Laser polishing was used to reduce the surface roughness and improve the surface properties of alumina ceramics. In this paper, a response surface experimental design scheme is used to establish a mathematical model based on the Box-Behnken central combination principle, with the surface roughness as the optimization target to optimize the optimal process parameters for the laser polishing of alumina ceramics, to suppress the polished surface cracks by preheating the material, and to study the changes of surface properties of laser-polished alumina ceramics under different preheating temperatures. The optimal laser polishing process parameters were optimized by response surface experiments with a scanning speed of 323.5 mm/s, a laser power of 73.63 W, a pulse frequency of 2.3 kHz, and a scanning spacing of 0.09 mm; compared with the initial surface roughness of 4.67 μm, the polished surface roughness was 0.96 μm under the experimentally optimized polishing parameters, and the surface cracks were suppressed after the preheating treatment. The surface roughness was further reduced to 0.74 μm, and the surface wear coefficient was reduced from 0.5939 to 0.5725, while the surface hardness was increased from 1810 to 2063 HV. Optimization of the laser polishing process parameters through the response surface can significantly reduce the surface roughness of the material, while the flame preheating, assisted by the laser-polished surface wear resistance and hardness, is improved.
Keywords: alumina ceramics; laser polishing; preheating; response surface method; roughness.