Thermo-Mechanical Approach to Material Extrusion Process During Fused Filament Fabrication of Polymeric Samples

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Modeling

Background:

• Fused filament fabrication (FFF) offers design flexibility but faces mechanical challenges like residual stresses and warpage.
• These issues stem from complex thermal profiles during FFF, impacting structural integrity.
• Polylactic acid (PLA) is widely used, necessitating improved understanding and prediction of its FFF performance.

Purpose of the Study:

• To introduce a computational framework for coupled thermo-mechanical simulations of the FFF process.
• To enable accurate prediction of residual stresses, geometric distortions, and warpage in FFF parts.
• To validate the simulation framework against experimental data for process optimization and design validation.

Main Methods:

• Developed a computational framework using ABAQUS finite element software.
• Created an automated subroutine to convert G-code into a time-resolved event series for finite element activation.
• Explicitly modeled sequential stages: printing, cooling, and detachment, including a transient thermal model and mechanical simulation.

Main Results:

• The simulation framework accurately predicted residual stresses and warpage in FFF-fabricated PLA components.
• The model successfully incorporated the detachment stage, enhancing prediction realism.
• Achieved an average deviation of approximately 10.6% between predicted and measured displacements, validating the model's spatial distribution and magnitude predictions.

Conclusions:

• The developed computational framework provides a practical tool for predicting and mitigating mechanical challenges in FFF.
• The inclusion of the detachment stage offers a more experimentally validated approach to warpage and residual stress analysis.
• The simulation's accuracy supports its use for process optimization and design validation in engineering applications.