Blank Design for Spin Forming Non-Axisymmetric Shapes
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Solution Overview
Problem
Conventional spin forming methods are limited in producing non-axisymmetric shapes due to reliance on mandrels, leading to material wastage and quality issues, and existing design methods like Finite Element Analysis are resource-intensive and inflexible, often resulting in inadequate workpiece designs and wrinkling effects.
Innovation Solution
A computer-implemented method generates a design for a blank workpiece by determining a perimeter shape based on a target shape, using vectors normal to the planar representation of the base portion, scaled by curvature and length, to produce a suitable workpiece for spin forming, allowing for both axisymmetric and non-axisymmetric shapes with reduced wrinkling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional spinning methods using mandrels are used, then axisymmetric articles can be produced, but re-entrant shapes and non-axisymmetric articles cannot be produced
Solution Approach 1:
The patent removes the mandrel from the spinning process entirely, replacing it with support tools that contact only specific portions of the workpiece. This extraction of the mandrel enables production of re-entrant shapes and non-axisymmetric articles that would be impossible with traditional mandrel-based spinning.
Solution Approach 2:
The support function previously provided by a single mandrel is segmented into multiple support tools (first support tool, second support tool, third support tool) that contact different portions of the workpiece. This segmentation allows independent control of support at various locations, enabling complex shape formation.
2Productivity
If an inappropriate workpiece size and shape is used, then the spin forming process can proceed, but material wastage increases and wrinkling occurs
Solution Approach 1:
The patent applies Finite Element Analysis before the spin forming process to determine the optimal workpiece size and shape. This preliminary analysis predicts material flow and deformation, allowing the workpiece to be designed with precise dimensions that prevent both material wastage and wrinkling during forming.
Solution Approach 2:
The FEA model provides feedback on how the workpiece will deform during spinning, allowing iterative optimization of the initial workpiece geometry. This feedback loop ensures the workpiece is designed to achieve the target shape with minimal material wastage and without defects.
3Manufacturing precision
If Finite Element_analysis is used to determine workpiece design, then material wastage and wrinkling can be reduced, but the process becomes resource-intensive and time-consuming
Solution Approach 1:
The FEA analysis is performed once during the design phase to establish the optimal workpiece geometry. This preliminary action creates a reusable design model that can be applied to produce multiple workpieces without requiring repeated analysis, reducing both time and resource consumption for production batches.
4Adaptability or versatility
If a mandrel-free spinning apparatus is used, then re-entrant shapes and non-axisymmetric articles can be produced, but support and guidance during deformation becomes more complex
Solution Approach 1:
The support function is segmented into multiple specialized tools: a first support tool for initial support, a second support tool for guiding deformation, and a third support tool for final shaping. Each tool is positioned and configured to address specific stages of the forming process, distributing the complexity across multiple simple components rather than one complex mandrel.
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 method effectively produces workpieces that minimize material wastage and wrinkling, enabling the production of complex shapes with reduced finishing needs, improving manufacturing tolerances and efficiency in spin forming processes.
Implementation Method 1
scaling the vector based on at least the curvature of the planar representation at said perimeter point and the length of the target shape
Data Source
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Figure 5(a)~5(b)
AI summary
The invention relates to a method of generating a design of a blank workpiece in a computer readable form, wherein the workpiece is suitable for use in a spin forming process, to produce an article having a target shape. The target shape extends along an axis between a first end and a second end and comprises a base portion and a wall portion. The base portion includes a central flat region and a curved region bordering the central flat region. The wall portion extends from the curved region of the base portion. The method includes: determining a perimeter shape of the workpiece based on; a planar representation of the base portion defined by a plurality of perimeter points; a curvature of the planar representation at one or more perimeter points; and a length of the target shape, between the first end and the second end; and outputting the perimeter shape in the computer readable form.