大直径整体叶轮分步法电解加工工艺与试验

Process and Test of Electrochemical Machining of Large Diameter Integral Impeller by Fractional Step Machining Method

在对大直径整体叶轮的叶片特征和过去电解加工(ECM)方法比较分析的基础上提出了一种叶片分步加工的电解加工方法。首先确立了分步法的加工顺序,采用专用仿真软件对叶片的被加工区域进行划分,使前道工序加工后留下的区域满足后道工序的电解加工要求;在此基础上计算各工序的加工运动路径,并根据机床运动配置形式给出了叶片加工所需的四轴联动算法,通过软件自动生成数控加工自动编程;借助于CAD/CAE/CAM软件设计了一组加工阴极并进行了工艺试验。试验结果表明,通过合理的区域划分,叶盆、叶背和叶根的加工过程具有较好的稳定性,叶背、叶根的加工精度得到了较好的控制。该工艺方法可望较高精度地解决大直径整体叶轮叶片型面加工难题。

An electrochemical machining（ECM）process by the fractional step method is proposed for the machining of large diameter integral impellers on the basis of an analysis of the blade features and a comparison of the available process schemes.First,the machining procedure is determined.A special purpose simulation software is used to classify the machining region of the work-piece and reserve the area to meet the processing requirements of the next procedure.On this basis,the motion tracks of the tool cathode are calculated in all procedures.The computational methods of 4-axis linkage displacement of the ECM machine tool are presented and the numerical control programs are automatically produced through the software.A set of tool cathodes are worked out by the CAD/CAE/CAM software and a group of experiments are done.The test results show that the machining courses of the blade basin,blade back and blade root are very steady by this reasonable classification,and the machining accuracy of the blade basin,blade root is well controlled.It is very probable that the process could be used to solve the machining problems of the blade surface with high accuracy.