Modeling and optimization of direct metal laser sintering process

Direct metal laser sintering (DMLS) is a novel class of rapid manufacturing process that can fabricate functional parts of any complexity. However, the DMLS process takes almost 6-12 h to build parts of even small-moderate size. Reducing the build time of the parts is the key to success of the DMLS process at commercial level. A common solution to reduce the part build time is to sinter the parts with maximum allowable layer thickness. However, doing so will make staircase effect more prominent and lead to the poor surface accuracy of the part. In this paper, a bi-criteria-based optimization approach is presented to address this issue. The sub-processes, namely, part orientation, layer thickness identification, and laser scanning directions, are optimized with an aim to build the parts with: (a) minimum amount of time and (b) minimum surface inaccuracy. In addition, the material shrinkage is also incorporated in the proposed model. Parts with varying complexities are analyzed to elucidate the applicability of proposed approach. Comparisons with traditional slicing approaches are also made.