Surface finishing of an additively manufactured part using electrochemical jet machining

Abstract

The development and expansion activities of additive manufacturing (AM) are at their peak as complex parts with intricate features can be easily manufactured by various AM processes. However, obtaining a good surface finish for the AM parts has remained a challenging task. The surface defects and irregularities over intricate parts pose challenges during machining with conventional processes. Therefore, a simple, cost-effective, non-contact surface finishing approach is required to post-process the external and internal surfaces of AM metallic parts. This article reports the surface finishing of the SS316L part made by laser powder bed fusion (L-PBF) using a toolless electrochemical jet machining (ECJM), and investigations were performed to evaluate the different aspects of surface integrity. The experimental results revealed that surface irregularities and defects highlighted on the as-deposited samples were eliminated after ECJM.Moreover, after post-processing, the overlaid layer of oxides and carbides over the as-deposited sample surfaces was also removed. The maximum peak and valley height of the as-deposited surface were 30.1 µm and 41.6 µm, respectively. These heights have been reduced to 13.3 µm and 9.9 µm, respectively, while the arithmetical average roughness value 'Ra' has been reduced from 7.8 µm to 3 µm. The improvement in the mean value of 'Rz' and 'Ra' after post-processing was found to be 72%, and 61%, respectively. Therefore, the study concluded that the unique characteristic of the toolless electrochemical machining process is suitable for finishing the AM part.