[email protected] 1 1 Electron Beam Freeform Fabrication: A Fabrication Process that Revolutionizes Aircraft Structural Designs and Spacecraft Supportability Electron Beam Freeform Fabrication: A Fabrication Process that Revolutionizes Aircraft Structural Designs and Spacecraft Supportability Robert A. Hafley Karen M. Taminger NASA Langley Research Center Robert A. Hafley Karen M. Taminger NASA Langley Research Center International Conference on Additive Manufacturing 7-8 July 2010 International Conference on Additive Manufacturing 7-8 July 2010
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Electron Beam Freeform Fabrication: A Fabrication
Process that Revolutionizes Aircraft
Structural Designs and Spacecraft
Supportability
Electron Beam Freeform Fabrication: A Fabrication
Process that Revolutionizes Aircraft
Structural Designs and Spacecraft
Supportability
Robert A. Hafley
Karen M. Taminger
NASA Langley Research Center
Robert A. Hafley
Karen M. Taminger
NASA Langley Research Center
International Conference on Additive Manufacturing
7-8 July 2010
International Conference on Additive Manufacturing
7-8 July 2010
OutlineOutline
• Technology inception
• Characterization
• Technical challenges
• Current applications
• Influence on future designs
• Supportability in space
• Technology inception– Motivation– EBF3 process description– Benefits
• Characterization
• Technical challenges
• Current applications
• Influence on future designs
• Supportability in space
OutlineOutline
Metal Deposition ProcessesMetal Deposition Processes
Laser
5-10%5-10%
Continuous gated pulsed
Mirrors orfiber opticsMirrors orfiber optics
Inert gas
Powder,5-85%Powder,5-85%
0.5-9 lb/hr
Energy efficiencyEnergy
efficiency
Beam control
Beam deliveryBeam delivery
Environment
Feedstock efficiencyFeedstock efficiency
Max dep. rate
95%95%
Continuous,rastered
Magnetically steeredMagnetically steered
Vacuum
Wire, ~100%Wire, ~100%
> 30 lb/hr
E-Beam
EBF3 Core TechnologyEBF3 Core Technology
• Rapid metal fabrication process
– Layer-additive process
– No molds or tools
– Properties equivalent to wrought
– Demonstrated on Al, Ti, Ni, Fe-based alloys
• Slice CAD drawing
• E-beam creates melt pool
• Add wire to pool
• Translate layer-by-layer
EBF3 ProcessEBF3 Process
LaRC EBF3 System #1LaRC EBF3 System #1
• 42 kW gun
• 60 kV max
• 6-axis positioning
• 2m x 2.8m x 2.5m vacuum chamber
• 600mm x 1200mm x 1500mm build envelope
Benefits of EBF3Benefits of EBF3
• Near-net shape– Minimize scrap– Reduces part count
• Efficient designs– Lightweight– Enhanced performance
• Complex unitized components– Integral structures– Functionally graded materials
• “Green” manufacturing – Minimal waste products– Energy and feedstock efficient
EBF3 Saves ResourcesEBF3 Saves Resources
– =
3000 kg 2850 kg 150 kg
Conventional Machining:
Additive Manufacturing via EBF3:
– =
50 kg 150 kg
+
100 kg 100 kg
+ EBF3
• Technology inception
• Characterization– Microstructure– Mechanical properties
• Technical challenges
• Current applications
• Influence on future designs
• Supportability in space
OutlineOutline
Machined from plate Built by EBF3
2219 Al Microstructure2219 Al Microstructure
0.25 mm 0.25 mm
As-deposited T6 Condition
Rapid cool cast:•Cu segregation •Dendrites
Transformed:•Grain boundaries retained
2219 Al EBF3 Microstructure2219 Al EBF3 Microstructure
100 µm100 µm
2219 Al Tensile Data2219 Al Tensile Data
• EBF3 tensile properties comparable
to handbook data
0
25
50
75
Yield Ultimate Elongation
EBF3 + T62T62 typical
Ten
sil
e S
tren
gth
, ksi
0
10
Elo
ng
ati
on
, %
Ti-6Al-4V Tensile DataTi-6Al-4V Tensile Data
• EBF3 Ti-6-4 equivalent to annealed wrought product
0
50
100
150
Yield Ultimate Elongation
As-deposited
Annealed (Wrought)
0
5
10
15
Elo
ng
ati
on
, %
Ten
sil
e S
tren
gth
, ksi
• Technology inception
• Characterization
• Technical challenges– Preferential vaporization– Process control– Residual stress
• Current applications
• Influence on future designs
• Supportability in space
OutlineOutline2219
Loss of Al in Ti-6Al-4VLoss of Al in Ti-6Al-4V
• Al loss in vacuum
• Function of temperature and pressure
• Process repeatability
• Issue with other alloys too
89.5
90.5
5.4
6.6
Ti
Al
5 mm5 mm
Need for Process ControlNeed for Process Control
• Melt pool changes with temperature
• Monitor for process control
Thermal Residual StressesThermal Residual Stresses
• Localized heat induces distortion and residual stress
• Technology inception
• Characterization
• Technical challenges
• Current applications– Replace existing parts– Enable new complex parts
• Influence on future designs
• Supportability in space
OutlineOutline
Add Details onto ForgingsAdd Details onto Forgings
• Add features onto
simplified preform
• Reduces billet sizes and
buy-to-fly ratio
Cryotank ConceptCryotank Concept
• Form cylinder
• EBF3 stiffeners
• Tailored stiffener arrays
Complex ShapesComplex Shapes
• Build entire part
• Unitized structures
• Allows internal cavities
• Technology inception
• Characterization
• Technical challenges
• Current applications
• Influence on future designs– New unitized structural designs– Functionally-graded structures– Integrated systems
• Supportability in space
OutlineOutline
Novel Structural DesignsNovel Structural Designs
Curved stiffeners can be
optimized for:
• Performance• Low weight• Low noise• Damage tolerance
Aeroelastic TailoringAeroelastic Tailoring
Coupled bending-
torsion wingMonocoque wing
Design for AcousticsDesign for Acoustics
• Optimize stiffeners to tailor natural
resonance frequencies
Functional GradientsFunctional Gradients
Lengthwise gradient
Build height gradient
Locally control:
• Chemistry
• Microstructure
• Properties
• Technology inception
• Characterization
• Technical challenges
• Current applications
• Influence on future designs
• Supportability in space– In-space repair– Spin-off applications
OutlineOutline
• Long duration
missions
• Support autonomy
• Minimize resupply
from Earth
• Fab or repair parts
• Enhances mission
success
Need for SupportabilityNeed for Supportability
Remote Terrestrial RepairsRemote Terrestrial Repairs
Similar self-supportability needs
on Earth:
• Navy ships• Army supply in-theater• Remote science bases
SummarySummary
• Led by LaRC since inception
• Disruptive technology
• Cross-cutting:– Aeronautics– Space– Other industry sectors
• Enables new structural designs
• Demonstrated in 0-g for use in-space
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