Thermal study during milling of Ti6Al4V produced by Electron Beam Melting (EBM) process

Abstract

Electron Beam Melting (EBM) process, an additive manufacturing technique is now used to make real functional parts and these parts need finish machining to ensure better surface quality. Temperature rise is one of the main factors that determine the productivity in the metal cutting industry. This study was aimed at determining the differences in temperature and forces at the cutting zone along with heat partition at the tool-material interface while milling Ti6Al4V produced by EBM processes when compared to Ti6Al4V produced by conventional lamination process. An innovative hybrid approach was used to determine the heat flux and study the effects of temperature using both milling and tribological experiments. Milling was done under finishing conditions with a feed rate of 0.1 mm/tooth and cutting speed of 50 m/min. Ti6Al4V produced by EBM process generated about twice the heat flux that enters the cutting tool and leads to 50% lower tool life when compared to the one produced by the conventional hot rolling process which was used as a reference. This change in thermal behavior is attributed to the differences in the microstructure of Ti6Al4V based on the corresponding process routes which modified the type tool-material interactions and wear mechanisms. Results provide a better understanding of the thermal effects while milling EBM-Ti6Al4V and prove that cutting conditions have to be optimized to ensure higher material removal rates and better surface integrity of the parts.