In turning operations, it is effective to use a larger corner radius or a lower feed rate to obtain a good machined surface. However, turning at lower feed rates decreases productivity and it has a negative influence on the turning operation because of the continuous chip. In turning of a shaft having a step of specified corner R, it is important whether the corner radius of the turning insert is the same as specified corner R or lower than it. A turning tool with a large corner radius cannot adapt to cutting a shaft having a step of specified corner R. In this study, the surface roughness, cutting force, and tool wear were experimentally investigated in order to clarify the cutting performance of the turning insert having an arc-shaped finishing edge formed at the point of intersection between the corner radius and the end cutting edge. Work piece material SKD11 was turned with two kinds of turning inserts that had different radii of the arc-shaped finishing edge.
The main results obtained are as follows. (1) The machined surface of the insert having an arc-shaped finish edge was better than that of the normal insert. (2) The wear progress of the insert having an arc-shaped finish edge was slightly slower than that of the normal insert. (3) The cutting force of the insert having an arc-shaped finish edge was almost the same as that of the normal insert.