On the Design and 3D Printing of Thin Stochastic Porous Structures Made of PLA

Thin stochastic porous structures have potential applications as flexible structural components and functional elements in heat and mass transfer systems, filtration and separation membranes, tissue engineering scaffolds, and lightweight structures requiring controlled porosity and permeability. However, accurately designing and fabricating these structures using affordable additive manufacturing technologies remains challenging. This study presents a computer-aided design (CAD) method for generating thin stochastic porous structures and evaluates their printability in polylactic acid (PLA) using fused filament fabrication (FFF). The method divides a planar region into cells and generates polygonal pores with random sizes, shapes, and orientations, while avoiding disconnected regions and excessively thin walls. An analytical formulation calculates porosity, and a sensitivity analysis identifies key geometric parameters. Sixteen specimens were fabricated using a commercially available, affordable 3D printer across four configurations with varying structural and layer thicknesses and deposition passes. The structures were evaluated for pore geometry, porosity, and thickness accuracy. Of the configurations tested, a designed thickness of 200μm fabricated with two deposition passes of 100μm each achieved the highest average intersection over union (87.56%), the highest average F1 score (93.36%), the lowest average relative porosity error (2.38%), and the smallest relative thickness deviation (approximately 15%). These results show that thin stochastic porous PLA structures can be fabricated using a commercially available FFF printer. The findings also underscore the importance of selecting appropriate layer thicknesses and deposition strategies to improve geometric fidelity.