Wear mechanisms and performance of abrasively ground polycrystalline diamond tools of different diamond grains in machining titanium alloy

Abrasive grinding, electrical discharge machining and laser machining are the three approaches to manufacture polycrystalline diamond (PCD) tools. However, the performance of PCD tools made by the three methods was found different. Customized PCD tools made of three different PCD materials were fabricated by abrasive grinding in this paper. Through a series of cutting experiments, cutting forces, cutting temperatures, morphological characteristics of wear areas on tool surface, and the geometric parameters of chips were analysed to investigate the wear mechanisms, cutting performance, as well as the effects of material structure. It was found that adhesive-abrasive process and chemical diffusion were the main mechanism of wear of PCD tools. However, the wear processes of the three tools were different due to the difference in material structures. PCD tools made of uniformly sized diamond grains wear in a steady "spalling process". In contrast, PCD tools made of mix-size diamond grains suffered from large-scale fracture at the tool tip. The shapes of chips and the related geometric parameters reflected different wear processes. Chip shapes changed from spiral to strip with the growing of crater wear, segment chips were generated because of the change of tool geometry caused by the fracture of the tool tip.