Process-structure interactions in stretching-dominated lattices: how nodal toolpath fragmentation limits geometric isotropy in MEX-AM

Fractography suggests this penalty is associated with Nodal Toolpath Fragmentation (NTF), a slicer-induced discretization of the extrusion path at structural intersections that forces premature, interface-dominated failure. Conversely, compression physically suppresses NTF via contact stabilisation. This yields near-isotropic behaviour, with orientation-dependent strength varying by only 1.4%, and limits the compressive manufacturing penalty to 14% relative to numerical baselines.

This confirms geometry dictates compressive performance, while process defects govern tension. Deploying Maxwell-stable metamaterials requires process-aware design prioritising toolpath continuity. By isolating these bottlenecks, this work supports UN Sustainable Development Goals 9 and 12, optimising material efficiency for load-bearing structures.