3D Printing Metals

Understanding metal 3D printing processes:

Powder Bed Fusion:

DMLS/SLM (Laser-Based):
- Laser selectively melts metal powder
- Layer by layer construction
- High density (99%+)
- Most common metal AM process

Parameters:
- Laser power
- Scan speed
- Hatch spacing
- Layer thickness

Materials:
- Stainless steels
- Tool steels
- Titanium alloys
- Aluminum alloys
- Nickel superalloys
- Cobalt chrome

EBM (Electron Beam Melting):
- Electron beam in vacuum
- Higher energy, faster
- Reduced residual stress
- Titanium and cobalt chrome focus

Leading Machines:
- EOS (M series)
- SLM Solutions
- 3D Systems (DMP)
- GE Additive (Concept Laser, Arcam)
- Trumpf

Binder Jetting:

Process:
- Binder deposited on powder
- Green part formed
- Debinding and sintering
- Near-net-shape production

Advantages:
- Faster than laser
- No thermal stress during build
- Higher volume potential
- Lower machine cost

Considerations:
- Shrinkage during sintering
- Some porosity
- Size limitations
- Material limitations

Leaders:
- HP Metal Jet
- Desktop Metal
- ExOne (now part of Desktop Metal)

Directed Energy Deposition:

Process:
- Material (wire or powder) fed to melt pool
- Laser, arc, or electron beam energy
- Build up material on substrate

Applications:
- Large parts
- Repair and rebuild
- Feature addition
- Hybrid machines

Types:
- LENS (laser with powder)
- Wire arc AM (WAAM)
- Electron beam wire

Understanding metal AM materials and quality:

Material Considerations:

Powder Characteristics:
- Particle size distribution
- Sphericity
- Flowability
- Chemical composition
- Contamination control

Powder Handling:
- Storage (moisture, oxidation)
- Sieving and recycling
- Traceability
- Safety (reactive metals)

Metallurgy:

As-Built Properties:
- Unique microstructure
- Directional properties
- Residual stress
- Porosity presence

Heat Treatment:
- Stress relief
- Solution treatment
- Aging
- HIP (Hot Isostatic Pressing)

Property Considerations:
- Tensile strength
- Fatigue life
- Elongation
- Hardness
- Anisotropy

Quality Assurance:

Process Monitoring:
- Melt pool monitoring
- Layer imaging
- Thermal monitoring
- In-situ quality control

Post-Build Inspection:
- Visual inspection
- Dimensional verification
- CT scanning
- Destructive testing

Non-Destructive Testing:
- CT scanning (most comprehensive)
- Ultrasonic
- Radiography
- Dye penetrant

Qualification:

Material Qualification:
- Property characterization
- Process window development
- Specification development
- Documentation

Part Qualification:
- Design validation
- Process validation
- First article inspection
- Ongoing monitoring

Industry Standards:
- ASTM F3301 (titanium)
- ASTM F3055 (nickel alloys)
- AMS specifications
- Customer specifications

Metal AM applications and finishing:

Application Domains:

Aerospace:
- Fuel nozzles (GE LEAP)
- Brackets and housings
- Engine components
- Weight reduction (30-70%)

Medical:
- Orthopedic implants
- Dental crowns and bridges
- Surgical instruments
- Patient-specific devices

Tooling:
- Conformal cooling injection molds
- Die cast tooling
- Press tooling
- Reduced cycle times

Energy:
- Turbine components
- Heat exchangers
- Nuclear applications
- Combustion hardware

Post-Processing:

Support Removal:
- Wire EDM for access
- Machining
- Manual removal
- Critical consideration in design

Heat Treatment:
- Stress relief (essential for most)
- Solution treatment
- Aging
- HIP for critical parts

Surface Finishing:
- Machining critical surfaces
- Abrasive flow machining
- Electropolishing
- Bead blasting

Machining:
- Critical dimensions
- Mating surfaces
- Threading
- Feature refinement

Hybrid Manufacturing:

Concept:
- Combine additive and subtractive
- Build near-net shape
- Machine to final dimension
- Best of both worlds

Approaches:
- AM then machine (separate operations)
- Hybrid machines (combined capability)
- Add features to existing parts

Benefits:
- Optimized workflow
- Quality surfaces where needed
- Complex internal features
- Practical production approach

Building expertise in metal 3D printing:

Technical Roles:

Metal AM Technician:
Operate metal printers:
- Machine operation
- Build setup
- Powder handling
- Post-processing
- $50,000-$75,000

Metal AM Process Engineer:
Develop and optimize processes:
- Parameter development
- Material qualification
- Quality systems
- $75,000-$115,000

AM Materials Engineer:
Material science focus:
- Material characterization
- Powder management
- Property development
- $80,000-$120,000

AM Quality Engineer:
Quality assurance:
- Inspection methods
- Process control
- Qualification
- $75,000-$110,000

Industry Positions:

Service Bureau:
Contract manufacturing:
- High variety
- Customer interaction
- Broad experience

OEM/End User:
Internal production:
- Deep application knowledge
- Integrated operations
- Product focus

Equipment Manufacturer:
Machine/material vendors:
- Technology development
- Customer support
- Field applications

Skills Required:

Technical:
- Metallurgy fundamentals
- Process understanding
- CAD/CAM proficiency
- Quality methods

Safety:
- Powder handling
- Laser safety
- Reactive materials
- PPE requirements

Certifications:
- AWS D20 certifications (developing)
- Vendor certifications
- Metallurgy credentials
- NDT certifications

Education:
- Materials science
- Mechanical engineering
- Manufacturing engineering
- Technical degrees with experience

Metal AM expertise commands premium compensation in growing market.