Effects of innovative cooling/lubrication techniques on machining performance in the milling of inconel x-750 super alloy for sustainable manufacturing

In this study, the effects of innovative and sustainable cooling/lubrication methods on machining performance in milling of nickel based Inconel X-750 super alloy were investigated. Experiments were carried out in two stages at CNC vertical machining center using coated cemented carbide tools. For this purpose, the nanofluids were prepared by adding four different concentrations hBN, MoS2 and graphite nanoparticles into vegetable based oil. Experiments were carried out at constant cutting speed (45 m/min), feed rate (0.10 mm/rev) and cutting depth (0.5 mm). Cutting force, surface roughness, cutting temperature, tool wear and life effects were investigated under dry, MQL and 12 different NanoMQL conditions. NanoMQL cutting condition has shown the better performance in all cutting conditions at 0.50 vol% concentration ratio. NanoMQL cutting condition was superior to other cutting conditions at 0.50 vol% concentration ratio. hBN nanofluid cutting condition with 0.50 vol% concentration showed better performance at cutting force 25.7%-18.86%, surface roughness 54.26%-45.42% and tool life 222%-48.7% according to dry and MQL cutting conditions, respectively. In the second stage of the study, nanoparticles were added into oil with equal concentration (0.25%+0.25 vol%) and three different hybrid nanofluid were prepared. Experiments were carried out at three different Hybrid NanoMQL cutting conditions (hBN+graphite, hBN+MoS2 and graphite+MoS2), cutting speed (30, 45 and 60 m/min), feed rate (0.05, 0.10 and 0.15 mm/rev) and constant cutting depth (0.5 mm). According to the results; hBN+graphite cutting condition showed better performance at cutting force (314 N), surface roughness (0.180 µm), cutting temperature (115 ˚C) and tool life compared to other cutting conditions. Finally, the effects of machining parameters on cutting force, surface roughness, cutting temperature and tool life were analyzed through ANOVA. According to the ANOVA analysis; the most important machining parameters affecting the cutting force, surface roughness, cutting temperature and tool life were 89.03% feed rate, 74.22% feed rate, 67.43% cutting speed and 85.95% cutting speed, respectively.