Offline laser power modulation in LPBF additive manufacturing including kinematic and technological constraints

Purpose: In Laser Power Bed Fusion (LPBF), the process and operating parameters influence the mechanical and geometrical characteristics of the manufactured parts. Therefore, the optimization and control of these parameters are mandatory to improve the quality of the produced parts. During manufacturing, the process parameters are usually constant whatever the part size or the built layer. With such settings, the manufacturing process may lead to an inhomogeneous thermal behavior and locally overheating areas, impacting the part quality. The aim of this study is to take advantage of an analytical thermal model to modulate the laser power upstream of manufacturing. Design/methodology/approach: The approach takes place in two steps: the first step consists in calculating the preheating temperature at the considered point and the second one determines the power modulation of the laser to reach the desired temperature at this point. Findings Numerical investigations on several use cases show the effectiveness of the method to control the overheated areas and to homogenize the simulated temperature distribution. Originality/value: The specificity of this model lies in its ability to directly calculate the amount of energy to be supplied without any iterative calculation. Furthermore, to be as close as possible to the technology used on LPBF machines, the kinematic behavior of the scanning head and the laser response time are also integrated into the calculation.