Double-Contoured Shim Fabrication for Complex Mating Surfaces
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Solution Overview
Problem
Conventional shimming techniques, including manual and predictive shimming, often require time-consuming gap measurement and shim fabrication processes, as they only address surface contour deviations on one side of the mating surfaces, which is inadequate for complex aerodynamic shapes in the aerospace industry.
Innovation Solution
A system and method for fabricating double-contoured shims that include complementary contoured surfaces on both sides, allowing for precise alignment and assembly of parts with surface contour variations on both mating surfaces, using predictive shimming techniques and 3D measurement data to generate shim models before assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional shimming techniques are used to address surface contour deviations, then the shim fabrication process is simplified, but the assembly accuracy is insufficient for complex aerodynamic shapes
Solution Approach 1:
The shim is divided into two distinct contoured surfaces, each addressing the surface contour deviations of one mating part. This segmentation allows each surface to be optimized independently for its specific mating interface, thereby achieving high assembly accuracy for complex aerodynamic shapes while maintaining a systematic fabrication approach
Solution Approach 2:
Each surface of the shim is given a specific contoured geometry tailored to match the deviations of its corresponding mating part. This local quality approach ensures that each shim surface is precisely adapted to its specific interface requirements, achieving high assembly accuracy without requiring complete redesign of the entire shim fabrication process
2Productivity
If predictive shimming is used to reduce manufacturing time, then production efficiency is improved, but the shim only addresses one mating surface contour
Solution Approach 1:
The predictive shimming process is segmented to separately measure and model both mating surfaces before assembly. This allows the shim to be designed with two contoured surfaces that each address the specific deviations of one mating part, thereby achieving complete surface contour coverage while maintaining production efficiency through predictive fabrication
Solution Approach 2:
Both mating surfaces are measured and modeled in advance before assembly, allowing the double-contoured shim to be fabricated beforehand with the correct geometry for both interfaces. This preliminary action on both surfaces enables complete contour coverage to be achieved through predictive shimming without requiring post-assembly adjustments
3Ease of manufacture
If a single-contoured shim is fabricated to fill the gap, then the fabrication process is simpler, but the fit between complex aerodynamic parts is insufficient
Solution Approach 1:
The shim fabrication process is segmented into two distinct surface generation operations, one for each contoured surface. This segmentation allows each surface to be independently optimized for its mating interface while maintaining a systematic and repeatable fabrication process, thereby achieving high fit quality without proportionally increasing fabrication complexity
Solution Approach 2:
The shim is given curved or contoured surfaces that match the aerodynamic shapes of the mating parts, rather than flat surfaces. This curvature approach ensures that the shim conformally fits to complex aerodynamic surfaces, achieving high fit quality and aerodynamic performance while using standard fabrication techniques capable of producing curved surfaces
Data Source
AI summary
A system for fabricating a double-contoured shim includes a model generator and a manufacturing system. The model generator generates a shim model to fill a gap between a first mating-surface and a second mating-surface. The model generator generates a virtual plane that divides the shim model into a first shim model and a second shim model. A first shim is fabricated based on the first shim model. The first shim includes a first contoured shim-surface that is complementary to a first mating-surface area of the first mating-surface and a first planar shim-surface that is opposite the first contoured shim-surface. A second shim is fabricated based on the second shim model. The second shim includes a second contoured shim-surface that is complementary to a second mating-surface area of the second mating-surface and a second planar shim-surface that is opposite the second contoured shim-surface.