is a very important part of the combined electrical machining technology.This article discusses its key techniques,such as the design of cathodes and their moving tracks for machining a 3D-flow closed impeller,and proposes a new process of machining a cavity in the impeller by means of more than two cathodess. The 3D problem is simplified as into a 2D problem by stratification and superposition,and the machining surfaces of the cathodes are obtained by using the numerical method. Then the optimization of the cathodes cathode structure,the fixtures of cathodes,and the machining NC programs are completed. Furthermore,a series of technological experiments are made and a 3D-flow closed impeller is machined successfully by the combined electrical machining method. The test results show that the NC-ECM for the pre-processing is useful in production,raising the manufacturing efficiency by 40% while reducing electrode wear by 50% for electron discharge machining （EDM）.