The effect of support structure geometry on surface topography of selectively laser melted parts

Abstract

Additive manufacturing is a modern manufacturing technique that provides extreme design freedom and ability to manufacture multiple parts with high complexities at the same time. Various fabrication techniques have been developed and this study focuses on selective laser melting (SLM) due to its ability to provide near-perfect complex parts at low cost, while being able to work with a wide range of materials. In SLM, the part is manufactured layer-by-layer, by melting and solidification of powder material under controlled inert conditions. The fabrication of complex geometries is not possible without proper allocation of support structures for the part, which keeps the component intact and retains structural stability while manufacturing. Supports are attached to the part and are to be removed after fabrication in such a way that the required surface finish is not compromised. The challenge is to provide appropriate support structures after analyzing the part and the part orientation while ameliorating the functionality of removability, reducing material consumption, and enhancing structural support. Inconel 718 is a type of high-strength corrosion resistant super alloy, which consists of nickel and chromium. It can withstand extremely high pressure and heat which makes it suitable for high-end applications such as aerospace and petroleum. This study focuses on the surface topography for Inconel 718 parts after the removal of various support structures. A comprehensive report on optimal support structure design is provided after studying the fundamental parameters from design, fabrication, and testing phases. Varying the support structure design resulted in a range of surface qualities.