Lawrence Livermore National Laboratory



Jenny Wang

Overview

Additive manufacturing (AM) of multi-material objects enables the design of complex, three-dimensional architectures such as printed electronics and devices. The ability to detect the composition of multi-material printed inks in real time is an emerging need for a range of manufacturing applications.

Our study demonstratedthe feasibility of using an in situ sensor to locally measure the composition of inks as they are being printed to facilitate greater control over the resulting properties and functionality of printed materials. Dielectric properties of microscale embedded metal particles in a dielectric matrix weremeasured and characterized as a function of particle size, shape, volume percentage, and frequency. We determined that particle shape has a much greater influence on impedance measurements thanparticle size. Measurements agreed with calculations based on an anisotropic Maxwell-Garnett dielectric function model. The resulting data can be used to generate a calibration curve correlating metal loading with impedance or capacitance that can be used withan in situ sensor for compositional measurements during extrusion-based AM.

Impact on Mission

Our research leveraged Lawrence Livermore National Laboratory's core competency in advanced materials and expanded the Laboratory's expertise in materials for energy storage.

Publications, Presentations, Etc.

Wang, J., et al. 2019. "Electrical Properties of Copper Loaded Polymer Composites." SPIE Smart Structures + Nondestructive Evaluation, Denver, CO, March 2019. LLNL-CONF-767977.

——— . 2019. "Characterization of Metal-Polymer Composites for In Situ Direct Ink Write Sensing Applications." Solid Freeform Fabrication Symposium, Austin, TX, August 2019. LLNL-PRES-769203.