Simultaneous in Situ X-ray Scattering and Infrared Imaging of Polymer Extrusion in Additive Manufacturing

Area of Science:

• Materials Science
• Polymer Science
• Additive Manufacturing

Background:

• Understanding the relationship between printing parameters and material properties is crucial for advanced additive manufacturing.
• Crystallization kinetics and thermomechanical behavior significantly influence the performance of 3D printed polymers.

Purpose of the Study:

• To investigate the effect of nozzle motion orientation on the in-situ development of crystalline structure and thermomechanical properties during 3D material extrusion printing.
• To correlate thermal profiles and diffusion behavior with the resulting material integrity and mechanical performance.

Main Methods:

• In situ wide-angle X-ray scattering and infrared imaging were employed during 3D printing.
• Neutron reflectivity was used to measure tracer diffusion coefficients and their temperature dependence.
• Mechanical testing, including torsional strength measurements, was performed on printed samples.

Main Results:

• Nozzle motion along the short axis resulted in higher thermal retention, delaying crystallization onset.
• Extended time above the glass transition temperature led to increased crystallinity but also enhanced brittleness.
• Anisotropic thermal retention was observed, with higher values in the horizontal plane, correlating with increased torsional strength.

Conclusions:

• Printing orientation significantly influences thermal profiles, crystallization kinetics, and anisotropic mechanical properties in 3D printed materials.
• A time/temperature framework was established to define optimal printing conditions for achieving desired mechanical integrity by minimizing diffusion length.
• The findings provide critical insights for optimizing 3D printing processes to tailor material performance for specific applications.