3D-Printed Aircraft Shims for Precise Skin-to-Airframe 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 use of conventional assembly fixtures and adhesives which are messy, time-consuming, and add thickness.
Innovation Solution
A method and system utilizing Additive Manufacturing to create highly accurate shims by digitally modeling the airframe and skin components, allowing for precise assembly without adhesives, and using materials like aluminum, titanium, or plastics for the shims, which are formed directly onto the airframe using the digital model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional assembly fixtures and adhesives are used to attach aircraft skin to airframe sections, then the components can be joined together, but the process becomes messy, time-consuming, and adds unnecessary thickness to the assembly
Solution Approach 1:
The invention extracts and eliminates the adhesive from the assembly process entirely. Instead of using adhesives to bond the skin to the airframe, the patent uses precision shims filled with compliant material that mechanically fill gaps and allow direct attachment, removing the harmful messy and time-consuming adhesive application and curing processes
Solution Approach 2:
The invention changes the physical state and properties of the shim material by infusing it with compliant material after the shim structure is formed. This allows the rigid shim to provide precise dimensional control while the compliant infused material provides flexibility and gap filling, eliminating the need for adhesives
2Productivity
If separate airframe sections are produced to allow modular assembly, then manufacturing flexibility is improved, but achieving tight tolerance bounds becomes difficult and lengthy shimming processes are required
Solution Approach 1:
The invention performs preliminary action by creating a digital model of the required shim before any physical manufacturing. The shim geometry is designed and validated in the digital realm to precisely fit the gaps between modular airframe sections, ensuring that when the physical shim is manufactured and installed, it will achieve the required tight tolerance bounds without requiring iterative adjustment
Solution Approach 2:
The invention uses digital copying and modeling to create a precise virtual representation of the shim that fills the gap between airframe sections. This digital model can be repeatedly used to guide manufacturing and verification processes, ensuring consistent precision across multiple production runs without requiring physical prototypes or trial assemblies
3Manufacturing precision
If traditional shimming processes are used to fill gaps between airframe sections, then gaps can be filled, but the process becomes lengthy and expensive
Solution Approach 1:
The invention replaces the traditional mechanical shimming process (manual measurement, cutting, fitting, and adjusting of shim pieces) with an additive manufacturing process guided by digital models. The shim is built layer by layer in three dimensions, eliminating the need for manual material removal and iterative fitting, thus dramatically reducing both time and cost while maintaining high precision
Solution Approach 2:
The invention changes the manufacturing approach from subtractive (cutting and shaping traditional shim material) to additive (building the shim layer by layer using additive manufacturing). This parameter change in the manufacturing process enables complex geometries to be created directly from digital models without requiring lengthy manual fabrication and adjustment processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise attachment of aircraft skins with reduced need for adhesives, minimizing thickness and assembly time, and allows for more accurate and efficient production of aircraft airframes within tight tolerance bounds.
Implementation Method 1
performing an Additive Manufacturing, AM, process to form the shim directly onto the surface of the at least part of the aircraft airframe, the AM process using the digital model of the shim
Data Source
AI summary
A method of producing a shim for use in an aircraft, the method comprising: providing an aircraft airframe; measuring a surface of the airframe; creating a digital model of the airframe using those measurements; providing an aircraft skin; measuring a surface of the aircraft skin; creating a digital model of the aircraft skin using those measurements; digitally assembling the digital model of the airframe with the digital model of the aircraft skin; using the digitally assembled models, creating a digital model of a shim, the digital model of the shim substantially filling a gap between the digitally assembled digital models of the airframe and the skin; and producing a physical shim using the digital model of the shim.