Tribological performance of a hybrid CryoMQL system on Ti6Al4V milling

Ti6Al4V has high thermal resistance at elevated temperatures and is lightweight. Even with superior characteristics, in manufacturing, Ti6Al4V is considered one of hard to machine materials. Therefore, an advanced technique, cryogenic cooling with LN2 coolant and MQL lubrication (CryoMQL), is proposed for milling Ti6Al4V using coated carbide tools at heavy machining conditions. The impact of the eco-friendly system on the machining outcomes was examined at different cutting speeds and compared with minimum quantity lubrication (MQL). Various machining results such as tool wear mechanisms, cutting forces, cutting temperature, surface quality, and chip morphology were thoroughly studied in this study. The analysis shows that the CryoMQL environment decreases tool wear, cutting forces, surface roughness, and microhardness by 33%, 18%, 43%, and 25%, respectively, compared to the MQL method. The surface topography and chip back surface obtained with CryoMQL also present a smoother surface with fewer scratches than MQL.