Micro-milling machinability of DED additive titanium Ti-6Al-4V

This work investigates the micro-milling machinability of Ti-6Al-4V alloy produced by a Laser Engineered Net Shaping (LENS) additive manufacturing (AM) process with a specific focus on surface quality, cutting forces and burr formation. The effects of additive deposition parameters are also investigated since the material thermal history during processing can affect porosity and mechanical behavior of the samples, giving different milling performances. The material characterization of samples is done through micrographies, hardness tests and porosity evaluation. The roughness of the machined surfaces shows a statistical distinction between the AM and wrought titanium samples. Similar behavior is seen with the cutting forces, which increase with an increase of hardness of the AM samples. The results also show an increased trend towards burr formation in case of down milling of AM samples compared to wrought titanium samples. The future prospective is to take into account the machinability properties as functional material characteristics to optimize through the deposition process. (C) 2017 Published by Elsevier B.V.