Influence of diamond layer chamfer parameters on performance of PDC cutters

Objectives: The precise control of diamond layer chamfer parameters has a complex influence on the comprehensive performance of PDC cutters. This control not only helps to expand ideas in PDC cutter design but also improves the overall efficiency of drilling tools. To fully analyze the effect of diamond layer chamfer parameters on the performance of PDC cutters, this study examined the correlation between the chamfer size and chamfer angle of the diamond layer and the performance of PDC cutters, namely wear resistance, impact toughness, drilling efficiency, and damage forms. It provided a scientific basis for optimizing the structure of PDC cutters to enhance the operational efficiency and reliability of PDC bits under complex geological conditions. Methods: The study combined experimental research and theoretical analysis. Two types of PDC cutters, planar type and micro-arc type, which are widely used in the market at present, were selected as experimental objects. Samples with different chamfer sizes (0.2, 0.3, 0.4, 0.5 mm) and chamfer angles (15°, 30°, 45°) were prepared using precision machining techniques. The samples were systematically heat-treated to simulate the actual welding process before testing, and the performance of the PDC cutters was evaluated by analyzing wear resistance, impact toughness, and drilling efficiency. Additionally, the interaction between the PDC cutter and rock was simulated by turning experiments, and the wear area and the damage forms were observed, measured, and analyzed using a microscope. Results: The experimental results revealed the influence of diamond chamfer parameters on the performance of PDC cutters. On the one hand, the chamfer size had a critical value of about 0.3 mm. When the chamfer size was less than or equal to this critical value, the wear ratio of PDC cutters was high, the grinding time was short, the energy level of breakage was low, impact toughness was low, and the primary form of damage was broken edges, which adversely affected the service life and drilling efficiency of the cutter. When the chamfer size exceeded the critical value, the PDC cutter wear ratio decreased, the grinding time increased, the damage energy level was high, impact toughness nearly doubled, the accumulated absorbed energy reached more than 1 000 J, and the predominant damage form was delamination, effectively extending the service life of the cutter. On the other hand, the influence of chamfer angle on the wear resistance and impact toughness of PDC cutters exhibited a linear relationship. As the chamfer angle increased, the wear ratio of PDC cutters gradually decreased, the wear area increased, indicating a decrease in wear resistance, and impact toughness increased correspondingly. In addition, the influence of the PDC cutter's shape on wear resistance and impact toughness was similar to that of the chamfer angle, namely, planar cutters had a high wear ratio and short grinding time, while micro-arc cutters had a reduced wear ratio but improved impact toughness. This provided an important basis for optimizing the chamfer angle and designing the shape structure of PDC cutters. By moderately increasing the chamfer angle or adopting a camber design, the comprehensive performance of the cutter could be improved to a certain extent. Conclusions: Through systematic experiments and analysis, the effect of diamond chamfer parameters on the comprehensive performance of PDC cutters is revealed. Especially, the discovery of the critical value of chamfer size provides guidance for the optimal design of PDC cutters. The fine regulation of diamond layer chamfer parameters presents a new approach to improving the performance of PDC cutters. In the development and production of PDC bits, the influence of these parameters should be fully considered. The performance of PDC cutters can be optimized by accurately regulating the chamfer size, chamfer angle, and shape structure, thereby further enhancing the drilling efficiency and service life of PDC bits.