Papers by Keyword: CBN Abrasive

Abstract: This article presents preliminary investigations on the cutting ability of the singer layer metal-bonded cBN grinding wheel manufactured by electroplating method at Vietnamese laboratory. The cutting ability of the grinding wheel is evaluated by two factors: grinding ratio G and surface roughness of workpiece. These results are compared to those of the Japanese grinding wheels. The experimental results showed that the fabricated cBN grinding wheel has good cutting ability with high grinding ratio G. The value of the grinding ratio was 600 to 1800 in the grinding process of SKD11 steel (hardness of 62-63HRC) at the grinding speed V of 12.56m/s, feed rate S of 300mm/min, depth of cut t of 0.01mm. The maximum grinding ratio (1800) is equivalent to the average grinding ratio of the Japanese grinding wheel. The grinding ratio is also maintained up to 26 cutting hours. The good grinding surface was achieved with the average Ra of 2.5μm. In addition, the bonding of cBN abrasive to the wheel body was observed with scanning electron microscope (SEM) of the surface of grinding wheel after the cutting process. The SEM image shown that the cBN abrasive particles were not removed from the wheel surface.

Abstract: Gear honing processing is a kind of processing method which belongs to the point-contact generating gear finishing. Its movement form is equivalent to a pair of gears transmission which the surface of the gear-honing-tool is adhered a layer of grinding grain. When it works in rolling processing, the contact-point between the workpiece and gear-honing-tool is moving. Then the moving point becomes a line in the space, and with the gear-honing-tool being in axial play, a standard flank of tooth is finished. Using the gear meshing principle, kinematics model of relative sliding velocity in the contact-point between the workpiece and tools is established, based on which the contact-line equation. and acceleration equation. at the contact-point are derived. The contact-line is solved in a given parameters of the workpiece and tool in MATLAB. The theoretical derivation and experimental results show that the speed in diverse along the direction of the tooth depth is the main reason for the roughness value and surface texture of workpiece. The acceleration of contact-line at the tooth flank is different, and it is leading reason that the processed workpiece gears appear profile distortion. Finally, the testing system is established for researching honing gear process. It is showed in the results that the acceleration difference can lead to the CBN abrasive falling away from gear honing tool, and even the "anti-cutting" phenomenon.

Abstract: This paper used spatial random cutting plane method for modeling the real irregular grain shapes, and method of smoothed particle hydrodynamic (SPH) was used to establish CBN grinding wheel abrasive wear model. In order to research the wear mechanism of CBN abrasive and the relationships between grinding parameters and grinding wheel wear, simulation of the wheel abrasive wear process was simulated by the LS-DYNA explicit dynamics. According to the results obtained by simulation of abrasive wear model which has the same law with the actual wear abrasive, it is has realistic instructive significance to the actual grinding process of vitrified CBN grinding wheel.

Abstract: In this paper, accord to effect of CBN abrasives in vitrified wheel, eight kinds CBN abrasives were analyzed for its room performance, microcosmic crystal photographs, high temperature performance and corrosion resistance, by right of single grain pressure-resistant intensity apparatus, SEM and DTA etc advanced apparatus. The test results indicated performance of domestic part single crystal CBN has been reached or exceed overseas same product.

Abstract: This paper analyses the material removal and surface forming mechanism of ultrasonic auxiliary gear honing. According to the Huygens principle of diffraction, a theory is proposed firstly that the ultrasonic waves transmit through the being honed gear in toroidal form, and the mathematical equation of the abrasive trace is built that expresses the relative movement between CBN abrasive and the gear surface. The equation is accordant with the experimental result. The paper concludes that the material removal of the gear surface depends on two factors, one is that CBN abrasives scratch the gear surface, and the other is that the gear surface vibrating itself along its normal direction impacts the abrasives.