ARL-SR-0357 ● JULY 2016

US Army Research Laboratory

Advances in Additive Manufacturing

Compiled by Marc S Pepi

A Compilation of Presentations by Marc Pepi, Todd Palmer, 

Jennifer Sietins, Jonathan Miller, Dan Berrigan, and Ricardo Rodriquez

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ARL-SR-0357 ● JULY 2016

US Army Research Laboratory

Advances in Additive Manufacturing

Compiled by Marc S Pepi

A Compilation of Presentations by Marc Pepi, Todd Palmer, 

Jennifer Sietins, Jonathan Miller, Dan Berrigan, and Ricardo Rodriquez

Approved for public release; distribution is unlimited.
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Advances in Additive Manufacturing

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Marc S Pepi

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14. ABSTRACT

This special report is a compilation of the presentations provided at the 2016 Society for Machinery Failure Prevention 

Technology conference in Dayton, OH, on 23–26 May 2016. These 6 briefs were presented in the Additive Manufacturing 

session and provide a summary of work being performed in additive manufacturing by the Army, Air Force, and academia 

(Penn State University). 

15. SUBJECT TERMS

3-D printing, validation and verification, nondestructive inspection, print-on-the-move, prototyping

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Marc S Pepi

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Contents

Acknowledgments iv

1. Introduction 1

2. Agile Additive Manufacturing in Austere Environments (Marc Pepi, 

Army Research Laboratory, Weapons and Materials Research 

Directorate) 3

3. Role of Processing-Structure-Property Relationships in Developing 

Certification Protocols for Ti-6Al-4V Components (Todd Palmer, 

Pennsylvania State University, Applied Research Laboratory) 19

4. Additive Manufacturing Characterization Utilizing X-ray Computed 

Tomography (Jennifer Sietins, Army Research Laboratory, Weapons 

and Materials Research Directorate) 51

5. Quality Assurance Methods for Additive Manufacturing Processes: 

Motivation, Challenges, and Opportunities (Jonathan Miller, Air 

Force Research Laboratory/Metals Branch) 63

6. Air Force Vision and Challenges for Additive Manufacturing of 

Functional and Soft Matter Materials (Dan Berrigan, Air Force 

Research Laboratory/Metals Branch) 73

7. Army Research Laboratory’s Additive Manufacturing for the Future 

Expeditionary Force (Ricardo Rodriguez, Army Research Laboratory, 

Weapons and Materials Research Directorate) 83

List of Symbols, Abbreviations, and Acronyms101 101

Distribution List 102
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Acknowledgments

The following personnel were instrumental in providing contributions to the briefs 

herein:

Army Research Laboratory, Weapons and Materials Research Directorate

• Raymond Wildman

• Nicole Zander

• Margaret Gillan

• Andrew Gaynor 

• William Green 

• Larry Holmes

Pennsylvania State University, Applied Research Laboratory

• Rich Martukanitz 

• Ken Meinert 

• Ted Reutzel

• Jay Keist

• Griffin Jones

• Jay Tressler

• Ed Good

• Pan Michaleris

• Michael Gouge

• Erik Denlinger

• Jarred Heigel

• Dennis Krizcky

• T DebRoy

• Long-Qing Chen

• Ashwin Raghavan
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• B Carroll

• Allison Beese

• Patrick Hricko

• Huiliang Hue

• Reggie Hamilton

• Beth Bimber

Air Force Research Laboratory, Metals Branch

• Eddie Schwalbach

• Mike Groeber

• Benjamin Leever

• James Hardin

• Phillip Buskohl

• Abby Juhl

• Ryan Kohlmeyer

• Aaron Blake

• Ming Shao

• Jason Wilkinson

• Giorgio Bazzan

• Michael Durstock

Rutgers University

• Rik Riman 
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1. Introduction

The Society of Machinery Failure Prevention Technology (MFPT) held its first 

session in additive manufacturing (AM) at the 2016 conference in Dayton, Ohio,

on May 24th, 2016. The presentations included work being performed within the 

Department of Defense (Army Research Laboratory [ARL] and Air Force Research 

Laboratory [AFRL]) as well as academia (Penn State University’s Applied 

Research Laboratory) in the area of AM, with a focus on the technologies that the 

MFPT community could provide assistance with in this area (nondestructive testing 

and inspection, prognostics, diagnostics, structural health monitoring, failure 

analysis, data management, and sensors). This report includes all 6 of the 

presentations briefed at the conference.

Additive manufacturing is an emerging and disruptive technology that is 

transforming the manufacturing industry by allowing the designer to convert a 

computer model to a finished product in a few steps while overcoming the 

constraints associated with traditional manufacturing. There are many different 

technologies that comprise additive manufacturing, with the ability of utilizing 

polymer materials, metals, ceramics, fibers, and combinations therein. 

Marc Pepi (Team Leader, Near-Net Shape Processing Team, ARL) briefed the 

status of an ARL program titled “On-Demand Manufacturing of Recycled, 

Reclaimed and Indigenous Materials”. Mr Pepi indicated that AM on the battlefield 

could provide a logistical and tactical advantage for the Warfighter. This research 

focuses on 3 different aspects of additive manufacturing on the battlefield: 1) 

researching the formation of AM-grade metal powder from battlefield scrap and 

operating base waste, 2) potential of 3-D printing with sand to make casting molds 

for traditional casting processes on the battlefield, and 3) the use of recycled 

polymeric materials as feedstock for 3-D printers already on the battlefield within 

the Army Rapid Equipping Force Expeditionary Laboratory. Todd Palmer (Senior 

Research Associate and Associate Professor, Pennsylvania State University, 

Applied Research Laboratory) subsequently briefed his presentation “Role of 

Processing-Structure-Property Relationships in Developing Certification Protocols 

for Ti-6Al-4V Components”, stressing that AM certification requires an 

understanding of the processing-structure-property relationships of the materials 

used for AM. He showed the importance of locking down the manufacturing 

process steps for repeatability in structure and properties of Ti-6Al-4V. Jennifer 

Sietins (Materials Engineer, ARL) then briefed “Additive Manufacturing 

Characterization Utilizing X-ray Computed Tomography”, which showed the 

impact of X-ray computed tomography (CT) in the nondestructive inspection of 
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AM parts for quality control, dimensional tolerance, and microstructural 

characterization.

The second AM session at the conference commenced with Jonathan Miller (AM 

Lead for Materials and Manufacturing Directorate, AFRL) presenting “Quality 

Assurance Methods for Additive Manufacturing Processes: Motivation, Challenges 

and Opportunities”, summarizing the importance of understanding the many 

implicit details of AM processing that affect the final structure and properties of the 

built component. Dan Berrigan (Program Manager and Research Scientist, AFRL) 

followed with a presentation titled “Air Force Vision and Challenges for Additive 

Manufacturing of Functional and Soft Matter Materials”, focusing on flexible 

hybrid electronics. He highlighted a few projects in additively manufactured 

electronics (e.g., batteries, capacitors, antennas) that span bench-level research to 

engineered solutions. In addition, he discussed the path forward as AFRL begins to 

explore the fundamental materials and processing challenges associated with 

pattern stimuli responsive materials and design of soft mechanical 

structures/actuators. The final paper was presented by Ricardo Rodriguez 

(Materials Engineer, ARL), entitled “ARL’s Additive Manufacturing for the Future 

Expeditionary Force”. This brief summarized the impact AM will have as the Army 

changes its focus from a traditional force into a more expeditionary force and hybrid 

AM techniques developed at ARL.
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2. Agile Additive Manufacturing in Austere Environments

Marc Pepi 

(Army Research Laboratory, Weapons and Materials Research Directorate)

Additive manufacturing provides many cost-saving advantages to industry and the 

ability to manufacture complex and unique designs and geometries in a timely 

fashion. It also provides a more environmentally friendly means of production 

(leads to less waste than subtractive manufacturing). The Department of Defense is 

now interested in additive manufacturing as a means of being able to produce parts 

“on-demand” in extreme environments, such as on a ship or on a forward-operating 

base. However, there are technical challenges that need to be overcome to fully 

achieve this capability in the future. One such challenge is part quality, and the 

qualification and certification of parts produced in this manner to ensure the parts 

will not fail in service. This paper will discuss this and other challenges in more 

detail, and will provide a lead for other briefs on additive manufacturing to be 

featured in the same session.
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3. Role of Processing-Structure-Property Relationships in 

Developing Certification Protocols for Ti-6Al-4V 

Components

Todd Palmer

(Pennsylvania State University, Applied Research Laboratory)

A fundamental understanding of processing-structure-property relationships is a 

key prerequisite to the eventual development and implementation of a certification 

protocol for additively manufactured (AM) components. One unique aspect of the 

AM process is the role that geometry plays on these relationships and how it can be 

integrated into certification. These relationships are defined here for specific 

directed energy deposition AM processing conditions in Ti-6Al-4V by correlating 

microstructural features with the resulting static mechanical properties. By 

concentrating on simple geometries, we can characterize variations in the resulting 

microstructures and mechanical properties at all locations within the Ti-6Al-4V 

builds. As a result, the relationships between the processing conditions and the 

resulting structure and properties of the build are quantified and used in the 

selection of processing conditions that ensure adequate mechanical properties and 

performance in the final design. Based on these results, a methodology that 

establishes fundamental relationships between the AM processing conditions, the 

microstructural features, and the mechanical properties is under development. As 

part of this effort, an analysis of the uncertainty in mechanical property data for Ti6Al-4V AM components and a methodology for identifying minimum design 

values is being developed.
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4. Additive Manufacturing Characterization Utilizing X-ray 

Computed Tomography

Jennifer Sietins

(Army Research Laboratory, Weapons and Materials Research Directorate)

X-ray computed tomography (CT) is a valuable technique for quality control 

measures, part inspection, dimensional analysis, microstructural characterization, 

and void identification and quantification. This nondestructive characterization 

technique allows for 3D imaging that readily captures defects and voids on the 

conditions that the attenuation, which is approximately related to the material 

density, is distinctly different from the surrounding material, and the resolution is 

sufficient for the feature or defect sizes of interest. This work summarizes the CT 

capabilities at the Army Research Laboratory, with a specific emphasis on the 

characterization of 3D-printed structures. Analysis examples will include 

quantification of tolerance differences between the designed and manufactured 

parts, void sizes and distributions, in-situ compression tests for brittle and elastic 

truss structures, and mechanical behavior simulations for meshes generated from 

the CT scan data. These tools can enable faster process optimization time frames 

and ensure that the final part does not have voids above a critical size prior to 

fielding.
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5. Quality Assurance Methods for Additive Manufacturing 

Processes: Motivation, Challenges, and Opportunities

Jonathan Miller

(Air Force Research Laboratory/Metals Branch)

There has been significant work to date in the metal powder bed fusion community 

focused on understanding the influence of global processing parameters on 

microstructure and defect content (e.g., beam speed, power, spot size). However, a 

range of other implicit details are important, though they are not necessarily simply 

described. The present work focuses on the development of a novel technique to 

assess the impact of the energy input process details on material quality. This 

requires transformation of both in-situ process monitoring data and build-intent 

information into a voxelized representation, subsequent fusion with postbuild 

X-ray computed tomography measurements, and analysis to identify correlations 

between processing details and structure. An example case generated in laser 

powder bed fusion of Ti-6Al-4V demonstrates this process by identifying 

correlations between location-specific processing details and porosity.
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6. Air Force Vision and Challenges for Additive Manufacturing 

of Functional and Soft Matter Materials

Dan Berrigan

(Air Force Research Laboratory/Metals Branch)

Flexible hybrid electronics (blending printed and places devices) is the focus of our 

research team at the Air Force Research Laboratory’s Materials and Manufacturing 

Directorate. In this talk we highlight a few projects in additively manufactured 

electronics (e.g., batteries, capacitors, antennas) that span bench-level research to 

engineered solutions. In addition, we will discuss our path forward as we begin to 

explore the fundamental materials and processing challenges associated with 

pattern stimuli responsive materials and design of soft mechanical structures/

actuators.
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7. Army Research Laboratory’s Additive Manufacturing for the 

Future Expeditionary Force

Ricardo Rodriguez 

(Army Research Laboratory, Weapons and Materials Research Directorate)

One major Army focus is in converting our traditional force into a more 

expeditionary force. This will result in severe reductions in the logistics tail but will 

require Army forces to become more adaptive. Units, equipment, and personnel 

will need to be configurable and reconfigurable based on mission parameters. To 

accomplish this, the Army will be conducting more in-field, or point-of-need, 

manufacturing than ever before. Other areas of concentration include man-machine 

interface, capabilities organic to the Warfighter, unmanned systems, networks, and 

robotics. Many of the materials and technologies needed to accomplish these goals 

are still experimental, if they exist at all. This presentation will cover the Army 

Research Laboratory’s Additive Manufacturing activities and discuss several 

research topics that will allow for the success of this future expeditionary force.
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List of Symbols, Abbreviations, and Acronyms

3-D 3-dimensional

AFRL Air Force Research Laboratory

AM additive manufacturing

ARL Army Research Laboratory

CT computed tomography

MFPT Machinery Failure Prevention Technology
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IMAL HRA MAIL & RECORDS

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