Electroformed Metallic Shield with Triangular Wire Edge
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Solution Overview
Problem
The existing electroforming process for creating metallic shields with sharp, well-defined edges for aerofoil components in gas turbine engines faces challenges such as difficult mandrel manufacturing, high charge concentration leading to increased radius of curvature, and resulting mechanical weakness.
Innovation Solution
A method involving a mandrel with a matching metal wire having a triangular cross-section is used for electro-deposition, allowing the metal wire to define the sharp edge, thereby avoiding the need for a sharp mandrel edge and enhancing mechanical strength by providing an internal abutment surface that increases thickness without increasing the edge radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sharp mandrel edge is used to form a sharp metallic shield edge, then the edge definition is improved, but the mandrel manufacturing difficulty increases and the deposited metal thickness increases leading to larger radius of curvature
Solution Approach 1:
A sacrificial wire is introduced as an intermediary element between the mandrel and the electroforming process. The wire with its sharp edge serves as the actual template for the shield edge, while the mandrel only needs to hold the wire, eliminating the need for sharp mandrel edges. After electroforming, the wire is removed, leaving the desired sharp edge on the metallic shield.
Solution Approach 2:
Instead of directly forming the sharp edge on the mandrel, the sharp edge geometry is copied onto the sacrificial wire first. The wire acts as a reusable template that can be precisely manufactured and then replicated onto the metallic shield through electroforming, separating the edge definition function from the mandrel.
2Manufacturing precision
If careful shielding is used to reduce charge concentration, then the radius of curvature is reduced, but the deposited metal becomes thin at the sharp edge with a sharp internal groove
Solution Approach 1:
The sacrificial wire acts as a mediator that collects and distributes the electroformed metal uniformly along the sharp edge region. The wire's geometry controls the deposition pattern, ensuring adequate metal thickness at the edge while preventing excessive deposition that would increase radius of curvature. The wire is later removed, leaving sufficient metal thickness for structural integrity.
Solution Approach 2:
The invention changes the geometric parameters of the template from a sharp mandrel edge to a wire with specific dimensions (diameter D and length L). By optimizing these parameters, the electroforming process achieves uniform metal distribution with adequate thickness while maintaining sharp edge definition, resolving the conflict between precision and strength.
3Adaptability or versatility
If electroforming is used to create complex curved metallic elements, then the manufacturing flexibility is improved, but the edge sharpness deteriorates due to charge concentration at sharp edges
Solution Approach 1:
The sacrificial wire serves as an intermediary that decouples the complex curvature formation capability of electroforming from the edge sharpness requirement. The wire can be precisely manufactured with sharp edges, and when held against the mandrel during electroforming, it guides the metal deposition to reproduce sharp edges even on complexly curved surfaces.
Solution Approach 2:
The edge formation function is segmented from the overall shield geometry formation. The mandrel defines the complex curvature, while the sacrificial wire separately defines the sharp edge. This segmentation allows each element to be optimized independently - the mandrel for complex shape and the wire for sharp edge precision.
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 the formation of metallic shields with sharp, well-defined edges and increased mechanical strength, simplifying mandrel manufacturing and maintaining a small radius of curvature.
Implementation Method 1
aligning and affixing the base surface of the wire on the surface of the mandrel edge
Implementation Method 2
electro-depositing metal onto the mandrel and metal wire to form the metallic shield comprising the deposited metal and the metal wire
Data Source
AI summary
The present invention provides a method of making a metallic shield for shielding an edge of a component e.g. an aerofoil component such as a gas turbine blade or vane. The method comprises:providing a mandrel with a mandrel edge having a shape conforming to the shape of the component edge, wherein the mandrel edge comprises a surface having a width, W1; providing a metal wire having a substantially triangular radial cross-section with a base surface of width W2, wherein W2 equals W1; aligning and affixing the base surface of the wire on the surface of the mandrel edge;electro-depositing metal onto the mandrel and metal wire to form the metallic shield comprising the deposited metal and the metal wire; andremoving the metallic shield from the mandrel.