Aircraft Panel Tooling for Tolerance Stack-Up Control
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Solution Overview
Problem
Existing methods for manufacturing interchangeable and replaceable component parts, particularly in the aerospace industry, face challenges such as misalignment, tolerance stack-up, and degradation of control tools due to thermal cycles, leading to costly and time-consuming maintenance and inventory management issues, especially in military aircraft where quick replacement is critical.
Innovation Solution
A method and apparatus that utilize a specific production process and tooling methodology to control tolerance stack-ups and process variations by coordinating tools with engineering nominals, using numerically controlled tooling devices and assembly apparatus that include machining centers and templates to ensure precise alignment and assembly, reducing the need for physical gages and mitigating thermal expansion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If physical gages and tooling families are used to manufacture panels, then panels can be assembled to form aircraft skin, but the control tools deviate from engineering nominals over time due to thermal cycles and degradation
Solution Approach 1:
The patent uses physical gages as master copies of the engineering nominal geometry. These gages are used to create tooling families that replicate the exact dimensions and tolerances from engineering drawings, ensuring that all panels are manufactured to the same precise specifications without deviation over time.
Solution Approach 2:
The patent creates physical gages and tooling families in advance before panel manufacturing begins. These pre-prepared tools are designed to maintain their dimensional stability and resist thermal expansion, ensuring that precision is maintained throughout the manufacturing process without requiring frequent recalibration.
2Ease of manufacture
If carbon epoxy bond molds are used to bond composite panels, then panels can be assembled, but the molds degrade over time resulting in contours that deviate from nominal
Solution Approach 1:
The patent recognizes that carbon epoxy bond molds have limited service life and degrade over time. The solution involves creating durable master gages that can be used repeatedly to recreate panel contours, effectively replacing the degradable molds with long-lasting reference standards that maintain nominal accuracy throughout their service life.
Solution Approach 2:
The patent changes the material parameters of the control tools from degradable carbon epoxy bond molds to thermally stable materials with low coefficients of thermal expansion. This parameter change ensures that the control tools maintain their dimensional stability and do not deviate from nominal contours even after repeated thermal cycles.
3Ease of manufacture
If substructure frames are manufactured with material subject to thermal expansion, then frames can be assembled, but the frames deviate from engineering nominal values due to coefficient of thermal expansion difference
Solution Approach 1:
The patent explicitly accounts for thermal expansion effects by selecting materials for the substructure frames and bond molds that have matching or compatible coefficients of thermal expansion. This minimizes differential expansion and contraction during thermal cycles, preventing deviation from engineering nominal values.
Solution Approach 2:
The patent changes the thermal parameters of the materials used in frame manufacturing to match the coefficient of thermal expansion between different components. This ensures that all parts expand and contract uniformly during thermal cycles, maintaining dimensional accuracy and preventing gaps or misalignment.
4Ease of manufacture
If single rail hand router tools are used to trim thin composite panels, then panels can be trimmed, but hand routing is not capable of repeatedly providing trim that meets engineering specifications
Solution Approach 1:
The patent replaces manual single-rail hand router tools with automated routing systems that use the physical gages and tooling families as guides. This substitution of mechanical systems eliminates the variability and inconsistency of manual operation, enabling repeated trimming operations that consistently meet engineering specifications through automated precision control.
Data Source
AI summary
A manufacturing method and apparatus is disclosed, whereby a specific production process is used in conjunction with a specific tooling methodology to provide a tooling process package that is capable of controlling tolerance stack-ups and process variations by accounting for them at each step in the process. One application particularly suited for the present invention is in the manufacturing of panels that are assembled to form the skins of a tiltrotor aircraft (11).