Simultaneous optimization of topology and process parameters for laser-powder bed fusion additive manufacturing

Abstract

Additive manufacturing (AM) technology is used in sectors such as automotive and aerospace, due to its advantages in producing complex and lightweight structures. However, it is necessary to reduce the total manufacturing costs for AM technology to become widespread. The topology optimization (TO) studies in the literature typically optimize only the design without taking into account the manufacturing phase or sequentially optimize the topology first and then the process parameters. On the other hand, simultaneous optimization of topology together with process parameters provides more efficient and less costly solutions. This paper describes a strategy for simultaneous optimization of topology along with process parameters of the laser-powder bed fusion (L-PBF) process. The topology, laser power, scanning speed, energy density, and yield strength are controlled by integrating the overall process-property-structure-performance relationship of the L-PBF process into the optimization. The proposed simultaneous optimization method aims to minimize the total cost function including material, manufacturing, and energy costs. Moreover, the constraint functions of the optimization include the volume fraction, the strength of the structure, and the energy density calculated according to the process parameters. The proposed method is successfully applied to three different design problems as cantilever beam, MBB beam, and L bracket, respectively. The results of different TO methods including conventional TO (compliance minimization), structural TO (similar to stress-constrained TO), and sequential process parameters and topology optimization are compared with the results of the proposed method. It is found that the proposed method provided the minimum cost results, and the obtained designs met the structural requirements.