Optimization of L-PBF Laser Scan Path Compensation Design for Mitigation Thermal Gradient in Overhang Structure without Support Structure

Abstract

The Laser Powder Bed Fusion (L-PBF) process, which fabricate a final component layer by layer using metal powder, offers advantages in reducing production time and costs. Recently, it has been extensively utilized in the aerospace industry for manufacturing components such as turbo pumps and combustors. These aerospace components often have complex shapes and frequently include overhang structures. In the typical L-PBF process, overhang structures are addressed by inhibiting their formation through the Design for Additive Manufacturing (DfAM) process or by using support structures, which are later removed through post- processing. However, when overhang structures occur in areas that are difficult to post-processing, it becomes necessary to produce components with overhang structures without the use of support structures. The L- PBF process employs high-energy lasers to rapidly melt and cool metal powder, resulting in substantial thermal gradients. This can lead to issues such as warping, distortion, and cracking in the produced components, especially in overhang structures, and the challenges become more significant when producing without support structures, causing substantial deformations. This study focused on optimizing laser scan path compensation design to mitigate thermal gradients in overhang structures, aiming to suppress deformations. Through monitoring the effects of thermal gradient mitigation, reduction in deformations and dross formation, and improvement in cooling rates, the study concluded that optimizing laser scanning path compensation design is effective in the production of overhang structures without support structures.