Aircraft Airframe Shim Modeling for Tight-Tolerance Assembly
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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 tolerances, leading to lengthy and costly shimming processes, and the need for dedicated assembly fixtures for each process.
Innovation Solution
A method involving digital modeling and additive manufacturing to produce shims and airframe components with precise tolerances, using CNC machining and 3D modeling to create digital models of components, which are then machined and assembled with robotic systems, allowing for accurate alignment and assembly without traditional assembly tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate airframe sections are produced and assembled using traditional methods, then assembly flexibility is maintained, but manufacturing precision deteriorates due to difficulty in achieving tight tolerances
Solution Approach 1:
The patent applies preliminary action by creating a digital twin model of the entire airframe assembly before physical production. This digital model allows all components and shims to be virtually assembled and validated for fit and tolerance compliance before any physical parts are manufactured, enabling precision tolerance verification in advance and avoiding costly rework during physical assembly.
Solution Approach 2:
The patent creates a digital copy (digital twin) of the physical airframe assembly process. This digital model replicates the entire assembly structure, including frames, shear webs, and shims, allowing virtual testing of assembly tolerances and fit-up scenarios without requiring physical prototypes or test assemblies, thereby achieving high precision validation beforehand.
2Manufacturing precision
If traditional assembly fixtures are used for each assembly process, then component positioning accuracy is improved, but device complexity increases due to need for dedicated fixtures
Solution Approach 1:
The patent eliminates the need for multiple dedicated assembly fixtures by using a universal digital twin model that can represent and validate any assembly configuration. The digital model serves as a universal virtual fixture that can accommodate different airframe sections, components, and assembly scenarios without requiring physical fixture changes, thereby reducing device complexity while maintaining positioning accuracy.
Solution Approach 2:
The patent replaces the mechanical assembly fixture system with a digital information system. Instead of using physical fixtures to locate and position components during assembly, the invention uses a digital twin model to virtually locate, position, and validate all components beforehand. This substitution of mechanical systems with digital information processing eliminates the complexity of physical fixtures while maintaining or improving positioning accuracy.
3Manufacturing precision
If shimming processes are used to fill gaps between airframe sections, then assembly fit-up is improved, but loss of time increases due to lengthy shimming procedures
Solution Approach 1:
The patent performs preliminary action by calculating and determining the exact shim specifications in the digital twin model before physical production. All shim dimensions, positions, and thicknesses are virtually tested and finalized in the digital assembly, allowing precise shim fabrication without trial-and-error during physical assembly, thereby dramatically reducing shimming process time while maintaining fit-up quality.
4Manufacturing precision
If dedicated assembly fixtures are manufactured for each process, then assembly accuracy is improved, but production cost increases due to expensive fixture manufacturing
Solution Approach 1:
The patent replaces expensive physical assembly fixtures with a digital twin model that provides equivalent or superior positioning and validation capabilities. The digital model eliminates the need to manufacture costly dedicated fixtures for each assembly process, as all positioning and fit-up validation is performed virtually beforehand. This substitution significantly reduces production costs while maintaining or improving assembly accuracy.
Data Source
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AI summary
A method of producing a shim for use in an aircraft airframe (200) comprising: providing a plurality of component parts (202, 204) of the aircraft airframe (200); measuring a surface of each of the component parts (202, 204) and creating a digital models of the component part (202, 204) therefrom; digitally assembling together the digital models of the component parts (202, 204) thereby to produce a digital model (600) of at least part of the aircraft airframe (200); using that digital model (600), creating a digital model of a shim (604), the digital model of the shim (604) filling a gap between at least two digital models of component parts (202, 204) in the digital model (600) of at least part of the aircraft airframe (200); and producing a physical shim using the digital model of the shim (604).