Influence of interface in electrical properties of 3D printed structures

Area of Science:

• Additive Manufacturing
• Materials Science
• Electrical Engineering

Background:

• Layer-by-layer fabrication in material extrusion-based additive manufacturing (MEAM) results in anisotropic material properties.
• Understanding electrical anisotropy is crucial for developing MEAM-based sensors and actuators.

Purpose of the Study:

• To investigate the anisotropy in electrical impedance of MEAM-printed parts.
• To analyze the influence of print parameters, specifically extrusion temperature and print speed, on electrical impedance.
• To elucidate the relationship between interfacial properties and overall electrical behavior.

Main Methods:

• Utilized stacked filament samples to isolate and study interfaces in MEAM.
• Quantified anisotropy by measuring electrical impedance across (Z-specimen) and along (F-specimen) fiber orientation.
• Employed scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) to examine interfacial characteristics.

Main Results:

• The ratio of impedance across to along fiber orientation (Z/F ratio) remained constant (2.15 ± 0.23) despite variations in extrusion temperature and print speed.
• Electrical impedance scaling per interface was dependent on extrusion temperature, with higher temperatures resulting in lower impedance (~6.5 Ω/interface at 230 °C vs. ~12.5 Ω/interface at 190 °C).
• SEM and EDS analyses confirmed the absence of air gaps and oxidation at the interfaces, suggesting other factors contribute to interfacial impedance.

Conclusions:

• The study provides a framework for modeling and predicting the electrical behavior of MEAM components.
• The findings highlight the critical role of extrusion temperature in controlling electrical impedance, independent of print speed.
• The proposed specimen design and characterization methodology enable efficient evaluation of various print parameters, reducing resource consumption.