Two-Step Post-processing Treatment to Improve Additive Manufactured AlSi10Mg Surface Finish

Additive manufactured (AM) aluminum alloys show good performance as lightweight critical parts for different industrial applications. However, the poor surface finish of as-printed parts due to the ''Staircase Effect'' is an obstacle to the implementation of AM for industry practice. In this study, a two-step post processing technique was developed to improve surface finish of 3D-printed AlSi10Mg. In the first step, the as-printed AlSi10Mg sample was chemically etched to remove the outer skin oxide layer and the dangling loose powder particles; in the second step, the chemically treated sample was electrochemically polished in an alkaline electrolyte to further smoothen the surface. The surface morphology of treated and reference parts were observed with SEM; the surface roughness (Ra) was measured with stylus profilometer to understand the smoothening mechanism and the effects of the process parameters. After this post processing treatment, the Ra was found to be typically decreased by at least 50%, for a much-improved surface finish.