Analytical Modeling of Cutting Forces Considering Material Softening Effect in Laser-Assisted Milling of AerMet100 Steel

AerMet100 steel is a typical difficult-to-cut material, and laser-assisted milling (LAM) is a promising machining technology for this kind of material. In LAM process, the material is softened by the thermal effect of laser beam, which improves the machinability of the materials. And finally, the cutting forces are reduced compared with conventional milling (CM). This paper presents an analytical model considering material softening effect to predict the cutting force during LAM. The cutting force is produced by shearing and ploughing action. Both laser source and cutting tool are discretized into elements. Based on the Johnson-Cook (J-C) constitutive model and the thermal model due to laser beam and cutting action, the shear plane temperature and the shear flow stress considering the combined effects of laser heating and plastic deformation are calculated iteratively, and the influence of material softening effect on cutting force coefficients is taken into account. A series of experiments carried out on AerMet100 steel demonstrate the accuracy of the cutting force model, and the results show that the three-axis cutting force in LAM is reduced by up to 33.9%. Besides, the influence of laser parameters related to material softening effect on the cutting force is discussed based on the proposed model.