Topological influence on the tensile performance of multi-material SLA 3D printed cellular structures

Most vat photopolymerisation processes remain limited to a single material, so lattice structures combining a brittle and ductile polymer within one part have not been demonstrated. This work introduces a multi-material stereolithography platform with a novel dual-blade coating system that processes two photopolymers within a single vat and can be retrofitted to existing systems. A custom voxel-based pipeline enables material assignment down to [Formula: see text] voxel resolution. Using two chemically compatible photopolymers with a strong mechanical contrast ([Formula: see text] compared to [Formula: see text], [Formula: see text] compared to[Formula: see text]), the aim was to quantify how unit cell topologies govern the tensile performance of multi-material cellular solids.From a design space of [Formula: see text] configurations (five cell topologies with two sizes, three volume fractions and two lattice material combinations), a D-optimal subset of [Formula: see text] configurations was used to train different models, which were assessed against an unseen validation set. The models predicted maximum stress, corresponding strain, and stress at break with an [Formula: see text] up to [Formula: see text] and MAPE of [Formula: see text]. A rule-of-mixtures response dominates, with material switching at low lattice fractions shifting [Formula: see text] up to [Formula: see text]. The demonstrated framework provides a validated workflow for explorative statistics-driven design of multi-material lattices.