Numerical simulation of continuous laser microdrilling of ultrathick aluminum honeycomb sandwich panels

Ultrathick aluminum honeycomb sandwich panels, which have high strength/stiffness-to-weight ratio, have been applied widely in satellites and other aerospace fields. However, the ultrathick aluminum honeycomb sandwich panels are difficult to be machined. In many cases, laser ablation is used for the microdrilling demand of aluminum honeycomb sandwich panels. The heat flux density is the key factor during laser machining, and the microdrilling parameters, including defocusing amount and incident angle, can lead to the change of the temperature fields of upper panel, cell walls, and lower panel. To study the microdrilling process quantitatively, the finite element model (FEM) is performed to evaluate the temperature evolution of aluminum honeycomb sandwich panels during continuous laser irradiation. Moreover, continuous laser microdrilling characteristics of upper panel, cell walls and lower panel are discussed via numerical simulation. The relative errors with respect to experimental results are in range of 8% showing that simulation results of laser microdrilling are reasonable. Thus, the mechanism of laser microdrilling revealed in this study can be significant for improving the processing quality of aluminum honeycomb sandwich panels.