Influence of electrolytes on surface texture characteristics generated by electrochemical micromachining

Abstract

Generation of microsurface texture is an important technology for surface engineering that can produce a significant improvement of engineering components in aspects to wear resistance, friction coefficient, load capacities, part lubrication, etc. This research proposes a novel approach of maskless electrochemical micromachining (EMM), which is anodic dissolution based on electrochemical reaction. One reused textured cathode tool with patterned SU-8 2150 mask can fabricate many work samples economically with less time. Maskless EMM set-up with developed EMM cell and vertical crossflow electrolyte supply system is used to generate micro circular patterns on stainless steel (SUS 304) using three different types of electrolytes such as NaCl, NaNO3 and NaCl + NaNO3. The influences of major process parameters such as interelectrode gap (IEG), flow rate, machining time and electrolyte concentration on mean radial overcut and mean machining depth have been investigated using these electrolytes. Out of these three electrolytes, only NaCl + NaNO3 of 20 g l−1 is selected as the best electrolyte with other best parameter settings such as applied voltage of 12 V, duty ratio of 30%, pulse frequency of 5 kHz, flow rate of 3.12 m3 hr−1, IEG of 50 µm and machining time of 3 minutes for generating good textured characteristics with overcut of 27.581 µm and depth of 15.1 µm. Analyses have also been done to investigate the textured characteristics using these electrolytes for acquiring the best parametric combination with suitable electrolyte.