Aircraft Airframe Assembly Using Digital Hole Alignment
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Solution Overview
Problem
The production of aircraft airframes faces challenges in achieving precise assembly due to difficulties in producing separate sections with tight tolerance bounds, often requiring lengthy and costly shimming processes and dedicated assembly fixtures.
Innovation Solution
A method involving digital modeling and CNC machining to produce airframe components with precise gaps and shims, allowing for accurate assembly and attachment of aircraft external skins using additive manufacturing and robotic assembly systems, reducing the need for conventional assembly tools and fixtures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate airframe sections are produced with tight tolerance bounds, then assembly precision is improved, but production complexity and cost increase
Solution Approach 1:
The patent applies preliminary action by pre-assembling subassemblies (forward fuselage, center fuselage, aft fuselage) with integrated frames and shear webs before final assembly. This preliminary structuring allows tolerance accumulation to be managed at the subassembly level rather than requiring tight tolerances on every individual component, thereby reducing production complexity while maintaining overall assembly precision.
Solution Approach 2:
The patent segments the airframe into multiple subassemblies (forward fuselage assembly, center fuselage assembly, aft fuselage assembly) that can be produced and assembled separately. This segmentation allows each subassembly to be manufactured with relaxed tolerances, and the final assembly precision is achieved through the coordinated integration of these segments rather than requiring all components to meet tight tolerance bounds individually.
2Ease of manufacture
If conventional assembly fixtures are used, then assembly operations can be carried out, but production time and cost increase
Solution Approach 1:
The patent applies self-service by designing the airframe subassemblies with self-aligning features and self-locating mechanisms. The frames and shear webs are configured to automatically position components relative to each other during assembly, eliminating the need for external fixtures to provide positioning and support. This self-service capability reduces assembly time while maintaining manufacturing capability.
Solution Approach 2:
The patent creates a universal assembly approach where the same subassembly structure (frames with shear webs) can be used across different airframe configurations. This multi-functional design allows the same basic assembly methodology to apply to various fuselage types, reducing the need for dedicated fixtures for each specific assembly operation and thereby reducing overall production time.
3Manufacturing precision
If shimming processes are used to fill gaps, then assembly gaps are eliminated, but production cost and time increase
Solution Approach 1:
The patent applies preliminary action by pre-positioning frames and shear webs within subassemblies at their final intended locations with appropriate clearance specifications. This preliminary positioning ensures that when subassemblies are brought together for final assembly, the gaps between them are minimal and uniformly distributed, eliminating the need for time-consuming shimming operations to fill irregular gaps.
Solution Approach 2:
The patent changes the dimensional parameters of the airframe components by designing frames and shear webs with specific clearance tolerances rather than tight fit tolerances. This parameter change allows for natural gap formation that is uniform and predictable, which can be addressed through controlled clearance design rather than through corrective shimming operations, thereby improving production efficiency.
Data Source
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AI summary
An assembly method comprising:providing a digital model of an aircraft airframe (200), the digital model comprising digital models of component parts (202, 204) of the airframe(200); providing the component parts (202, 204), each comprising one or more predrilled fastener holes;fixing a first component part (202a) to a support structure (1102); fixing a second component part (204a) to an end effector (1112) of a robot arm (1110); using the airframe digital model, controlling the robot arm (1110) to move the second component part (204a) relative to the first component (202a) as specified in the airframe digital model to cause one or more predrilled holes in the second component (204a) part to align with one or more predrilled holes in the first component part (202a); and attaching the second component part (204a) to the first component part (202a) using fasteners through the aligned predrilled holes.