The effect of the vibratory surface finishing process on surface integrity and dimensional deviation of selective laser melted parts

Abstract

Selective laser melting (SLM) is an additive manufacturing method used in aerospace and biomedical industries due to its ability to fabricate complex geometries with excellent mechanical properties. However, achieving the desired surface quality can be challenging. Vibratory surface finishing (VSF) is a widely used post-processing technique in engineering industries to improve surface quality. In this study, SLM-produced stainless steel 316L samples with different geometries, including samples with flat surfaces (SFS), samples with bulged surfaces (SBS), and samples with concave surfaces (SCS), were processed using triangular, spherical, and cylindrical media shapes for different processing times. The research aimed to analyze the surface integrity and dimensional deviation of each sample type after VSF. Our study employed a full factorial design of experiments (DoE) to assess the influences on the surface integrity, dimensional deviations, surface morphology, and surface hardness of 316L stainless steel parts produced via SLM. After VSF, the average Ra value was reduced by 75% after 9 h of operation, achieving the lowest Ra value (1.68 μm) using spherical media. Spherical media also reduced Ra values on concave surfaces by approximately 71%, with a reduction from 14.55 to 4.15 μm. The study found that VSF helps improve surface roughness while affecting the components’ average dimensional deviation and subsurface microhardness. The microhardness measurement showed a value of 220 HV, which was approximately 6.4% higher than the bulk hardness.