Predicting and optimizing the dimensions of rod in lattice structures fabricated by laser powder bed fusion

Abstract

Laser powder bed fusion (LPBF) is a highly effective method for manufacturing complex parts and is widely used in industry for creating lattice structures. However, during the manufacturing process, the actual dimensions and shapes of the lattice structure rod often deviate significantly from the design model due to limited understanding of the structure-process-property relationship in LPBF. This makes it difficult to carry out targeted structural design and process planning based on the technical characteristics of LPBF. This paper investigates the relationship between melt pool dimensions and lattice structure rod dimensions through theoretical analyses. Based on melt pool dimensions obtained with the help of numerical simulation, a prediction model for the actual dimensions of lattice structure rod is established. We design experiments to validate the accuracy of the predictive model, using LPBF to fabricate rods with varying inclinations, dimensions, and cross-sectional shapes. The actual dimensions are measured under a microscope and compared with the predicted dimensions. The results indicate a difference of no more than 0.1 mm. Furthermore, the experiments reveal a correlation between scan path curvature and actual dimensions. Based on this correlation, the dimensional prediction model is corrected, resulting in an improved generalization performance of the model for parts with varying scan paths. Based on the dimension prediction model, we propose an optimization method to modify the CAD dimensions of the rod to ensure the consistency between the actual and designed dimensions of the rod.