Tool wear mechanisms and its influence on machining tribology of face milled titanium alloy under sustainable hybrid lubri-cooling

Cryogenic cooling has excellent cooling and poor lubrication, while minimum quantity lubrication (MQL) has vice versa. Therefore, eco-friendly hybrid lubri-coolants are getting attention nowadays to achieve sufficient cooling and lubrication for high-speed machining hard-to-cut materials. In this research, ethanol, Blaser oil, and hybrid ethanol-Blaser oil lubri-coolants with and without dry ice are compared regarding machinability performance measures i.e., tool flank wear. For in-depth analysis, scanning electron microscope (SEM), Electron deposition Spectroscopy (EDS) line, point and ED-mapping was used to analyze workpiece chemical elemental deposition on tool flank edge. Experimental findings have shown that compared to dry conditions, the hybrid ethanol-ester oil-dry ice significantly improved the tool life up to 66%, ester oil for 57%, and ethanol for 43%, respectively. More important, SEM of flank wear has shown adhesion, micro-chipping, and abrasion as dominant wear phenomena, when face milling Ti-6Al-4 V under hybrid lubri-coolants.