Electrochemical micromachining of steel and nickel-base superalloys

This paper describes a technology for Electrochemical Machining (ECM) designed and tested for microstructuring of free -form surfaces with NC-controlled pin electrodes. Its purpose is to present exemplaryly the possibilities of ECM for machining of nickel-base superalloys under easy to use chemical conditions. The advantages of ECM are noncontact and force free machining of any conductive material. The basis of the removal process is the anodic dissolution of the machined material. The launch of the ECM for micromachining in industry is retarded by acid solutions which are necessary at present for precise ECM in micrometer scale, the limited precision of achieved geometries and the process duration. Nickel-base superalloys and steel are common materials in tool making but hard to machine. Therefore ECM seems to be an applicable process for machining it. 3D contouring under easy to use chemical conditions and reasonable costs should be possible. In difference to other works(1) sodium nitrate and citric acid in aqueous solutions were used.