Aircraft Assembly Fixture Alignment Without Shimming

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Solution Overview

Problem

Aircraft airframe production 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 traditional assembly tools are specific and costly, necessitating the development of more efficient methods for aligning and attaching airframe components.

Innovation Solution

A method and apparatus for producing an assembly tool that determines the precise position and orientation of airframe components relative to each other, using a reference structure replica of the attachment point, and secures pickup devices to support components accurately, enabling precise alignment and assembly of aircraft fuselage sections with reduced need for shimming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If separate airframe sections are produced independently, then production flexibility and independent component manufacturing are improved, but assembly precision and alignment accuracy deteriorate

Engineering Contradiction:
Improveindependent component productionVSAvoidassembly alignment accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-establishing precise reference surfaces and alignment features on each airframe section during independent production. These reference surfaces are prepared in advance with high precision machining, enabling accurate alignment when sections are assembled together, thus resolving the contradiction between independent production and assembly precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses master templates and reference surfaces that serve as precise copies or replicas of the ideal geometry. These master references are used to replicate the exact alignment and positioning across multiple sections during independent production, ensuring that when assembled, the sections fit together with high precision without requiring post-assembly shimming.

Inventive Principle:
Principle #26Copying

2Manufacturing precision

If traditional dedicated assembly tools are used for each assembly process, then assembly precision is improved, but device complexity and production costs increase

Engineering Contradiction:
Improveassembly precisionVSAvoidnumber of dedicated tools
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements universality by designing assembly fixtures and tools that can serve multiple functions and be used across different assembly operations. Instead of requiring a dedicated tool for each specific assembly task, the fixtures are designed with adjustable and reconfigurable features that allow them to accommodate various airframe sections and assembly requirements, thereby reducing the total number of tools needed while maintaining assembly precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If airframe sections are produced with tight tolerance bounds, then final assembly quality is improved, but production time and costs increase due to lengthy shimming processes

Engineering Contradiction:
Improvetolerance complianceVSAvoidshimming process duration
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by performing precision machining and alignment feature creation during the initial production phase, before assembly. Reference surfaces are established with tight tolerances in advance, and alignment fixtures are prepared beforehand, eliminating the need for time-consuming shimming operations during the actual assembly process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent replaces the traditional mechanical shimming process with a precision fixture-based alignment system. Instead of using shims to adjust and fill gaps between sections, the invention uses precisely manufactured fixtures with reference surfaces that mechanically constrain and align sections directly, thereby eliminating the shimming step and reducing production time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3134783B1Assembly tool production
Publication Date: 2021.03.03 BAE SYSTEMS PLC
  • EP3134783B1 patent drawingFigure 1~2
  • EP3134783B1 patent drawingFigure 3
  • EP3134783B1 patent drawingFigure 4

AI summary

Disclosed is a method of producing an assembly tool (60) for assembling a first system (4) comprising one or more components (8-12). The method comprises: for each component (8-12), determining, when the first system (4) is attached to a second system (5), a position and orientation of that component (8-12) relative to the second system (5) and positions and orientations relative to the second system (5) at which that component (8-12) is to be supported; providing a frame (62); attaching, to the frame (62), a reference structure (64); providing a plurality of pickup devices (66-72) each having a receiving element (74-80) for receiving a component (8-12); and securing each pickup device (66-72) to the frame (62) such that a position and orientation relative to the reference structure (64) of each receiving element (74-80) is the same as a position and orientation at which a component (8-12) is to be supported.