The effect of coating material and geometry of cutting tool and cutting speed on machinability properties of Inconel 718 super alloys

In this study, the effects of cutting tool coating material and cutting speed on cutting forces and surface roughness are investigated. For this purpose, nickel based super alloy Inconel 718 is machined at dry cutting conditions with three different cemented carbide tools in CNC lathe. Metal removing process is carried out for five different cutting speeds (15, 30, 45, 60, 75 m/min.) while 2 mm depth of cut and 0.20 mm/rev feed rate are to be constant. Main cutting force, Fc is considered to be cutting force as a criterion. In the experiments, depending on the tool coating material, lowest main cutting force is found to be 506 N at 75 m/min with multicoated cemented carbide insert whose top layer is coated by Al2O3. Lowest average surface roughness (0.806 μm) is obtained at the cutting speed of 15 m/min with single coated (TiN) cemented carbide inserts.