Comparative Study on Cutting Performance of Chaser and Triangle-Shaped Inserts in Inconel 718 Turning

The effect of cutting teeth number on the cutting force, surface roughness, tool wear rate and the cutting chip shape characteristics is systematically evaluated. A novel five teeth chaser insert (C tool) which could turn the workpiece at five cutting points simultaneously is involved in comparison with the standard triangle shaped insert (T tool), in the purpose of solving the problems of cutting heat concentration and rapid tool failures in the Inconel 718 machining process. Comparative orthogonal cutting experiments of the C tool and T tool show that the cutting depth is the significant influencing factor of the cutting forces. Meanwhile, the five cutting teeth of the C tool show the effectiveness of dispersing the cutting forces as well as improving the cutting efficiency. The feed rate is the significant factor to affect the root-mean-square surface roughness (Ra) of workpiece machined by the T tool, while the significant influencing variable of Ra for the C tool is the cutting depth due to its unique tool geometry (0° rake angle) in the axial feeding process. Moreover, due to the dispersing effect, the cutting edges on the C tool exhibits lower tool wear rate than that of the T tool under the same axial feed. The chips are regular continuous long chips for the T tool, while the irregular continuous chips with the characteristic of saw-toothed profile are obtained due to its unique 0° rake angle. The C tool shows the valid potential for effectively dispersing the cutting heat and slowing down the tool wear rate in the Inconel 718 machining process.