Fabrication, Mechanics, and Reliability Analysis for Three-Dimensional Printed Lattice Designs

Abstract

The use of 3D printing for lattice structures has led to advances in diverse applications benefitting from mechanically efficient designs. 3D printed lattices are often used to carry loads, however, printing defects and inconsistencies potentially hinder performance. Here, we investigate the design, fabrication, mechanics, and reliability of lattices with repeating cubic unit cells using probabilistic analysis. Lattices were designed with 500µm diameter beams and unit cell lengths from 0.8mm to 1.6mm. Lattices were printed with stereolithography and had average beam diameters from 509µm to 622µm, thereby demonstrating a deviation from design intentions. Mechanical experiments were conducted to quantify the exponential increase in yield stress for the relative density of lattices that facilitated probabilistic failure analysis. Sensitivity analysis demonstrated performance was most sensitive to fluctuations in beam diameter (74%) and less to lattice yield stress (8%) for lattices with 1.6mm unit cells while lattices with smaller 1.0mm unit cells were most sensitive to yield stress (48%) and to beam diameter (43%) fluctuations. These findings provide new insights linking design, fabrication, mechanics, and reliability analysis for improved system design that is crucial for engineers to consider as 3D printing becomes more widely adopted.

Design for Additive Manufacturing: Recent Innovations and Future Directions

“…Mechanics can also fluctuate due to manufacturing inconsistencies for the same design. Studies of DLP-printed lattices that tested 30 prints of the same design demonstrated a distribution of density and mechanical property measurements that occur due to fabrication inconsistencies [84]. The study investigated uncertainty and reliability for lattice mechanics and found that lattice failure due to yielding was highly affected by fluctuations in beam diameter.…”

Mechanics of 3D-Printed Polymer Lattices with Varied Design and Processing Strategies

“…Support material size was determined through preliminary testing to minimize support material to ensure its removal without destroying the surrounding structure while ensuring support material was printed large enough to facilitate structural stability during printing. Preliminary work and past studies informed these parameters as suitable limits for high-quality prints according to hardware constraints [41].…”

“…Polymers 2022, 14, x FOR PEER REVIEW 4 of 19 support material to ensure its removal without destroying the surrounding structure while ensuring support material was printed large enough to facilitate structural stability during printing. Preliminary work and past studies informed these parameters as suitable limits for high-quality prints according to hardware constraints [41]. Envision One Rapid Prototype software (EnvisionTec, Dearborn, MI, USA, version: 1.23.4820) was used to prepare digital files from STLs and add support material structure.…”

“…In DLP printing of polyurethane acrylate, experimental results were sensitive to strain rates and anisotropy, and structures demonstrated complex fracture behaviors depending on loading conditions [39]. Understanding how design and fabrication affect mechanical performance is essential for designing structures for specified applications, where DLP printing provides unique capabilities for applications such as bone tissue engineering [40,41]. Bone tissue scaffolds have been previously investigated using stereolithography printing for altering lattice topological design [42].…”