a5c-ai CNC Programming Skill
Purpose
The CNC Programming skill provides expert capabilities for CNC programming and toolpath optimization using CAM software, enabling efficient and accurate machining of mechanical components.
Capabilities
- Mastercam, NX CAM, Fusion 360 workflow automation
- Toolpath strategy selection (roughing, finishing)
- Cutting parameter optimization (feeds, speeds)
- Tool selection and library management
- Work holding and fixture consideration
- Toolpath simulation and verification
- G-code generation and post-processing
- Cycle time estimation and optimization
Usage Guidelines
Machining Strategy
Roughing Operations
Material Removal Strategies
Strategy Application Advantages Adaptive/Dynamic General roughing Constant chip load Pocket Enclosed areas Efficient material removal Facing Flat surfaces Surface prep Plunge rough Deep pockets Axial chip evacuation Stock Allowance
Finishing allowance = 0.25-0.5 mm (typical) Semi-finish allowance = 0.5-1.0 mm Rough allowance = Stock - finish - semi-finishStep-Over Guidelines
Adaptive roughing: 10-25% tool diameter Pocket roughing: 50-75% tool diameter Depth of cut: 1-2x tool diameter (end mills)
Finishing Operations
Surface Finish Strategies
Strategy Application Surface Finish Parallel Flat surfaces Ra 0.8-1.6 um Contour Walls, profiles Ra 0.8-1.6 um Scallop 3D surfaces Ra 1.6-3.2 um Pencil Corners, fillets Clean-up Step-Over for Finish
Cusp height = r - sqrt(r^2 - (s/2)^2) For cusp height = 0.01 mm, r = 5 mm: Step-over s = 0.89 mm
Cutting Parameters
Speed and Feed Calculation
Cutting Speed (SFM): V = pi * D * N / 12 (imperial)
V = pi * D * N / 1000 (metric)
Feed Rate: F = f * z * N
Where:
V = cutting speed (SFM or m/min)
D = tool diameter
N = spindle speed (RPM)
f = feed per tooth
z = number of teeth
F = feed rate (IPM or mm/min)
Material-Specific Parameters
| Material | Speed (SFM) | Feed/Tooth (in) | Notes |
|---|---|---|---|
| Aluminum | 500-1000 | 0.004-0.008 | High spindle, coolant |
| Steel (mild) | 80-120 | 0.003-0.006 | Flood coolant |
| Steel (hard) | 50-80 | 0.002-0.004 | Reduce speed |
| Stainless | 60-100 | 0.002-0.005 | Rigid setup |
| Titanium | 40-60 | 0.002-0.004 | High pressure coolant |
Tool Selection
End Mill Selection
| Application | Tool Type | Coating |
|---|---|---|
| Aluminum roughing | 2-3 flute, polished | Uncoated/ZrN |
| Aluminum finishing | 2-3 flute, high helix | Uncoated |
| Steel roughing | 4+ flute, variable helix | AlTiN/TiAlN |
| Steel finishing | 4+ flute | AlTiN |
| Hardened steel | Ball nose, solid carbide | AlCrN |
Tool Life Management
Tool life tracking:
- Material removed (cm3)
- Cutting time (minutes)
- Parts produced
Replace at:
- Wear land > 0.3 mm
- Surface finish degradation
- Dimension out of tolerance
Work Holding
Fixture Considerations
Clamping Force
- Calculate cutting forces
- Apply safety factor (2-3x)
- Distribute clamp forces
- Avoid part distortion
Accessibility
- Clear all tool paths
- Consider tool length
- Allow chip evacuation
- Enable coolant flow
Program Verification
Simulation Checks
- Tool collision detection
- Fixture interference
- Rapid traverse clearance
- Stock remaining verification
First Article
- Reduced feed rate (50%)
- Single block mode
- Verify dimensions
- Adjust offsets as needed
Process Integration
- ME-018: CNC Programming and Verification
Input Schema
{
"part_model": "CAD file reference",
"material": {
"name": "string",
"hardness": "string (e.g., HRC 30)"
},
"machine": {
"type": "3-axis|4-axis|5-axis|lathe",
"controller": "Fanuc|Siemens|Haas|other",
"spindle_max": "number (RPM)",
"rapids": "number (mm/min)"
},
"tolerances": {
"dimensional": "number (mm)",
"surface_finish": "number (Ra um)"
},
"production_volume": "prototype|low|medium|high"
}
Output Schema
{
"program_info": {
"program_number": "string",
"operations": "number",
"total_tools": "number"
},
"cycle_time": {
"machining": "number (min)",
"non-cutting": "number (min)",
"total": "number (min)"
},
"tool_list": [
{
"tool_number": "number",
"description": "string",
"diameter": "number (mm)",
"length": "number (mm)"
}
],
"setup_sheet": {
"work_offset": "string",
"fixture": "string",
"stock_size": "array [L, W, H]"
},
"nc_file": "file reference"
}
Best Practices
- Verify model accuracy before programming
- Use consistent tool numbering conventions
- Include adequate clearance planes
- Optimize tool paths for minimum air cutting
- Simulate complete program before machining
- Document setup requirements clearly
Integration Points
- Connects with CAD Modeling for geometry
- Feeds into Process Planning for operations
- Supports FAI Inspection for first article
- Integrates with DFM Review for manufacturability