Influence of tool electrodes on machinability of stainless steel 420 using electrochemical micromachining process

The machining of stainless steel 420 using conventional machining techniques creates many problems such as tool wear, poor surface roughness, lesser dimensional accuracy and high heat-affected zone. These problems can be overcome by non-conventional machining techniques like ECM, EDM, LBM, PAM. Even in some non-conventional machining techniques, problems such as mechanical stress, heat-affected zone still prevail. Electrochemical machining (ECM) is a technology where there is no heat-affected zone and no thermal stresses. ECM uses the same principle of electrolysis for its operation. Using ECM difficult to machine materials can be machined which is almost impossible by conventional machining methods. Micromachined stainless steel 420 finds the application in the modification of implants in biomedical field. In this present work, the experiment has been conducted to study the machinability of stainless steel 420 using electrochemical micromachining process. The influence of two different tool electrodes (copper and brass) in micromachinability by varying process parameters such as applied voltage, electrolyte concentration, microtool feed rate and duty cycle using Taguchi method. The responses such as Material Removal Rate, Surface Roughness and Radial Overcut are analyzed using gray relational analysis. It is observed that the copper tool electrode has removed 20.91% more material than brass tool electrode; the surface roughness of brass tool electrode has produced 23.62% less than the copper tool electrode; and the radial overcut of copper tool electrode has generated 29.65% more than the brass tool electrode.