A comparative study of the cutting forces in high speed machining of Ti–6Al–4V and Inconel 718 with a round cutting edge tool

Titanium alloy Ti–6Al–4V and nickel-based superalloy Inconel 718 have been widely employed in modern manufacturing. The published literature on high speed machining (HSM) of the two materials often involves different machining set-up, which makes it difficult to directly apply the research findings from one material to the other to select the most appropriate tool geometry and cutting conditions. A comparative experimental study of HSM of Ti–6Al–4V and Inconel 718 is conducted in this paper using the same machining set-up. The scope of this study is limited in high speed finish machining, where the tool edge geometry plays a significant role. The experimental set-up and the methods of measuring the cutting forces and the tool edge radius are introduced. A total of 40 orthogonal high speed tube-cutting tests were performed, involving five levels of cutting speeds and four levels of feed rates. Based on extensive experimental data, the similarities and differences between HSM of Ti–6Al–4V and Inconel 718 are quantitatively compared and qualitatively explained in terms of four quantities: (1) the cutting force Fc, (2) the thrust force Ft, (3) the resultant force R, and (4) the force ratio Fc/Ft. A total of 12 empirical regression relationships are obtained.