Abstract: Laser-assisted machining (LAM) is an advanced technique to machine difficult-to-cut materials through laser preheating of local zones, which can reduce cutting forces and improve machining efficiency. In order to obtain the best machinability, one of the most important factors is to control the preheating temperature field. By quantitative and formula characterization of the actual output laser beam quality, an analytical model is adopted to characterize the temperature field induced by the moving laser source. Following, a controlling strategy is proposed for adapting the moving path of laser source to obtain the uniform distribution of temperature field in the cutting area of face-milling, which is then validated against the experimental data by surface and internal temperature. Furthermore, cutting tests under laser-assisted conditions and conventional conditions are performed to analyze the alterations of machinability induced by different machining techniques. Cutting forces and surface roughness are used for the analyses, and the results show that the milling forces can be effectively reduced by more than 10% and the surface roughness can be reduced by 30% with the implementation of the proposed controlling strategy, which further improves the machined surface quality. In summary, the proposed controlling strategy of preheating temperature field can effectively regulate the temperature of heat affected zone, which provides theoretical guidance for the active design of laser parameters, and have broad application prospects in the laser-assisted machining of difficult-to-cut materials.

Key words: laser-assisted milling, temperature field, parameter optimization, milling forces, surface roughness