Characterization of L-PBF lattice structures geometric defects

Abstract

An increasing interest in lattice structures is developing in various industrial sectors. These structures, composed of several cavities or voids, are used in a wide range of applications. They allow to lighten workpieces while maintaining good mechanical characteristics.Although these structures offer new design opportunities, they are difficult to manufacture because of their complex geometry and internal surfaces that are difficult to access. The special characteristics of lattice structures almost always require the use of additive manufacturing processes. By using lattice structures, new problems arise in additive manufacturing, such as lattice defects characterization and measurement issues.The objective of this study is to characterize the geometric defects of lattice structures obtained using L-PBF additive manufacturing process. Lattice structures exhibit not only common defects inherent to L-PBF process, but other geometric defects specific to their unit cell that require appropriate measurement systems and new processing techniques. This paper deals with a systematic approach to evaluate geometric defects obtained from Additive Manufacturing simulation software. First, lattice structures are generated using Rhino-Grasshoper visual programming capabilities. Then, virtual parts are built using Ansys Additive software. Registration methods are used thereafter to compare the simulated and the nominal models. The advantage of non-rigid methods such as CPD and BCPD for registration is highlighted. Finally, the obtained data can be used in the future to enhance the predictive modeling of geometric defects in L-PBF.