Functionally Graded Lattices in Photopolymer Additive Manufacturing: Gradient Definition, Interface Continuity and Performance

Qualification of the graded-lattice response fails when geometry, transport and material evolution are collapsed into one empirical setting. This review separates those effects by starting from the coupled balance that governs graded lattices. It then examines how digital gradient smoothness can be destroyed by voxelization and cure broadening and how local stiffness gradients redirect load and change collapse sequence. The evidence chain couples local geometry, full-field deformation, local mechanical response and commanded-versus-as-built gradient measurements with controlled tests such as 'manufacture discrete, smoothed-discrete and continuous gradients with the same endpoints'. Those measurements are used to distinguish failure mechanisms, calibrate models and define an acceptance envelope. The resulting framework is intended to answer minimum transition length for acceptable stress concentration with explicit uncertainty and stated limits of transfer.

ER-363.