Electroformed Sheath Mandrel Insert Geometry
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Solution Overview
Problem
Existing electroforming techniques face challenges in manufacturing sheaths with specific geometries and dimensions for protecting gas turbine engine airfoils, particularly the leading edge, which requires enhanced mechanical strength and durability against debris and foreign object impact.
Innovation Solution
An electroformed sheath with a mandrel insert made of a non-metallic composite or metallic material, such as graphite or nickel, is used to achieve desired geometries and dimensions, allowing for enhanced protection by electroplating a nickel or nickel-cobalt alloy sheath body with a wedge-shaped head section and varying side wall thicknesses, reducing weight and increasing impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional electroforming techniques are used to manufacture protective sheaths, then the sheath can be produced with adequate protection, but it is difficult to achieve certain geometries and dimensions required for enhanced leading edge protection
Solution Approach 1:
A mandrel insert is introduced as an intermediary tool during the electroforming process. This mandrel insert provides a physical template that guides the electroformed material to achieve precise geometries and dimensions that would be difficult to obtain through traditional electroforming alone, thereby resolving the contradiction between manufacturing precision and ease of manufacture
Solution Approach 2:
The patent modifies the electroforming process parameters by incorporating a mandrel insert with specific geometric features. This changes the physical parameters of the forming process, enabling the production of sheaths with enhanced leading edge geometries and controlled wall thicknesses that meet precise design requirements
2Strength
If the sheath wall thickness is increased to enhance impact resistance, then the protection capability improves, but the overall weight of the sheath increases
Solution Approach 1:
The mandrel insert creates non-uniform wall thickness distribution in the electroformed sheath, with thicker material deposited in high-stress impact zones and thinner material in lower-stress areas. This local quality variation achieves enhanced impact resistance where needed while minimizing overall weight
Solution Approach 2:
The sheath is formed as a composite structure with the electroformed metallic layer (nickel or nickel-cobalt alloy) providing impact resistance and the mandrel insert (non-metallic composite or metallic material) providing geometric support and thickness control, achieving strength-to-weight optimization
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
The solution provides a lightweight, durable electroformed sheath that effectively protects gas turbine airfoils from impact damage by incorporating a mandrel insert with specific geometry and material properties, enhancing the sheath's ability to withstand foreign object penetration and reduce overall mass.
Implementation Method 1
electroplating a nickel or nickel-cobalt alloy sheath body
Data Source
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AI summary
An electroformed sheath for protecting an airfoil includes a sheath body and a mandrel insert is provided. The sheath body includes a leading edge. The sheath body includes a pressure side wall and an opposed suction side wall, which side walls meet at the leading edge and extend away from the leading edge to define a cavity between the side walls. The sheath body includes a head section between the leading edge and the cavity. The mandrel insert is positioned between the pressure side and suction side walls, and includes a generally wedge-shaped geometry. A method for protecting an airfoil includes: 1) securing a mandrel insert to a mandrel; 2) electroplating a sheath body onto the mandrel and the mandrel insert; 3) removing the mandrel from the sheath body so that a sheath cavity is defined within the sheath body; and 4) securing the airfoil within the sheath cavity.