Composite Laminate Thickness Compensation via Metrology
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Solution Overview
Problem
Aircraft manufacturers face challenges in accurately identifying and correcting thickness variations in composite materials, which are common due to processing conditions and installation methods, leading to inefficiencies and increased costs with existing methods that require expensive precision milling machines and are less precise.
Innovation Solution
A non-contact method using metrological devices like laser interferometry to measure composite article profiles, analyze thickness data, and apply compensation layers to correct variations, with a system that includes a computer, broadgoods cutter, and light source for precise placement of compensation layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If post cure machining is used to correct thickness variations, then thickness precision is improved, but manufacturing cost and time increase
Solution Approach 1:
The patent applies compensation layers during the lay-up process before curing, rather than machining after curing. This preliminary action allows thickness corrections to be built into the part during manufacturing, eliminating the need for time-consuming post-cure machining operations while maintaining thickness precision.
Solution Approach 2:
The patent uses sacrificial compensation layers (such as foam or low-density composite materials) that are applied temporarily during manufacturing to correct thickness variations. These compensation layers are later removed or remain as non-critical features, avoiding the need for expensive precision milling machines while achieving the desired thickness precision.
2Manufacturing precision
If precision milling machines are used for post cure machining, then thickness precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive precision milling machines with inexpensive compensation layers made from common materials like foam or scrap composite plies. These cheap compensation materials are applied during lay-up to correct thickness variations, eliminating the need for costly precision machining equipment while maintaining thickness precision.
Solution Approach 2:
The patent changes the approach from mechanical removal of material (machining) to adding material (compensation layers). By changing the parameter of material addition versus removal, and using low-cost materials for compensation, the patent achieves thickness precision without requiring expensive precision milling machines.
3Ease of manufacture
If traditional lay-up procedures are used, then manufacturing simplicity is maintained, but thickness variation increases
Solution Approach 1:
The patent maintains the simplicity of traditional lay-up procedures by adding the compensation layer step during the lay-up process itself, before curing. This preliminary action of placing compensation plies in specific locations does not complicate the overall manufacturing process significantly but effectively reduces thickness variations in the final cured part.
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 method allows for accurate identification and correction of thickness variations, reducing the need for post-cure machining and minimizing weight and cost by ensuring thickness variations are within predetermined ranges, achieving precision and efficiency in aircraft component manufacturing.
Implementation Method 1
measuring the profiles of the composite article and its forming tool by non-contact means to generate a calculated thickness data set
Data Source
AI summary
A method is provided for the non-contact measurement of variations in thickness of composite materials and structures prepared from composite parts. Metrologic methods are employed to provide a 3D image of the structure or part. Variations that are greater than an acceptable amount can be corrected by adding a compensation layer to the surface of the structure or part.