Zhang Zhaoqin, Xu Jiaxuan, Zhu Yejun, Zhang Zhongxing, Zeng Weiqi
College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
Materials (Basel). 2024 Jun 2;17(11):2688. doi: 10.3390/ma17112688.
SiC ceramics are typically hard and brittle materials. Serious surface/subsurface damage occurs during the grinding process due to the poor self-sharpening ability of monocrystalline diamond grits. Nevertheless, recent findings have demonstrated that porous diamond grits can achieve high-efficiency and low-damage machining. However, research on the removal mechanism of porous diamond grit while grinding SiC ceramic materials is still in the bottleneck stage. A discrete element simulation model of the porous diamond grit while grinding SiC ceramics was established to optimize the grinding parameters (e.g., grinding wheel speed, undeformed chip thickness) and pore parameters (e.g., cutting edge density) of the porous diamond grit. The influence of these above parameters on the removal and damage of SiC ceramics was explored from a microscopic perspective, comparing with monocrystalline diamond grit. The results show that porous diamond grits cause less damage to SiC ceramics and have better grinding performance than monocrystalline diamond grits. In addition, the optimal cutting edge density and undeformed chip thickness should be controlled at 1-3 and 1-2 um, respectively, and the grinding wheel speed should be greater than 80 m/s. The research results lay a scientific foundation for the efficient and low-damage grinding of hard and brittle materials represented by SiC ceramics, exhibiting theoretical significance and practical value.
碳化硅陶瓷通常是硬而脆的材料。由于单晶金刚石磨粒的自锐性较差，在磨削过程中会产生严重的表面/亚表面损伤。然而，最近的研究结果表明，多孔金刚石磨粒可以实现高效低损伤加工。然而，关于多孔金刚石磨粒磨削碳化硅陶瓷材料时的去除机理研究仍处于瓶颈阶段。建立了多孔金刚石磨粒磨削碳化硅陶瓷的离散元仿真模型，以优化多孔金刚石磨粒的磨削参数（如砂轮速度、未变形切屑厚度）和孔隙参数（如刃口密度）。从微观角度探讨了上述参数对碳化硅陶瓷去除和损伤的影响，并与单晶金刚石磨粒进行了比较。结果表明，多孔金刚石磨粒对碳化硅陶瓷的损伤较小，磨削性能优于单晶金刚石磨粒。此外，最佳刃口密度和未变形切屑厚度应分别控制在1-3和1-2μm，砂轮速度应大于80m/s。研究结果为以碳化硅陶瓷为代表的硬脆材料的高效低损伤磨削奠定了科学基础，具有理论意义和实用价值。
