Purdue University Energetic Materials and Additive Manufacturing

1. Jeff Rhoads
School of Mechanical Engineering, RayW. Herrick Laboratories,
and the Birck NanotechnologyCenter
PurdueUniversity
April 26, 2017

2.  There has been significant research activity related to the
development of additive manufacturing techniques capable of
fabricating advanced geometries with an array of classical
materials.
 There has been a much smaller portion of research related to
additive manufacturing techniques compatible with functional
materials.
 Today’s focus:
 The development, and subsequent exploitation, of additive
manufacturing techniques amenable for use with energetic and
reactive material systems.
 Applications: Small-scale propulsion, electronics destruction, etc.
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Prof. Steve Son
• Energetic Materials
• Combustion Science
Prof. George Chiu
• Deposition Science
• Systems and Controls
Prof. Jeff Rhoads
• Energetic Material Physics
• Multiphysical Systems
Students:
• Raghav Ramachandran
• Allison Murray
• Trevor Fleck
• Whitney Novotny
• EricWestphal
Prof. I. Emre Gunduz
• Material Science
• Material Processing

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Ink-Based Additive Manufacturing of Energetic and
Reactive Materials
Additive Manufacturing of High-Viscosity Energetic
and Reactive Materials
Filament-Based Additive Manufacturing of
Energetic and Reactive Materials
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5. This research is supported by the U.S. Department of Defense, Defense Threat
Reduction Agency through grant No. HDTRA1-15-1-0010 and is managed by
Drs. Cathie Condron and D. Allen Dalton.The content of the information does
not necessarily reect the position or the policy of the U.S. federal government,
and no official endorsement should be inferred.

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What materials are
suitable for direct
integration with
functional MEMS
and CMOS devices?
Can selectively-
deposited energetics
surgically disable key
electrical or
electromechanical
components?
How much electrical energy is required to
initiate combustion/reaction in a selectively-
deposited energetic?
What influence do material parameters have
on the mechanical and reactive properties of
selectively-deposited or grown energetic
materials?

7.  Initial focus on nanothermites
 Prepare Al/CuO andAl/Bi2O3 with PVP in DMF
 Short-term, shelf-stable ink
 Vary volume fractions, surface coatings, mixing techniques, etc.
 Have begun initial forays into other energetic materials
 Nanothermite/binder composites
 Nitrocellulose material systems
 Printable metals
 Metalon silver and copper oxide
 Silver
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Manufacturer MicroDrop MicroFab BioFluidix
Model MD-K-130 MJ-AL-01 PipeJet P9
Nozzle Orfice 70 µm 80 µm 500 µm
Droplet Volume 20 – 180 pL 20 – 300 pL 10 – 60 nL
Viscosity Range < 20 cP < 20 cP 1 – 200 cP
Print Quality Lifetime + - 0
Cleaning - + -
Ink Flexibility + - +
Parameter Control + + -
Sample Throughput - - +
Clogging - + +
Ease of Use + - +
Nozzle Cost - - +

9. Before After
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1 layer, 250 nL, 8% Al/CuO with 0.5% PVP

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φ = 1 φ = 3
φ = 4 φ = 5
Tailored destruction achieved through variations in stoichiometry!

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Tailored Performance with Multi-Component Materials

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 A particular challenge associated with the additive
manufacturing of energetic and reactive material systems
is that they have inherently high viscosities and in many
cases critical temperatures close to the melting
point/glass transition temperature
 The majority of research completed to date has focused on
changing the material system to make it compatible with
commercial printers
 Solvents, gelling agents, etc…
 Our proprietary approach changes the process…

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Polymer clay with a viscosity of 10,000 Pa·s
printed with a 500 µm nozzle
Ammonium perchlorate propellant
with a viscosity of 5,000 Pa·s
(7 x 7 x 21 mm)
Ammonium perchlorate
propellant cross-section (>80%
solids loading)

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 Research Question: Can one formulate additive and
reactive material systems that are compatible with
commercial fused deposition modeling (FDM) systems?
 Simple Answer: Yes, if you hit the thermodynamic
material “sweet spot”

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 Initial Focus:
 Al/PVDF material systems
 In-house Processing
 Synthesis
 Pellet Formation
 Extrusion (Filabot)
 Printing (Makerbot/Monoprice)
 All Processes Controlled Remotely as Needed

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Slow BurningGas/Solid Generator

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TechnicalChallenge in Print Setting Optimization

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Tailored In-Fill Essential for Combustion Control

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DSC/TG Analysis of Filament and Printed Wire

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Ink-Based Additive Manufacturing of Energetic and
Reactive Materials
Additive Manufacturing of High-Viscosity Energetic
and Reactive Materials
Filament-Based Additive Manufacturing of
Energetic and Reactive Materials
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2
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