Effect of Relative Density in In-Plane Mechanical Properties of Common 3D-Printed Polylactic Acid Lattice Structures

Area of Science:

• Materials Science and Engineering
• Mechanical Engineering
• Additive Manufacturing (AM)

Background:

• Lattice structures are crucial for lightweight components in additive manufacturing (AM), serving as cores, supports, or infill patterns.
• The mechanical properties of AM parts are significantly influenced by the choice of infill pattern.

Purpose of the Study:

• To mechanically characterize and compare three common AM infill patterns: triangular, square, and hexagonal.
• To validate experimental findings against analytical and numerical models.
• To develop predictive models for the mechanical behavior of AM structures with varying infill densities.

Main Methods:

• Fused filament fabrication (FFF) using polylactic acid (PLA) for creating test samples.
• Compressive and tensile testing to evaluate mechanical properties.
• Parametric analysis involving varying infill density for numerical and analytical calculations.
• Comparison of experimental, numerical, and analytical results, including the proposal of numerical correlations for high-density honeycombs.

Main Results:

• The square infill pattern demonstrated superior stiffness compared to triangular and hexagonal patterns.
• A nonlinear correlation was observed between infill density and mechanical properties.
• Simplified models were proposed for predicting the compressive and tensile response of AM PLA structures.

Conclusions:

• The square infill pattern is the stiffest among the tested configurations for AM components.
• The study provides validated models for predicting the mechanical performance of AM parts based on infill geometry and density.
• Understanding infill pattern effects is critical for optimizing the structural integrity of 3D-printed components.