Annular Part Forming for Extended Trailing Edge Geometry
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Solution Overview
Problem
Current methods for forming annular parts, such as nacelle lip skins, face challenges in producing extended trailing edges due to complex three-dimensional curvature and material requirements, which often necessitate costly multi-stage processes and unsuitable deep drawing techniques.
Innovation Solution
An apparatus and method utilizing a punch with an annular shape and linear actuation system for forming an annular part from a preform, allowing coaxial movement and controlled forming processes with high surface finish and lubrication to minimize friction, enabling the creation of extended trailing edges in a single process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If deep drawing processes are used to form annular parts with extended trailing edges, then the complex three-dimensional curvature can be achieved, but the process becomes unsuitable and requires multiple stages with costly tooling
Solution Approach 1:
The forming process is divided into two distinct stages: a drawing stage that forms the main body of the annular part, and a redraw stage that specifically forms the extended trailing edge. This segmentation allows each stage to be optimized for its specific function, eliminating the need for multiple costly tooling setups while achieving the complex three-dimensional curvature.
Solution Approach 2:
The invention introduces axial movement of the punch in addition to the conventional radial drawing motion. This dimensional change enables the punch to first draw the blank radially to form the main body, then advance axially to redraw and extend the trailing edge, creating complex shapes that would otherwise require multiple tooling stages.
2Ease of manufacture
If conventional deep drawing processes are used, then manufacturing capability is maintained, but extended trailing edges cannot be produced due to process limitations
Solution Approach 1:
The punch is designed with dynamic capabilities, allowing it to perform both radial drawing and axial redrawing motions within a single setup. This dynamic forming approach enables the production of extended trailing edges by activating the axial movement capability only when needed, while maintaining compatibility with conventional manufacturing processes for standard shapes.
3Productivity
If single-stage forming processes are used, then productivity is improved, but the complex curvature and extended edges cannot be achieved
Solution Approach 1:
The single forming process is segmented into a drawing stage and a redraw stage, each optimized for specific geometric features. The drawing stage establishes the main body curvature, while the redraw stage refines the extended trailing edge. This internal segmentation within a single process maintains productivity while achieving the required manufacturing precision for smooth, turbulence-free surfaces.
4Strength
If intermediate heat treatments are applied, then material formability is improved, but the process complexity and cost increase
Solution Approach 1:
Instead of changing the thermal state of the material through intermediate heat treatments, the invention changes the mechanical forming parameters by introducing axial punch movement and controlled material flow during the redraw stage. This approach achieves the required material formability for extended trailing edges through optimized mechanical parameters rather than thermal processing, maintaining process simplicity.
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 efficient and cost-effective manufacture of annular parts with extended trailing edges, enhancing laminar flow and accommodating stringent de-icing requirements, while reducing the risk of wrinkling and buckling during the forming process.
Implementation Method 1
with lubrication to minimize friction
Implementation Method 2
displacing the punch to form a portion of the wall between the gripping means and the punch
Data Source
Figure 1
Figure 2~6
Figure 7~10
AI summary
An apparatus (31 ) for forming an annular part (53) comprising a punch (2) having a forming end with an external surface (32) shaped to correspond to the shape of the annular part (53). The apparatus further comprises a clamping arrangement (3, 5) for clamping a large diameter end of a preform (4) and a gripping arrangement (6, 7) for adjustably gripping a small diameter end of the preform (4). An actuation system is provided for facilitating relative coaxial movement only between the punch (2), the clamping arrangement (3, 5) and the gripping arrangement (6, 7).