Effect of 3D Printing Temperature Profile on Polymer Materials Behavior.

Area of Science:

• Materials Science
• Polymer Science
• Additive Manufacturing

Background:

• Printing time sequences influence the thermal history and crystallization behavior of 3D printed parts.
• Understanding these effects is crucial for optimizing mechanical properties and material performance.

Purpose of the Study:

• To analyze the impact of printing time sequences on the mechanical properties of 3D printed polylactic acid (PLA) samples.
• To correlate these properties with crystallization kinetics and rheological behavior.

Main Methods:

• Comparative analysis of samples printed simultaneously versus sequentially.
• Utilizing finite element analysis (FEA) for thermal and crystallization simulations.
• Employing rotational rheometry for volumetric contraction measurements.
• Characterizing mesostructure using X-ray tomography and scanning electron microscopy (SEM).

Main Results:

• Longer printing time delays between layers increase thermal excursion and lead to step-patterned crystallization, with higher crystal density in the center.
• Materials with faster crystallization kinetics exhibit faster and higher volumetric contraction.
• Sequentially printed samples demonstrate improved rigidity due to minimized time delays between layers.
• PLA 3D870, with higher crystallization rates, showed more microvoids than PLA 3D850, indicating reduced inter-layer cohesion.

Conclusions:

• Printing time sequences are a critical factor in determining the mechanical integrity and microstructure of 3D printed PLA parts.
• Optimizing printing strategies based on material crystallization kinetics can mitigate defects like microvoids and enhance part performance.
• The study highlights the trade-offs between printing speed, material properties, and final part quality in additive manufacturing.