📋 Case Study
Aerospace Titanium Bracket Fixture Redesign for 5-Axis Machining
Excessive workpiece distortion during high-feed milling causing GD&T violations on ±0.02 mm profile tolerance
🏗️ Project Overview
Tier-1 supplier for Boeing 787 wing spar brackets
🎯 Challenge
Excessive workpiece distortion during high-feed milling causing GD&T violations on ±0.02 mm profile tolerance
🔧 Design Approach
Redesigned 3-2-1 locator with compliant contact pads + dual-point hydraulic clamping aligned to part neutral axis
📐 Design Diagram
AI-generated project design illustration
📐 Key Calculations
Clamping Force Requirement
F_clamp ≥ F_cut / μ × SF
Result: 12.4 kN
Prevents micro-slip under dynamic loads
Fixture Rigidity Index
k = (E·I) / L³ × constant
Result: 8.2 kN/µm
Meets minimum 6.5 kN/µm threshold for Ti-6Al-4V milling
Thermal Drift Budget
δ = α·ΔT·L
Result: 3.7 µm @ ΔT=5°C
Within 1/3 of tolerance band
📊 Results
Cpk improved from 0.92 → 1.67; scrap rate dropped from 8.3% → 0.4%; cycle time reduced by 22%💡 Lessons Learned
- •Locating surface flatness must be < 25% of feature tolerance
- •Hydraulic clamping pressure must be monitored in real-time
- •Fixture thermal mass must exceed workpiece mass by 3× for stable conditions
✅ Key Takeaways
- 1Locating surface flatness must be < 25% of feature tolerance
- 2Hydraulic clamping pressure must be monitored in real-time
- 3Fixture thermal mass must exceed workpiece mass by 3× for stable conditions
📐 Prerequisites
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🔗 Engineering Applications
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