Electrochemical contour machining

In electrochemical machining, the removal of the metal to form a hole or to contour the surface is by anodic dissolution (Fig. 9.3). Clearly, for the process to have sufficient accuracy to be useful in engineering, the metal removal must occur under totally controlled conditions. This is possible to good tolerances but requires the design of a cathode, known as the tool, for each job. 

---