Research On Vitrified Bond Diamond Grinding Tools For Grinding PCD Cutter

Owing to high strength , good heat-resisting, good self-dressing ability and other unique properties, the vitrified bond diamond grinding tools is becoming one of the most potential tools in the application of grinding PCD cutter. In this research, effects of the composition of basic vitrified bond and mixed additives on the properties of vitrified bond and grinding tools were studied respectively. Effect of the proportion of abrasive to vitrified bond on the properties of grinding tools was discussed and the result of grinding was analyzed.The results indicated that when the R(K2O/ B2O₃) in the basic bond was 0.3, the refractoriness of the vitrified bond was 730℃, the fluidity was 125%,the wetting angle was 66 degree and the bending strength of grinding tools achieved maximum value of 50.45MPa. With the increase of R, the trend of bending strength of grinding tools versus R agreed well with the trend of N4 (the fraction of BO4 unit) versus R,so it was the N4 of vitrified bond that greatly influenced the the bending strength of grinding tools. ZnO-Bi₂O₃ and Sb2O₃-SnO₂ mixed additives were added to the basic vitrified bond respectively. When 4.5wt% Bi₂O₃ and 1.5wt% ZnO were added to the basic vitrified bond, the bending strength and hardness of the grinding tools both achieved maximums. Similarly,when 4.5wt% SnO₂ and 1.5wt% Sb2O₃ were added to the basic vitrified bond, the bending strength and hardness of the grinding tools both achieved maximums. In the system of binary mixed additives, the mixed additives effect, like"mixed alkali effect", was appeared. Through comparing with the properties of different vitrified bonds and grinding tools,an optimal recipe was obtained and can be stated as follows, that was 100wt% basic bond and 4.5wt% SnO₂ and 1.5wt% Sb2O₃, and the R value in basic bond was 0.3.When the proportion of abrasive to vitrified bond was 65:35, the bending strength and hardness of the grinding tools both attained maximums and the microstructure of samples was homogeneous. Compared with the current diamond grinding tools in the market, the diamond grinding tools prepared in this study in the application of grinding PCD cutter possessed better properties such as higher grinding efficiency, longer lifespan, higher durability, better self-dressing ability, higher rotational speed and better machining quality in the surface of PCD cutter.