Experimental studies on cryogenic CO2 face milling of Inconel 625 superalloy

In this study, face milling operation was carried out on an Inconel 625 superalloy. About 27 experiments (L-27) were conducted using Design of Experiments (DOE), which comprised three levels of cutting speed (V (c) ) and feed rate (f (z)) with a constant cutting depth (a(p) ). The study included three coolant environmental conditions such as no coolant (dry), normal coolant (wet) and cryogenic CO2 coolant. The output responses such as cutting temperature (T (s)), cutting forces (F-x, F-y and F-z ) and surface roughness (R (a)) were observed during the experiments. The results were optimized using the TOPSIS technique with ANOVA tests. The optimization results of highest closeness coefficient (C-i ) value indicated the lowest level of cryogenic CO2 coolant environment and the input parameters were the cutting speed (V (c)) 80 m/min and feed rate (f (z)) 0.05 mm/tooth. The optimization results of the highest closeness coefficient (C-i ) value were at cutting speed (V (c)) 80 m/min, feed rate (f (z)) 0.05 mm/tooth in cryogenic CO2 coolant environment. The findings indicated that cryogenic CO2 was both environmentally harmless and the best choice in comparison with dry and wet coolant.