This study mainly focuses to investigate the machining performances of variety of metal working fluid (MWF) strategies such as cryogenic (CO2), minimum quantity lubrication (MQL) and emulsion, into rake and flank face application during the face milling of titanium (Ti-6Al-4V grade 5) alloy. Modified CoroMill600 milling cutter with internal channels to inserts rake face and flank face delivery, and PVD coated inserts are used for the study. This novel approach of rake face and flank face delivery of MWF’s has been evaluated on machinability of the process, in terms of surface integrity, cutting forces and chip microstructure analysis. The results show that cryogenic CO2 machining has improved surface roughness (up to 34% and 38% for Ra and Rz respectively). Additional results show that efficient cooling at liquid CO2 condition reduces the friction between workpiece and tool, confirmed by observing chip microstructure. However, the cutting force has been found to increase as a result of higher shear resistance of the material at liquid CO2 machining, with evidences from the chip microstructure analysis. Up to 9% increase in hardness of the machined surface is observed at cryogenic environment compared to non-machined, indicates the cold strength hardening of the material. The overall results imply that the cryogenic CO2 offer best surface roughness and improved friction between tool and workpiece. Even though further studies are needed for the better understanding the results in terms of hardness of the machined workpiece via optimized cryogenic flow.
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