Two-Stage Press Forming for Gas Turbine Edge Protectors
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Solution Overview
Problem
Conventional methods for manufacturing three-dimensional edge protectors for gas turbine engine blades are inefficient and costly, as they require time-consuming and expensive processes like electroforming or progressive press forming, which lack precision and are not suitable for thin sheet metals.
Innovation Solution
A method involving a two-stage press forming process using primary and secondary die assemblies to form a U-shaped edge protector with a bent portion and planar sections, where the bent portion is formed first to conform to the leading edge, and then the planar sections are shaped to match the lateral sides, allowing for high precision and economic production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If electroforming process is used to form edge protector, then manufacturing precision is improved, but manufacturing cost and time consumption increase
Solution Approach 1:
The manufacturing process is divided into two separate press forming stages: a first press forming step to form the bent portion conforming to the leading edge, and a second press forming step to form the planar portions conforming to the lateral sides. This segmentation allows each stage to focus on specific geometric features, achieving high precision without the complexity of electroforming.
Solution Approach 2:
The bent portion of the edge protector is formed in advance during the first press forming step, creating a preformed work piece with the leading edge contour already established. This preliminary action simplifies the second pressing operation, as only the planar portions need to be formed subsequently, reducing overall process complexity while maintaining precision.
2Adaptability or versatility
If progressive press forming process is used to form three dimensional edge protector, then manufacturing capability is improved, but manufacturing cost and number of steps increase
Solution Approach 1:
The invention merges the formation of both the bent portion and planar portions into a single two-stage press forming process using one die assembly. The first pressing forms the bent portion, and the second pressing forms the planar portions, eliminating the need for multiple separate die assemblies required in progressive press forming, thereby improving productivity while maintaining three-dimensional forming capability.
3Adaptability or versatility
If hydro-forming is used to form edge protector, then forming capability for thick material is improved, but precision and suitability for thin sheet metal deteriorate
Solution Approach 1:
The invention replaces the hydro-forming mechanical system with a direct press forming system that uses mechanical pressure through dies and punches. This substitution allows for precise control of the forming process through direct contact between the tooling and the sheet metal, achieving high precision while being suitable for thin sheet metal materials that cannot be effectively formed by hydro-forming.
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
Enables the efficient and economical fabrication of high-precision three-dimensional edge protectors that closely conform to the blade's contours, reducing manufacturing costs and improving precision without interfering processes.
Implementation Method 1
press forming a piece of planar sheet metal into a preformed work piece having a U-shaped cross section by using a primary die assembly
Implementation Method 2
pushing the lateral die blocks onto the planar portions of the preformed work piece against the corresponding lateral sides of the punch
Data Source
AI summary
In primary press forming process, a piece of blank sheet metal is draw worked so as to form a preformed work piece (Wb) provided with a bent portion (a) substantially conforming to a three dimensional contour of a leading edge of a blade to be protected and extending along a longitudinal direction, and a pair of planar portions (b and c) extending from either side of the bent portion. In a secondary press forming process, the planar portions (b and c) of the preformed work piece are stretch formed into a final shape that conforms to the corresponding profile of the blade while the bent portion (a) of the preformed work piece is clamped and protected from deformation. In other words, the bent portion of an edge protector (100) is already given with the final shape of the edge protector by the primary press forming process while the planar portions (b and c) thereof are given with the final shape by the secondary press forming process so that the two press forming processes can be executed without interfering with each other, and only two relatively simple press forming processes are required for forming the complex three dimensional shape of the edge protector.