Design for additive manufacturing – material characterization and geometrical optimization

Abstract

Additive manufacturing (AM) is a more and more appreciated manufacturing technology. This grow-ing interest is related to the high flexibility of this approach and its capability to produce any geometry, opening new possibilities. An example is the improvement of the system performances exploiting lattice and reticular in substitution to the traditional solid design. Despite this premise, in real applications, part of the benefits is lost due to the inferior performances of the AM steels and the higher costs of additive manufacturing. In this scenario, the mechanical properties of a 17-4 PH SS produced via additive technology were characterized with experimental tests. The results were compared with data concerning the cast material. In this way, it was possible to execute a quantitative evaluation of the performance reduction. Three components, such as a hip prosthesis, a blow plastic bottle die, and an automotive gear, were chosen as representative examples. These three mechanical components are typically produced in quite different batch sizes. The hip prosthesis, the blow plastic bottle die, and the automotive gear were redesigned (design for AM) via a finite element (FE) approach. The new designs fulfill the original requirements in terms of strength showing however improved inertial properties. The original and new designs were exploited to quantify the benefits of introducing AM in different applications. of the original components. To achieve this goal, three reticular cell topologies such as BCC, BCCZ, and FCC were selected. Their strut diameters and cell size were changed based on FEM simulations combined with a multiobjective genetic algorithm. A potential average weight reduction between 21% and 23% was obtained for each component.