Additive Manufacturing Skill

Purpose

The Additive Manufacturing skill provides capabilities for AM process selection, design optimization, and build preparation, enabling effective use of additive technologies for prototyping and production applications.

Capabilities

• AM technology selection (SLS, DMLS, FDM, SLA)
• Design for additive manufacturing (DfAM)
• Build orientation optimization
• Support structure design and minimization
• Part nesting and build volume optimization
• Post-processing procedure specification
• Surface finish and tolerance expectations
• AM-specific material properties and considerations

Usage Guidelines

Technology Selection

Metal AM Processes

Process	Materials	Resolution	Applications
DMLS/SLM	Ti, Al, Steel, Inconel	30-50 um layer	Aerospace, medical
EBM	Ti, CoCr	50-100 um layer	Orthopedic implants
DED	Most metals	250+ um	Large parts, repair
Binder Jet	Steel, bronze	80-100 um	Tooling, high volume

Polymer AM Processes

Process	Materials	Resolution	Applications
SLS	Nylon, TPU	100-150 um	Functional prototypes
SLA/DLP	Photopolymers	25-100 um	High detail, patterns
FDM	ABS, PLA, PC, PEEK	100-300 um	Prototypes, tooling
MJF	Nylon	80 um	Production parts

Design for Additive Manufacturing

Self-Supporting Angles

Minimum self-supporting angle:
- Metal (DMLS): 45 degrees from horizontal
- Polymer (SLS): 0 degrees (self-supporting)
- FDM: 45 degrees (with support)
- SLA: 30-45 degrees

Overhang rule:
- Unsupported distance < 2 mm (metal)
- Unsupported distance < 5 mm (polymer)

Minimum Feature Sizes

Process	Min Wall	Min Hole	Min Detail
DMLS	0.4 mm	0.5 mm	0.2 mm
SLS	0.7 mm	1.0 mm	0.3 mm
SLA	0.5 mm	0.5 mm	0.1 mm
FDM	0.8 mm	2.0 mm	0.5 mm

Design Optimization

1. Topology Optimization

   • Define design space
   • Apply loads and constraints
   • Set mass reduction target
   • Interpret and refine results

2. Lattice Structures

   Type	Relative Density	Application
   Octet truss	10-40%	High stiffness
   Diamond	15-35%	Isotropic
   Gyroid	10-50%	Bone ingrowth
   Honeycomb	20-50%	Directional load

3. Part Consolidation

   • Identify assembly candidates
   • Evaluate function integration
   • Consider serviceability
   • Calculate cost/benefit

Build Preparation

Orientation Selection

Optimization criteria:
1. Minimize support volume
2. Optimize surface finish on critical surfaces
3. Reduce build height (time)
4. Ensure feature accuracy

Trade-off example:
- Flat orientation: Less support, rougher top surface
- Angled orientation: More support, better detail

Support Design

1. Support Types

   Type	Application	Removal
   Block	Large overhangs	Manual/machining
   Tree	Complex geometry	Manual
   Lattice	Heat dissipation	Manual
   Cone	Point supports	Manual

2. Support Minimization

   • Reorient part
   • Add self-supporting chamfers
   • Split and assemble
   • Modify geometry if allowed

Nesting and Packing

Minimum spacing:
- DMLS: 2-5 mm between parts
- SLS: 2-3 mm (powder acts as support)
- FDM: N/A (single part builds)
- SLA: 2-3 mm

Packing efficiency target: 5-15% of build volume

Post-Processing

Metal AM

1. Required

   • Stress relief (before removal)
   • Support removal
   • Heat treatment (as specified)

2. Optional

   • Machining critical surfaces
   • Shot peening
   • Polishing/finishing
   • HIP (for porosity closure)

Polymer AM

1. SLS/MJF

   • Depowder and clean
   • Dye or paint (optional)
   • Sealing (if required)

2. SLA/DLP

   • Wash (IPA or solvent)
   • UV post-cure
   • Support removal
   • Sanding/finishing

Process Integration

• ME-019: Additive Manufacturing Process Development

Input Schema

{
  "part_model": "CAD file reference",
  "material_requirement": {
    "type": "metal|polymer",
    "specific": "string (e.g., Ti6Al4V, Nylon 12)",
    "properties": "strength|stiffness|temperature|biocompatible"
  },
  "quantity": "number",
  "quality_requirements": {
    "tolerance": "number (mm)",
    "surface_finish": "string",
    "critical_features": "array"
  },
  "timeline": "prototype|production",
  "budget_constraint": "number (optional)"
}

Output Schema

{
  "process_recommendation": {
    "technology": "string",
    "material": "string",
    "machine": "string (if specific)"
  },
  "build_preparation": {
    "orientation": "description and rationale",
    "support_volume": "number (cm3)",
    "build_time": "number (hours)",
    "material_usage": "number (kg)"
  },
  "dfam_recommendations": [
    {
      "feature": "string",
      "issue": "string",
      "recommendation": "string"
    }
  ],
  "post_processing": "array of steps",
  "cost_estimate": {
    "material": "number",
    "machine_time": "number",
    "post_processing": "number",
    "total": "number"
  }
}

Best Practices

1. Design for AM from the start, not as afterthought
2. Understand process limitations before design
3. Optimize orientation for quality, not just time
4. Plan for post-processing in design stage
5. Validate material properties for application
6. Consider total cost including post-processing

Integration Points

• Connects with CAD Modeling for geometry
• Feeds into Material Testing for property validation
• Supports DFM Review for manufacturability
• Integrates with FAI Inspection for quality