Influence of Finish Machining on the Surface Integrity of Ti6Al4V Produced by Selective Laser Melting

Abstract

Selective Laser Melting (SLM) is a direct manufacturing technique that allows objects to be built by selectively melting successive layers of metal powder. There is an additional finish machining step that is required to achieve close tolerances and control the surface integrity of the final surface. This paper mainly deals with studying the influence of the finish machining step on the surface integrity of Ti6Al4 V parts produced by SLM technique. Three different building directions are considered. Changes in roughness, hardness of the machined surface and sub-surfaces are evaluated and compared with those of conventional hot rolled alloy. Cutting forces were also measured during milling process to study the influence of machining the SLM samples on the components of force in the three orthogonal directions. It is observed that the SLM samples show higher surface hardening behavior after machining and exert 22% greater axial force during the machining when compared to the conventional alloy.