Machining Performance on Multi-Layer Brazed Diamond Tools

An attempt has been made to investigate the new generational manufacturing technology for multi-layer diamond tools by brazing. A kind of new multi-layer brazed diamond core drills with random grains distribution was made by mixing diamond particles with brazing alloy powders. And a preliminary machining performance experiment was carried out through drilling granite. The testing results show the typical topography of the multi-layer brazed diamond core drills after drilling granite, just like that of multi-layer sintered ones, is that diamond grits drag long tails. Different from multi-layer sintered diamond core drills, no grit pull-outs can be seen during the whole drilling process because of chemical metallurgical effect between diamond grit and brazing alloy, the same as monolayer brazed diamond core drills. The main drawback to this kind of multi-layer brazed diamond tools is each individual particle is not subjected to the same drilling force throughout the drilling operation because of random grain distribution. This leads to premature fracture of the leading particles. Similarly, because large gaps between particles exist, the bond is being exposed to the workpiece, which leads to erosion of the bond. The overall performance is lower tool lives and slower drilling speeds. Therefore, ideally, diamond particles should be evenly distributed throughout the bond, which means they are all subject to the same drilling forces and the multi-layer brazed diamond tool is operated at its optimum efficiency.