目的 提高球墨铸铁铣削表面质量和刀具寿命。方法 通过刀具轨迹计算和切削试验，研究球墨铸铁平面铣削过程中切削刃数量对切削性能、刀具磨损和表面形貌特征的影响，并用分形维数和表面粗糙度共同表征表面形貌。结果 刀具轨迹分析表明，由于铣削过程中，刀具切削方向和进给方向间的夹角不断变化，铣削表面不同位置和方向的表面形貌存在差异，进而导致表面粗糙度存在较明显的差异。通过铣削试验研究切削刃数量对铣削表面不同位置和方向的几何特征的影响规律发现，随着切削刃数量的成倍增加，切削力显著增加，同时刀具磨损量降低了36.5%，表面粗糙度值降低了39.2%，表面轮廓分形维数值增加了4.8%。结论 增加切削刃数量可以使每齿切削力和刀具磨损均显著减小，刀具寿命显著增加，同时表面粗糙度减小，分形维数增大，即切削刃数量的增加使表面质量更好，表面轮廓结构更复杂。

The work aims to improve the surface quality of nodular cast iron by face milling and the service life of tool. As for the large-scale face milling of engine case and cylinder head with high power density, the high surface quality, high machining efficiency and longer tool life were required. The effects of number of cutting edges on the cutting performance, tool wear and surface morphology in face milling of nodular cast iron were studied by the tool path calculation and the cutting test. The surface morphology was characterized by the fractal dimension and the surface roughness. From the analysis of tool path, the inclination between cutting direction and feeding direction changed continuously during milling and the surface morphology of different positions and directions on the milling surface was also different, thus leading to different roughness values. The effect of number of cutting edges on the surface geometry at different positions and directions was studied through the milling test. It was found that with fold increase of cutting edge number, the cutting force increased, the tool wear amount was reduced by 36.5%, the surface roughness value was reduced by 39.2%, and the surface contour fractal dimension value increased by 4.8%. Increasing the number of cutting edges can reduce the cutting force and tool wear of each tooth significantly and increase the tool life, reduce the surface roughness and increase the fractal dimension. The increase of the number of cutting edges makes the surface quality better and the surface contour structure more complex.