Research On The Technique Of Induction Brazing Of Diamond Micro-Powder With Ni-Based Brazing Alloy And The Properties Of Brazed Diamond Micro-Powder

As an important part of the machining tools, brazed diamond grinding tools play an important role in the field of mechanical processing. Ni-based brazing alloy is widely applied in diamond brazing process. However, the high melting temperature of Ni-based brazing alloy may lead to the thermal damage of diamond. The methods to alleviate thermal damage of diamond such as the shortening of brazing time and the reducing of melting temperature of brazing alloy by adding alloy elements, are already used in brazed large-grain diamond tools. However the brazed diamond micro-powder lacks in a profound research. For these reasons, a brazed diamond micro-power tool which is suitable for precision machining was researched by induction heating with Ni-based brazing alloy.In this study, brazed diamond micro-powder bur as an example was made using Ni-based brazing alloy. The following innovative works were completed:(1) The induction brazing process was worked out through the thermal analysis of Ni-based brazing alloy. The induction brazing process condition was optimized combine with gas protection and rotating device, and brazed diamond micro-powder bur was fabricated successfully. The uniform and fine corrugations which increased the chip space were formed on the surface of the brazing alloy. The brazed diamond grits with an outcropping height distributed uniformly on the fluctuant surface.(2) Interface characteristics between diamond, brazing alloy and substrate were researched by SEM, XRD and EDS. The results showed that metallurgical bonding was obtained between diamond, brazing alloy and substrate. Dense and uniform Cr3C2 compound was formed between diamond and brazing alloy.(3) The grinding arc area temperature was measured at different grinding parameters and bur models according to the thermocouple and the Seebeck effect. The problem that infrared thermometry is difficult to measure the grinding arc area temperature accurately was solved through these methods. The results showed that the grinding arc area temperature of grinding tile with diamond micro-powder bur brazed by induction heating was 50% lower than that of the electroplated bur, the slotted bur effectively reduced the grinding arc area temperature, and the grinding arc area temperature with 6-slots bur was 20% lower than that of unslotted bur.(4) The surface roughness of tile and ZL102 aluminum alloy ground by diamond micro-powder burs were measured through orthogonal test. The results showed that, the main factor of affecting roughness of tile and ZL102 aluminum alloy ground by diamond micro-powder burs is the number of slot, secondary factors are rotating speed of diamond micro-powder burs and the feeding load. The minimum Ra of the surface of grinding tile is 1.01μm, and the minimum Ra of the surface of grinding ZL102 aluminum alloy is 1.2μm.In the paper, the problems of thermal damage of brazed diamond micro-powder and small chip space of brazed diamond micro-powder tools were solved by induction heating. The special functions in the precision machining of diamond micro-powder tools was discussed. This study provided theoretical and experimental base for the widely application of the diamond micro-powder tools in precision machining.