Numerical investigation of novel process planning in the polymeric powder bed fusion

Multiple-laser and matrix-heat source exposures are emerging systems for powder bed fusion (PBF) to improve productivity. However, the newly available process planning such as scanning patterns may induce different transient thermal distribution and distortion in selective laser sintering or melting process. This work proposes novel scanning strategies for digital process planning in polymer PBF, including contour lines and novel inner scanning patterns. It provides detailed predictions of temperature gradient and distortion upon processing and the shrinkage/warping of printed components. Novel scanning strategies of subarea-sequential, subarea-parallel, and matrix-randomized scanning strategies are addressed here. The thermal-recrystallization-mechanical model for laser sintering is employed to reveal the underlying mechanism upon different process planning strategies. Thereafter, the matrix-randomized scanning mode can obviously reduce the building time of each layer into millisecond level. The advanced subarea-sequential scanning pattern is able to minimize shrinkage and warping. The systemic framework of digital process planning is provided through numerical investigation of scanning strategies and multi-physics modeling, which are an important aspect in the advanced digital twin of additive manufacturing.