Laser surface masking of stainless steel for electrochemical machining process

This paper presents the use of a nanosecond pulse laser for masking the AISI316L stainless steel surface prior to the electrochemical machining process. The laser-masked surface was prepared with an attempt to grow a chromium oxide layer as a passive mask for the selective electrochemical machining process. The effects of laser power, traverse speed, and scan overlap on the roughness, surface height, and chemical composition of laser-masked region were investigated in this study. The influence of electric current and electrochemical etching time on the machined surface morphology was also examined in the experiment. The results showed that using the laser power of 3–4 W associated with the laser traverse speed of 30–50 mm/s can provide the oxide mask with low roughness on the stainless steel surface. The electrochemical machining rate of laser-masked surface was only 0.16 μm/s, while the removal rate of unmasked surface was 0.36 μm/s. Although there was no significant difference between the scan overlaps on the obtained surface roughness, the 0% overlap was suggested to keep the surface masking time and total heat input toward the workpiece at minimum.