Wear resistance of polycrystalline diamond cutters for drill bits

Abstract

In the present work, the wear resistance of GES 1313 polycrystalline diamond (PCD) cutters (produced by E6), which are cylindrical in form (diameter 13.44 mm, height 13 mm), in turning granite and abrasive wheels at different speeds is investigated. The optimal cutting speed is determined, and comparative data are obtained for the cutting of Mansurovsk granite and 64C (SiC) abrasive wheels, so as to develop recommendations regarding the test conditions for PCD cutters. The wear resistance is characterized in two ways: as the ratio of the loss of volume of the diamond layer to the volume of machined material removed (when it is a dimensionless number); or by the quantity of machined material removed with a fixed degree of cutter wear (when it is expressed in cm3 with respect to 1-mm wear of the rear surface). In cutting granite, the cutting speed varies from 80 to 320 m/min; in cutting abrasive wheels, the cutting speed is 500 m/min. To calculate the volume of the PCD cutters, 3D models of the worn sections are constructed by means of Kompas 3D software, and a calibration curve for determining the volume of material removed by wear at the rear surface of the PCD cutters is plotted. The cutting angle is–22°. The change in volume of the worn section of the PCD cutter with change in the cutting angle from–20 to–25° is less than the measuring precision of the wear area up to 0.8-mm blunting. Increase in speed from 80 to 160 m/min in cutting granite reduces the wear resistance of the PCD cutters by a factor of 12. The relative wear of the PCD cutters in cutting granite is (0.01–0.02) × 10–6, which is 20 times less than in cutting 64C abrasive wheels. The relative wear of the PCD cutters in cutting abrasive wheels does not depend on the blunting of the rear surface up to values of 1.4 mm. This method may be recommended for rapid determination of the wear resistance of PCD. The proposed method of calculating the worn volume of the PCD by means of Kompas 3D or other appropriate software may be used to assess the relative wear resistance of abrasives and cutting materials.