Study of topology optimization parameters and scaffold structures in additive manufacturing

Abstract

This work falls within the scope of topology optimization procedures and additive manufacturing technologies. In recent years the topology optimization has become a perfect tool to maximize the potential and freedom that these revolutionary manufacturing technologies offer, allowing to conceive designs that utilize available resources optimally. However, there are still many theoretical and practical issues regarding automatic integration of both technologies. This investigation aims to advance in this line of research, where algorithms that provide the ability to control and minimize support structures will be developed. These scaffold structures are usually necessary when additive manufacturing is used to construct the geometries obtained after the optimization process. The algorithms to be implemented in this project would offer the possibility to control the formation of scaffold structure and minimize them when necessary. For this purpose, this introductory paper discusses the effect of different parameters and restrictions that may have an influence on the formation of scaffold structures and are eventually involved in the topology optimization process. Considered parameters include the filter radius applied for mesh independency, penalization factor in the SIMP power law and the perimeter constrain. These strategies are frequently used to assure existence of solutions and mesh independent 0-1 designs, when a high degree of complexity is usually undesired for traditional manufacturing. This paper discusses the effect of these parameters on the length and inclination of members present in the optimum topologies. The requirement for several Additive Manufacturing processes to use support structures for large overhangs provides justification for investigating additional and specific methods for including this measure into the optimization process. In this line of work the authors will also propose a new approach to evaluate the global angle and overhang of a topology with intermediate densities, which can be incorporated as a manufacturing constraint into the topology optimization process in order to explicitly specify the amount of support structures desired in the final solution.