Optimization of pulsed electrochemical micromachining in stainless steel

The machining of materials at micro and submicroscales is considered a key technology of the future and plays a role increasingly important in the miniaturization of complete machines, with important applications as bioengineering, MEMS, microsensors and microactuators. In this work the process of Pulsed Electrochemical Micromachining was studied. The experiments were carried out in a workpiece of Stainless Steel sunk in an electrochemical cell with an electrode of Tungsten with very small diameter (2-8 m). Pulses of voltage with very small width are introduced between the electrode and the part, so that the current is confined under the area of the tool tip. With this method microholes and microslots were obtained. It is observed that there is a minimum pulse-on time for each value of the voltage to make the current flow. Nevertheless, for values of voltage of 7 V and higher there is always material removal for any value of pulse-on time. A maximum ratio between pulse-on time and period of 1/3 and an interelectrode gap in the order of micrometers are required to provide a localized material removal under the tip of the tool. In these conditions, the confinement will decrease when the pulse on-time increases. The main parameter that determines the material removal rate in the process is the current intensity. Surface roughness increases with pulse-on time, as well as the average current of the process and hence the material removal rate. Therefore, there is a compromise between surface finish and material removal rate. (C) 2018 The Authors. Published by Elsevier B.V.