Evaluation of the Tool Set Overhang Effect on Surface Topography in the Finish Turning Process of Inconel 718 alloy

The study focuses on evaluating the influence of the overhang of the tool holder used on the surface quality, defined by the surface topography of the machined surface. The tests were carried out on samples made of Inconel 718 material in the form of a sleeve, under finish turning conditions with constant cutting parameters. Themachinedmaterialwas subjected to heat treatment, including solution treatment and precipitation hardening, as a result of which it obtained a hardness of 45 +/- 2HRC. Two types of lathe tool holders with overhangs of 120mm and 700 mm were used. These holders are dedicated to turning external surfaces and holes, respectively. V-shaped cutting inserts from five different tool manufacturers, made of fine-grained carbide and coated with PVD and CVD coatings, were used for the tests. The value of the obtained surface stereometry parameters was evaluated. On the basis of the conducted research, it was found that the quality of the machined surface, assessed by the 3D roughness parameters, is affected by the type of the tool holder used. The obtained results show that, when considering the obtained surface topography, it should be noted that not only the type of the cutting insert coating, but also the nature of its wear has a significant impact, especially when a long cutting path is required.