Two-Step Method for Integrating Triply Periodic Minimal Surface Structures of Different Types with Large Differences in Pore Size

Aiming at the integration of triply periodic minimal surface (TPMS) structures with different types and large differences in pore size, a two-step transition method is proposed. Taking P-type and G-type TPMSs as examples, the unit cell number of the P-structure is gradually adjusted to the target size first, and then a smooth transition between P- and G-structures with the same unit number is realized via a Cauchy linear weight function, eliminating geometric defects caused by direct hybridization. Samples are modeled by Mathematica 11.2 and fabricated via selective laser sintering of nylon powder. The experimental results show that the transition zone is defect-free, the volume fraction is close to the designed value, and the structural stiffness is increased by ~40% compared with the traditional direct transition method. This work provides an effective strategy for designing and manufacturing high-performance gradient porous structures via additive manufacturing.