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

The high melting temperature of Ni-based brazing alloy used to braze diamond could cause the thermal damage of diamond grits, especially for diamond micro-powder. In addition, brazed diamond micro-powder tools had small chip space and poor heat dissipation. Some researchers had explored all kinds of methods to alleviate thermal damage of diamond. But, the effects of the methods were poor due to the separate use of them. In addition, the problem of small chip space of diamond micro-powder tools was not yet solved. Therefore, in the paper thermal damage and small chip space of brazed diamond micro-powder were solved, and the processing performance of brazed diamond micro-powder was improved through the use of low melting point of Cu-Sn-Ti brazing alloy and induction brazing.In this study, brazed diamond micro-powder bur was made as an example. The following innovative works were completed:(1) Cu-Sn-Ti brazing alloy and induction brazing were used to braze diamond micro-powder, in order to reduce brazing temperature and short brazing time. The results found that, spindle-like compound TiC is formed on the surface of brazed diamond grits and chemical bonding is carried out at the interface of diamond grits and the brazing alloy. TiC is grown along the crystal plane of brazed diamond. The method afforded a fluctuant surface on the brazing alloy. The brazed diamond grits with an outcropping height distributed uniformly on the fluctuant surface. The fluctuant surface showed a certain chip space. These characteristics of the tool increased the grinding efficiency and decreased the temperature of the grinding arc area.’(2) According to the theory of thermocouple, a non-standard thermocouple was made to measure the temperature in grinding arc area of ZL102 ground by diamond micro-powder burs. The results showed that, the minimum average temperature of grinding ZL102 could only be 172℃ when the feeding load is 12.5 N with no slot bur at 1000r/min(3) The material removal rates of tile and ZL102 ground by diamond micro-powder burs were measured through grinding test. The results showed that, the material removal rate of grinding tile with 3 slots bur at 3150 r/min and the load of 12.5 N is the highest. The material removal rate of grinding ZL102 with 3 slots bur at 1000 r/min and the load of 15 N is the highest.(4) The surface roughness of tile and ZL102 ground by diamond micro-powder burs were analyzed through orthogonal test. The results showed that, the main factor of affecting roughness of tile and ZL102 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 is 1.2μm.In the paper, many methods were combined to solve the difficult problems of thermal damage of brazed diamond micro-powder and small chip space of brazed diamond micro-powder tools. The application of diamond micro-powder tools in the precision machining was discussed. One method to measure grinding arc area temperature of metal material ground by diamond tools was provided. In addition, the influence processing parameters on the material removal rate and surface roughness were studied, and the optimal processing conditions of brazed diamond micro-powder burs were determined.