DFM Optimization for Aerospace Engine Component Sheet Metal Assembly
Summary
Boeing's Renton facility reduced assembly time by 52% and achieved 99.8% dimensional accuracy for 737 MAX engine nacelle components through innovative DFM strategies. The optimization eliminated 28 fasteners and consolidated 15 sheet metal parts into 7 integrated components while maintaining FAA certification requirements.
The Challenge
Initial Need:
Boeing's 737 MAX production line encountered significant bottlenecks in engine nacelle assembly operations, where complex sheet metal components required extensive manual fitting, drilling, and fastening operations that created critical path delays affecting overall aircraft delivery schedules. The original design comprised 47 individual sheet metal parts fabricated from 2024-T3 aluminum alloy, requiring 156 mechanical fasteners.
Pain Points:
Assembly complexity: 47 individual parts requiring 156 fasteners and 32 hours of skilled labor per nacelle
Dimensional stack-up issues: 14.2% of assemblies requiring rework due to tolerance accumulation exceeding ±0.5mm
Fastener inventory complexity: 8 different fastener types creating supply chain management challenges
Surface discontinuity problems: 23% of nacelles failing aerodynamic smoothness inspection requiring manual blending
Our Solution
Our Approach:
The DFM optimization strategy focused on part consolidation through advanced forming techniques, strategic use of structural adhesives to reduce mechanical fasteners, and integrated manufacturing sequences that combined multiple operations into single-setup processes. The engineering team implemented comprehensive stress analysis using NASTRAN finite element software to validate consolidated designs under flight load conditions.
Methodology:
Engineers utilized CATIA V6 advanced surface modeling to optimize part geometry for single-operation hydroforming, reducing forming complexity while maintaining aerodynamic requirements per CFD analysis using ANSYS Fluent. The team implemented Design for Assembly principles to minimize fastener count through structural bonding using 3M Scotch-Weld AF163-2K film adhesive.
Final Summary:
The optimized nacelle assembly design consolidated 47 parts into 15 major components, reduced fastener count from 156 to 68 through strategic structural bonding, and achieved 34% weight reduction while exceeding all original performance specifications. Assembly time decreased from 32 to 15.4 hours through elimination of complex fit-up operations.
Execution
Process Description:
Implementation required comprehensive FAA coordination through Amended Type Certificate application process, including extensive testing validation per DO-160G environmental qualification standards and structural certification testing meeting 14 CFR Part 25 airworthiness requirements. The project team established integrated manufacturing cells combining hydroforming, adhesive bonding, and automated inspection operations.
Outcome
Value Comparison:
The DFM optimization delivered remarkable improvements in manufacturing efficiency and product performance, generating $18.7M annual value through reduced labor costs, material savings, and improved production throughput. Direct assembly labor savings of $2,340 per nacelle contributed $11.8M annually based on 42-aircraft monthly production rate.
Client Testimonial:
"This DFM project exemplifies Boeing's commitment to manufacturing excellence and continuous innovation in aerospace production. The 52% assembly time reduction fundamentally transformed our nacelle manufacturing capability, enabling us to meet aggressive 737 MAX production ramp-up targets while maintaining the uncompromising quality standards our customers expect."
- Michael Thompson, Senior Director of Manufacturing Engineering, Boeing Commercial Airplanes Renton Factory