Stacey L. Clark Deputy Director, Systems Engineering US Army RDECOM-ARDEC New Metal Powders and Inks for AM: Lessons Learned to Date

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1 Stacey L. Clark Deputy Director, Systems Engineering US Army RDECOM-ARDEC New Metal Powders and Inks for AM: Lessons Learned to Date sme.org/smartmfgseries

2 UNCLASSIFIED U.S. Army RDECOM-ARDEC Picatinny Arsenal, NJ U.S. Army RDECOM-ARL Aberdeen Proving Ground, MD (U) Novel Materials for Additive Manufacturing: US Army Initiatives Stacey L. Clark (Kerwien) Deputy Director, Systems Engineering Research Development and Engineering Command

3 (U) RDECOM Organization

4 (U) (U) Army Opportunities for AM Remote Weapon Systems, UGVs, UAVs Weapon Systems/Subsystems: Training & Planning Test & Analysis: Models, Test Platforms, BITs, Prognostics& Diagnostics Soldier Systems Spare Parts Munitions: Metal Parts, Fuzes, Energetics, Warheads Life Cycle Optimization: Parts Replacement & Improvement, Embedded Tracking & Monitoring

5 (U) Why Army is Interested? (U) Rapid Prototyping, direct from CAD (U) Factory in a truck / Fabrication-in-the-Field (U) Conformal designs & better interior volume utilization (U) Multi-use materials & components (U) Mission tailored, scalable weapons (U) More immune to obsolescence, spare parts

6 (U) New Materials of Interest (U) Factory in a truck / Fabrication-in-the-Field, Spare Parts (U) Conformal designs & better interior volume utilization, reduce parasitic mass (U) Multi-use materials & components with reduced weight and added capability. (U) Mission tailored, scalable weapons (U) Stronger, Cheaper Structural Metals (steel 4340) (U) Printed electronics to reduce packaging and open up available real estate (U) Composite printing

7 Army AM CoP Comprised of RDECOM, CASCOM, LCMC (Depots OIB) Serves as the Army Focal Point for AM Leading enterprise efforts in creating Parts Libraries, Tech Data Pkgs, Digital Thread PLM/ePDM efforts are ready to store both geometry and process information in enterprsie prouct data systems RDECOM enterprise approach along with DLA and OGAs can support accelerated industry use Developing protocols to certify conductive inks. Std Operating Procedures to handle reactive metals for AM Developed Army AM Roadmap with America Makes, Deloitte

8 Army Novel Materials (U) High Strength Low Alloy Steel 4340 for DMLS- POC: ARDEC, Elias Jelis (U) Novel inks for flexible and conformal electronics POC: ARDEC, Dan Schmidt, Jim Zunino; CERDEC, Dr. Kate Duncan (U) Composite Printing POC: ARDEC, Calvin Lim Other Work in RDECOM (not presented here) (U) Geometrically Complex Fibers POC: Army Research Lab (ARL), LJ Holmes, Eric Wetzel

9 DMLS: Steel Alloy 4340 POC: ARDEC, Elias Jelis DMLS process - laser fuses powder layer by layer until the part is built. The EOSINT M270 was used in the study. EOSINT M270

10 Experimental Part 1 Part 1 Recoating Direction Recoating Direction Fig 1a-b. Schematic (A) and picture of a build on the plate of the horizontal section of the location of the part, recoating direction and the location of 40 metallurgical cubes.

11 Introduction 4340 steel is a low alloy high strength steel. It is a widely used alloy for the DoD. It also has high fracture toughness. Energy Density, Scan Speed, Hatch Distance,Thickness (E=P/(t*v*d) where E is volumetric applied energy density, P is laser power, t is layer thickness, d is hatch distance; and v is laser scan speed 4. Adequate energy must be applied for full melting) Preliminary test data shows that mechanical properties (tensile strength and hardness) are comparable to wrought, when optimized process parameters are used not just correct energy density.

12 Microstructure of non optimal parameters 50x Micrograph of etched microstructure at 300 mm/sec higher scan speed than optimal parameters Public Release Distribution A

13 Powder Selection Figure 3. EOS 17-4 parameters powder with -44 micron 4340 steel powder Figure 4. EOS 17-4 parameters powder with micron 4340 steel powder DMLS

14 Parameter Optimization Mechanical Behavior of x-y tensile specimens Material Condition Modulus Yield Strength Tensile Elongation Typical Wrought 4340 properties from ASM international 29,000 ksi 183 ksi 199ksi 15% Run A: DMLS of Virgin Powder 31,000 ksi ksi 199ksi 16-17% Run B: DMLS after once recycled powder. 31,000 ksi ksi 198ksi 16-17% Figure 8. Stress-Strain curve from data in Table 5. It is in comparison to a typical stress strain curve for structural steels.

15 (U) 2D Printing, Flexible, Conformal POC: ARDEC, Jim Zunino, Dan Schmidt; CERDEC Dr. Kate Duncan (U) Printed Electronics (U) Direct Write Materials (U) Printed Novel Materials

16 (U) Non-Contact Examples Ink Jet Aerosol Jet (U) E-Jet

17 (U) Contact / Direct Write Examples (U) MicroPen DipPen Nanolithography

18 (U) Technique Selection & Considerations (U) Materials Ink Type, Thermal Properties, Electrical Properties, Additives, Viscosities, Surface Tension, Post Processing, etc. Substrates Type, Shape, Size, Hardness/Conformality, morphology, topology, surface interactions, etc. Compatibility Inks, substrates, post processing, encapsulation, etc. (U) Physical Constraints / Requirements Resolution Line, Spacing, Dimensional, Roughness, Edge Control Registration Thickness / Roughness (U) Economics Throughput Masters Plates, Stencils, Screens Material Costs Waste (U) Manufacturability / Scale-Up

19 (U) Ink Comparisons

20 Ink Qualification Procedure Material as-received (in liquid or paste form) Material properties Particle size, morphology, and distribution using scanning electron microscopy or equivalent microscopy Contact angle on relevant substrates Viscosity Surface Tension Effects of filtering on solid loading Thermogravimetric analysis mass spectrometry (TG-Mass Spec) Shelf life and pot-life assessment Visual inspection (color) Printing properties Layering/stacking ability Resolution/drop dispersion/ leaking Optimal printing parameters (speed, inkjet waveform, dispensing gap) Nozzle size requirements/limitations

21 Ink Qualification Procedure Material after printing process Curing/sintering process (thermal, UV, etc.) In-situ measurements during the curing process (where applicable) Color and visual inspection in fully cured state Adhesion to relevant substrates Electrical properties (resistance of a given geometry, sheet resistance) Abrasion/scratch resistance Bending test and cycles to failure Printed height/geometry per layer Material compatibility/solderability Interconnect/eyelet pressing Oxidation resistance and environment exposure Current carrying capacity

22 Composite Printing Place composite fibers in precise locations Materials: Nylon Fiberglass (various % of fill) Equipment: MarkForged Mark2

23 Composite Printing Advances in composite engineering and manufacturing allows us to fill in gaps and needs that the ARMY has for lightweighting components. Traditional manufacturing of composite parts requires a large capital investments in molds and human labor to try out one design. Composite printing/additive manufacturing can cut down time and cost of materials.

24 Peak Stress (psi) Peak Stress (psi) Composite Printing Specimens Percent Fill (%) vs Peak Stress (psi) Specimens: 6000 Nylon Fill Only 1. 20% Nylon Hexagonal Fill 2. 20%Nylon Rectangle Fill 3. 20% Nylon Triangle Fill % Nylon Hexagonal Fill % Nylon Rectangle Fill % Nylon Triangle Fill The permutations of parameters become exponential NYLON_TRIANGLE NYLON_RECTANGLE NYLON_HEX Nylon-Fiberglass Reinforcement 1. 20% Nylon Hexagonal Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters 2. 20% Nylon Rectangle Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters 3. 20% Nylon Triangle Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters % Nylon Hexagonal Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters % Nylon Rectangle Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters % Nylon Triangle Fill 8 Fiberglass Layers 4 Top, 4 Bottom, 2 Concentric Perimeters Peak Stress of Hexagonal Fills with and without Fiberglass Percent Fill (%) Percent Fill (%) 20% Fill Nylon Hex 100% Fill Nylon Hex 100% Fiberglass Fill Concentric

25 Composite Printing Database The database for composite printing is still developing Design tools are also developing More materials expected to be used, in addition to Nylon and Fiberglass.

26 Summary The drive for Army-centric novel materials based on: economics, reducing weight, decreasing parasitic mass and tailoring structures. Databases being developed in concert with many OGA, industry and academic partners. Focus on Metals AM, Flexible Electronics and Composite Printing