Judy Schneider, PhD Department of Mechanical and Aerospace Engineering University of Alabama in Huntsville Greg Hyatt, PhD Advanced Solutions Development Senior Vice President & Chief Technical Officer DMG/MORI SEIKI USA Majid Babai Branch Chief, Nonmetallic Manufacturing Branch NASA-Marshall Space Flight Center
NASA s Motivation Powder bed additive manufacturing processes show a huge potential for rapid fabrication of complex assemblies, but are currently limited in size for large scale components such as liquid rocket engine nozzles (LRE) RS-25 RL-10A-4 J-2X, Regen Only RD-180 SLM Build Boxes 10x10x10 16x24x19 90 46 70 56 Nozzle Diameter
Background The NASA has invested heavily in AM technology to fabricate liquid rocket engine due to low volume production needs of complete geometry components. Powder bed techniques have been successfully used in the production of monolithic, small component builds. Other complimentary techniques are being pursued for larger builds and bi-metallic builds. The complimentary techniques also have application to repairs.
Powder Based AM Processes Powder Bed Laser Source: Solid state diode Powder size: ~45mm Build platform: X-Y plane layerwise Build volume: 630mm x 400mm x 500mm (Concept Laser X-Line 1000R) Blown Powder Laser Source: Solid state diode Powder size: ~100mm Build platform: 5-axis CNC platform Build Volume: 734mm x 650mm x 559mm (DMG Mori Lasertec 65 3D)
Additive/Subtractive Platforms DMG Mori Lasertec 65 Build from a 5 axis milling platform Capable of conventional precision 5 axis CNC milling and free form blown powder deposition http://us.dmgmori.com/products/lasertec/lasertec-additivemanufacturing/lasertec-65-3d#intro
Development of bi-metallic builds DMG Mori Develops Hybrid Additive/Subtractive Machine, released 12/19/13 Blown powder systems are able to print free-form components. Multiple nozzles can be used to transition metals during a build. Technology utilizes coarser powders than powder bed (100 mm vs 45 mm) Targeted goal DMG to provide following builds: cylinders of Inconel 718/GrCu84 flat panels of Inconel NASA to provide machining and heat treat UAH to characterize and test Characterization Matrix Inconel 718 GrCu84 Interface Metallography x x x Tensile x x Bend tests x LCF fatigue x x
Free form AM of bi-metallic components Bi-metallic build for Presto (4.5 OD x 4 high) Build part for the NASA Cu core with Ni jacket Inconel specimens for mechanical property measurements and microstructural characterization. Excellent interface bond achieved between Cu and Ni. Simulated interface geometry Integral propagation tube Specimens obtained with NASA funding in collaboration with DMG-Mori
Good melt-in obtained on initial bi-metallic builds 200 μm 50 μm 20 μm 10 μm Un-etched micrographs of GRCop 84/Inconel 718 Interface
Maturation of Repair Processes Machining can now be integrated with the deposition process Complex features can now be added to substrates In the beginning only simple surfaces could be rebuilt 9 AMMO Gregory Hyatt Ph.D.
Hybrid Process for Complex Repairs Repair machined Filler added by AM to chamber Plugs inserted in ports Damaged material removed Original chamber 10 AMMO Gregory Hyatt Ph.D.
LASER Welding The AM machine can be used for welding as well as deposition Inconel 718 11 AMMO Gregory Hyatt Ph.D.
Multiple Alloys Multiple alloys can be combined is a single build Carbide facing for wear resistance Copper for heat disipation Cobalt Chrome for corrosion 12 AMMO Gregory Hyatt Ph.D.
Enabling Technologies Required Automatic changer for deposition tool required to support specialized heads Example of ID deposition head to access bores Larger LASERs enable higher deposition rates (kg per hour rather than grams per hour 13 AMMO Gregory Hyatt Ph.D.
Enabling Technologies Nozzles can interfere with existing features Single nozzles can address this when fitted with a 6th axis (patent pending) 14 AMMO Gregory Hyatt Ph.D.
To Visualize the Process 15 AMMO Gregory Hyatt Ph.D.
Acknowledgments UAH gratefully acknowledges the funding provided by: Aetos Systems Grant No. Contract NNM14AA15C / Subcontract No. 2019.A52, Additive/subtractive manufacturing of combustion devices, TPOC: M. Babai. Presto Foundation Grant.