Dimensional and geometrical deviations of an assembly with a lattice structure manufactured by a material extrusion process: numerical and experimental results

During the additive manufacturing process, some geometrical deviations can arise, due to several thermomechanical phenomena that make residual stress rise. The study of dimensional and geometrical deviations connected with a manufacturing process is very important to achieve high-quality parts and to be able to assemble the obtained parts to arrive at assembly products with the desired functional requirements. This work aims to show a numerical procedure to predict the dimensional and geometrical deviations from the nominal of two parts in ABS material with a lattice structure inside an assembly that starts from the models of the parts obtained by simulating the material extrusion process. The idea is to control the volume of the lattice parts using the proposed measurement routines that take into account the surfaces of the lattice parts commonly used to couple them. Once virtually printed, the proposed numerical procedure converts each of the two parts constituting the assembly into a skin model shape representation to which least squares algorithms are applied to define dimensional and geometrical errors of the boundary surfaces of the part. The model was validated using a set of experimental tests; both the parts of the assembly were manufactured and their boundary surfaces were measured by a coordinate measuring machine. The obtained results were compared with those numerically obtained and a very good agreement was found.