Nacelle Leading Edge Forming with Offset-Axis Punch Droop Shaping
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Solution Overview
Problem
The formation of nacelle leading edges for gas turbine engines requires complex and costly multi-stage processes, including deep drawings and spin forming, which are further complicated by the need for angular droop designs, leading to manufacturing difficulties.
Innovation Solution
A method and apparatus involving an actuation assembly, punch, and die that position and move a preform to form a nacelle leading edge, allowing for relative motion along multiple axes to shape the preform into a nacelle leading edge with an angular droop, using clamps and a preform holder to control material flow and minimize spring back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multi-stage deep drawing or spin forming processes are used to form nacelle leading edges, then the nacelle leading edge can be formed, but the process becomes complex and requires costly tooling
Solution Approach 1:
The forming process is divided into two distinct stages: first forming the preform with a punch along a first axis, then offsetting the punch to a second axis to form the final nacelle leading edge with angular droop. This segmentation allows each stage to use simpler, dedicated tooling rather than requiring complex multi-functional tooling for the entire process.
Solution Approach 2:
The punch is designed to be dynamically repositionable between two different axes. The punch can be offset from the first axis to the second axis between forming operations, allowing the same punch to create different geometries (preform vs. final part) without requiring separate fixed tooling for each operation.
2Ease of manufacture
If intermediate heat treatments are applied during nacelle leading edge formation, then material formability is improved, but the manufacturing process becomes more complex and time-consuming
Solution Approach 1:
The preform is created in advance with a geometry that is optimized for the final forming operation. By pre-shaping the material into a configuration that is more favorable for the second forming stage, the material becomes more formable during the final operation without requiring intermediate heat treatments to improve ductility or reduce forming forces.
3Adaptability or versatility
If angular droop designs are incorporated into nacelle leading edges, then the aerodynamic performance is improved, but the manufacturing difficulty increases
Solution Approach 1:
The punch is intentionally offset from the central axis of the die to create an asymmetric forming condition. This asymmetric positioning of the punch relative to the die allows the material to be formed into the desired angular droop geometry, which would be difficult to achieve with symmetric forming operations.
Solution Approach 2:
The solution moves the forming operation from a single-axis (radial) dimension to a two-dimensional approach by offsetting the punch along a second axis that is different from the first axis. This dimensional change enables the creation of angular droop features that require non-radial material flow and geometry.
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 simplifies the nacelle leading edge formation process by reducing the need for complex tooling and intermediate heat treatments, enabling efficient production of nacelle leading edges with angular droop designs while minimizing material failure and friction.
Implementation Method 1
a portion of the preform is formed over a leading edge of the punch
Implementation Method 2
The punch is offset so that the punch is annularly disposed about a second axis, different than the first axis
Data Source
AI summary
An apparatus for forming a nacelle leading edge includes an actuation assembly, a punch, and a die. The punch is in communication with the actuation assembly and annularly disposed about a first axis. The punch is configured to mate with an interior surface of a preform. The die is in communication with the actuation assembly and disposed within the first axis. The die is configured to retain an exterior surface of the preform. The actuation assembly is configured to effect relative motion between the punch and the preform. The actuation assembly is configured to offset the punch so that the punch is annularly disposed about a second axis, different than the first axis.