Although laser powder bed fusion (PBF/LB) was one of the first industrially viable additive
manufacturing (AM) methods for end-use part production, polyamides remain grossly dominant
at both the commercial- and research scale. The research community continues to develop and
refine “rapid screening” methods for evaluating the suitability of new polymers for PBF/LB. The
so-called “SLS Process Window,” which is the difference between melting and crystallization
temperature measured at 10 K min-1 as originally outlined in the patent literature, is perhaps the
most often reported screening method. Although perhaps appropriate as part of a larger study, the
simplistic guidelines put forth by the “SLS Process Window” are not sufficiently scientifically
rigorous to understand how crystallization kinetics affects successful 3D printing. The common
understanding of the SLS Process Window omits details from published theories of polymer
crystallization. as evidenced by published assumptions and methods in PBF/LB process modeling
papers. The authors explain polymer crystallization in the PBF/LB context and propose replacing
the “process window” with crystallization halftime and physical gelation for new material
screening. These measurements better represent behavior critical for ensuring a lengthy
coexistence of solid powder and molten polymer affecting warp-free parts.Mechanical Engineerin
