The Machinability of Ti-6Al-4V Fabricated by Laser Powder Bed Fusion with Different Build Orientations in Thermal-Assisted Machining

Additively manufactured titanium alloys such as Ti-6Al-4V have been used as functional components in industry due to their excellent mechanical properties. However, the machining of these alloys is a challenge due to their enhanced tensile/yield strength, low elastic modulus, poor thermal conductivity, and microstructural anisotropy. Thermal-assisted machining (TAM), as a hybrid manufacturing technology, can improve the machinability of additively manufactured alloys. The main aim of this paper is to investigate the effect of temperature buildup on the machinability of additively manufactured Ti alloy with different build directions in the TAM process. It was found that the surface integrity was notably enhanced by preheating, and it was the best at 90° build orientation. Serrated chips were generated at room temperature, and curlier chips were formed in high-preheating machining environment. By analyzing the surface quality, the influence of the build-up orientation on the surface quality at different temperatures was evaluated.