Acoustic and Electromagnetic Characterization for Accelerated Development of Additive Manufacturing

Project Overview

Advanced manufacturing (AM) processes currently need in-situ characterization diagnostics which can provide real-time (or near real-time) feedback to improve build performance and quality. In this project we developed a new electromagnetic and a new acoustic diagnostic for droplet-on-demand liquid metal jetting (DDLMJ) and laser powder bed fusion (LPBF) AM processes, respectively. Additionally, we explored electrical impedance tomography (EIT) for detecting defects in AM lattice structures.

A millimeter-wave diagnostic for in-situ monitoring of DDLMJ manufacturing systems was conceived, developed, tested in controlled laboratory experiments, and implemented on a Lawrence Livermore National Laboratory (LLNL) DDLMJ system with tin droplets. The diagnostic was then improved upon and implemented on an LLNL DDLMJ system with copper droplets. Data from this diagnostic was used to predict droplet characteristics (such as size, shape, and velocity) using a physics inversion algorithm and with machine learning (MI) algorithms.

An all-optical surface acoustic wave (SAW) diagnostic was conceived, developed, and implemented on LLNL created single melt line samples to characterize subsurface voids and surface features such as melt line geometry and metal splatter. The ground truth for these features was established using micro-x-ray computed tomography (CT) and structured light optical measurements.

EIT algorithms were developed to detect damaged or missing struts in lattice structures created using AM. The algorithms were implemented on synthetic data generated via simulation and on experimental data collected on exemplar structures.

Mission Impact

This project supports LLNL's core competency in Advanced Materials and Manufacturing. The novel AM diagnostics developed in this Lab Directed Research and Development (LDRD) effort are critical science and technology capabilities to meet future national security missions. These diagnostics will support the current and future use of AM processes in the energy, environmental, and security missions of the Department of Energy .

Publications, Presentations, and Patents

Tammy Chang, Owen Mays, Saptarshi Mukherjee, Nicholas Watkins, Andrew Pascall, Jason Jeffries, Joseph Tringe, "An in-situ millimeter-wave diagnostic for droplet characterization during jetting-based additive manufacturing processes," Proceedings Volume 11380, Nondestructive Characterization and Monitoring of Advanced Materials, Aerospace, Civil Infrastructure, and Transportation XIV 1138008 (2020). https://doi.org/10.1117/12.2547937.

Tammy Chang, Owen Mays, Saptarshi Mukherjee, Nicholas Watkins, Andrew Pascall, Jason Jeffries, Joseph Tringe, "An in-situ millimeter-wave diagnostic for droplet characterization during jetting-based additive manufacturing processes." in video conference presentation in SPIE Smart Structures and Nondestructive Evaluation Conference. April 27, 2020.

Tammy Chang, Saptarshi Mukherjee, Nicholas N. Watkins, David M. Stobbe, Owen Mays, Emer V. Baluyot, Andrew J. Pascall and Joseph W. Tringe, "In-situ monitoring for liquid metal jetting using a millimeter-wave impedance diagnostic," Nature Scientific Reports 10, 22325 (2020). https://doi.org/10.1038/s41598-020-79266-2.

Rosa Morales, Todd Murray, Kathryn Harke, Joseph Tringe, and David Stobbe, "Laser Ultrasonic Monitoring of Thermal Processes." In ASME 2020 Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE). August 25-26, 2020.

Abigail Gilmore, Saptarshi Mukherjee, Tammy Chang, and David Stobbe, "Electrical impedance characterization for damage detection in highly conductive additively manufactured metal mesh structures."In  ASME 2021 Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE) July 28-30, 2021.

Rosa Morales, Kathryn Harke, Joseph Tringe, David Stobbe, and Todd Murray, "Real-time Laser Ultrasonic Monitoring of Thermal Processes." In ASME 2021 Annual Review of Progress in Quantitative Nondestructive Evaluation (QNDE). July 28-30, 2021.

Rosa Morales, Kathryn Harke, Joseph Tringe, David Stobbe, and Todd Murray, "Real-Time Laser Ultrasonic Monitoring of Thermal Processes." In ASNT 16th International Symposium of Nondestructive Characterization of Materials. August 2021.

Rosa Morales, Kathryn Harke, Joseph Tringe, David Stobbe, and Todd Murray, "Real-Time Laser Ultrasonic Monitoring of Laser-Induced Heating and Melting Processes."In CASIS LLNL Workshop. August 2021.

Saptarshi Mukherjee, Abigail Gilmore, Tammy Chang, David Stobbe, "Electrical impedance tomography based on adjoint field-sensitivity for damage detection in highly conductive additively manufactured metal mesh structures." In CASIS LLNL Workshop. August 2021.

Tammy Chang, Saptarshi Mukherjee, Nick Watkins, Edward Benavidez, Abigail Gilmore, Andrew Pascall, and David Stobbe, "Millimeter-Wave Electromagnetic Monitoring for Liquid Metal Droplet-on-Demand Printing," Journal of Applied Physics (in-press).

Aniruddha Gaikwad, Tammy Chang, Brian Giera, Nicholas Watkins, Saptarshi Mukherjee, Andrew Pascall, David Stobbe, and Prahalada Rao, "Droplet Diagnostics in Droplet-on-Demand Liquid Demand Liquid Metal Jetting Using Heterogenous Sensing." In Solid Freeform Fabrication Symposium. August 2021.