Defect mitigation and surface enhancement of additively manufactured AlSi10Mg internal features using electro-thermal post-treatment

Metal additive manufacturing (AM) technology is drawing outstanding attention in industries due to the inherent design freedom that facilitates complex part production. In recent times, substantial focus has been directed at the fabrication of components with internal features such as injection nozzles, cooling channels etc. However, metal AM holes are characterized by poor surface integrity and form inaccuracy. The widely adopted posttreatment variants utilizing laser, chemicals and mechanical forces face challenges in overcoming the aforementioned limitations. Therefore, the present study proposes a low energy electric discharge internal processing (EDIP) method in lieu of existing post-treatment methods. EDIP ensures successful elimination of surface irregularities thereby contributing smooth surface finish. Moreover, EDIP improves circularity by -88.8% and -70.1% for horizontally and vertically built holes respectively. Further, contamination of processed surface due to tool electrode material migration during EDIP is negligible. Thus, EDIP method can favour the acceptability of processed AM holes in industrial applications.