ACTUAL CONTACT AREA ON THE WORN CLEARANCE FACE OF THE CUTTER WITH THE ROUND KYBORITE INSERT

Abstract

For a tool equipped with a circular cutting insert, a dependence is proposed for calculating the nominal area of the contact area on the back surface. It is proved that the actual area of the contact area of the tool differs significantly from the nominal one due to the presence of a system of micro-irregularities, which makes a difference in the assessment of machining process parameters. Using the example of a tool equipped with a circular cutting insert made of polycrystalline cubic boron nitride ciborite, an approach to determining the actual contact area of the back surface with the workpiece during finishing turning of hardened steel is considered. The possibility of taking into account the influence of the system of irregularities in the contact area, determined by the parameters of its topography, on the size of the actual area is shown, and the ratio of the actual and nominal areas of the contact areas of the tool is determined, and it is found that, depending on the degree of development of the microrelief, the ratio of the actual and nominal areas of the contact surface of the cutter differs by at least 20%. It is shown that the actual contact area is also related to the total length of the main and auxiliary cutting edges, determined by the maximum values of the main and auxiliary angles in the cutter plan, and the size of the wear chamfer on the back surface of the cutter.